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FFMPEG-FILTERS(1)					     FFMPEG-FILTERS(1)

NAME
       ffmpeg-filters -	FFmpeg filters

DESCRIPTION
       This document describes filters,	sources, and sinks provided by the
       libavfilter library.

FILTERING INTRODUCTION
       Filtering in FFmpeg is enabled through the libavfilter library.

       In libavfilter, a filter	can have multiple inputs and multiple outputs.
       To illustrate the sorts of things that are possible, we consider	the
       following filtergraph.

			       [main]
	       input --> split ---------------------> overlay --> output
			   |				 ^
			   |[tmp]		   [flip]|
			   +-----> crop	--> vflip -------+

       This filtergraph	splits the input stream	in two streams,	then sends one
       stream through the crop filter and the vflip filter, before merging it
       back with the other stream by overlaying	it on top. You can use the
       following command to achieve this:

	       ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT

       The result will be that the top half of the video is mirrored onto the
       bottom half of the output video.

       Filters in the same linear chain	are separated by commas, and distinct
       linear chains of	filters	are separated by semicolons. In	our example,
       crop,vflip are in one linear chain, split and overlay are separately in
       another.	The points where the linear chains join	are labelled by	names
       enclosed	in square brackets. In the example, the	split filter generates
       two outputs that	are associated to the labels [main] and	[tmp].

       The stream sent to the second output of split, labelled as [tmp], is
       processed through the crop filter, which	crops away the lower half part
       of the video, and then vertically flipped. The overlay filter takes in
       input the first unchanged output	of the split filter (which was
       labelled	as [main]), and	overlay	on its lower half the output generated
       by the crop,vflip filterchain.

       Some filters take in input a list of parameters:	they are specified
       after the filter	name and an equal sign,	and are	separated from each
       other by	a colon.

       There exist so-called source filters that do not	have an	audio/video
       input, and sink filters that will not have audio/video output.

GRAPH
       The graph2dot program included in the FFmpeg tools directory can	be
       used to parse a filtergraph description and issue a corresponding
       textual representation in the dot language.

       Invoke the command:

	       graph2dot -h

       to see how to use graph2dot.

       You can then pass the dot description to	the dot	program	(from the
       graphviz	suite of programs) and obtain a	graphical representation of
       the filtergraph.

       For example the sequence	of commands:

	       echo <GRAPH_DESCRIPTION>	| \
	       tools/graph2dot -o graph.tmp && \
	       dot -Tpng graph.tmp -o graph.png	&& \
	       display graph.png

       can be used to create and display an image representing the graph
       described by the	GRAPH_DESCRIPTION string. Note that this string	must
       be a complete self-contained graph, with	its inputs and outputs
       explicitly defined.  For	example	if your	command	line is	of the form:

	       ffmpeg -i infile	-vf scale=640:360 outfile

       your GRAPH_DESCRIPTION string will need to be of	the form:

	       nullsrc,scale=640:360,nullsink

       you may also need to set	the nullsrc parameters and add a format	filter
       in order	to simulate a specific input file.

FILTERGRAPH DESCRIPTION
       A filtergraph is	a directed graph of connected filters. It can contain
       cycles, and there can be	multiple links between a pair of filters. Each
       link has	one input pad on one side connecting it	to one filter from
       which it	takes its input, and one output	pad on the other side
       connecting it to	one filter accepting its output.

       Each filter in a	filtergraph is an instance of a	filter class
       registered in the application, which defines the	features and the
       number of input and output pads of the filter.

       A filter	with no	input pads is called a "source", and a filter with no
       output pads is called a "sink".

   Filtergraph syntax
       A filtergraph has a textual representation, which is recognized by the
       -filter/-vf/-af and -filter_complex options in ffmpeg and -vf/-af in
       ffplay, and by the "avfilter_graph_parse_ptr()" function	defined	in
       libavfilter/avfilter.h.

       A filterchain consists of a sequence of connected filters, each one
       connected to the	previous one in	the sequence. A	filterchain is
       represented by a	list of	","-separated filter descriptions.

       A filtergraph consists of a sequence of filterchains. A sequence	of
       filterchains is represented by a	list of	";"-separated filterchain
       descriptions.

       A filter	is represented by a string of the form:
       [in_link_1]...[in_link_N]filter_name=arguments[out_link_1]...[out_link_M]

       filter_name is the name of the filter class of which the	described
       filter is an instance of, and has to be the name	of one of the filter
       classes registered in the program.  The name of the filter class	is
       optionally followed by a	string "=arguments".

       arguments is a string which contains the	parameters used	to initialize
       the filter instance. It may have	one of two forms:

       o   A ':'-separated list	of key=value pairs.

       o   A ':'-separated list	of value. In this case,	the keys are assumed
	   to be the option names in the order they are	declared. E.g. the
	   "fade" filter declares three	options	in this	order -- type,
	   start_frame and nb_frames. Then the parameter list in:0:30 means
	   that	the value in is	assigned to the	option type, 0 to start_frame
	   and 30 to nb_frames.

       o   A ':'-separated list	of mixed direct	value and long key=value
	   pairs. The direct value must	precede	the key=value pairs, and
	   follow the same constraints order of	the previous point. The
	   following key=value pairs can be set	in any preferred order.

       If the option value itself is a list of items (e.g. the "format"	filter
       takes a list of pixel formats), the items in the	list are usually
       separated by |.

       The list	of arguments can be quoted using the character ' as initial
       and ending mark,	and the	character \ for	escaping the characters	within
       the quoted text;	otherwise the argument string is considered terminated
       when the	next special character (belonging to the set []=;,) is
       encountered.

       The name	and arguments of the filter are	optionally preceded and
       followed	by a list of link labels.  A link label	allows one to name a
       link and	associate it to	a filter output	or input pad. The preceding
       labels in_link_1	... in_link_N, are associated to the filter input
       pads, the following labels out_link_1 ... out_link_M, are associated to
       the output pads.

       When two	link labels with the same name are found in the	filtergraph, a
       link between the	corresponding input and	output pad is created.

       If an output pad	is not labelled, it is linked by default to the	first
       unlabelled input	pad of the next	filter in the filterchain.  For
       example in the filterchain

	       nullsrc,	split[L1], [L2]overlay,	nullsink

       the split filter	instance has two output	pads, and the overlay filter
       instance	two input pads.	The first output pad of	split is labelled
       "L1", the first input pad of overlay is labelled	"L2", and the second
       output pad of split is linked to	the second input pad of	overlay, which
       are both	unlabelled.

       In a filter description,	if the input label of the first	filter is not
       specified, "in" is assumed; if the output label of the last filter is
       not specified, "out" is assumed.

       In a complete filterchain all the unlabelled filter input and output
       pads must be connected. A filtergraph is	considered valid if all	the
       filter input and	output pads of all the filterchains are	connected.

       Libavfilter will	automatically insert scale filters where format
       conversion is required. It is possible to specify swscale flags for
       those automatically inserted scalers by prepending "sws_flags=flags;"
       to the filtergraph description.

       Here is a BNF description of the	filtergraph syntax:

	       <NAME>		  ::= sequence of alphanumeric characters and '_'
	       <LINKLABEL>	  ::= "[" <NAME> "]"
	       <LINKLABELS>	  ::= <LINKLABEL> [<LINKLABELS>]
	       <FILTER_ARGUMENTS> ::= sequence of chars	(possibly quoted)
	       <FILTER>		  ::= [<LINKLABELS>] <NAME> ["=" <FILTER_ARGUMENTS>] [<LINKLABELS>]
	       <FILTERCHAIN>	  ::= <FILTER> [,<FILTERCHAIN>]
	       <FILTERGRAPH>	  ::= [sws_flags=<flags>;] <FILTERCHAIN> [;<FILTERGRAPH>]

   Notes on filtergraph	escaping
       Filtergraph description composition entails several levels of escaping.
       See the "Quoting	and escaping" section in the ffmpeg-utils(1) manual
       for more	information about the employed escaping	procedure.

       A first level escaping affects the content of each filter option	value,
       which may contain the special character ":" used	to separate values, or
       one of the escaping characters "\'".

       A second	level escaping affects the whole filter	description, which may
       contain the escaping characters "\'" or the special characters "[],;"
       used by the filtergraph description.

       Finally,	when you specify a filtergraph on a shell commandline, you
       need to perform a third level escaping for the shell special characters
       contained within	it.

       For example, consider the following string to be	embedded in the
       drawtext	filter description text	value:

	       this is a 'string': may contain one, or more, special characters

       This string contains the	"'" special escaping character,	and the	":"
       special character, so it	needs to be escaped in this way:

	       text=this is a \'string\'\: may contain one, or more, special characters

       A second	level of escaping is required when embedding the filter
       description in a	filtergraph description, in order to escape all	the
       filtergraph special characters. Thus the	example	above becomes:

	       drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters

       (note that in addition to the "\'" escaping special characters, also
       "," needs to be escaped).

       Finally an additional level of escaping is needed when writing the
       filtergraph description in a shell command, which depends on the
       escaping	rules of the adopted shell. For	example, assuming that "\" is
       special and needs to be escaped with another "\", the previous string
       will finally result in:

	       -vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters"

TIMELINE EDITING
       Some filters support a generic enable option. For the filters
       supporting timeline editing, this option	can be set to an expression
       which is	evaluated before sending a frame to the	filter.	If the
       evaluation is non-zero, the filter will be enabled, otherwise the frame
       will be sent unchanged to the next filter in the	filtergraph.

       The expression accepts the following values:

       t   timestamp expressed in seconds, NAN if the input timestamp is
	   unknown

       n   sequential number of	the input frame, starting from 0

       pos the position	in the file of the input frame,	NAN if unknown

       w
       h   width and height of the input frame if video

       Additionally, these filters support an enable command that can be used
       to re-define the	expression.

       Like any	other filtering	option,	the enable option follows the same
       rules.

       For example, to enable a	blur filter (smartblur)	from 10	seconds	to 3
       minutes,	and a curves filter starting at	3 seconds:

	       smartblur = enable='between(t,10,3*60)',
	       curves	 = enable='gte(t,3)' : preset=cross_process

       See "ffmpeg -filters" to	view which filters have	timeline support.

AUDIO FILTERS
       When you	configure your FFmpeg build, you can disable any of the
       existing	filters	using "--disable-filters".  The	configure output will
       show the	audio filters included in your build.

       Below is	a description of the currently available audio filters.

   acompressor
       A compressor is mainly used to reduce the dynamic range of a signal.
       Especially modern music is mostly compressed at a high ratio to improve
       the overall loudness. It's done to get the highest attention of a
       listener, "fatten" the sound and	bring more "power" to the track.  If a
       signal is compressed too	much it	may sound dull or "dead" afterwards or
       it may start to "pump" (which could be a	powerful effect	but can	also
       destroy a track completely).  The right compression is the key to reach
       a professional sound and	is the high art	of mixing and mastering.
       Because of its complex settings it may take a long time to get the
       right feeling for this kind of effect.

       Compression is done by detecting	the volume above a chosen level
       "threshold" and dividing	it by the factor set with "ratio".  So if you
       set the threshold to -12dB and your signal reaches -6dB a ratio of 2:1
       will result in a	signal at -9dB.	Because	an exact manipulation of the
       signal would cause distortion of	the waveform the reduction can be
       levelled	over the time. This is done by setting "Attack"	and "Release".
       "attack"	determines how long the	signal has to rise above the threshold
       before any reduction will occur and "release" sets the time the signal
       has to fall below the threshold to reduce the reduction again. Shorter
       signals than the	chosen attack time will	be left	untouched.  The
       overall reduction of the	signal can be made up afterwards with the
       "makeup"	setting. So compressing	the peaks of a signal about 6dB	and
       raising the makeup to this level	results	in a signal twice as loud than
       the source. To gain a softer entry in the compression the "knee"
       flattens	the hard edge at the threshold in the range of the chosen
       decibels.

       The filter accepts the following	options:

       level_in
	   Set input gain. Default is 1. Range is between 0.015625 and 64.

       threshold
	   If a	signal of second stream	rises above this level it will affect
	   the gain reduction of the first stream.  By default it is 0.125.
	   Range is between 0.00097563 and 1.

       ratio
	   Set a ratio by which	the signal is reduced. 1:2 means that if the
	   level rose 4dB above	the threshold, it will be only 2dB above after
	   the reduction.  Default is 2. Range is between 1 and	20.

       attack
	   Amount of milliseconds the signal has to rise above the threshold
	   before gain reduction starts. Default is 20.	Range is between 0.01
	   and 2000.

       release
	   Amount of milliseconds the signal has to fall below the threshold
	   before reduction is decreased again.	Default	is 250.	Range is
	   between 0.01	and 9000.

       makeup
	   Set the amount by how much signal will be amplified after
	   processing.	Default	is 2. Range is from 1 and 64.

       knee
	   Curve the sharp knee	around the threshold to	enter gain reduction
	   more	softly.	 Default is 2.82843. Range is between 1	and 8.

       link
	   Choose if the "average" level between all channels of input stream
	   or the louder("maximum") channel of input stream affects the
	   reduction. Default is "average".

       detection
	   Should the exact signal be taken in case of "peak" or an RMS	one in
	   case	of "rms". Default is "rms" which is mostly smoother.

       mix How much to use compressed signal in	output.	Default	is 1.  Range
	   is between 0	and 1.

   acrossfade
       Apply cross fade	from one input audio stream to another input audio
       stream.	The cross fade is applied for specified	duration near the end
       of first	stream.

       The filter accepts the following	options:

       nb_samples, ns
	   Specify the number of samples for which the cross fade effect has
	   to last.  At	the end	of the cross fade effect the first input audio
	   will	be completely silent. Default is 44100.

       duration, d
	   Specify the duration	of the cross fade effect. See the Time
	   duration section in the ffmpeg-utils(1) manual for the accepted
	   syntax.  By default the duration is determined by nb_samples.  If
	   set this option is used instead of nb_samples.

       overlap,	o
	   Should first	stream end overlap with	second stream start. Default
	   is enabled.

       curve1
	   Set curve for cross fade transition for first stream.

       curve2
	   Set curve for cross fade transition for second stream.

	   For description of available	curve types see	afade filter
	   description.

       Examples

       o   Cross fade from one input to	another:

		   ffmpeg -i first.flac	-i second.flac -filter_complex acrossfade=d=10:c1=exp:c2=exp output.flac

       o   Cross fade from one input to	another	but without overlapping:

		   ffmpeg -i first.flac	-i second.flac -filter_complex acrossfade=d=10:o=0:c1=exp:c2=exp output.flac

   acrusher
       Reduce audio bit	resolution.

       This filter is bit crusher with enhanced	functionality. A bit crusher
       is used to audibly reduce number	of bits	an audio signal	is sampled
       with. This doesn't change the bit depth at all, it just produces	the
       effect. Material	reduced	in bit depth sounds more harsh and "digital".
       This filter is able to even round to continuous values instead of
       discrete	bit depths.  Additionally it has a D/C offset which results in
       different crushing of the lower and the upper half of the signal.  An
       Anti-Aliasing setting is	able to	produce	"softer" crushing sounds.

       Another feature of this filter is the logarithmic mode.	This setting
       switches	from linear distances between bits to logarithmic ones.	 The
       result is a much	more "natural" sounding	crusher	which doesn't gate low
       signals for example. The	human ear has a	logarithmic perception,	too so
       this kind of crushing is	much more pleasant.  Logarithmic crushing is
       also able to get	anti-aliased.

       The filter accepts the following	options:

       level_in
	   Set level in.

       level_out
	   Set level out.

       bits
	   Set bit reduction.

       mix Set mixing amount.

       mode
	   Can be linear: "lin"	or logarithmic:	"log".

       dc  Set DC.

       aa  Set anti-aliasing.

       samples
	   Set sample reduction.

       lfo Enable LFO. By default disabled.

       lforange
	   Set LFO range.

       lforate
	   Set LFO rate.

   adelay
       Delay one or more audio channels.

       Samples in delayed channel are filled with silence.

       The filter accepts the following	option:

       delays
	   Set list of delays in milliseconds for each channel separated by
	   '|'.	 At least one delay greater than 0 should be provided.	Unused
	   delays will be silently ignored. If number of given delays is
	   smaller than	number of channels all remaining channels will not be
	   delayed.  If	you want to delay exact	number of samples, append 'S'
	   to number.

       Examples

       o   Delay first channel by 1.5 seconds, the third channel by 0.5
	   seconds and leave the second	channel	(and any other channels	that
	   may be present) unchanged.

		   adelay=1500|0|500

       o   Delay second	channel	by 500 samples,	the third channel by 700
	   samples and leave the first channel (and any	other channels that
	   may be present) unchanged.

		   adelay=0|500S|700S

   aecho
       Apply echoing to	the input audio.

       Echoes are reflected sound and can occur	naturally amongst mountains
       (and sometimes large buildings) when talking or shouting; digital echo
       effects emulate this behaviour and are often used to help fill out the
       sound of	a single instrument or vocal. The time difference between the
       original	signal and the reflection is the "delay", and the loudness of
       the reflected signal is the "decay".  Multiple echoes can have
       different delays	and decays.

       A description of	the accepted parameters	follows.

       in_gain
	   Set input gain of reflected signal. Default is 0.6.

       out_gain
	   Set output gain of reflected	signal.	Default	is 0.3.

       delays
	   Set list of time intervals in milliseconds between original signal
	   and reflections separated by	'|'. Allowed range for each "delay" is
	   "(0 - 90000.0]".  Default is	1000.

       decays
	   Set list of loudnesses of reflected signals separated by '|'.
	   Allowed range for each "decay" is "(0 - 1.0]".  Default is 0.5.

       Examples

       o   Make	it sound as if there are twice as many instruments as are
	   actually playing:

		   aecho=0.8:0.88:60:0.4

       o   If delay is very short, then	it sound like a	(metallic) robot
	   playing music:

		   aecho=0.8:0.88:6:0.4

       o   A longer delay will sound like an open air concert in the
	   mountains:

		   aecho=0.8:0.9:1000:0.3

       o   Same	as above but with one more mountain:

		   aecho=0.8:0.9:1000|1800:0.3|0.25

   aemphasis
       Audio emphasis filter creates or	restores material directly taken from
       LPs or emphased CDs with	different filter curves. E.g. to store music
       on vinyl	the signal has to be altered by	a filter first to even out the
       disadvantages of	this recording medium.	Once the material is played
       back the	inverse	filter has to be applied to restore the	distortion of
       the frequency response.

       The filter accepts the following	options:

       level_in
	   Set input gain.

       level_out
	   Set output gain.

       mode
	   Set filter mode. For	restoring material use "reproduction" mode,
	   otherwise use "production" mode. Default is "reproduction" mode.

       type
	   Set filter type. Selects medium. Can	be one of the following:

	   col select Columbia.

	   emi select EMI.

	   bsi select BSI (78RPM).

	   riaa
	       select RIAA.

	   cd  select Compact Disc (CD).

	   50fm
	       select 50Xs (FM).

	   75fm
	       select 75Xs (FM).

	   50kf
	       select 50Xs (FM-KF).

	   75kf
	       select 75Xs (FM-KF).

   aeval
       Modify an audio signal according	to the specified expressions.

       This filter accepts one or more expressions (one	for each channel),
       which are evaluated and used to modify a	corresponding audio signal.

       It accepts the following	parameters:

       exprs
	   Set the '|'-separated expressions list for each separate channel.
	   If the number of input channels is greater than the number of
	   expressions,	the last specified expression is used for the
	   remaining output channels.

       channel_layout, c
	   Set output channel layout. If not specified,	the channel layout is
	   specified by	the number of expressions. If set to same, it will use
	   by default the same input channel layout.

       Each expression in exprs	can contain the	following constants and
       functions:

       ch  channel number of the current expression

       n   number of the evaluated sample, starting from 0

       s   sample rate

       t   time	of the evaluated sample	expressed in seconds

       nb_in_channels
       nb_out_channels
	   input and output number of channels

       val(CH)
	   the value of	input channel with number CH

       Note: this filter is slow. For faster processing	you should use a
       dedicated filter.

       Examples

       o   Half	volume:

		   aeval=val(ch)/2:c=same

       o   Invert phase	of the second channel:

		   aeval=val(0)|-val(1)

   afade
       Apply fade-in/out effect	to input audio.

       A description of	the accepted parameters	follows.

       type, t
	   Specify the effect type, can	be either "in" for fade-in, or "out"
	   for a fade-out effect. Default is "in".

       start_sample, ss
	   Specify the number of the start sample for starting to apply	the
	   fade	effect.	Default	is 0.

       nb_samples, ns
	   Specify the number of samples for which the fade effect has to
	   last. At the	end of the fade-in effect the output audio will	have
	   the same volume as the input	audio, at the end of the fade-out
	   transition the output audio will be silence.	Default	is 44100.

       start_time, st
	   Specify the start time of the fade effect. Default is 0.  The value
	   must	be specified as	a time duration; see the Time duration section
	   in the ffmpeg-utils(1) manual for the accepted syntax.  If set this
	   option is used instead of start_sample.

       duration, d
	   Specify the duration	of the fade effect. See	the Time duration
	   section in the ffmpeg-utils(1) manual for the accepted syntax.  At
	   the end of the fade-in effect the output audio will have the	same
	   volume as the input audio, at the end of the	fade-out transition
	   the output audio will be silence.  By default the duration is
	   determined by nb_samples.  If set this option is used instead of
	   nb_samples.

       curve
	   Set curve for fade transition.

	   It accepts the following values:

	   tri select triangular, linear slope (default)

	   qsin
	       select quarter of sine wave

	   hsin
	       select half of sine wave

	   esin
	       select exponential sine wave

	   log select logarithmic

	   ipar
	       select inverted parabola

	   qua select quadratic

	   cub select cubic

	   squ select square root

	   cbr select cubic root

	   par select parabola

	   exp select exponential

	   iqsin
	       select inverted quarter of sine wave

	   ihsin
	       select inverted half of sine wave

	   dese
	       select double-exponential seat

	   desi
	       select double-exponential sigmoid

       Examples

       o   Fade	in first 15 seconds of audio:

		   afade=t=in:ss=0:d=15

       o   Fade	out last 25 seconds of a 900 seconds audio:

		   afade=t=out:st=875:d=25

   afftfilt
       Apply arbitrary expressions to samples in frequency domain.

       real
	   Set frequency domain	real expression	for each separate channel
	   separated by	'|'. Default is	"1".  If the number of input channels
	   is greater than the number of expressions, the last specified
	   expression is used for the remaining	output channels.

       imag
	   Set frequency domain	imaginary expression for each separate channel
	   separated by	'|'. If	not set, real option is	used.

	   Each	expression in real and imag can	contain	the following
	   constants:

	   sr  sample rate

	   b   current frequency bin number

	   nb  number of available bins

	   ch  channel number of the current expression

	   chs number of channels

	   pts current frame pts

       win_size
	   Set window size.

	   It accepts the following values:

	   w16
	   w32
	   w64
	   w128
	   w256
	   w512
	   w1024
	   w2048
	   w4096
	   w8192
	   w16384
	   w32768
	   w65536

	   Default is "w4096"

       win_func
	   Set window function.	Default	is "hann".

       overlap
	   Set window overlap. If set to 1, the	recommended overlap for
	   selected window function will be picked. Default is 0.75.

       Examples

       o   Leave almost	only low frequencies in	audio:

		   afftfilt="1-clip((b/nb)*b,0,1)"

   aformat
       Set output format constraints for the input audio. The framework	will
       negotiate the most appropriate format to	minimize conversions.

       It accepts the following	parameters:

       sample_fmts
	   A '|'-separated list	of requested sample formats.

       sample_rates
	   A '|'-separated list	of requested sample rates.

       channel_layouts
	   A '|'-separated list	of requested channel layouts.

	   See the Channel Layout section in the ffmpeg-utils(1) manual	for
	   the required	syntax.

       If a parameter is omitted, all values are allowed.

       Force the output	to either unsigned 8-bit or signed 16-bit stereo

	       aformat=sample_fmts=u8|s16:channel_layouts=stereo

   agate
       A gate is mainly	used to	reduce lower parts of a	signal.	This kind of
       signal processing reduces disturbing noise between useful signals.

       Gating is done by detecting the volume below a chosen level threshold
       and dividing it by the factor set with ratio. The bottom	of the noise
       floor is	set via	range. Because an exact	manipulation of	the signal
       would cause distortion of the waveform the reduction can	be levelled
       over time. This is done by setting attack and release.

       attack determines how long the signal has to fall below the threshold
       before any reduction will occur and release sets	the time the signal
       has to rise above the threshold to reduce the reduction again.  Shorter
       signals than the	chosen attack time will	be left	untouched.

       level_in
	   Set input level before filtering.  Default is 1. Allowed range is
	   from	0.015625 to 64.

       range
	   Set the level of gain reduction when	the signal is below the
	   threshold.  Default is 0.06125. Allowed range is from 0 to 1.

       threshold
	   If a	signal rises above this	level the gain reduction is released.
	   Default is 0.125. Allowed range is from 0 to	1.

       ratio
	   Set a ratio by which	the signal is reduced.	Default	is 2. Allowed
	   range is from 1 to 9000.

       attack
	   Amount of milliseconds the signal has to rise above the threshold
	   before gain reduction stops.	 Default is 20 milliseconds. Allowed
	   range is from 0.01 to 9000.

       release
	   Amount of milliseconds the signal has to fall below the threshold
	   before the reduction	is increased again. Default is 250
	   milliseconds.  Allowed range	is from	0.01 to	9000.

       makeup
	   Set amount of amplification of signal after processing.  Default is
	   1. Allowed range is from 1 to 64.

       knee
	   Curve the sharp knee	around the threshold to	enter gain reduction
	   more	softly.	 Default is 2.828427125. Allowed range is from 1 to 8.

       detection
	   Choose if exact signal should be taken for detection	or an RMS like
	   one.	 Default is "rms". Can be "peak" or "rms".

       link
	   Choose if the average level between all channels or the louder
	   channel affects the reduction.  Default is "average". Can be
	   "average" or	"maximum".

   alimiter
       The limiter prevents an input signal from rising	over a desired
       threshold.  This	limiter	uses lookahead technology to prevent your
       signal from distorting.	It means that there is a small delay after the
       signal is processed. Keep in mind that the delay	it produces is the
       attack time you set.

       The filter accepts the following	options:

       level_in
	   Set input gain. Default is 1.

       level_out
	   Set output gain. Default is 1.

       limit
	   Don't let signals above this	level pass the limiter.	Default	is 1.

       attack
	   The limiter will reach its attenuation level	in this	amount of time
	   in milliseconds. Default is 5 milliseconds.

       release
	   Come	back from limiting to attenuation 1.0 in this amount of
	   milliseconds.  Default is 50	milliseconds.

       asc When	gain reduction is always needed	ASC takes care of releasing to
	   an average reduction	level rather than reaching a reduction of 0 in
	   the release time.

       asc_level
	   Select how much the release time is affected	by ASC,	0 means	nearly
	   no changes in release time while 1 produces higher release times.

       level
	   Auto	level output signal. Default is	enabled.  This normalizes
	   audio back to 0dB if	enabled.

       Depending on picked setting it is recommended to	upsample input 2x or
       4x times	with aresample before applying this filter.

   allpass
       Apply a two-pole	all-pass filter	with central frequency (in Hz)
       frequency, and filter-width width.  An all-pass filter changes the
       audio's frequency to phase relationship without changing	its frequency
       to amplitude relationship.

       The filter accepts the following	options:

       frequency, f
	   Set frequency in Hz.

       width_type
	   Set method to specify band-width of filter.

	   h   Hz

	   q   Q-Factor

	   o   octave

	   s   slope

       width, w
	   Specify the band-width of a filter in width_type units.

   aloop
       Loop audio samples.

       The filter accepts the following	options:

       loop
	   Set the number of loops.

       size
	   Set maximal number of samples.

       start
	   Set first sample of loop.

   amerge
       Merge two or more audio streams into a single multi-channel stream.

       The filter accepts the following	options:

       inputs
	   Set the number of inputs. Default is	2.

       If the channel layouts of the inputs are	disjoint, and therefore
       compatible, the channel layout of the output will be set	accordingly
       and the channels	will be	reordered as necessary.	If the channel layouts
       of the inputs are not disjoint, the output will have all	the channels
       of the first input then all the channels	of the second input, in	that
       order, and the channel layout of	the output will	be the default value
       corresponding to	the total number of channels.

       For example, if the first input is in 2.1 (FL+FR+LF) and	the second
       input is	FC+BL+BR, then the output will be in 5.1, with the channels in
       the following order: a1,	a2, b1,	a3, b2,	b3 (a1 is the first channel of
       the first input,	b1 is the first	channel	of the second input).

       On the other hand, if both input	are in stereo, the output channels
       will be in the default order: a1, a2, b1, b2, and the channel layout
       will be arbitrarily set to 4.0, which may or may	not be the expected
       value.

       All inputs must have the	same sample rate, and format.

       If inputs do not	have the same duration,	the output will	stop with the
       shortest.

       Examples

       o   Merge two mono files	into a stereo stream:

		   amovie=left.wav [l] ; amovie=right.mp3 [r] ;	[l] [r]	amerge

       o   Multiple merges assuming 1 video stream and 6 audio streams in
	   input.mkv:

		   ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6"	-c:a pcm_s16le output.mkv

   amix
       Mixes multiple audio inputs into	a single output.

       Note that this filter only supports float samples (the amerge and pan
       audio filters support many formats). If the amix	input has integer
       samples then aresample will be automatically inserted to	perform	the
       conversion to float samples.

       For example

	       ffmpeg -i INPUT1	-i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT

       will mix	3 input	audio streams to a single output with the same
       duration	as the first input and a dropout transition time of 3 seconds.

       It accepts the following	parameters:

       inputs
	   The number of inputs. If unspecified, it defaults to	2.

       duration
	   How to determine the	end-of-stream.

	   longest
	       The duration of the longest input. (default)

	   shortest
	       The duration of the shortest input.

	   first
	       The duration of the first input.

       dropout_transition
	   The transition time,	in seconds, for	volume renormalization when an
	   input stream	ends. The default value	is 2 seconds.

   anequalizer
       High-order parametric multiband equalizer for each channel.

       It accepts the following	parameters:

       params
	   This	option string is in format: "cchn f=cf w=w g=g t=f | ..."
	   Each	equalizer band is separated by '|'.

	   chn Set channel number to which equalization	will be	applied.  If
	       input doesn't have that channel the entry is ignored.

	   f   Set central frequency for band.	If input doesn't have that
	       frequency the entry is ignored.

	   w   Set band	width in hertz.

	   g   Set band	gain in	dB.

	   t   Set filter type for band, optional, can be:

	       0   Butterworth,	this is	default.

	       1   Chebyshev type 1.

	       2   Chebyshev type 2.

       curves
	   With	this option activated frequency	response of anequalizer	is
	   displayed in	video stream.

       size
	   Set video stream size. Only useful if curves	option is activated.

       mgain
	   Set max gain	that will be displayed.	Only useful if curves option
	   is activated.  Setting this to a reasonable value makes it possible
	   to display gain which is derived from neighbour bands which are too
	   close to each other and thus	produce	higher gain when both are
	   activated.

       fscale
	   Set frequency scale used to draw frequency response in video
	   output.  Can	be linear or logarithmic. Default is logarithmic.

       colors
	   Set color for each channel curve which is going to be displayed in
	   video stream.  This is list of color	names separated	by space or by
	   '|'.	 Unrecognised or missing colors	will be	replaced by white
	   color.

       Examples

       o   Lower gain by 10 of central frequency 200Hz and width 100 Hz	for
	   first 2 channels using Chebyshev type 1 filter:

		   anequalizer=c0 f=200	w=100 g=-10 t=1|c1 f=200 w=100 g=-10 t=1

       Commands

       This filter supports the	following commands:

       change
	   Alter existing filter parameters.  Syntax for the commands is :
	   "fN|f=freq|w=width|g=gain"

	   fN is existing filter number, starting from 0, if no	such filter is
	   available error is returned.	 freq set new frequency	parameter.
	   width set new width parameter in herz.  gain	set new	gain parameter
	   in dB.

	   Full	filter invocation with asendcmd	may look like this:
	   asendcmd=c='4.0 anequalizer change
	   0|f=200|w=50|g=1',anequalizer=...

   anull
       Pass the	audio source unchanged to the output.

   apad
       Pad the end of an audio stream with silence.

       This can	be used	together with ffmpeg -shortest to extend audio streams
       to the same length as the video stream.

       A description of	the accepted options follows.

       packet_size
	   Set silence packet size. Default value is 4096.

       pad_len
	   Set the number of samples of	silence	to add to the end. After the
	   value is reached, the stream	is terminated. This option is mutually
	   exclusive with whole_len.

       whole_len
	   Set the minimum total number	of samples in the output audio stream.
	   If the value	is longer than the input audio length, silence is
	   added to the	end, until the value is	reached. This option is
	   mutually exclusive with pad_len.

       If neither the pad_len nor the whole_len	option is set, the filter will
       add silence to the end of the input stream indefinitely.

       Examples

       o   Add 1024 samples of silence to the end of the input:

		   apad=pad_len=1024

       o   Make	sure the audio output will contain at least 10000 samples, pad
	   the input with silence if required:

		   apad=whole_len=10000

       o   Use ffmpeg to pad the audio input with silence, so that the video
	   stream will always result the shortest and will be converted	until
	   the end in the output file when using the shortest option:

		   ffmpeg -i VIDEO -i AUDIO -filter_complex "[1:0]apad"	-shortest OUTPUT

   aphaser
       Add a phasing effect to the input audio.

       A phaser	filter creates series of peaks and troughs in the frequency
       spectrum.  The position of the peaks and	troughs	are modulated so that
       they vary over time, creating a sweeping	effect.

       A description of	the accepted parameters	follows.

       in_gain
	   Set input gain. Default is 0.4.

       out_gain
	   Set output gain. Default is 0.74

       delay
	   Set delay in	milliseconds. Default is 3.0.

       decay
	   Set decay. Default is 0.4.

       speed
	   Set modulation speed	in Hz. Default is 0.5.

       type
	   Set modulation type.	Default	is triangular.

	   It accepts the following values:

	   triangular, t
	   sinusoidal, s

   apulsator
       Audio pulsator is something between an autopanner and a tremolo.	 But
       it can produce funny stereo effects as well. Pulsator changes the
       volume of the left and right channel based on a LFO (low	frequency
       oscillator) with	different waveforms and	shifted	phases.	 This filter
       have the	ability	to define an offset between left and right channel. An
       offset of 0 means that both LFO shapes match each other.	 The left and
       right channel are altered equally - a conventional tremolo.  An offset
       of 50% means that the shape of the right	channel	is exactly shifted in
       phase (or moved backwards about half of the frequency) -	pulsator acts
       as an autopanner. At 1 both curves match	again. Every setting in
       between moves the phase shift gapless between all stages	and produces
       some "bypassing"	sounds with sine and triangle waveforms. The more you
       set the offset near 1 (starting from the	0.5) the faster	the signal
       passes from the left to the right speaker.

       The filter accepts the following	options:

       level_in
	   Set input gain. By default it is 1. Range is	[0.015625 - 64].

       level_out
	   Set output gain. By default it is 1.	Range is [0.015625 - 64].

       mode
	   Set waveform	shape the LFO will use.	Can be one of: sine, triangle,
	   square, sawup or sawdown. Default is	sine.

       amount
	   Set modulation. Define how much of original signal is affected by
	   the LFO.

       offset_l
	   Set left channel offset. Default is 0. Allowed range	is [0 -	1].

       offset_r
	   Set right channel offset. Default is	0.5. Allowed range is [0 - 1].

       width
	   Set pulse width. Default is 1. Allowed range	is [0 -	2].

       timing
	   Set possible	timing mode. Can be one	of: bpm, ms or hz. Default is
	   hz.

       bpm Set bpm. Default is 120. Allowed range is [30 - 300]. Only used if
	   timing is set to bpm.

       ms  Set ms. Default is 500. Allowed range is [10	- 2000]. Only used if
	   timing is set to ms.

       hz  Set frequency in Hz.	Default	is 2. Allowed range is [0.01 - 100].
	   Only	used if	timing is set to hz.

   aresample
       Resample	the input audio	to the specified parameters, using the
       libswresample library. If none are specified then the filter will
       automatically convert between its input and output.

       This filter is also able	to stretch/squeeze the audio data to make it
       match the timestamps or to inject silence / cut out audio to make it
       match the timestamps, do	a combination of both or do neither.

       The filter accepts the syntax [sample_rate:]resampler_options, where
       sample_rate expresses a sample rate and resampler_options is a list of
       key=value pairs,	separated by ":". See the the "Resampler Options"
       section in the ffmpeg-resampler(1) manual for the complete list of
       supported options.

       Examples

       o   Resample the	input audio to 44100Hz:

		   aresample=44100

       o   Stretch/squeeze samples to the given	timestamps, with a maximum of
	   1000	samples	per second compensation:

		   aresample=async=1000

   areverse
       Reverse an audio	clip.

       Warning:	This filter requires memory to buffer the entire clip, so
       trimming	is suggested.

       Examples

       o   Take	the first 5 seconds of a clip, and reverse it.

		   atrim=end=5,areverse

   asetnsamples
       Set the number of samples per each output audio frame.

       The last	output packet may contain a different number of	samples, as
       the filter will flush all the remaining samples when the	input audio
       signals its end.

       The filter accepts the following	options:

       nb_out_samples, n
	   Set the number of frames per	each output audio frame. The number is
	   intended as the number of samples per each channel.	Default	value
	   is 1024.

       pad, p
	   If set to 1,	the filter will	pad the	last audio frame with zeroes,
	   so that the last frame will contain the same	number of samples as
	   the previous	ones. Default value is 1.

       For example, to set the number of per-frame samples to 1234 and disable
       padding for the last frame, use:

	       asetnsamples=n=1234:p=0

   asetrate
       Set the sample rate without altering the	PCM data.  This	will result in
       a change	of speed and pitch.

       The filter accepts the following	options:

       sample_rate, r
	   Set the output sample rate. Default is 44100	Hz.

   ashowinfo
       Show a line containing various information for each input audio frame.
       The input audio is not modified.

       The shown line contains a sequence of key/value pairs of	the form
       key:value.

       The following values are	shown in the output:

       n   The (sequential) number of the input	frame, starting	from 0.

       pts The presentation timestamp of the input frame, in time base units;
	   the time base depends on the	filter input pad, and is usually
	   1/sample_rate.

       pts_time
	   The presentation timestamp of the input frame in seconds.

       pos position of the frame in the	input stream, -1 if this information
	   in unavailable and/or meaningless (for example in case of synthetic
	   audio)

       fmt The sample format.

       chlayout
	   The channel layout.

       rate
	   The sample rate for the audio frame.

       nb_samples
	   The number of samples (per channel) in the frame.

       checksum
	   The Adler-32	checksum (printed in hexadecimal) of the audio data.
	   For planar audio, the data is treated as if all the planes were
	   concatenated.

       plane_checksums
	   A list of Adler-32 checksums	for each data plane.

   astats
       Display time domain statistical information about the audio channels.
       Statistics are calculated and displayed for each	audio channel and,
       where applicable, an overall figure is also given.

       It accepts the following	option:

       length
	   Short window	length in seconds, used	for peak and trough RMS
	   measurement.	 Default is 0.05 (50 milliseconds). Allowed range is
	   "[0.1 - 10]".

       metadata
	   Set metadata	injection. All the metadata keys are prefixed with
	   "lavfi.astats.X", where "X" is channel number starting from 1 or
	   string "Overall". Default is	disabled.

	   Available keys for each channel are:	DC_offset Min_level Max_level
	   Min_difference Max_difference Mean_difference Peak_level RMS_peak
	   RMS_trough Crest_factor Flat_factor Peak_count Bit_depth

	   and for Overall: DC_offset Min_level	Max_level Min_difference
	   Max_difference Mean_difference Peak_level RMS_level RMS_peak
	   RMS_trough Flat_factor Peak_count Bit_depth Number_of_samples

	   For example full key	look like this "lavfi.astats.1.DC_offset" or
	   this	"lavfi.astats.Overall.Peak_count".

	   For description what	each key means read below.

       reset
	   Set number of frame after which stats are going to be recalculated.
	   Default is disabled.

       A description of	each shown parameter follows:

       DC offset
	   Mean	amplitude displacement from zero.

       Min level
	   Minimal sample level.

       Max level
	   Maximal sample level.

       Min difference
	   Minimal difference between two consecutive samples.

       Max difference
	   Maximal difference between two consecutive samples.

       Mean difference
	   Mean	difference between two consecutive samples.  The average of
	   each	difference between two consecutive samples.

       Peak level dB
       RMS level dB
	   Standard peak and RMS level measured	in dBFS.

       RMS peak	dB
       RMS trough dB
	   Peak	and trough values for RMS level	measured over a	short window.

       Crest factor
	   Standard ratio of peak to RMS level (note: not in dB).

       Flat factor
	   Flatness (i.e. consecutive samples with the same value) of the
	   signal at its peak levels (i.e. either Min level or Max level).

       Peak count
	   Number of occasions (not the	number of samples) that	the signal
	   attained either Min level or	Max level.

       Bit depth
	   Overall bit depth of	audio. Number of bits used for each sample.

   atempo
       Adjust audio tempo.

       The filter accepts exactly one parameter, the audio tempo. If not
       specified then the filter will assume nominal 1.0 tempo.	Tempo must be
       in the [0.5, 2.0] range.

       Examples

       o   Slow	down audio to 80% tempo:

		   atempo=0.8

       o   To speed up audio to	125% tempo:

		   atempo=1.25

   atrim
       Trim the	input so that the output contains one continuous subpart of
       the input.

       It accepts the following	parameters:

       start
	   Timestamp (in seconds) of the start of the section to keep. I.e.
	   the audio sample with the timestamp start will be the first sample
	   in the output.

       end Specify time	of the first audio sample that will be dropped,	i.e.
	   the audio sample immediately	preceding the one with the timestamp
	   end will be the last	sample in the output.

       start_pts
	   Same	as start, except this option sets the start timestamp in
	   samples instead of seconds.

       end_pts
	   Same	as end,	except this option sets	the end	timestamp in samples
	   instead of seconds.

       duration
	   The maximum duration	of the output in seconds.

       start_sample
	   The number of the first sample that should be output.

       end_sample
	   The number of the first sample that should be dropped.

       start, end, and duration	are expressed as time duration specifications;
       see the Time duration section in	the ffmpeg-utils(1) manual.

       Note that the first two sets of the start/end options and the duration
       option look at the frame	timestamp, while the _sample options simply
       count the samples that pass through the filter. So start/end_pts	and
       start/end_sample	will give different results when the timestamps	are
       wrong, inexact or do not	start at zero. Also note that this filter does
       not modify the timestamps. If you wish to have the output timestamps
       start at	zero, insert the asetpts filter	after the atrim	filter.

       If multiple start or end	options	are set, this filter tries to be
       greedy and keep all samples that	match at least one of the specified
       constraints. To keep only the part that matches all the constraints at
       once, chain multiple atrim filters.

       The defaults are	such that all the input	is kept. So it is possible to
       set e.g.	 just the end values to	keep everything	before the specified
       time.

       Examples:

       o   Drop	everything except the second minute of input:

		   ffmpeg -i INPUT -af atrim=60:120

       o   Keep	only the first 1000 samples:

		   ffmpeg -i INPUT -af atrim=end_sample=1000

   bandpass
       Apply a two-pole	Butterworth band-pass filter with central frequency
       frequency, and (3dB-point) band-width width.  The csg option selects a
       constant	skirt gain (peak gain =	Q) instead of the default: constant
       0dB peak	gain.  The filter roll off at 6dB per octave (20dB per
       decade).

       The filter accepts the following	options:

       frequency, f
	   Set the filter's central frequency. Default is 3000.

       csg Constant skirt gain if set to 1. Defaults to	0.

       width_type
	   Set method to specify band-width of filter.

	   h   Hz

	   q   Q-Factor

	   o   octave

	   s   slope

       width, w
	   Specify the band-width of a filter in width_type units.

   bandreject
       Apply a two-pole	Butterworth band-reject	filter with central frequency
       frequency, and (3dB-point) band-width width.  The filter	roll off at
       6dB per octave (20dB per	decade).

       The filter accepts the following	options:

       frequency, f
	   Set the filter's central frequency. Default is 3000.

       width_type
	   Set method to specify band-width of filter.

	   h   Hz

	   q   Q-Factor

	   o   octave

	   s   slope

       width, w
	   Specify the band-width of a filter in width_type units.

   bass
       Boost or	cut the	bass (lower) frequencies of the	audio using a two-pole
       shelving	filter with a response similar to that of a standard hi-fi's
       tone-controls. This is also known as shelving equalisation (EQ).

       The filter accepts the following	options:

       gain, g
	   Give	the gain at 0 Hz. Its useful range is about -20	(for a large
	   cut)	to +20 (for a large boost).  Beware of clipping	when using a
	   positive gain.

       frequency, f
	   Set the filter's central frequency and so can be used to extend or
	   reduce the frequency	range to be boosted or cut.  The default value
	   is 100 Hz.

       width_type
	   Set method to specify band-width of filter.

	   h   Hz

	   q   Q-Factor

	   o   octave

	   s   slope

       width, w
	   Determine how steep is the filter's shelf transition.

   biquad
       Apply a biquad IIR filter with the given	coefficients.  Where b0, b1,
       b2 and a0, a1, a2 are the numerator and denominator coefficients
       respectively.

   bs2b
       Bauer stereo to binaural	transformation,	which improves headphone
       listening of stereo audio records.

       It accepts the following	parameters:

       profile
	   Pre-defined crossfeed level.

	   default
	       Default level (fcut=700,	feed=50).

	   cmoy
	       Chu Moy circuit (fcut=700, feed=60).

	   jmeier
	       Jan Meier circuit (fcut=650, feed=95).

       fcut
	   Cut frequency (in Hz).

       feed
	   Feed	level (in Hz).

   channelmap
       Remap input channels to new locations.

       It accepts the following	parameters:

       map Map channels	from input to output. The argument is a	'|'-separated
	   list	of mappings, each in the "in_channel-out_channel" or
	   in_channel form. in_channel can be either the name of the input
	   channel (e.g. FL for	front left) or its index in the	input channel
	   layout.  out_channel	is the name of the output channel or its index
	   in the output channel layout. If out_channel	is not given then it
	   is implicitly an index, starting with zero and increasing by	one
	   for each mapping.

       channel_layout
	   The channel layout of the output stream.

       If no mapping is	present, the filter will implicitly map	input channels
       to output channels, preserving indices.

       For example, assuming a 5.1+downmix input MOV file,

	       ffmpeg -i in.mov	-filter	'channelmap=map=DL-FL|DR-FR' out.wav

       will create an output WAV file tagged as	stereo from the	downmix
       channels	of the input.

       To fix a	5.1 WAV	improperly encoded in AAC's native channel order

	       ffmpeg -i in.wav	-filter	'channelmap=1|2|0|5|3|4:5.1' out.wav

   channelsplit
       Split each channel from an input	audio stream into a separate output
       stream.

       It accepts the following	parameters:

       channel_layout
	   The channel layout of the input stream. The default is "stereo".

       For example, assuming a stereo input MP3	file,

	       ffmpeg -i in.mp3	-filter_complex	channelsplit out.mkv

       will create an output Matroska file with	two audio streams, one
       containing only the left	channel	and the	other the right	channel.

       Split a 5.1 WAV file into per-channel files:

	       ffmpeg -i in.wav	-filter_complex
	       'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
	       -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
	       front_center.wav	-map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
	       side_right.wav

   chorus
       Add a chorus effect to the audio.

       Can make	a single vocal sound like a chorus, but	can also be applied to
       instrumentation.

       Chorus resembles	an echo	effect with a short delay, but whereas with
       echo the	delay is constant, with	chorus,	it is varied using using
       sinusoidal or triangular	modulation.  The modulation depth defines the
       range the modulated delay is played before or after the delay. Hence
       the delayed sound will sound slower or faster, that is the delayed
       sound tuned around the original one, like in a chorus where some	vocals
       are slightly off	key.

       It accepts the following	parameters:

       in_gain
	   Set input gain. Default is 0.4.

       out_gain
	   Set output gain. Default is 0.4.

       delays
	   Set delays. A typical delay is around 40ms to 60ms.

       decays
	   Set decays.

       speeds
	   Set speeds.

       depths
	   Set depths.

       Examples

       o   A single delay:

		   chorus=0.7:0.9:55:0.4:0.25:2

       o   Two delays:

		   chorus=0.6:0.9:50|60:0.4|0.32:0.25|0.4:2|1.3

       o   Fuller sounding chorus with three delays:

		   chorus=0.5:0.9:50|60|40:0.4|0.32|0.3:0.25|0.4|0.3:2|2.3|1.3

   compand
       Compress	or expand the audio's dynamic range.

       It accepts the following	parameters:

       attacks
       decays
	   A list of times in seconds for each channel over which the
	   instantaneous level of the input signal is averaged to determine
	   its volume. attacks refers to increase of volume and	decays refers
	   to decrease of volume. For most situations, the attack time
	   (response to	the audio getting louder) should be shorter than the
	   decay time, because the human ear is	more sensitive to sudden loud
	   audio than sudden soft audio. A typical value for attack is 0.3
	   seconds and a typical value for decay is 0.8	seconds.  If specified
	   number of attacks & decays is lower than number of channels,	the
	   last	set attack/decay will be used for all remaining	channels.

       points
	   A list of points for	the transfer function, specified in dB
	   relative to the maximum possible signal amplitude. Each key points
	   list	must be	defined	using the following syntax:
	   "x0/y0|x1/y1|x2/y2|...." or "x0/y0 x1/y1 x2/y2 ...."

	   The input values must be in strictly	increasing order but the
	   transfer function does not have to be monotonically rising. The
	   point "0/0" is assumed but may be overridden	(by "0/out-dBn").
	   Typical values for the transfer function are	"-70/-70|-60/-20".

       soft-knee
	   Set the curve radius	in dB for all joints. It defaults to 0.01.

       gain
	   Set the additional gain in dB to be applied at all points on	the
	   transfer function. This allows for easy adjustment of the overall
	   gain.  It defaults to 0.

       volume
	   Set an initial volume, in dB, to be assumed for each	channel	when
	   filtering starts. This permits the user to supply a nominal level
	   initially, so that, for example, a very large gain is not applied
	   to initial signal levels before the companding has begun to
	   operate. A typical value for	audio which is initially quiet is -90
	   dB. It defaults to 0.

       delay
	   Set a delay,	in seconds. The	input audio is analyzed	immediately,
	   but audio is	delayed	before being fed to the	volume adjuster.
	   Specifying a	delay approximately equal to the attack/decay times
	   allows the filter to	effectively operate in predictive rather than
	   reactive mode. It defaults to 0.

       Examples

       o   Make	music with both	quiet and loud passages	suitable for listening
	   to in a noisy environment:

		   compand=.3|.3:1|1:-90/-60|-60/-40|-40/-30|-20/-20:6:0:-90:0.2

	   Another example for audio with whisper and explosion	parts:

		   compand=0|0:1|1:-90/-900|-70/-70|-30/-9|0/-3:6:0:0:0

       o   A noise gate	for when the noise is at a lower level than the
	   signal:

		   compand=.1|.1:.2|.2:-900/-900|-50.1/-900|-50/-50:.01:0:-90:.1

       o   Here	is another noise gate, this time for when the noise is at a
	   higher level	than the signal	(making	it, in some ways, similar to
	   squelch):

		   compand=.1|.1:.1|.1:-45.1/-45.1|-45/-900|0/-900:.01:45:-90:.1

       o   2:1 compression starting at -6dB:

		   compand=points=-80/-80|-6/-6|0/-3.8|20/3.5

       o   2:1 compression starting at -9dB:

		   compand=points=-80/-80|-9/-9|0/-5.3|20/2.9

       o   2:1 compression starting at -12dB:

		   compand=points=-80/-80|-12/-12|0/-6.8|20/1.9

       o   2:1 compression starting at -18dB:

		   compand=points=-80/-80|-18/-18|0/-9.8|20/0.7

       o   3:1 compression starting at -15dB:

		   compand=points=-80/-80|-15/-15|0/-10.8|20/-5.2

       o   Compressor/Gate:

		   compand=points=-80/-105|-62/-80|-15.4/-15.4|0/-12|20/-7.6

       o   Expander:

		   compand=attacks=0:points=-80/-169|-54/-80|-49.5/-64.6|-41.1/-41.1|-25.8/-15|-10.8/-4.5|0/0|20/8.3

       o   Hard	limiter	at -6dB:

		   compand=attacks=0:points=-80/-80|-6/-6|20/-6

       o   Hard	limiter	at -12dB:

		   compand=attacks=0:points=-80/-80|-12/-12|20/-12

       o   Hard	noise gate at -35 dB:

		   compand=attacks=0:points=-80/-115|-35.1/-80|-35/-35|20/20

       o   Soft	limiter:

		   compand=attacks=0:points=-80/-80|-12.4/-12.4|-6/-8|0/-6.8|20/-2.8

   compensationdelay
       Compensation Delay Line is a metric based delay to compensate differing
       positions of microphones	or speakers.

       For example, you	have recorded guitar with two microphones placed in
       different location. Because the front of	sound wave has fixed speed in
       normal conditions, the phasing of microphones can vary and depends on
       their location and interposition. The best sound	mix can	be achieved
       when these microphones are in phase (synchronized). Note	that distance
       of ~30 cm between microphones makes one microphone to capture signal in
       antiphase to another microphone.	That makes the final mix sounding
       moody.  This filter helps to solve phasing problems by adding different
       delays to each microphone track and make	them synchronized.

       The best	result can be reached when you take one	track as base and
       synchronize other tracks	one by one with	it.  Remember that
       synchronization/delay tolerance depends on sample rate, too.  Higher
       sample rates will give more tolerance.

       It accepts the following	parameters:

       mm  Set millimeters distance. This is compensation distance for fine
	   tuning.  Default is 0.

       cm  Set cm distance. This is compensation distance for tightening
	   distance setup.  Default is 0.

       m   Set meters distance.	This is	compensation distance for hard
	   distance setup.  Default is 0.

       dry Set dry amount. Amount of unprocessed (dry) signal.	Default	is 0.

       wet Set wet amount. Amount of processed (wet) signal.  Default is 1.

       temp
	   Set temperature degree in Celsius. This is the temperature of the
	   environment.	 Default is 20.

   crystalizer
       Simple algorithm	to expand audio	dynamic	range.

       The filter accepts the following	options:

       i   Sets	the intensity of effect	(default: 2.0).	Must be	in range
	   between 0.0 (unchanged sound) to 10.0 (maximum effect).

       c   Enable clipping. By default is enabled.

   dcshift
       Apply a DC shift	to the audio.

       This can	be useful to remove a DC offset	(caused	perhaps	by a hardware
       problem in the recording	chain) from the	audio. The effect of a DC
       offset is reduced headroom and hence volume. The	astats filter can be
       used to determine if a signal has a DC offset.

       shift
	   Set the DC shift, allowed range is [-1, 1]. It indicates the	amount
	   to shift the	audio.

       limitergain
	   Optional. It	should have a value much less than 1 (e.g. 0.05	or
	   0.02) and is	used to	prevent	clipping.

   dynaudnorm
       Dynamic Audio Normalizer.

       This filter applies a certain amount of gain to the input audio in
       order to	bring its peak magnitude to a target level (e.g. 0 dBFS).
       However,	in contrast to more "simple" normalization algorithms, the
       Dynamic Audio Normalizer	*dynamically* re-adjusts the gain factor to
       the input audio.	 This allows for applying extra	gain to	the "quiet"
       sections	of the audio while avoiding distortions	or clipping the	"loud"
       sections. In other words: The Dynamic Audio Normalizer will "even out"
       the volume of quiet and loud sections, in the sense that	the volume of
       each section is brought to the same target level. Note, however,	that
       the Dynamic Audio Normalizer achieves this goal *without* applying
       "dynamic	range compressing". It will retain 100%	of the dynamic range
       *within*	each section of	the audio file.

       f   Set the frame length	in milliseconds. In range from 10 to 8000
	   milliseconds.  Default is 500 milliseconds.	The Dynamic Audio
	   Normalizer processes	the input audio	in small chunks, referred to
	   as frames. This is required,	because	a peak magnitude has no
	   meaning for just a single sample value. Instead, we need to
	   determine the peak magnitude	for a contiguous sequence of sample
	   values. While a "standard" normalizer would simply use the peak
	   magnitude of	the complete file, the Dynamic Audio Normalizer
	   determines the peak magnitude individually for each frame. The
	   length of a frame is	specified in milliseconds. By default, the
	   Dynamic Audio Normalizer uses a frame length	of 500 milliseconds,
	   which has been found	to give	good results with most files.  Note
	   that	the exact frame	length,	in number of samples, will be
	   determined automatically, based on the sampling rate	of the
	   individual input audio file.

       g   Set the Gaussian filter window size.	In range from 3	to 301,	must
	   be odd number. Default is 31.  Probably the most important
	   parameter of	the Dynamic Audio Normalizer is	the "window size" of
	   the Gaussian	smoothing filter. The filter's window size is
	   specified in	frames,	centered around	the current frame. For the
	   sake	of simplicity, this must be an odd number. Consequently, the
	   default value of 31 takes into account the current frame, as	well
	   as the 15 preceding frames and the 15 subsequent frames. Using a
	   larger window results in a stronger smoothing effect	and thus in
	   less	gain variation,	i.e. slower gain adaptation. Conversely, using
	   a smaller window results in a weaker	smoothing effect and thus in
	   more	gain variation,	i.e. faster gain adaptation.  In other words,
	   the more you	increase this value, the more the Dynamic Audio
	   Normalizer will behave like a "traditional" normalization filter.
	   On the contrary, the	more you decrease this value, the more the
	   Dynamic Audio Normalizer will behave	like a dynamic range
	   compressor.

       p   Set the target peak value. This specifies the highest permissible
	   magnitude level for the normalized audio input. This	filter will
	   try to approach the target peak magnitude as	closely	as possible,
	   but at the same time	it also	makes sure that	the normalized signal
	   will	never exceed the peak magnitude.  A frame's maximum local gain
	   factor is imposed directly by the target peak magnitude. The
	   default value is 0.95 and thus leaves a headroom of 5%*.  It	is not
	   recommended to go above this	value.

       m   Set the maximum gain	factor.	In range from 1.0 to 100.0. Default is
	   10.0.  The Dynamic Audio Normalizer determines the maximum possible
	   (local) gain	factor for each	input frame, i.e. the maximum gain
	   factor that does not	result in clipping or distortion. The maximum
	   gain	factor is determined by	the frame's highest magnitude sample.
	   However, the	Dynamic	Audio Normalizer additionally bounds the
	   frame's maximum gain	factor by a predetermined (global) maximum
	   gain	factor.	This is	done in	order to avoid excessive gain factors
	   in "silent" or almost silent	frames.	By default, the	maximum	gain
	   factor is 10.0, For most inputs the default value should be
	   sufficient and it usually is	not recommended	to increase this
	   value. Though, for input with an extremely low overall volume
	   level, it may be necessary to allow even higher gain	factors. Note,
	   however, that the Dynamic Audio Normalizer does not simply apply a
	   "hard" threshold (i.e. cut off values above the threshold).
	   Instead, a "sigmoid"	threshold function will	be applied. This way,
	   the gain factors will smoothly approach the threshold value,	but
	   never exceed	that value.

       r   Set the target RMS. In range	from 0.0 to 1.0. Default is 0.0	-
	   disabled.  By default, the Dynamic Audio Normalizer performs	"peak"
	   normalization.  This	means that the maximum local gain factor for
	   each	frame is defined (only)	by the frame's highest magnitude
	   sample. This	way, the samples can be	amplified as much as possible
	   without exceeding the maximum signal	level, i.e. without clipping.
	   Optionally, however,	the Dynamic Audio Normalizer can also take
	   into	account	the frame's root mean square, abbreviated RMS. In
	   electrical engineering, the RMS is commonly used to determine the
	   power of a time-varying signal. It is therefore considered that the
	   RMS is a better approximation of the	"perceived loudness" than just
	   looking at the signal's peak	magnitude. Consequently, by adjusting
	   all frames to a constant RMS	value, a uniform "perceived loudness"
	   can be established. If a target RMS value has been specified, a
	   frame's local gain factor is	defined	as the factor that would
	   result in exactly that RMS value.  Note, however, that the maximum
	   local gain factor is	still restricted by the	frame's	highest
	   magnitude sample, in	order to prevent clipping.

       n   Enable channels coupling. By	default	is enabled.  By	default, the
	   Dynamic Audio Normalizer will amplify all channels by the same
	   amount. This	means the same gain factor will	be applied to all
	   channels, i.e.  the maximum possible	gain factor is determined by
	   the "loudest" channel.  However, in some recordings,	it may happen
	   that	the volume of the different channels is	uneven,	e.g. one
	   channel may be "quieter" than the other one(s).  In this case, this
	   option can be used to disable the channel coupling. This way, the
	   gain	factor will be determined independently	for each channel,
	   depending only on the individual channel's highest magnitude
	   sample. This	allows for harmonizing the volume of the different
	   channels.

       c   Enable DC bias correction. By default is disabled.  An audio	signal
	   (in the time	domain)	is a sequence of sample	values.	 In the
	   Dynamic Audio Normalizer these sample values	are represented	in the
	   -1.0	to 1.0 range, regardless of the	original input format.
	   Normally, the audio signal, or "waveform", should be	centered
	   around the zero point.  That	means if we calculate the mean value
	   of all samples in a file, or	in a single frame, then	the result
	   should be 0.0 or at least very close	to that	value. If, however,
	   there is a significant deviation of the mean	value from 0.0,	in
	   either positive or negative direction, this is referred to as a DC
	   bias	or DC offset. Since a DC bias is clearly undesirable, the
	   Dynamic Audio Normalizer provides optional DC bias correction.
	   With	DC bias	correction enabled, the	Dynamic	Audio Normalizer will
	   determine the mean value, or	"DC correction"	offset,	of each	input
	   frame and subtract that value from all of the frame's sample	values
	   which ensures those samples are centered around 0.0 again. Also, in
	   order to avoid "gaps" at the	frame boundaries, the DC correction
	   offset values will be interpolated smoothly between neighbouring
	   frames.

       b   Enable alternative boundary mode. By	default	is disabled.  The
	   Dynamic Audio Normalizer takes into account a certain neighbourhood
	   around each frame. This includes the	preceding frames as well as
	   the subsequent frames. However, for the "boundary" frames, located
	   at the very beginning and at	the very end of	the audio file,	not
	   all neighbouring frames are available. In particular, for the first
	   few frames in the audio file, the preceding frames are not known.
	   And,	similarly, for the last	few frames in the audio	file, the
	   subsequent frames are not known. Thus, the question arises which
	   gain	factors	should be assumed for the missing frames in the
	   "boundary" region. The Dynamic Audio	Normalizer implements two
	   modes to deal with this situation. The default boundary mode
	   assumes a gain factor of exactly 1.0	for the	missing	frames,
	   resulting in	a smooth "fade in" and "fade out" at the beginning and
	   at the end of the input, respectively.

       s   Set the compress factor. In range from 0.0 to 30.0. Default is 0.0.
	   By default, the Dynamic Audio Normalizer does not apply
	   "traditional" compression. This means that signal peaks will	not be
	   pruned and thus the full dynamic range will be retained within each
	   local neighbourhood.	However, in some cases it may be desirable to
	   combine the Dynamic Audio Normalizer's normalization	algorithm with
	   a more "traditional"	compression.  For this purpose,	the Dynamic
	   Audio Normalizer provides an	optional compression (thresholding)
	   function. If	(and only if) the compression feature is enabled, all
	   input frames	will be	processed by a soft knee thresholding function
	   prior to the	actual normalization process. Put simply, the
	   thresholding	function is going to prune all samples whose magnitude
	   exceeds a certain threshold value.  However,	the Dynamic Audio
	   Normalizer does not simply apply a fixed threshold value. Instead,
	   the threshold value will be adjusted	for each individual frame.  In
	   general, smaller parameters result in stronger compression, and
	   vice	versa.	Values below 3.0 are not recommended, because audible
	   distortion may appear.

   earwax
       Make audio easier to listen to on headphones.

       This filter adds	`cues' to 44.1kHz stereo (i.e. audio CD	format)	audio
       so that when listened to	on headphones the stereo image is moved	from
       inside your head	(standard for headphones) to outside and in front of
       the listener (standard for speakers).

       Ported from SoX.

   equalizer
       Apply a two-pole	peaking	equalisation (EQ) filter. With this filter,
       the signal-level	at and around a	selected frequency can be increased or
       decreased, whilst (unlike bandpass and bandreject filters) that at all
       other frequencies is unchanged.

       In order	to produce complex equalisation	curves,	this filter can	be
       given several times, each with a	different central frequency.

       The filter accepts the following	options:

       frequency, f
	   Set the filter's central frequency in Hz.

       width_type
	   Set method to specify band-width of filter.

	   h   Hz

	   q   Q-Factor

	   o   octave

	   s   slope

       width, w
	   Specify the band-width of a filter in width_type units.

       gain, g
	   Set the required gain or attenuation	in dB.	Beware of clipping
	   when	using a	positive gain.

       Examples

       o   Attenuate 10	dB at 1000 Hz, with a bandwidth	of 200 Hz:

		   equalizer=f=1000:width_type=h:width=200:g=-10

       o   Apply 2 dB gain at 1000 Hz with Q 1 and attenuate 5 dB at 100 Hz
	   with	Q 2:

		   equalizer=f=1000:width_type=q:width=1:g=2,equalizer=f=100:width_type=q:width=2:g=-5

   extrastereo
       Linearly	increases the difference between left and right	channels which
       adds some sort of "live"	effect to playback.

       The filter accepts the following	options:

       m   Sets	the difference coefficient (default: 2.5). 0.0 means mono
	   sound (average of both channels), with 1.0 sound will be unchanged,
	   with	-1.0 left and right channels will be swapped.

       c   Enable clipping. By default is enabled.

   firequalizer
       Apply FIR Equalization using arbitrary frequency	response.

       The filter accepts the following	option:

       gain
	   Set gain curve equation (in dB). The	expression can contain
	   variables:

	   f   the evaluated frequency

	   sr  sample rate

	   ch  channel number, set to 0	when multichannels evaluation is
	       disabled

	   chid
	       channel id, see libavutil/channel_layout.h, set to the first
	       channel id when multichannels evaluation	is disabled

	   chs number of channels

	   chlayout
	       channel_layout, see libavutil/channel_layout.h

	   and functions:

	   gain_interpolate(f)
	       interpolate gain	on frequency f based on	gain_entry

	   cubic_interpolate(f)
	       same as gain_interpolate, but smoother

	   This	option is also available as command. Default is
	   gain_interpolate(f).

       gain_entry
	   Set gain entry for gain_interpolate function. The expression	can
	   contain functions:

	   entry(f, g)
	       store gain entry	at frequency f with value g

	   This	option is also available as command.

       delay
	   Set filter delay in seconds.	Higher value means more	accurate.
	   Default is 0.01.

       accuracy
	   Set filter accuracy in Hz. Lower value means	more accurate.
	   Default is 5.

       wfunc
	   Set window function.	Acceptable values are:

	   rectangular
	       rectangular window, useful when gain curve is already smooth

	   hann
	       hann window (default)

	   hamming
	       hamming window

	   blackman
	       blackman	window

	   nuttall3
	       3-terms continuous 1st derivative nuttall window

	   mnuttall3
	       minimum 3-terms discontinuous nuttall window

	   nuttall
	       4-terms continuous 1st derivative nuttall window

	   bnuttall
	       minimum 4-terms discontinuous nuttall (blackman-nuttall)	window

	   bharris
	       blackman-harris window

	   tukey
	       tukey window

       fixed
	   If enabled, use fixed number	of audio samples. This improves	speed
	   when	filtering with large delay. Default is disabled.

       multi
	   Enable multichannels	evaluation on gain. Default is disabled.

       zero_phase
	   Enable zero phase mode by subtracting timestamp to compensate
	   delay.  Default is disabled.

       scale
	   Set scale used by gain. Acceptable values are:

	   linlin
	       linear frequency, linear	gain

	   linlog
	       linear frequency, logarithmic (in dB) gain (default)

	   loglin
	       logarithmic (in octave scale where 20 Hz	is 0) frequency,
	       linear gain

	   loglog
	       logarithmic frequency, logarithmic gain

       dumpfile
	   Set file for	dumping, suitable for gnuplot.

       dumpscale
	   Set scale for dumpfile. Acceptable values are same with scale
	   option.  Default is linlog.

       fft2
	   Enable 2-channel convolution	using complex FFT. This	improves speed
	   significantly.  Default is disabled.

       Examples

       o   lowpass at 1000 Hz:

		   firequalizer=gain='if(lt(f,1000), 0,	-INF)'

       o   lowpass at 1000 Hz with gain_entry:

		   firequalizer=gain_entry='entry(1000,0); entry(1001, -INF)'

       o   custom equalization:

		   firequalizer=gain_entry='entry(100,0); entry(400, -4); entry(1000, -6); entry(2000, 0)'

       o   higher delay	with zero phase	to compensate delay:

		   firequalizer=delay=0.1:fixed=on:zero_phase=on

       o   lowpass on left channel, highpass on	right channel:

		   firequalizer=gain='if(eq(chid,1), gain_interpolate(f), if(eq(chid,2), gain_interpolate(1e6+f), 0))'
		   :gain_entry='entry(1000, 0);	entry(1001,-INF); entry(1e6+1000,0)':multi=on

   flanger
       Apply a flanging	effect to the audio.

       The filter accepts the following	options:

       delay
	   Set base delay in milliseconds. Range from 0	to 30. Default value
	   is 0.

       depth
	   Set added swep delay	in milliseconds. Range from 0 to 10. Default
	   value is 2.

       regen
	   Set percentage regeneration (delayed	signal feedback). Range	from
	   -95 to 95.  Default value is	0.

       width
	   Set percentage of delayed signal mixed with original. Range from 0
	   to 100.  Default value is 71.

       speed
	   Set sweeps per second (Hz). Range from 0.1 to 10. Default value is
	   0.5.

       shape
	   Set swept wave shape, can be	triangular or sinusoidal.  Default
	   value is sinusoidal.

       phase
	   Set swept wave percentage-shift for multi channel. Range from 0 to
	   100.	 Default value is 25.

       interp
	   Set delay-line interpolation, linear	or quadratic.  Default is
	   linear.

   hdcd
       Decodes High Definition Compatible Digital (HDCD) data. A 16-bit	PCM
       stream with embedded HDCD codes is expanded into	a 20-bit PCM stream.

       The filter supports the Peak Extend and Low-level Gain Adjustment
       features	of HDCD, and detects the Transient Filter flag.

	       ffmpeg -i HDCD16.flac -af hdcd OUT24.flac

       When using the filter with wav, note the	default	encoding for wav is
       16-bit, so the resulting	20-bit stream will be truncated	back to
       16-bit. Use something like -acodec pcm_s24le after the filter to	get
       24-bit PCM output.

	       ffmpeg -i HDCD16.wav -af	hdcd OUT16.wav
	       ffmpeg -i HDCD16.wav -af	hdcd -acodec pcm_s24le OUT24.wav

       The filter accepts the following	options:

       disable_autoconvert
	   Disable any automatic format	conversion or resampling in the	filter
	   graph.

       process_stereo
	   Process the stereo channels together. If target_gain	does not match
	   between channels, consider it invalid and use the last valid
	   target_gain.

       cdt_ms
	   Set the code	detect timer period in ms.

       force_pe
	   Always extend peaks above -3dBFS even if PE isn't signaled.

       analyze_mode
	   Replace audio with a	solid tone and adjust the amplitude to signal
	   some	specific aspect	of the decoding	process. The output file can
	   be loaded in	an audio editor	alongside the original to aid
	   analysis.

	   "analyze_mode=pe:force_pe=true" can be used to see all samples
	   above the PE	level.

	   Modes are:

	   0, off
	       Disabled

	   1, lle
	       Gain adjustment level at	each sample

	   2, pe
	       Samples where peak extend occurs

	   3, cdt
	       Samples where the code detect timer is active

	   4, tgm
	       Samples where the target	gain does not match between channels

   highpass
       Apply a high-pass filter	with 3dB point frequency.  The filter can be
       either single-pole, or double-pole (the default).  The filter roll off
       at 6dB per pole per octave (20dB	per pole per decade).

       The filter accepts the following	options:

       frequency, f
	   Set frequency in Hz.	Default	is 3000.

       poles, p
	   Set number of poles.	Default	is 2.

       width_type
	   Set method to specify band-width of filter.

	   h   Hz

	   q   Q-Factor

	   o   octave

	   s   slope

       width, w
	   Specify the band-width of a filter in width_type units.  Applies
	   only	to double-pole filter.	The default is 0.707q and gives	a
	   Butterworth response.

   join
       Join multiple input streams into	one multi-channel stream.

       It accepts the following	parameters:

       inputs
	   The number of input streams.	It defaults to 2.

       channel_layout
	   The desired output channel layout. It defaults to stereo.

       map Map channels	from inputs to output. The argument is a '|'-separated
	   list	of mappings, each in the "input_idx.in_channel-out_channel"
	   form. input_idx is the 0-based index	of the input stream.
	   in_channel can be either the	name of	the input channel (e.g.	FL for
	   front left) or its index in the specified input stream. out_channel
	   is the name of the output channel.

       The filter will attempt to guess	the mappings when they are not
       specified explicitly. It	does so	by first trying	to find	an unused
       matching	input channel and if that fails	it picks the first unused
       input channel.

       Join 3 inputs (with properly set	channel	layouts):

	       ffmpeg -i INPUT1	-i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT

       Build a 5.1 output from 6 single-channel	streams:

	       ffmpeg -i fl -i fr -i fc	-i sl -i sr -i lfe -filter_complex
	       'join=inputs=6:channel_layout=5.1:map=0.0-FL|1.0-FR|2.0-FC|3.0-SL|4.0-SR|5.0-LFE'
	       out

   ladspa
       Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin.

       To enable compilation of	this filter you	need to	configure FFmpeg with
       "--enable-ladspa".

       file, f
	   Specifies the name of LADSPA	plugin library to load.	If the
	   environment variable	LADSPA_PATH is defined,	the LADSPA plugin is
	   searched in each one	of the directories specified by	the colon
	   separated list in LADSPA_PATH, otherwise in the standard LADSPA
	   paths, which	are in this order: HOME/.ladspa/lib/,
	   /usr/local/lib/ladspa/, /usr/lib/ladspa/.

       plugin, p
	   Specifies the plugin	within the library. Some libraries contain
	   only	one plugin, but	others contain many of them. If	this is	not
	   set filter will list	all available plugins within the specified
	   library.

       controls, c
	   Set the '|' separated list of controls which	are zero or more
	   floating point values that determine	the behavior of	the loaded
	   plugin (for example delay, threshold	or gain).  Controls need to be
	   defined using the following syntax:
	   c0=value0|c1=value1|c2=value2|..., where valuei is the value	set on
	   the i-th control.  Alternatively they can be	also defined using the
	   following syntax: value0|value1|value2|..., where valuei is the
	   value set on	the i-th control.  If controls is set to "help", all
	   available controls and their	valid ranges are printed.

       sample_rate, s
	   Specify the sample rate, default to 44100. Only used	if plugin have
	   zero	inputs.

       nb_samples, n
	   Set the number of samples per channel per each output frame,
	   default is 1024. Only used if plugin	have zero inputs.

       duration, d
	   Set the minimum duration of the sourced audio. See the Time
	   duration section in the ffmpeg-utils(1) manual for the accepted
	   syntax.  Note that the resulting duration may be greater than the
	   specified duration, as the generated	audio is always	cut at the end
	   of a	complete frame.	 If not	specified, or the expressed duration
	   is negative,	the audio is supposed to be generated forever.	Only
	   used	if plugin have zero inputs.

       Examples

       o   List	all available plugins within amp (LADSPA example plugin)
	   library:

		   ladspa=file=amp

       o   List	all available controls and their valid ranges for "vcf_notch"
	   plugin from "VCF" library:

		   ladspa=f=vcf:p=vcf_notch:c=help

       o   Simulate low	quality	audio equipment	using "Computer	Music Toolkit"
	   (CMT) plugin	library:

		   ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12

       o   Add reverberation to	the audio using	TAP-plugins (Tom's Audio
	   Processing plugins):

		   ladspa=file=tap_reverb:tap_reverb

       o   Generate white noise, with 0.2 amplitude:

		   ladspa=file=cmt:noise_source_white:c=c0=.2

       o   Generate 20 bpm clicks using	plugin "C* Click - Metronome" from the
	   "C* Audio Plugin Suite" (CAPS) library:

		   ladspa=file=caps:Click:c=c1=20'

       o   Apply "C* Eq10X2 - Stereo 10-band equaliser"	effect:

		   ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2

       o   Increase volume by 20dB using fast lookahead	limiter	from Steve
	   Harris "SWH Plugins"	collection:

		   ladspa=fast_lookahead_limiter_1913:fastLookaheadLimiter:20|0|2

       o   Attenuate low frequencies using Multiband EQ	from Steve Harris "SWH
	   Plugins" collection:

		   ladspa=mbeq_1197:mbeq:-24|-24|-24|0|0|0|0|0|0|0|0|0|0|0|0

       Commands

       This filter supports the	following commands:

       cN  Modify the N-th control value.

	   If the specified value is not valid,	it is ignored and prior	one is
	   kept.

   loudnorm
       EBU R128	loudness normalization.	Includes both dynamic and linear
       normalization modes.  Support for both single pass (livestreams,	files)
       and double pass (files) modes.  This algorithm can target IL, LRA, and
       maximum true peak.

       The filter accepts the following	options:

       I, i
	   Set integrated loudness target.  Range is -70.0 - -5.0. Default
	   value is -24.0.

       LRA, lra
	   Set loudness	range target.  Range is	1.0 - 20.0. Default value is
	   7.0.

       TP, tp
	   Set maximum true peak.  Range is -9.0 - +0.0. Default value is
	   -2.0.

       measured_I, measured_i
	   Measured IL of input	file.  Range is	-99.0 -	+0.0.

       measured_LRA, measured_lra
	   Measured LRA	of input file.	Range is  0.0 -	99.0.

       measured_TP, measured_tp
	   Measured true peak of input file.  Range is	-99.0 -	+99.0.

       measured_thresh
	   Measured threshold of input file.  Range is -99.0 - +0.0.

       offset
	   Set offset gain. Gain is applied before the true-peak limiter.
	   Range is  -99.0 - +99.0. Default is +0.0.

       linear
	   Normalize linearly if possible.  measured_I,	measured_LRA,
	   measured_TP,	and measured_thresh must also to be specified in order
	   to use this mode.  Options are true or false. Default is true.

       dual_mono
	   Treat mono input files as "dual-mono". If a mono file is intended
	   for playback	on a stereo system, its	EBU R128 measurement will be
	   perceptually	incorrect.  If set to "true", this option will
	   compensate for this effect.	Multi-channel input files are not
	   affected by this option.  Options are true or false.	Default	is
	   false.

       print_format
	   Set print format for	stats. Options are summary, json, or none.
	   Default value is none.

   lowpass
       Apply a low-pass	filter with 3dB	point frequency.  The filter can be
       either single-pole or double-pole (the default).	 The filter roll off
       at 6dB per pole per octave (20dB	per pole per decade).

       The filter accepts the following	options:

       frequency, f
	   Set frequency in Hz.	Default	is 500.

       poles, p
	   Set number of poles.	Default	is 2.

       width_type
	   Set method to specify band-width of filter.

	   h   Hz

	   q   Q-Factor

	   o   octave

	   s   slope

       width, w
	   Specify the band-width of a filter in width_type units.  Applies
	   only	to double-pole filter.	The default is 0.707q and gives	a
	   Butterworth response.

   pan
       Mix channels with specific gain levels. The filter accepts the output
       channel layout followed by a set	of channels definitions.

       This filter is also designed to efficiently remap the channels of an
       audio stream.

       The filter accepts parameters of	the form: "l|outdef|outdef|..."

       l   output channel layout or number of channels

       outdef
	   output channel specification, of the	form:
	   "out_name=[gain*]in_name[(+-)[gain*]in_name...]"

       out_name
	   output channel to define, either a channel name (FL,	FR, etc.) or a
	   channel number (c0, c1, etc.)

       gain
	   multiplicative coefficient for the channel, 1 leaving the volume
	   unchanged

       in_name
	   input channel to use, see out_name for details; it is not possible
	   to mix named	and numbered input channels

       If the `=' in a channel specification is	replaced by `<', then the
       gains for that specification will be renormalized so that the total is
       1, thus avoiding	clipping noise.

       Mixing examples

       For example, if you want	to down-mix from stereo	to mono, but with a
       bigger factor for the left channel:

	       pan=1c|c0=0.9*c0+0.1*c1

       A customized down-mix to	stereo that works automatically	for 3-,	4-, 5-
       and 7-channels surround:

	       pan=stereo| FL <	FL + 0.5*FC + 0.6*BL + 0.6*SL |	FR < FR	+ 0.5*FC + 0.6*BR + 0.6*SR

       Note that ffmpeg	integrates a default down-mix (and up-mix) system that
       should be preferred (see	"-ac" option) unless you have very specific
       needs.

       Remapping examples

       The channel remapping will be effective if, and only if:

       *<gain coefficients are zeroes or ones,>
       *<only one input	per channel output,>

       If all these conditions are satisfied, the filter will notify the user
       ("Pure channel mapping detected"), and use an optimized and lossless
       method to do the	remapping.

       For example, if you have	a 5.1 source and want a	stereo audio stream by
       dropping	the extra channels:

	       pan="stereo| c0=FL | c1=FR"

       Given the same source, you can also switch front	left and front right
       channels	and keep the input channel layout:

	       pan="5.1| c0=c1 | c1=c0 | c2=c2 | c3=c3 | c4=c4 | c5=c5"

       If the input is a stereo	audio stream, you can mute the front left
       channel (and still keep the stereo channel layout) with:

	       pan="stereo|c1=c1"

       Still with a stereo audio stream	input, you can copy the	right channel
       in both front left and right:

	       pan="stereo| c0=FR | c1=FR"

   replaygain
       ReplayGain scanner filter. This filter takes an audio stream as an
       input and outputs it unchanged.	At end of filtering it displays
       "track_gain" and	"track_peak".

   resample
       Convert the audio sample	format,	sample rate and	channel	layout.	It is
       not meant to be used directly.

   rubberband
       Apply time-stretching and pitch-shifting	with librubberband.

       The filter accepts the following	options:

       tempo
	   Set tempo scale factor.

       pitch
	   Set pitch scale factor.

       transients
	   Set transients detector.  Possible values are:

	   crisp
	   mixed
	   smooth
       detector
	   Set detector.  Possible values are:

	   compound
	   percussive
	   soft
       phase
	   Set phase.  Possible	values are:

	   laminar
	   independent
       window
	   Set processing window size.	Possible values	are:

	   standard
	   short
	   long
       smoothing
	   Set smoothing.  Possible values are:

	   off
	   on
       formant
	   Enable formant preservation when shift pitching.  Possible values
	   are:

	   shifted
	   preserved
       pitchq
	   Set pitch quality.  Possible	values are:

	   quality
	   speed
	   consistency
       channels
	   Set channels.  Possible values are:

	   apart
	   together

   sidechaincompress
       This filter acts	like normal compressor but has the ability to compress
       detected	signal using second input signal.  It needs two	input streams
       and returns one output stream.  First input stream will be processed
       depending on second stream signal.  The filtered	signal then can	be
       filtered	with other filters in later stages of processing. See pan and
       amerge filter.

       The filter accepts the following	options:

       level_in
	   Set input gain. Default is 1. Range is between 0.015625 and 64.

       threshold
	   If a	signal of second stream	raises above this level	it will	affect
	   the gain reduction of first stream.	By default is 0.125. Range is
	   between 0.00097563 and 1.

       ratio
	   Set a ratio about which the signal is reduced. 1:2 means that if
	   the level raised 4dB	above the threshold, it	will be	only 2dB above
	   after the reduction.	 Default is 2. Range is	between	1 and 20.

       attack
	   Amount of milliseconds the signal has to rise above the threshold
	   before gain reduction starts. Default is 20.	Range is between 0.01
	   and 2000.

       release
	   Amount of milliseconds the signal has to fall below the threshold
	   before reduction is decreased again.	Default	is 250.	Range is
	   between 0.01	and 9000.

       makeup
	   Set the amount by how much signal will be amplified after
	   processing.	Default	is 2. Range is from 1 and 64.

       knee
	   Curve the sharp knee	around the threshold to	enter gain reduction
	   more	softly.	 Default is 2.82843. Range is between 1	and 8.

       link
	   Choose if the "average" level between all channels of side-chain
	   stream or the louder("maximum") channel of side-chain stream
	   affects the reduction. Default is "average".

       detection
	   Should the exact signal be taken in case of "peak" or an RMS	one in
	   case	of "rms". Default is "rms" which is mainly smoother.

       level_sc
	   Set sidechain gain. Default is 1. Range is between 0.015625 and 64.

       mix How much to use compressed signal in	output.	Default	is 1.  Range
	   is between 0	and 1.

       Examples

       o   Full	ffmpeg example taking 2	audio inputs, 1st input	to be
	   compressed depending	on the signal of 2nd input and later
	   compressed signal to	be merged with 2nd input:

		   ffmpeg -i main.flac -i sidechain.flac -filter_complex "[1:a]asplit=2[sc][mix];[0:a][sc]sidechaincompress[compr];[compr][mix]amerge"

   sidechaingate
       A sidechain gate	acts like a normal (wideband) gate but has the ability
       to filter the detected signal before sending it to the gain reduction
       stage.  Normally	a gate uses the	full range signal to detect a level
       above the threshold.  For example: If you cut all lower frequencies
       from your sidechain signal the gate will	decrease the volume of your
       track only if not enough	highs appear. With this	technique you are able
       to reduce the resonation	of a natural drum or remove "rumbling" of
       muted strokes from a heavily distorted guitar.  It needs	two input
       streams and returns one output stream.  First input stream will be
       processed depending on second stream signal.

       The filter accepts the following	options:

       level_in
	   Set input level before filtering.  Default is 1. Allowed range is
	   from	0.015625 to 64.

       range
	   Set the level of gain reduction when	the signal is below the
	   threshold.  Default is 0.06125. Allowed range is from 0 to 1.

       threshold
	   If a	signal rises above this	level the gain reduction is released.
	   Default is 0.125. Allowed range is from 0 to	1.

       ratio
	   Set a ratio about which the signal is reduced.  Default is 2.
	   Allowed range is from 1 to 9000.

       attack
	   Amount of milliseconds the signal has to rise above the threshold
	   before gain reduction stops.	 Default is 20 milliseconds. Allowed
	   range is from 0.01 to 9000.

       release
	   Amount of milliseconds the signal has to fall below the threshold
	   before the reduction	is increased again. Default is 250
	   milliseconds.  Allowed range	is from	0.01 to	9000.

       makeup
	   Set amount of amplification of signal after processing.  Default is
	   1. Allowed range is from 1 to 64.

       knee
	   Curve the sharp knee	around the threshold to	enter gain reduction
	   more	softly.	 Default is 2.828427125. Allowed range is from 1 to 8.

       detection
	   Choose if exact signal should be taken for detection	or an RMS like
	   one.	 Default is rms. Can be	peak or	rms.

       link
	   Choose if the average level between all channels or the louder
	   channel affects the reduction.  Default is average. Can be average
	   or maximum.

       level_sc
	   Set sidechain gain. Default is 1. Range is from 0.015625 to 64.

   silencedetect
       Detect silence in an audio stream.

       This filter logs	a message when it detects that the input audio volume
       is less or equal	to a noise tolerance value for a duration greater or
       equal to	the minimum detected noise duration.

       The printed times and duration are expressed in seconds.

       The filter accepts the following	options:

       duration, d
	   Set silence duration	until notification (default is 2 seconds).

       noise, n
	   Set noise tolerance.	Can be specified in dB (in case	"dB" is
	   appended to the specified value) or amplitude ratio.	Default	is
	   -60dB, or 0.001.

       Examples

       o   Detect 5 seconds of silence with -50dB noise	tolerance:

		   silencedetect=n=-50dB:d=5

       o   Complete example with ffmpeg	to detect silence with 0.0001 noise
	   tolerance in	silence.mp3:

		   ffmpeg -i silence.mp3 -af silencedetect=noise=0.0001	-f null	-

   silenceremove
       Remove silence from the beginning, middle or end	of the audio.

       The filter accepts the following	options:

       start_periods
	   This	value is used to indicate if audio should be trimmed at
	   beginning of	the audio. A value of zero indicates no	silence	should
	   be trimmed from the beginning. When specifying a non-zero value, it
	   trims audio up until	it finds non-silence. Normally,	when trimming
	   silence from	beginning of audio the start_periods will be 1 but it
	   can be increased to higher values to	trim all audio up to specific
	   count of non-silence	periods.  Default value	is 0.

       start_duration
	   Specify the amount of time that non-silence must be detected	before
	   it stops trimming audio. By increasing the duration,	bursts of
	   noises can be treated as silence and	trimmed	off. Default value is
	   0.

       start_threshold
	   This	indicates what sample value should be treated as silence. For
	   digital audio, a value of 0 may be fine but for audio recorded from
	   analog, you may wish	to increase the	value to account for
	   background noise.  Can be specified in dB (in case "dB" is appended
	   to the specified value) or amplitude	ratio. Default value is	0.

       stop_periods
	   Set the count for trimming silence from the end of audio.  To
	   remove silence from the middle of a file, specify a stop_periods
	   that	is negative. This value	is then	treated	as a positive value
	   and is used to indicate the effect should restart processing	as
	   specified by	start_periods, making it suitable for removing periods
	   of silence in the middle of the audio.  Default value is 0.

       stop_duration
	   Specify a duration of silence that must exist before	audio is not
	   copied any more. By specifying a higher duration, silence that is
	   wanted can be left in the audio.  Default value is 0.

       stop_threshold
	   This	is the same as start_threshold but for trimming	silence	from
	   the end of audio.  Can be specified in dB (in case "dB" is appended
	   to the specified value) or amplitude	ratio. Default value is	0.

       leave_silence
	   This	indicates that stop_duration length of audio should be left
	   intact at the beginning of each period of silence.  For example, if
	   you want to remove long pauses between words	but do not want	to
	   remove the pauses completely. Default value is 0.

       detection
	   Set how is silence detected.	Can be "rms" or	"peak".	Second is
	   faster and works better with	digital	silence	which is exactly 0.
	   Default value is "rms".

       window
	   Set ratio used to calculate size of window for detecting silence.
	   Default value is 0.02. Allowed range	is from	0 to 10.

       Examples

       o   The following example shows how this	filter can be used to start a
	   recording that does not contain the delay at	the start which
	   usually occurs between pressing the record button and the start of
	   the performance:

		   silenceremove=1:5:0.02

       o   Trim	all silence encountered	from beginning to end where there is
	   more	than 1 second of silence in audio:

		   silenceremove=0:0:0:-1:1:-90dB

   sofalizer
       SOFAlizer uses head-related transfer functions (HRTFs) to create
       virtual loudspeakers around the user for	binaural listening via
       headphones (audio formats up to 9 channels supported).  The HRTFs are
       stored in SOFA files (see <http://www.sofacoustics.org/>	for a
       database).  SOFAlizer is	developed at the Acoustics Research Institute
       (ARI) of	the Austrian Academy of	Sciences.

       To enable compilation of	this filter you	need to	configure FFmpeg with
       "--enable-netcdf".

       The filter accepts the following	options:

       sofa
	   Set the SOFA	file used for rendering.

       gain
	   Set gain applied to audio. Value is in dB. Default is 0.

       rotation
	   Set rotation	of virtual loudspeakers	in deg.	Default	is 0.

       elevation
	   Set elevation of virtual speakers in	deg. Default is	0.

       radius
	   Set distance	in meters between loudspeakers and the listener	with
	   near-field HRTFs. Default is	1.

       type
	   Set processing type.	Can be time or freq. time is processing	audio
	   in time domain which	is slow.  freq is processing audio in
	   frequency domain which is fast.  Default is freq.

       speakers
	   Set custom positions	of virtual loudspeakers. Syntax	for this
	   option is: <CH> <AZIM> <ELEV>[|<CH> <AZIM> <ELEV>|...].  Each
	   virtual loudspeaker is described with short channel name following
	   with	azimuth	and elevation in degreees.  Each virtual loudspeaker
	   description is separated by '|'.  For example to override front
	   left	and front right	channel	positions use: 'speakers=FL 45 15|FR
	   345 15'.  Descriptions with unrecognised channel names are ignored.

       Examples

       o   Using ClubFritz6 sofa file:

		   sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=1

       o   Using ClubFritz12 sofa file and bigger radius with small rotation:

		   sofalizer=sofa=/path/to/ClubFritz12.sofa:type=freq:radius=2:rotation=5

       o   Similar as above but	with custom speaker positions for front	left,
	   front right,	back left and back right and also with custom gain:

		   "sofalizer=sofa=/path/to/ClubFritz6.sofa:type=freq:radius=2:speakers=FL 45|FR 315|BL	135|BR 225:gain=28"

   stereotools
       This filter has some handy utilities to manage stereo signals, for
       converting M/S stereo recordings	to L/R signal while having control
       over the	parameters or spreading	the stereo image of master track.

       The filter accepts the following	options:

       level_in
	   Set input level before filtering for	both channels. Defaults	is 1.
	   Allowed range is from 0.015625 to 64.

       level_out
	   Set output level after filtering for	both channels. Defaults	is 1.
	   Allowed range is from 0.015625 to 64.

       balance_in
	   Set input balance between both channels. Default is 0.  Allowed
	   range is from -1 to 1.

       balance_out
	   Set output balance between both channels. Default is	0.  Allowed
	   range is from -1 to 1.

       softclip
	   Enable softclipping.	Results	in analog distortion instead of	harsh
	   digital 0dB clipping. Disabled by default.

       mutel
	   Mute	the left channel. Disabled by default.

       muter
	   Mute	the right channel. Disabled by default.

       phasel
	   Change the phase of the left	channel. Disabled by default.

       phaser
	   Change the phase of the right channel. Disabled by default.

       mode
	   Set stereo mode. Available values are:

	   lr>lr
	       Left/Right to Left/Right, this is default.

	   lr>ms
	       Left/Right to Mid/Side.

	   ms>lr
	       Mid/Side	to Left/Right.

	   lr>ll
	       Left/Right to Left/Left.

	   lr>rr
	       Left/Right to Right/Right.

	   lr>l+r
	       Left/Right to Left + Right.

	   lr>rl
	       Left/Right to Right/Left.

       slev
	   Set level of	side signal. Default is	1.  Allowed range is from
	   0.015625 to 64.

       sbal
	   Set balance of side signal. Default is 0.  Allowed range is from -1
	   to 1.

       mlev
	   Set level of	the middle signal. Default is 1.  Allowed range	is
	   from	0.015625 to 64.

       mpan
	   Set middle signal pan. Default is 0.	Allowed	range is from -1 to 1.

       base
	   Set stereo base between mono	and inversed channels. Default is 0.
	   Allowed range is from -1 to 1.

       delay
	   Set delay in	milliseconds how much to delay left from right channel
	   and vice versa. Default is 0. Allowed range is from -20 to 20.

       sclevel
	   Set S/C level. Default is 1.	Allowed	range is from 1	to 100.

       phase
	   Set the stereo phase	in degrees. Default is 0. Allowed range	is
	   from	0 to 360.

       Examples

       o   Apply karaoke like effect:

		   stereotools=mlev=0.015625

       o   Convert M/S signal to L/R:

		   "stereotools=mode=ms>lr"

   stereowiden
       This filter enhance the stereo effect by	suppressing signal common to
       both channels and by delaying the signal	of left	into right and vice
       versa, thereby widening the stereo effect.

       The filter accepts the following	options:

       delay
	   Time	in milliseconds	of the delay of	left signal into right and
	   vice	versa.	Default	is 20 milliseconds.

       feedback
	   Amount of gain in delayed signal into right and vice	versa. Gives a
	   delay effect	of left	signal in right	output and vice	versa which
	   gives widening effect. Default is 0.3.

       crossfeed
	   Cross feed of left into right with inverted phase. This helps in
	   suppressing the mono. If the	value is 1 it will cancel all the
	   signal common to both channels. Default is 0.3.

       drymix
	   Set level of	input signal of	original channel. Default is 0.8.

   treble
       Boost or	cut treble (upper) frequencies of the audio using a two-pole
       shelving	filter with a response similar to that of a standard hi-fi's
       tone-controls. This is also known as shelving equalisation (EQ).

       The filter accepts the following	options:

       gain, g
	   Give	the gain at whichever is the lower of ~22 kHz and the Nyquist
	   frequency. Its useful range is about	-20 (for a large cut) to +20
	   (for	a large	boost).	Beware of clipping when	using a	positive gain.

       frequency, f
	   Set the filter's central frequency and so can be used to extend or
	   reduce the frequency	range to be boosted or cut.  The default value
	   is 3000 Hz.

       width_type
	   Set method to specify band-width of filter.

	   h   Hz

	   q   Q-Factor

	   o   octave

	   s   slope

       width, w
	   Determine how steep is the filter's shelf transition.

   tremolo
       Sinusoidal amplitude modulation.

       The filter accepts the following	options:

       f   Modulation frequency	in Hertz. Modulation frequencies in the
	   subharmonic range (20 Hz or lower) will result in a tremolo effect.
	   This	filter may also	be used	as a ring modulator by specifying a
	   modulation frequency	higher than 20 Hz.  Range is 0.1 - 20000.0.
	   Default value is 5.0	Hz.

       d   Depth of modulation as a percentage.	Range is 0.0 - 1.0.  Default
	   value is 0.5.

   vibrato
       Sinusoidal phase	modulation.

       The filter accepts the following	options:

       f   Modulation frequency	in Hertz.  Range is 0.1	- 20000.0. Default
	   value is 5.0	Hz.

       d   Depth of modulation as a percentage.	Range is 0.0 - 1.0.  Default
	   value is 0.5.

   volume
       Adjust the input	audio volume.

       It accepts the following	parameters:

       volume
	   Set audio volume expression.

	   Output values are clipped to	the maximum value.

	   The output audio volume is given by the relation:

		   <output_volume> = <volume> *	<input_volume>

	   The default value for volume	is "1.0".

       precision
	   This	parameter represents the mathematical precision.

	   It determines which input sample formats will be allowed, which
	   affects the precision of the	volume scaling.

	   fixed
	       8-bit fixed-point; this limits input sample format to U8, S16,
	       and S32.

	   float
	       32-bit floating-point; this limits input	sample format to FLT.
	       (default)

	   double
	       64-bit floating-point; this limits input	sample format to DBL.

       replaygain
	   Choose the behaviour	on encountering	ReplayGain side	data in	input
	   frames.

	   drop
	       Remove ReplayGain side data, ignoring its contents (the
	       default).

	   ignore
	       Ignore ReplayGain side data, but	leave it in the	frame.

	   track
	       Prefer the track	gain, if present.

	   album
	       Prefer the album	gain, if present.

       replaygain_preamp
	   Pre-amplification gain in dB	to apply to the	selected replaygain
	   gain.

	   Default value for replaygain_preamp is 0.0.

       eval
	   Set when the	volume expression is evaluated.

	   It accepts the following values:

	   once
	       only evaluate expression	once during the	filter initialization,
	       or when the volume command is sent

	   frame
	       evaluate	expression for each incoming frame

	   Default value is once.

       The volume expression can contain the following parameters.

       n   frame number	(starting at zero)

       nb_channels
	   number of channels

       nb_consumed_samples
	   number of samples consumed by the filter

       nb_samples
	   number of samples in	the current frame

       pos original frame position in the file

       pts frame PTS

       sample_rate
	   sample rate

       startpts
	   PTS at start	of stream

       startt
	   time	at start of stream

       t   frame time

       tb  timestamp timebase

       volume
	   last	set volume value

       Note that when eval is set to once only the sample_rate and tb
       variables are available,	all other variables will evaluate to NAN.

       Commands

       This filter supports the	following commands:

       volume
	   Modify the volume expression.  The command accepts the same syntax
	   of the corresponding	option.

	   If the specified expression is not valid, it	is kept	at its current
	   value.

       replaygain_noclip
	   Prevent clipping by limiting	the gain applied.

	   Default value for replaygain_noclip is 1.

       Examples

       o   Halve the input audio volume:

		   volume=volume=0.5
		   volume=volume=1/2
		   volume=volume=-6.0206dB

	   In all the above example the	named key for volume can be omitted,
	   for example like in:

		   volume=0.5

       o   Increase input audio	power by 6 decibels using fixed-point
	   precision:

		   volume=volume=6dB:precision=fixed

       o   Fade	volume after time 10 with an annihilation period of 5 seconds:

		   volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame

   volumedetect
       Detect the volume of the	input video.

       The filter has no parameters. The input is not modified.	Statistics
       about the volume	will be	printed	in the log when	the input stream end
       is reached.

       In particular it	will show the mean volume (root	mean square), maximum
       volume (on a per-sample basis), and the beginning of a histogram	of the
       registered volume values	(from the maximum value	to a cumulated 1/1000
       of the samples).

       All volumes are in decibels relative to the maximum PCM value.

       Examples

       Here is an excerpt of the output:

	       [Parsed_volumedetect_0  0xa23120] mean_volume: -27 dB
	       [Parsed_volumedetect_0  0xa23120] max_volume: -4	dB
	       [Parsed_volumedetect_0  0xa23120] histogram_4db:	6
	       [Parsed_volumedetect_0  0xa23120] histogram_5db:	62
	       [Parsed_volumedetect_0  0xa23120] histogram_6db:	286
	       [Parsed_volumedetect_0  0xa23120] histogram_7db:	1042
	       [Parsed_volumedetect_0  0xa23120] histogram_8db:	2551
	       [Parsed_volumedetect_0  0xa23120] histogram_9db:	4609
	       [Parsed_volumedetect_0  0xa23120] histogram_10db: 8409

       It means	that:

       o   The mean square energy is approximately -27 dB, or 10^-2.7.

       o   The largest sample is at -4 dB, or more precisely between -4	dB and
	   -5 dB.

       o   There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6	dB, etc.

       In other	words, raising the volume by +4	dB does	not cause any
       clipping, raising it by +5 dB causes clipping for 6 samples, etc.

AUDIO SOURCES
       Below is	a description of the currently available audio sources.

   abuffer
       Buffer audio frames, and	make them available to the filter chain.

       This source is mainly intended for a programmatic use, in particular
       through the interface defined in	libavfilter/asrc_abuffer.h.

       It accepts the following	parameters:

       time_base
	   The timebase	which will be used for timestamps of submitted frames.
	   It must be either a floating-point number or	in
	   numerator/denominator form.

       sample_rate
	   The sample rate of the incoming audio buffers.

       sample_fmt
	   The sample format of	the incoming audio buffers.  Either a sample
	   format name or its corresponding integer representation from	the
	   enum	AVSampleFormat in libavutil/samplefmt.h

       channel_layout
	   The channel layout of the incoming audio buffers.  Either a channel
	   layout name from channel_layout_map in libavutil/channel_layout.c
	   or its corresponding	integer	representation from the	AV_CH_LAYOUT_*
	   macros in libavutil/channel_layout.h

       channels
	   The number of channels of the incoming audio	buffers.  If both
	   channels and	channel_layout are specified, then they	must be
	   consistent.

       Examples

	       abuffer=sample_rate=44100:sample_fmt=s16p:channel_layout=stereo

       will instruct the source	to accept planar 16bit signed stereo at
       44100Hz.	 Since the sample format with name "s16p" corresponds to the
       number 6	and the	"stereo" channel layout	corresponds to the value 0x3,
       this is equivalent to:

	       abuffer=sample_rate=44100:sample_fmt=6:channel_layout=0x3

   aevalsrc
       Generate	an audio signal	specified by an	expression.

       This source accepts in input one	or more	expressions (one for each
       channel), which are evaluated and used to generate a corresponding
       audio signal.

       This source accepts the following options:

       exprs
	   Set the '|'-separated expressions list for each separate channel.
	   In case the channel_layout option is	not specified, the selected
	   channel layout depends on the number	of provided expressions.
	   Otherwise the last specified	expression is applied to the remaining
	   output channels.

       channel_layout, c
	   Set the channel layout. The number of channels in the specified
	   layout must be equal	to the number of specified expressions.

       duration, d
	   Set the minimum duration of the sourced audio. See the Time
	   duration section in the ffmpeg-utils(1) manual for the accepted
	   syntax.  Note that the resulting duration may be greater than the
	   specified duration, as the generated	audio is always	cut at the end
	   of a	complete frame.

	   If not specified, or	the expressed duration is negative, the	audio
	   is supposed to be generated forever.

       nb_samples, n
	   Set the number of samples per channel per each output frame,
	   default to 1024.

       sample_rate, s
	   Specify the sample rate, default to 44100.

       Each expression in exprs	can contain the	following constants:

       n   number of the evaluated sample, starting from 0

       t   time	of the evaluated sample	expressed in seconds, starting from 0

       s   sample rate

       Examples

       o   Generate silence:

		   aevalsrc=0

       o   Generate a sin signal with frequency	of 440 Hz, set sample rate to
	   8000	Hz:

		   aevalsrc="sin(440*2*PI*t):s=8000"

       o   Generate a two channels signal, specify the channel layout (Front
	   Center + Back Center) explicitly:

		   aevalsrc="sin(420*2*PI*t)|cos(430*2*PI*t):c=FC|BC"

       o   Generate white noise:

		   aevalsrc="-2+random(0)"

       o   Generate an amplitude modulated signal:

		   aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"

       o   Generate 2.5	Hz binaural beats on a 360 Hz carrier:

		   aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) | 0.1*sin(2*PI*(360+2.5/2)*t)"

   anullsrc
       The null	audio source, return unprocessed audio frames. It is mainly
       useful as a template and	to be employed in analysis / debugging tools,
       or as the source	for filters which ignore the input data	(for example
       the sox synth filter).

       This source accepts the following options:

       channel_layout, cl
	   Specifies the channel layout, and can be either an integer or a
	   string representing a channel layout. The default value of
	   channel_layout is "stereo".

	   Check the channel_layout_map	definition in
	   libavutil/channel_layout.c for the mapping between strings and
	   channel layout values.

       sample_rate, r
	   Specifies the sample	rate, and defaults to 44100.

       nb_samples, n
	   Set the number of samples per requested frames.

       Examples

       o   Set the sample rate to 48000	Hz and the channel layout to
	   AV_CH_LAYOUT_MONO.

		   anullsrc=r=48000:cl=4

       o   Do the same operation with a	more obvious syntax:

		   anullsrc=r=48000:cl=mono

       All the parameters need to be explicitly	defined.

   flite
       Synthesize a voice utterance using the libflite library.

       To enable compilation of	this filter you	need to	configure FFmpeg with
       "--enable-libflite".

       Note that the flite library is not thread-safe.

       The filter accepts the following	options:

       list_voices
	   If set to 1,	list the names of the available	voices and exit
	   immediately.	Default	value is 0.

       nb_samples, n
	   Set the maximum number of samples per frame.	Default	value is 512.

       textfile
	   Set the filename containing the text	to speak.

       text
	   Set the text	to speak.

       voice, v
	   Set the voice to use	for the	speech synthesis. Default value	is
	   "kal". See also the list_voices option.

       Examples

       o   Read	from file speech.txt, and synthesize the text using the
	   standard flite voice:

		   flite=textfile=speech.txt

       o   Read	the specified text selecting the "slt" voice:

		   flite=text='So fare thee well, poor devil of	a Sub-Sub, whose commentator I am':voice=slt

       o   Input text to ffmpeg:

		   ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil	of a Sub-Sub, whose commentator	I am':voice=slt

       o   Make	ffplay speak the specified text, using "flite" and the "lavfi"
	   device:

		   ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'

       For more	information about libflite, check:
       <http://www.speech.cs.cmu.edu/flite/>

   anoisesrc
       Generate	a noise	audio signal.

       The filter accepts the following	options:

       sample_rate, r
	   Specify the sample rate. Default value is 48000 Hz.

       amplitude, a
	   Specify the amplitude (0.0 -	1.0) of	the generated audio stream.
	   Default value is 1.0.

       duration, d
	   Specify the duration	of the generated audio stream. Not specifying
	   this	option results in noise	with an	infinite length.

       color, colour, c
	   Specify the color of	noise. Available noise colors are white, pink,
	   and brown.  Default color is	white.

       seed, s
	   Specify a value used	to seed	the PRNG.

       nb_samples, n
	   Set the number of samples per each output frame, default is 1024.

       Examples

       o   Generate 60 seconds of pink noise, with a 44.1 kHz sampling rate
	   and an amplitude of 0.5:

		   anoisesrc=d=60:c=pink:r=44100:a=0.5

   sine
       Generate	an audio signal	made of	a sine wave with amplitude 1/8.

       The audio signal	is bit-exact.

       The filter accepts the following	options:

       frequency, f
	   Set the carrier frequency. Default is 440 Hz.

       beep_factor, b
	   Enable a periodic beep every	second with frequency beep_factor
	   times the carrier frequency.	Default	is 0, meaning the beep is
	   disabled.

       sample_rate, r
	   Specify the sample rate, default is 44100.

       duration, d
	   Specify the duration	of the generated audio stream.

       samples_per_frame
	   Set the number of samples per output	frame.

	   The expression can contain the following constants:

	   n   The (sequential)	number of the output audio frame, starting
	       from 0.

	   pts The PTS (Presentation TimeStamp)	of the output audio frame,
	       expressed in TB units.

	   t   The PTS of the output audio frame, expressed in seconds.

	   TB  The timebase of the output audio	frames.

	   Default is 1024.

       Examples

       o   Generate a simple 440 Hz sine wave:

		   sine

       o   Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5
	   seconds:

		   sine=220:4:d=5
		   sine=f=220:b=4:d=5
		   sine=frequency=220:beep_factor=4:duration=5

       o   Generate a 1	kHz sine wave following	"1602,1601,1602,1601,1602"
	   NTSC	pattern:

		   sine=1000:samples_per_frame='st(0,mod(n,5));	1602-not(not(eq(ld(0),1)+eq(ld(0),3)))'

AUDIO SINKS
       Below is	a description of the currently available audio sinks.

   abuffersink
       Buffer audio frames, and	make them available to the end of filter
       chain.

       This sink is mainly intended for	programmatic use, in particular
       through the interface defined in	libavfilter/buffersink.h or the
       options system.

       It accepts a pointer to an AVABufferSinkContext structure, which
       defines the incoming buffers' formats, to be passed as the opaque
       parameter to "avfilter_init_filter" for initialization.

   anullsink
       Null audio sink;	do absolutely nothing with the input audio. It is
       mainly useful as	a template and for use in analysis / debugging tools.

VIDEO FILTERS
       When you	configure your FFmpeg build, you can disable any of the
       existing	filters	using "--disable-filters".  The	configure output will
       show the	video filters included in your build.

       Below is	a description of the currently available video filters.

   alphaextract
       Extract the alpha component from	the input as a grayscale video.	This
       is especially useful with the alphamerge	filter.

   alphamerge
       Add or replace the alpha	component of the primary input with the
       grayscale value of a second input. This is intended for use with
       alphaextract to allow the transmission or storage of frame sequences
       that have alpha in a format that	doesn't	support	an alpha channel.

       For example, to reconstruct full	frames from a normal YUV-encoded video
       and a separate video created with alphaextract, you might use:

	       movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out]

       Since this filter is designed for reconstruction, it operates on	frame
       sequences without considering timestamps, and terminates	when either
       input reaches end of stream. This will cause problems if	your encoding
       pipeline	drops frames. If you're	trying to apply	an image as an overlay
       to a video stream, consider the overlay filter instead.

   ass
       Same as the subtitles filter, except that it doesn't require libavcodec
       and libavformat to work.	On the other hand, it is limited to ASS
       (Advanced Substation Alpha) subtitles files.

       This filter accepts the following option	in addition to the common
       options from the	subtitles filter:

       shaping
	   Set the shaping engine

	   Available values are:

	   auto
	       The default libass shaping engine, which	is the best available.

	   simple
	       Fast, font-agnostic shaper that can do only substitutions

	   complex
	       Slower shaper using OpenType for	substitutions and positioning

	   The default is "auto".

   atadenoise
       Apply an	Adaptive Temporal Averaging Denoiser to	the video input.

       The filter accepts the following	options:

       0a  Set threshold A for 1st plane. Default is 0.02.  Valid range	is 0
	   to 0.3.

       0b  Set threshold B for 1st plane. Default is 0.04.  Valid range	is 0
	   to 5.

       1a  Set threshold A for 2nd plane. Default is 0.02.  Valid range	is 0
	   to 0.3.

       1b  Set threshold B for 2nd plane. Default is 0.04.  Valid range	is 0
	   to 5.

       2a  Set threshold A for 3rd plane. Default is 0.02.  Valid range	is 0
	   to 0.3.

       2b  Set threshold B for 3rd plane. Default is 0.04.  Valid range	is 0
	   to 5.

	   Threshold A is designed to react on abrupt changes in the input
	   signal and threshold	B is designed to react on continuous changes
	   in the input	signal.

       s   Set number of frames	filter will use	for averaging. Default is 33.
	   Must	be odd number in range [5, 129].

       p   Set what planes of frame filter will	use for	averaging. Default is
	   all.

   avgblur
       Apply average blur filter.

       The filter accepts the following	options:

       sizeX
	   Set horizontal kernel size.

       planes
	   Set which planes to filter. By default all planes are filtered.

       sizeY
	   Set vertical	kernel size, if	zero it	will be	same as	"sizeX".
	   Default is 0.

   bbox
       Compute the bounding box	for the	non-black pixels in the	input frame
       luminance plane.

       This filter computes the	bounding box containing	all the	pixels with a
       luminance value greater than the	minimum	allowed	value.	The parameters
       describing the bounding box are printed on the filter log.

       The filter accepts the following	option:

       min_val
	   Set the minimal luminance value. Default is 16.

   bitplanenoise
       Show and	measure	bit plane noise.

       The filter accepts the following	options:

       bitplane
	   Set which plane to analyze. Default is 1.

       filter
	   Filter out noisy pixels from	"bitplane" set above.  Default is
	   disabled.

   blackdetect
       Detect video intervals that are (almost)	completely black. Can be
       useful to detect	chapter	transitions, commercials, or invalid
       recordings. Output lines	contains the time for the start, end and
       duration	of the detected	black interval expressed in seconds.

       In order	to display the output lines, you need to set the loglevel at
       least to	the AV_LOG_INFO	value.

       The filter accepts the following	options:

       black_min_duration, d
	   Set the minimum detected black duration expressed in	seconds. It
	   must	be a non-negative floating point number.

	   Default value is 2.0.

       picture_black_ratio_th, pic_th
	   Set the threshold for considering a picture "black".	 Express the
	   minimum value for the ratio:

		   <nb_black_pixels> / <nb_pixels>

	   for which a picture is considered black.  Default value is 0.98.

       pixel_black_th, pix_th
	   Set the threshold for considering a pixel "black".

	   The threshold expresses the maximum pixel luminance value for which
	   a pixel is considered "black". The provided value is	scaled
	   according to	the following equation:

		   <absolute_threshold>	= <luminance_minimum_value> + <pixel_black_th> * <luminance_range_size>

	   luminance_range_size	and luminance_minimum_value depend on the
	   input video format, the range is [0-255] for	YUV full-range formats
	   and [16-235]	for YUV	non full-range formats.

	   Default value is 0.10.

       The following example sets the maximum pixel threshold to the minimum
       value, and detects only black intervals of 2 or more seconds:

	       blackdetect=d=2:pix_th=0.00

   blackframe
       Detect frames that are (almost) completely black. Can be	useful to
       detect chapter transitions or commercials. Output lines consist of the
       frame number of the detected frame, the percentage of blackness,	the
       position	in the file if known or	-1 and the timestamp in	seconds.

       In order	to display the output lines, you need to set the loglevel at
       least to	the AV_LOG_INFO	value.

       This filter exports frame metadata "lavfi.blackframe.pblack".  The
       value represents	the percentage of pixels in the	picture	that are below
       the threshold value.

       It accepts the following	parameters:

       amount
	   The percentage of the pixels	that have to be	below the threshold;
	   it defaults to 98.

       threshold, thresh
	   The threshold below which a pixel value is considered black;	it
	   defaults to 32.

   blend, tblend
       Blend two video frames into each	other.

       The "blend" filter takes	two input streams and outputs one stream, the
       first input is the "top"	layer and second input is "bottom" layer.  By
       default,	the output terminates when the longest input terminates.

       The "tblend" (time blend) filter	takes two consecutive frames from one
       single stream, and outputs the result obtained by blending the new
       frame on	top of the old frame.

       A description of	the accepted options follows.

       c0_mode
       c1_mode
       c2_mode
       c3_mode
       all_mode
	   Set blend mode for specific pixel component or all pixel components
	   in case of all_mode.	Default	value is "normal".

	   Available values for	component modes	are:

	   addition
	   addition128
	   and
	   average
	   burn
	   darken
	   difference
	   difference128
	   divide
	   dodge
	   freeze
	   exclusion
	   glow
	   hardlight
	   hardmix
	   heat
	   lighten
	   linearlight
	   multiply
	   multiply128
	   negation
	   normal
	   or
	   overlay
	   phoenix
	   pinlight
	   reflect
	   screen
	   softlight
	   subtract
	   vividlight
	   xor
       c0_opacity
       c1_opacity
       c2_opacity
       c3_opacity
       all_opacity
	   Set blend opacity for specific pixel	component or all pixel
	   components in case of all_opacity. Only used	in combination with
	   pixel component blend modes.

       c0_expr
       c1_expr
       c2_expr
       c3_expr
       all_expr
	   Set blend expression	for specific pixel component or	all pixel
	   components in case of all_expr. Note	that related mode options will
	   be ignored if those are set.

	   The expressions can use the following variables:

	   N   The sequential number of	the filtered frame, starting from 0.

	   X
	   Y   the coordinates of the current sample

	   W
	   H   the width and height of currently filtered plane

	   SW
	   SH  Width and height	scale depending	on the currently filtered
	       plane. It is the	ratio between the corresponding	luma plane
	       number of pixels	and the	current	plane ones. E.g. for YUV4:2:0
	       the values are "1,1" for	the luma plane,	and "0.5,0.5" for
	       chroma planes.

	   T   Time of the current frame, expressed in seconds.

	   TOP,	A
	       Value of	pixel component	at current location for	first video
	       frame (top layer).

	   BOTTOM, B
	       Value of	pixel component	at current location for	second video
	       frame (bottom layer).

       shortest
	   Force termination when the shortest input terminates. Default is 0.
	   This	option is only defined for the "blend" filter.

       repeatlast
	   Continue applying the last bottom frame after the end of the
	   stream. A value of 0	disable	the filter after the last frame	of the
	   bottom layer	is reached.  Default is	1. This	option is only defined
	   for the "blend" filter.

       Examples

       o   Apply transition from bottom	layer to top layer in first 10
	   seconds:

		   blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))'

       o   Apply 1x1 checkerboard effect:

		   blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)'

       o   Apply uncover left effect:

		   blend=all_expr='if(gte(N*SW+X,W),A,B)'

       o   Apply uncover down effect:

		   blend=all_expr='if(gte(Y-N*SH,0),A,B)'

       o   Apply uncover up-left effect:

		   blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)'

       o   Split diagonally video and shows top	and bottom layer on each side:

		   blend=all_expr=if(gt(X,Y*(W/H)),A,B)

       o   Display differences between the current and the previous frame:

		   tblend=all_mode=difference128

   boxblur
       Apply a boxblur algorithm to the	input video.

       It accepts the following	parameters:

       luma_radius, lr
       luma_power, lp
       chroma_radius, cr
       chroma_power, cp
       alpha_radius, ar
       alpha_power, ap

       A description of	the accepted options follows.

       luma_radius, lr
       chroma_radius, cr
       alpha_radius, ar
	   Set an expression for the box radius	in pixels used for blurring
	   the corresponding input plane.

	   The radius value must be a non-negative number, and must not	be
	   greater than	the value of the expression "min(w,h)/2" for the luma
	   and alpha planes, and of "min(cw,ch)/2" for the chroma planes.

	   Default value for luma_radius is "2". If not	specified,
	   chroma_radius and alpha_radius default to the corresponding value
	   set for luma_radius.

	   The expressions can contain the following constants:

	   w
	   h   The input width and height in pixels.

	   cw
	   ch  The input chroma	image width and	height in pixels.

	   hsub
	   vsub
	       The horizontal and vertical chroma subsample values. For
	       example,	for the	pixel format "yuv422p",	hsub is	2 and vsub is
	       1.

       luma_power, lp
       chroma_power, cp
       alpha_power, ap
	   Specify how many times the boxblur filter is	applied	to the
	   corresponding plane.

	   Default value for luma_power	is 2. If not specified,	chroma_power
	   and alpha_power default to the corresponding	value set for
	   luma_power.

	   A value of 0	will disable the effect.

       Examples

       o   Apply a boxblur filter with the luma, chroma, and alpha radii set
	   to 2:

		   boxblur=luma_radius=2:luma_power=1
		   boxblur=2:1

       o   Set the luma	radius to 2, and alpha and chroma radius to 0:

		   boxblur=2:1:cr=0:ar=0

       o   Set the luma	and chroma radii to a fraction of the video dimension:

		   boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1

   bwdif
       Deinterlace the input video ("bwdif" stands for "Bob Weaver
       Deinterlacing Filter").

       Motion adaptive deinterlacing based on yadif with the use of w3fdif and
       cubic interpolation algorithms.	It accepts the following parameters:

       mode
	   The interlacing mode	to adopt. It accepts one of the	following
	   values:

	   0, send_frame
	       Output one frame	for each frame.

	   1, send_field
	       Output one frame	for each field.

	   The default value is	"send_field".

       parity
	   The picture field parity assumed for	the input interlaced video. It
	   accepts one of the following	values:

	   0, tff
	       Assume the top field is first.

	   1, bff
	       Assume the bottom field is first.

	   -1, auto
	       Enable automatic	detection of field parity.

	   The default value is	"auto".	 If the	interlacing is unknown or the
	   decoder does	not export this	information, top field first will be
	   assumed.

       deint
	   Specify which frames	to deinterlace.	Accept one of the following
	   values:

	   0, all
	       Deinterlace all frames.

	   1, interlaced
	       Only deinterlace	frames marked as interlaced.

	   The default value is	"all".

   chromakey
       YUV colorspace color/chroma keying.

       The filter accepts the following	options:

       color
	   The color which will	be replaced with transparency.

       similarity
	   Similarity percentage with the key color.

	   0.01	matches	only the exact key color, while	1.0 matches
	   everything.

       blend
	   Blend percentage.

	   0.0 makes pixels either fully transparent, or not transparent at
	   all.

	   Higher values result	in semi-transparent pixels, with a higher
	   transparency	the more similar the pixels color is to	the key	color.

       yuv Signals that	the color passed is already in YUV instead of RGB.

	   Litteral colors like	"green"	or "red" don't make sense with this
	   enabled anymore.  This can be used to pass exact YUV	values as
	   hexadecimal numbers.

       Examples

       o   Make	every green pixel in the input image transparent:

		   ffmpeg -i input.png -vf chromakey=green out.png

       o   Overlay a greenscreen-video on top of a static black	background.

		   ffmpeg -f lavfi -i color=c=black:s=1280x720 -i video.mp4 -shortest -filter_complex "[1:v]chromakey=0x70de77:0.1:0.2[ckout];[0:v][ckout]overlay[out]"	-map "[out]" output.mkv

   ciescope
       Display CIE color diagram with pixels overlaid onto it.

       The filter accepts the following	options:

       system
	   Set color system.

	   ntsc, 470m
	   ebu,	470bg
	   smpte
	   240m
	   apple
	   widergb
	   cie1931
	   rec709, hdtv
	   uhdtv, rec2020
       cie Set CIE system.

	   xyy
	   ucs
	   luv
       gamuts
	   Set what gamuts to draw.

	   See "system"	option for available values.

       size, s
	   Set ciescope	size, by default set to	512.

       intensity, i
	   Set intensity used to map input pixel values	to CIE diagram.

       contrast
	   Set contrast	used to	draw tongue colors that	are out	of active
	   color system	gamut.

       corrgamma
	   Correct gamma displayed on scope, by	default	enabled.

       showwhite
	   Show	white point on CIE diagram, by default disabled.

       gamma
	   Set input gamma. Used only with XYZ input color space.

   codecview
       Visualize information exported by some codecs.

       Some codecs can export information through frames using side-data or
       other means. For	example, some MPEG based codecs	export motion vectors
       through the export_mvs flag in the codec	flags2 option.

       The filter accepts the following	option:

       mv  Set motion vectors to visualize.

	   Available flags for mv are:

	   pf  forward predicted MVs of	P-frames

	   bf  forward predicted MVs of	B-frames

	   bb  backward	predicted MVs of B-frames

       qp  Display quantization	parameters using the chroma planes.

       mv_type,	mvt
	   Set motion vectors type to visualize. Includes MVs from all frames
	   unless specified by frame_type option.

	   Available flags for mv_type are:

	   fp  forward predicted MVs

	   bp  backward	predicted MVs

       frame_type, ft
	   Set frame type to visualize motion vectors of.

	   Available flags for frame_type are:

	   if  intra-coded frames (I-frames)

	   pf  predicted frames	(P-frames)

	   bf  bi-directionally	predicted frames (B-frames)

       Examples

       o   Visualize forward predicted MVs of all frames using ffplay:

		   ffplay -flags2 +export_mvs input.mp4	-vf codecview=mv_type=fp

       o   Visualize multi-directionals	MVs of P and B-Frames using ffplay:

		   ffplay -flags2 +export_mvs input.mp4	-vf codecview=mv=pf+bf+bb

   colorbalance
       Modify intensity	of primary colors (red,	green and blue)	of input
       frames.

       The filter allows an input frame	to be adjusted in the shadows,
       midtones	or highlights regions for the red-cyan,	green-magenta or blue-
       yellow balance.

       A positive adjustment value shifts the balance towards the primary
       color, a	negative value towards the complementary color.

       The filter accepts the following	options:

       rs
       gs
       bs  Adjust red, green and blue shadows (darkest pixels).

       rm
       gm
       bm  Adjust red, green and blue midtones (medium pixels).

       rh
       gh
       bh  Adjust red, green and blue highlights (brightest pixels).

	   Allowed ranges for options are "[-1.0, 1.0]". Defaults are 0.

       Examples

       o   Add red color cast to shadows:

		   colorbalance=rs=.3

   colorkey
       RGB colorspace color keying.

       The filter accepts the following	options:

       color
	   The color which will	be replaced with transparency.

       similarity
	   Similarity percentage with the key color.

	   0.01	matches	only the exact key color, while	1.0 matches
	   everything.

       blend
	   Blend percentage.

	   0.0 makes pixels either fully transparent, or not transparent at
	   all.

	   Higher values result	in semi-transparent pixels, with a higher
	   transparency	the more similar the pixels color is to	the key	color.

       Examples

       o   Make	every green pixel in the input image transparent:

		   ffmpeg -i input.png -vf colorkey=green out.png

       o   Overlay a greenscreen-video on top of a static background image.

		   ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.3:0.2[ckout];[0:v][ckout]overlay[out]" -map "[out]" output.flv

   colorlevels
       Adjust video input frames using levels.

       The filter accepts the following	options:

       rimin
       gimin
       bimin
       aimin
	   Adjust red, green, blue and alpha input black point.	 Allowed
	   ranges for options are "[-1.0, 1.0]". Defaults are 0.

       rimax
       gimax
       bimax
       aimax
	   Adjust red, green, blue and alpha input white point.	 Allowed
	   ranges for options are "[-1.0, 1.0]". Defaults are 1.

	   Input levels	are used to lighten highlights (bright tones), darken
	   shadows (dark tones), change	the balance of bright and dark tones.

       romin
       gomin
       bomin
       aomin
	   Adjust red, green, blue and alpha output black point.  Allowed
	   ranges for options are "[0, 1.0]". Defaults are 0.

       romax
       gomax
       bomax
       aomax
	   Adjust red, green, blue and alpha output white point.  Allowed
	   ranges for options are "[0, 1.0]". Defaults are 1.

	   Output levels allows	manual selection of a constrained output level
	   range.

       Examples

       o   Make	video output darker:

		   colorlevels=rimin=0.058:gimin=0.058:bimin=0.058

       o   Increase contrast:

		   colorlevels=rimin=0.039:gimin=0.039:bimin=0.039:rimax=0.96:gimax=0.96:bimax=0.96

       o   Make	video output lighter:

		   colorlevels=rimax=0.902:gimax=0.902:bimax=0.902

       o   Increase brightness:

		   colorlevels=romin=0.5:gomin=0.5:bomin=0.5

   colorchannelmixer
       Adjust video input frames by re-mixing color channels.

       This filter modifies a color channel by adding the values associated to
       the other channels of the same pixels. For example if the value to
       modify is red, the output value will be:

	       <red>=<red>*<rr>	+ <blue>*<rb> +	<green>*<rg> + <alpha>*<ra>

       The filter accepts the following	options:

       rr
       rg
       rb
       ra  Adjust contribution of input	red, green, blue and alpha channels
	   for output red channel.  Default is 1 for rr, and 0 for rg, rb and
	   ra.

       gr
       gg
       gb
       ga  Adjust contribution of input	red, green, blue and alpha channels
	   for output green channel.  Default is 1 for gg, and 0 for gr, gb
	   and ga.

       br
       bg
       bb
       ba  Adjust contribution of input	red, green, blue and alpha channels
	   for output blue channel.  Default is	1 for bb, and 0	for br,	bg and
	   ba.

       ar
       ag
       ab
       aa  Adjust contribution of input	red, green, blue and alpha channels
	   for output alpha channel.  Default is 1 for aa, and 0 for ar, ag
	   and ab.

	   Allowed ranges for options are "[-2.0, 2.0]".

       Examples

       o   Convert source to grayscale:

		   colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3

       o   Simulate sepia tones:

		   colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131

   colormatrix
       Convert color matrix.

       The filter accepts the following	options:

       src
       dst Specify the source and destination color matrix. Both values	must
	   be specified.

	   The accepted	values are:

	   bt709
	       BT.709

	   fcc FCC

	   bt601
	       BT.601

	   bt470
	       BT.470

	   bt470bg
	       BT.470BG

	   smpte170m
	       SMPTE-170M

	   smpte240m
	       SMPTE-240M

	   bt2020
	       BT.2020

       For example to convert from BT.601 to SMPTE-240M, use the command:

	       colormatrix=bt601:smpte240m

   colorspace
       Convert colorspace, transfer characteristics or color primaries.	 Input
       video needs to have an even size.

       The filter accepts the following	options:

       all Specify all color properties	at once.

	   The accepted	values are:

	   bt470m
	       BT.470M

	   bt470bg
	       BT.470BG

	   bt601-6-525
	       BT.601-6	525

	   bt601-6-625
	       BT.601-6	625

	   bt709
	       BT.709

	   smpte170m
	       SMPTE-170M

	   smpte240m
	       SMPTE-240M

	   bt2020
	       BT.2020

       space
	   Specify output colorspace.

	   The accepted	values are:

	   bt709
	       BT.709

	   fcc FCC

	   bt470bg
	       BT.470BG	or BT.601-6 625

	   smpte170m
	       SMPTE-170M or BT.601-6 525

	   smpte240m
	       SMPTE-240M

	   ycgco
	       YCgCo

	   bt2020ncl
	       BT.2020 with non-constant luminance

       trc Specify output transfer characteristics.

	   The accepted	values are:

	   bt709
	       BT.709

	   bt470m
	       BT.470M

	   bt470bg
	       BT.470BG

	   gamma22
	       Constant	gamma of 2.2

	   gamma28
	       Constant	gamma of 2.8

	   smpte170m
	       SMPTE-170M, BT.601-6 625	or BT.601-6 525

	   smpte240m
	       SMPTE-240M

	   srgb
	       SRGB

	   iec61966-2-1
	       iec61966-2-1

	   iec61966-2-4
	       iec61966-2-4

	   xvycc
	       xvycc

	   bt2020-10
	       BT.2020 for 10-bits content

	   bt2020-12
	       BT.2020 for 12-bits content

       primaries
	   Specify output color	primaries.

	   The accepted	values are:

	   bt709
	       BT.709

	   bt470m
	       BT.470M

	   bt470bg
	       BT.470BG	or BT.601-6 625

	   smpte170m
	       SMPTE-170M or BT.601-6 525

	   smpte240m
	       SMPTE-240M

	   film
	       film

	   smpte431
	       SMPTE-431

	   smpte432
	       SMPTE-432

	   bt2020
	       BT.2020

       range
	   Specify output color	range.

	   The accepted	values are:

	   tv  TV (restricted) range

	   mpeg
	       MPEG (restricted) range

	   pc  PC (full) range

	   jpeg
	       JPEG (full) range

       format
	   Specify output color	format.

	   The accepted	values are:

	   yuv420p
	       YUV 4:2:0 planar	8-bits

	   yuv420p10
	       YUV 4:2:0 planar	10-bits

	   yuv420p12
	       YUV 4:2:0 planar	12-bits

	   yuv422p
	       YUV 4:2:2 planar	8-bits

	   yuv422p10
	       YUV 4:2:2 planar	10-bits

	   yuv422p12
	       YUV 4:2:2 planar	12-bits

	   yuv444p
	       YUV 4:4:4 planar	8-bits

	   yuv444p10
	       YUV 4:4:4 planar	10-bits

	   yuv444p12
	       YUV 4:4:4 planar	12-bits

       fast
	   Do a	fast conversion, which skips gamma/primary correction. This
	   will	take significantly less	CPU, but will be mathematically
	   incorrect. To get output compatible with that produced by the
	   colormatrix filter, use fast=1.

       dither
	   Specify dithering mode.

	   The accepted	values are:

	   none
	       No dithering

	   fsb Floyd-Steinberg dithering

       wpadapt
	   Whitepoint adaptation mode.

	   The accepted	values are:

	   bradford
	       Bradford	whitepoint adaptation

	   vonkries
	       von Kries whitepoint adaptation

	   identity
	       identity	whitepoint adaptation (i.e. no whitepoint adaptation)

       iall
	   Override all	input properties at once. Same accepted	values as all.

       ispace
	   Override input colorspace. Same accepted values as space.

       iprimaries
	   Override input color	primaries. Same	accepted values	as primaries.

       itrc
	   Override input transfer characteristics. Same accepted values as
	   trc.

       irange
	   Override input color	range. Same accepted values as range.

       The filter converts the transfer	characteristics, color space and color
       primaries to the	specified user values. The output value, if not
       specified, is set to a default value based on the "all" property. If
       that property is	also not specified, the	filter will log	an error. The
       output color range and format default to	the same value as the input
       color range and format. The input transfer characteristics, color
       space, color primaries and color	range should be	set on the input data.
       If any of these are missing, the	filter will log	an error and no
       conversion will take place.

       For example to convert the input	to SMPTE-240M, use the command:

	       colorspace=smpte240m

   convolution
       Apply convolution 3x3 or	5x5 filter.

       The filter accepts the following	options:

       0m
       1m
       2m
       3m  Set matrix for each plane.  Matrix is sequence of 9 or 25 signed
	   integers.

       0rdiv
       1rdiv
       2rdiv
       3rdiv
	   Set multiplier for calculated value for each	plane.

       0bias
       1bias
       2bias
       3bias
	   Set bias for	each plane. This value is added	to the result of the
	   multiplication.  Useful for making the overall image	brighter or
	   darker. Default is 0.0.

       Examples

       o   Apply sharpen:

		   convolution="0 -1 0 -1 5 -1 0 -1 0:0	-1 0 -1	5 -1 0 -1 0:0 -1 0 -1 5	-1 0 -1	0:0 -1 0 -1 5 -1 0 -1 0"

       o   Apply blur:

		   convolution="1 1 1 1	1 1 1 1	1:1 1 1	1 1 1 1	1 1:1 1	1 1 1 1	1 1 1:1	1 1 1 1	1 1 1 1:1/9:1/9:1/9:1/9"

       o   Apply edge enhance:

		   convolution="0 0 0 -1 1 0 0 0 0:0 0 0 -1 1 0	0 0 0:0	0 0 -1 1 0 0 0 0:0 0 0 -1 1 0 0	0 0:5:1:1:1:0:128:128:128"

       o   Apply edge detect:

		   convolution="0 1 0 1	-4 1 0 1 0:0 1 0 1 -4 1	0 1 0:0	1 0 1 -4 1 0 1 0:0 1 0 1 -4 1 0	1 0:5:5:5:1:0:128:128:128"

       o   Apply emboss:

		   convolution="-2 -1 0	-1 1 1 0 1 2:-2	-1 0 -1	1 1 0 1	2:-2 -1	0 -1 1 1 0 1 2:-2 -1 0 -1 1 1 0	1 2"

   copy
       Copy the	input source unchanged to the output. This is mainly useful
       for testing purposes.

   coreimage
       Video filtering on GPU using Apple's CoreImage API on OSX.

       Hardware	acceleration is	based on an OpenGL context. Usually, this
       means it	is processed by	video hardware.	However, software-based	OpenGL
       implementations exist which means there is no guarantee for hardware
       processing. It depends on the respective	OSX.

       There are many filters and image	generators provided by Apple that come
       with a large variety of options.	The filter has to be referenced	by its
       name along with its options.

       The coreimage filter accepts the	following options:

       list_filters
	   List	all available filters and generators along with	all their
	   respective options as well as possible minimum and maximum values
	   along with the default values.

		   list_filters=true

       filter
	   Specify all filters by their	respective name	and options.  Use
	   list_filters	to determine all valid filter names and	options.
	   Numerical options are specified by a	float value and	are
	   automatically clamped to their respective value range.  Vector and
	   color options have to be specified by a list	of space separated
	   float values. Character escaping has	to be done.  A special option
	   name	"default" is available to use default options for a filter.

	   It is required to specify either "default" or at least one of the
	   filter options.  All	omitted	options	are used with their default
	   values.  The	syntax of the filter string is as follows:

		   filter=<NAME>@<OPTION>=<VALUE>[@<OPTION>=<VALUE>][@...][#<NAME>@<OPTION>=<VALUE>[@<OPTION>=<VALUE>][@...]][#...]

       output_rect
	   Specify a rectangle where the output	of the filter chain is copied
	   into	the input image. It is given by	a list of space	separated
	   float values:

		   output_rect=x\ y\ width\ height

	   If not given, the output rectangle equals the dimensions of the
	   input image.	 The output rectangle is automatically cropped at the
	   borders of the input	image. Negative	values are valid for each
	   component.

		   output_rect=25\ 25\ 100\ 100

       Several filters can be chained for successive processing	without	GPU-
       HOST transfers allowing for fast	processing of complex filter chains.
       Currently, only filters with zero (generators) or exactly one (filters)
       input image and one output image	are supported. Also, transition
       filters are not yet usable as intended.

       Some filters generate output images with	additional padding depending
       on the respective filter	kernel.	The padding is automatically removed
       to ensure the filter output has the same	size as	the input image.

       For image generators, the size of the output image is determined	by the
       previous	output image of	the filter chain or the	input image of the
       whole filterchain, respectively.	The generators do not use the pixel
       information of this image to generate their output. However, the
       generated output	is blended onto	this image, resulting in partial or
       complete	coverage of the	output image.

       The coreimagesrc	video source can be used for generating	input images
       which are directly fed into the filter chain. By	using it, providing
       input images by another video source or an input	video is not required.

       Examples

       o   List	all filters available:

		   coreimage=list_filters=true

       o   Use the CIBoxBlur filter with default options to blur an image:

		   coreimage=filter=CIBoxBlur@default

       o   Use a filter	chain with CISepiaTone at default values and
	   CIVignetteEffect with its center at 100x100 and a radius of 50
	   pixels:

		   coreimage=filter=CIBoxBlur@default#CIVignetteEffect@inputCenter=100\	100@inputRadius=50

       o   Use nullsrc and CIQRCodeGenerator to	create a QR code for the
	   FFmpeg homepage, given as complete and escaped command-line for
	   Apple's standard bash shell:

		   ffmpeg -f lavfi -i nullsrc=s=100x100,coreimage=filter=CIQRCodeGenerator@inputMessage=https\\\\\://FFmpeg.org/@inputCorrectionLevel=H	-frames:v 1 QRCode.png

   crop
       Crop the	input video to given dimensions.

       It accepts the following	parameters:

       w, out_w
	   The width of	the output video. It defaults to "iw".	This
	   expression is evaluated only	once during the	filter configuration,
	   or when the w or out_w command is sent.

       h, out_h
	   The height of the output video. It defaults to "ih".	 This
	   expression is evaluated only	once during the	filter configuration,
	   or when the h or out_h command is sent.

       x   The horizontal position, in the input video,	of the left edge of
	   the output video. It	defaults to "(in_w-out_w)/2".  This expression
	   is evaluated	per-frame.

       y   The vertical	position, in the input video, of the top edge of the
	   output video.  It defaults to "(in_h-out_h)/2".  This expression is
	   evaluated per-frame.

       keep_aspect
	   If set to 1 will force the output display aspect ratio to be	the
	   same	of the input, by changing the output sample aspect ratio. It
	   defaults to 0.

       exact
	   Enable exact	cropping. If enabled, subsampled videos	will be
	   cropped at exact width/height/x/y as	specified and will not be
	   rounded to nearest smaller value.  It defaults to 0.

       The out_w, out_h, x, y parameters are expressions containing the
       following constants:

       x
       y   The computed	values for x and y. They are evaluated for each	new
	   frame.

       in_w
       in_h
	   The input width and height.

       iw
       ih  These are the same as in_w and in_h.

       out_w
       out_h
	   The output (cropped)	width and height.

       ow
       oh  These are the same as out_w and out_h.

       a   same	as iw /	ih

       sar input sample	aspect ratio

       dar input display aspect	ratio, it is the same as (iw / ih) * sar

       hsub
       vsub
	   horizontal and vertical chroma subsample values. For	example	for
	   the pixel format "yuv422p" hsub is 2	and vsub is 1.

       n   The number of the input frame, starting from	0.

       pos the position	in the file of the input frame,	NAN if unknown

       t   The timestamp expressed in seconds. It's NAN	if the input timestamp
	   is unknown.

       The expression for out_w	may depend on the value	of out_h, and the
       expression for out_h may	depend on out_w, but they cannot depend	on x
       and y, as x and y are evaluated after out_w and out_h.

       The x and y parameters specify the expressions for the position of the
       top-left	corner of the output (non-cropped) area. They are evaluated
       for each	frame. If the evaluated	value is not valid, it is approximated
       to the nearest valid value.

       The expression for x may	depend on y, and the expression	for y may
       depend on x.

       Examples

       o   Crop	area with size 100x100 at position (12,34).

		   crop=100:100:12:34

	   Using named options,	the example above becomes:

		   crop=w=100:h=100:x=12:y=34

       o   Crop	the central input area with size 100x100:

		   crop=100:100

       o   Crop	the central input area with size 2/3 of	the input video:

		   crop=2/3*in_w:2/3*in_h

       o   Crop	the input video	central	square:

		   crop=out_w=in_h
		   crop=in_h

       o   Delimit the rectangle with the top-left corner placed at position
	   100:100 and the right-bottom	corner corresponding to	the right-
	   bottom corner of the	input image.

		   crop=in_w-100:in_h-100:100:100

       o   Crop	10 pixels from the left	and right borders, and 20 pixels from
	   the top and bottom borders

		   crop=in_w-2*10:in_h-2*20

       o   Keep	only the bottom	right quarter of the input image:

		   crop=in_w/2:in_h/2:in_w/2:in_h/2

       o   Crop	height for getting Greek harmony:

		   crop=in_w:1/PHI*in_w

       o   Apply trembling effect:

		   crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)

       o   Apply erratic camera	effect depending on timestamp:

		   crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"

       o   Set x depending on the value	of y:

		   crop=in_w/2:in_h/2:y:10+10*sin(n/10)

       Commands

       This filter supports the	following commands:

       w, out_w
       h, out_h
       x
       y   Set width/height of the output video	and the	horizontal/vertical
	   position in the input video.	 The command accepts the same syntax
	   of the corresponding	option.

	   If the specified expression is not valid, it	is kept	at its current
	   value.

   cropdetect
       Auto-detect the crop size.

       It calculates the necessary cropping parameters and prints the
       recommended parameters via the logging system. The detected dimensions
       correspond to the non-black area	of the input video.

       It accepts the following	parameters:

       limit
	   Set higher black value threshold, which can be optionally specified
	   from	nothing	(0) to everything (255 for 8-bit based formats). An
	   intensity value greater to the set value is considered non-black.
	   It defaults to 24.  You can also specify a value between 0.0	and
	   1.0 which will be scaled depending on the bitdepth of the pixel
	   format.

       round
	   The value which the width/height should be divisible	by. It
	   defaults to 16. The offset is automatically adjusted	to center the
	   video. Use 2	to get only even dimensions (needed for	4:2:2 video).
	   16 is best when encoding to most video codecs.

       reset_count, reset
	   Set the counter that	determines after how many frames cropdetect
	   will	reset the previously detected largest video area and start
	   over	to detect the current optimal crop area. Default value is 0.

	   This	can be useful when channel logos distort the video area. 0
	   indicates 'never reset', and	returns	the largest area encountered
	   during playback.

   curves
       Apply color adjustments using curves.

       This filter is similar to the Adobe Photoshop and GIMP curves tools.
       Each component (red, green and blue) has	its values defined by N	key
       points tied from	each other using a smooth curve. The x-axis represents
       the pixel values	from the input frame, and the y-axis the new pixel
       values to be set	for the	output frame.

       By default, a component curve is	defined	by the two points (0;0)	and
       (1;1). This creates a straight line where each original pixel value is
       "adjusted" to its own value, which means	no change to the image.

       The filter allows you to	redefine these two points and add some more. A
       new curve (using	a natural cubic	spline interpolation) will be define
       to pass smoothly	through	all these new coordinates. The new defined
       points needs to be strictly increasing over the x-axis, and their x and
       y values	must be	in the [0;1] interval.	If the computed	curves
       happened	to go outside the vector spaces, the values will be clipped
       accordingly.

       The filter accepts the following	options:

       preset
	   Select one of the available color presets. This option can be used
	   in addition to the r, g, b parameters; in this case,	the later
	   options takes priority on the preset	values.	 Available presets
	   are:

	   none
	   color_negative
	   cross_process
	   darker
	   increase_contrast
	   lighter
	   linear_contrast
	   medium_contrast
	   negative
	   strong_contrast
	   vintage

	   Default is "none".

       master, m
	   Set the master key points. These points will	define a second	pass
	   mapping. It is sometimes called a "luminance" or "value" mapping.
	   It can be used with r, g, b or all since it acts like a post-
	   processing LUT.

       red, r
	   Set the key points for the red component.

       green, g
	   Set the key points for the green component.

       blue, b
	   Set the key points for the blue component.

       all Set the key points for all components (not including	master).  Can
	   be used in addition to the other key	points component options. In
	   this	case, the unset	component(s) will fallback on this all
	   setting.

       psfile
	   Specify a Photoshop curves file (".acv") to import the settings
	   from.

       plot
	   Save	Gnuplot	script of the curves in	specified file.

       To avoid	some filtergraph syntax	conflicts, each	key points list	need
       to be defined using the following syntax: "x0/y0	x1/y1 x2/y2 ...".

       Examples

       o   Increase slightly the middle	level of blue:

		   curves=blue='0/0 0.5/0.58 1/1'

       o   Vintage effect:

		   curves=r='0/0.11 .42/.51 1/0.95':g='0/0 0.50/0.48 1/1':b='0/0.22 .49/.44 1/0.8'

	   Here	we obtain the following	coordinates for	each components:

	   red "(0;0.11) (0.42;0.51) (1;0.95)"

	   green
	       "(0;0) (0.50;0.48) (1;1)"

	   blue
	       "(0;0.22) (0.49;0.44) (1;0.80)"

       o   The previous	example	can also be achieved with the associated
	   built-in preset:

		   curves=preset=vintage

       o   Or simply:

		   curves=vintage

       o   Use a Photoshop preset and redefine the points of the green
	   component:

		   curves=psfile='MyCurvesPresets/purple.acv':green='0/0 0.45/0.53 1/1'

       o   Check out the curves	of the "cross_process" profile using ffmpeg
	   and gnuplot:

		   ffmpeg -f lavfi -i color -vf	curves=cross_process:plot=/tmp/curves.plt -frames:v 1 -f null -
		   gnuplot -p /tmp/curves.plt

   datascope
       Video data analysis filter.

       This filter shows hexadecimal pixel values of part of video.

       The filter accepts the following	options:

       size, s
	   Set output video size.

       x   Set x offset	from where to pick pixels.

       y   Set y offset	from where to pick pixels.

       mode
	   Set scope mode, can be one of the following:

	   mono
	       Draw hexadecimal	pixel values with white	color on black
	       background.

	   color
	       Draw hexadecimal	pixel values with input	video pixel color on
	       black background.

	   color2
	       Draw hexadecimal	pixel values on	color background picked	from
	       input video, the	text color is picked in	such way so its	always
	       visible.

       axis
	   Draw	rows and columns numbers on left and top of video.

       opacity
	   Set background opacity.

   dctdnoiz
       Denoise frames using 2D DCT (frequency domain filtering).

       This filter is not designed for real time.

       The filter accepts the following	options:

       sigma, s
	   Set the noise sigma constant.

	   This	sigma defines a	hard threshold of "3 * sigma"; every DCT
	   coefficient (absolute value)	below this threshold with be dropped.

	   If you need a more advanced filtering, see expr.

	   Default is 0.

       overlap
	   Set number overlapping pixels for each block. Since the filter can
	   be slow, you	may want to reduce this	value, at the cost of a	less
	   effective filter and	the risk of various artefacts.

	   If the overlapping value doesn't permit processing the whole	input
	   width or height, a warning will be displayed	and according borders
	   won't be denoised.

	   Default value is blocksize-1, which is the best possible setting.

       expr, e
	   Set the coefficient factor expression.

	   For each coefficient	of a DCT block,	this expression	will be
	   evaluated as	a multiplier value for the coefficient.

	   If this is option is	set, the sigma option will be ignored.

	   The absolute	value of the coefficient can be	accessed through the c
	   variable.

       n   Set the blocksize using the number of bits. "1<<n" defines the
	   blocksize, which is the width and height of the processed blocks.

	   The default value is	3 (8x8)	and can	be raised to 4 for a blocksize
	   of 16x16. Note that changing	this setting has huge consequences on
	   the speed processing. Also, a larger	block size does	not
	   necessarily means a better de-noising.

       Examples

       Apply a denoise with a sigma of 4.5:

	       dctdnoiz=4.5

       The same	operation can be achieved using	the expression system:

	       dctdnoiz=e='gte(c, 4.5*3)'

       Violent denoise using a block size of "16x16":

	       dctdnoiz=15:n=4

   deband
       Remove banding artifacts	from input video.  It works by replacing
       banded pixels with average value	of referenced pixels.

       The filter accepts the following	options:

       1thr
       2thr
       3thr
       4thr
	   Set banding detection threshold for each plane. Default is 0.02.
	   Valid range is 0.00003 to 0.5.  If difference between current pixel
	   and reference pixel is less than threshold, it will be considered
	   as banded.

       range, r
	   Banding detection range in pixels. Default is 16. If	positive,
	   random number in range 0 to set value will be used. If negative,
	   exact absolute value	will be	used.  The range defines square	of
	   four	pixels around current pixel.

       direction, d
	   Set direction in radians from which four pixel will be compared. If
	   positive, random direction from 0 to	set direction will be picked.
	   If negative,	exact of absolute value	will be	picked.	For example
	   direction 0,	-PI or -2*PI radians will pick only pixels on same row
	   and -PI/2 will pick only pixels on same column.

       blur, b
	   If enabled, current pixel is	compared with average value of all
	   four	surrounding pixels. The	default	is enabled. If disabled
	   current pixel is compared with all four surrounding pixels. The
	   pixel is considered banded if only all four differences with
	   surrounding pixels are less than threshold.

       coupling, c
	   If enabled, current pixel is	changed	if and only if all pixel
	   components are banded, e.g. banding detection threshold is
	   triggered for all color components.	The default is disabled.

   decimate
       Drop duplicated frames at regular intervals.

       The filter accepts the following	options:

       cycle
	   Set the number of frames from which one will	be dropped. Setting
	   this	to N means one frame in	every batch of N frames	will be
	   dropped.  Default is	5.

       dupthresh
	   Set the threshold for duplicate detection. If the difference	metric
	   for a frame is less than or equal to	this value, then it is
	   declared as duplicate. Default is 1.1

       scthresh
	   Set scene change threshold. Default is 15.

       blockx
       blocky
	   Set the size	of the x and y-axis blocks used	during metric
	   calculations.  Larger blocks	give better noise suppression, but
	   also	give worse detection of	small movements. Must be a power of
	   two.	Default	is 32.

       ppsrc
	   Mark	main input as a	pre-processed input and	activate clean source
	   input stream. This allows the input to be pre-processed with
	   various filters to help the metrics calculation while keeping the
	   frame selection lossless. When set to 1, the	first stream is	for
	   the pre-processed input, and	the second stream is the clean source
	   from	where the kept frames are chosen. Default is 0.

       chroma
	   Set whether or not chroma is	considered in the metric calculations.
	   Default is 1.

   deflate
       Apply deflate effect to the video.

       This filter replaces the	pixel by the local(3x3)	average	by taking into
       account only values lower than the pixel.

       It accepts the following	options:

       threshold0
       threshold1
       threshold2
       threshold3
	   Limit the maximum change for	each plane, default is 65535.  If 0,
	   plane will remain unchanged.

   dejudder
       Remove judder produced by partially interlaced telecined	content.

       Judder can be introduced, for instance, by pullup filter. If the
       original	source was partially telecined content then the	output of
       "pullup,dejudder" will have a variable frame rate. May change the
       recorded	frame rate of the container. Aside from	that change, this
       filter will not affect constant frame rate video.

       The option available in this filter is:

       cycle
	   Specify the length of the window over which the judder repeats.

	   Accepts any integer greater than 1. Useful values are:

	   4   If the original was telecined from 24 to	30 fps (Film to	NTSC).

	   5   If the original was telecined from 25 to	30 fps (PAL to NTSC).

	   20  If a mixture of the two.

	   The default is 4.

   delogo
       Suppress	a TV station logo by a simple interpolation of the surrounding
       pixels. Just set	a rectangle covering the logo and watch	it disappear
       (and sometimes something	even uglier appear - your mileage may vary).

       It accepts the following	parameters:

       x
       y   Specify the top left	corner coordinates of the logo.	They must be
	   specified.

       w
       h   Specify the width and height	of the logo to clear. They must	be
	   specified.

       band, t
	   Specify the thickness of the	fuzzy edge of the rectangle (added to
	   w and h). The default value is 1. This option is deprecated,
	   setting higher values should	no longer be necessary and is not
	   recommended.

       show
	   When	set to 1, a green rectangle is drawn on	the screen to simplify
	   finding the right x,	y, w, and h parameters.	 The default value is
	   0.

	   The rectangle is drawn on the outermost pixels which	will be
	   (partly) replaced with interpolated values. The values of the next
	   pixels immediately outside this rectangle in	each direction will be
	   used	to compute the interpolated pixel values inside	the rectangle.

       Examples

       o   Set a rectangle covering the	area with top left corner coordinates
	   0,0 and size	100x77,	and a band of size 10:

		   delogo=x=0:y=0:w=100:h=77:band=10

   deshake
       Attempt to fix small changes in horizontal and/or vertical shift. This
       filter helps remove camera shake	from hand-holding a camera, bumping a
       tripod, moving on a vehicle, etc.

       The filter accepts the following	options:

       x
       y
       w
       h   Specify a rectangular area where to limit the search	for motion
	   vectors.  If	desired	the search for motion vectors can be limited
	   to a	rectangular area of the	frame defined by its top left corner,
	   width and height. These parameters have the same meaning as the
	   drawbox filter which	can be used to visualise the position of the
	   bounding box.

	   This	is useful when simultaneous movement of	subjects within	the
	   frame might be confused for camera motion by	the motion vector
	   search.

	   If any or all of x, y, w and	h are set to -1	then the full frame is
	   used. This allows later options to be set without specifying	the
	   bounding box	for the	motion vector search.

	   Default - search the	whole frame.

       rx
       ry  Specify the maximum extent of movement in x and y directions	in the
	   range 0-64 pixels. Default 16.

       edge
	   Specify how to generate pixels to fill blanks at the	edge of	the
	   frame. Available values are:

	   blank, 0
	       Fill zeroes at blank locations

	   original, 1
	       Original	image at blank locations

	   clamp, 2
	       Extruded	edge value at blank locations

	   mirror, 3
	       Mirrored	edge at	blank locations

	   Default value is mirror.

       blocksize
	   Specify the blocksize to use	for motion search. Range 4-128 pixels,
	   default 8.

       contrast
	   Specify the contrast	threshold for blocks. Only blocks with more
	   than	the specified contrast (difference between darkest and
	   lightest pixels) will be considered.	Range 1-255, default 125.

       search
	   Specify the search strategy.	Available values are:

	   exhaustive, 0
	       Set exhaustive search

	   less, 1
	       Set less	exhaustive search.

	   Default value is exhaustive.

       filename
	   If set then a detailed log of the motion search is written to the
	   specified file.

       opencl
	   If set to 1,	specify	using OpenCL capabilities, only	available if
	   FFmpeg was configured with "--enable-opencl". Default value is 0.

   detelecine
       Apply an	exact inverse of the telecine operation. It requires a
       predefined pattern specified using the pattern option which must	be the
       same as that passed to the telecine filter.

       This filter accepts the following options:

       first_field
	   top,	t
	       top field first

	   bottom, b
	       bottom field first The default value is "top".

       pattern
	   A string of numbers representing the	pulldown pattern you wish to
	   apply.  The default value is	23.

       start_frame
	   A number representing position of the first frame with respect to
	   the telecine	pattern. This is to be used if the stream is cut. The
	   default value is 0.

   dilation
       Apply dilation effect to	the video.

       This filter replaces the	pixel by the local(3x3)	maximum.

       It accepts the following	options:

       threshold0
       threshold1
       threshold2
       threshold3
	   Limit the maximum change for	each plane, default is 65535.  If 0,
	   plane will remain unchanged.

       coordinates
	   Flag	which specifies	the pixel to refer to. Default is 255 i.e. all
	   eight pixels	are used.

	   Flags to local 3x3 coordinates maps like this:

	       1 2 3
	       4   5
	       6 7 8

   displace
       Displace	pixels as indicated by second and third	input stream.

       It takes	three input streams and	outputs	one stream, the	first input is
       the source, and second and third	input are displacement maps.

       The second input	specifies how much to displace pixels along the
       x-axis, while the third input specifies how much	to displace pixels
       along the y-axis.  If one of displacement map streams terminates, last
       frame from that displacement map	will be	used.

       Note that once generated, displacements maps can	be reused over and
       over again.

       A description of	the accepted options follows.

       edge
	   Set displace	behavior for pixels that are out of range.

	   Available values are:

	   blank
	       Missing pixels are replaced by black pixels.

	   smear
	       Adjacent	pixels will spread out to replace missing pixels.

	   wrap
	       Out of range pixels are wrapped so they point to	pixels of
	       other side.

	   Default is smear.

       Examples

       o   Add ripple effect to	rgb input of video size	hd720:

		   ffmpeg -i INPUT -f lavfi -i nullsrc=s=hd720,lutrgb=128:128:128 -f lavfi -i nullsrc=s=hd720,geq='r=128+30*sin(2*PI*X/400+T):g=128+30*sin(2*PI*X/400+T):b=128+30*sin(2*PI*X/400+T)' -lavfi '[0][1][2]displace'	OUTPUT

       o   Add wave effect to rgb input	of video size hd720:

		   ffmpeg -i INPUT -f lavfi -i nullsrc=hd720,geq='r=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):g=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T)):b=128+80*(sin(sqrt((X-W/2)*(X-W/2)+(Y-H/2)*(Y-H/2))/220*2*PI+T))' -lavfi '[1]split[x][y],[0][x][y]displace'	OUTPUT

   drawbox
       Draw a colored box on the input image.

       It accepts the following	parameters:

       x
       y   The expressions which specify the top left corner coordinates of
	   the box. It defaults	to 0.

       width, w
       height, h
	   The expressions which specify the width and height of the box; if 0
	   they	are interpreted	as the input width and height. It defaults to
	   0.

       color, c
	   Specify the color of	the box	to write. For the general syntax of
	   this	option,	check the "Color" section in the ffmpeg-utils manual.
	   If the special value	"invert" is used, the box edge color is	the
	   same	as the video with inverted luma.

       thickness, t
	   The expression which	sets the thickness of the box edge. Default
	   value is 3.

	   See below for the list of accepted constants.

       The parameters for x, y,	w and h	and t are expressions containing the
       following constants:

       dar The input display aspect ratio, it is the same as (w	/ h) * sar.

       hsub
       vsub
	   horizontal and vertical chroma subsample values. For	example	for
	   the pixel format "yuv422p" hsub is 2	and vsub is 1.

       in_h, ih
       in_w, iw
	   The input width and height.

       sar The input sample aspect ratio.

       x
       y   The x and y offset coordinates where	the box	is drawn.

       w
       h   The width and height	of the drawn box.

       t   The thickness of the	drawn box.

	   These constants allow the x,	y, w, h	and t expressions to refer to
	   each	other, so you may for example specify "y=x/dar"	or "h=w/dar".

       Examples

       o   Draw	a black	box around the edge of the input image:

		   drawbox

       o   Draw	a box with color red and an opacity of 50%:

		   drawbox=10:20:200:60:red@0.5

	   The previous	example	can be specified as:

		   drawbox=x=10:y=20:w=200:h=60:color=red@0.5

       o   Fill	the box	with pink color:

		   drawbox=x=10:y=10:w=100:h=100:color=pink@0.5:t=max

       o   Draw	a 2-pixel red 2.40:1 mask:

		   drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red

   drawgrid
       Draw a grid on the input	image.

       It accepts the following	parameters:

       x
       y   The expressions which specify the coordinates of some point of grid
	   intersection	(meant to configure offset). Both default to 0.

       width, w
       height, h
	   The expressions which specify the width and height of the grid
	   cell, if 0 they are interpreted as the input	width and height,
	   respectively, minus "thickness", so image gets framed. Default to
	   0.

       color, c
	   Specify the color of	the grid. For the general syntax of this
	   option, check the "Color" section in	the ffmpeg-utils manual. If
	   the special value "invert" is used, the grid	color is the same as
	   the video with inverted luma.

       thickness, t
	   The expression which	sets the thickness of the grid line. Default
	   value is 1.

	   See below for the list of accepted constants.

       The parameters for x, y,	w and h	and t are expressions containing the
       following constants:

       dar The input display aspect ratio, it is the same as (w	/ h) * sar.

       hsub
       vsub
	   horizontal and vertical chroma subsample values. For	example	for
	   the pixel format "yuv422p" hsub is 2	and vsub is 1.

       in_h, ih
       in_w, iw
	   The input grid cell width and height.

       sar The input sample aspect ratio.

       x
       y   The x and y coordinates of some point of grid intersection (meant
	   to configure	offset).

       w
       h   The width and height	of the drawn cell.

       t   The thickness of the	drawn cell.

	   These constants allow the x,	y, w, h	and t expressions to refer to
	   each	other, so you may for example specify "y=x/dar"	or "h=w/dar".

       Examples

       o   Draw	a grid with cell 100x100 pixels, thickness 2 pixels, with
	   color red and an opacity of 50%:

		   drawgrid=width=100:height=100:thickness=2:color=red@0.5

       o   Draw	a white	3x3 grid with an opacity of 50%:

		   drawgrid=w=iw/3:h=ih/3:t=2:c=white@0.5

   drawtext
       Draw a text string or text from a specified file	on top of a video,
       using the libfreetype library.

       To enable compilation of	this filter, you need to configure FFmpeg with
       "--enable-libfreetype".	To enable default font fallback	and the	font
       option you need to configure FFmpeg with	"--enable-libfontconfig".  To
       enable the text_shaping option, you need	to configure FFmpeg with
       "--enable-libfribidi".

       Syntax

       It accepts the following	parameters:

       box Used	to draw	a box around text using	the background color.  The
	   value must be either	1 (enable) or 0	(disable).  The	default	value
	   of box is 0.

       boxborderw
	   Set the width of the	border to be drawn around the box using
	   boxcolor.  The default value	of boxborderw is 0.

       boxcolor
	   The color to	be used	for drawing box	around text. For the syntax of
	   this	option,	check the "Color" section in the ffmpeg-utils manual.

	   The default value of	boxcolor is "white".

       line_spacing
	   Set the line	spacing	in pixels of the border	to be drawn around the
	   box using box.  The default value of	line_spacing is	0.

       borderw
	   Set the width of the	border to be drawn around the text using
	   bordercolor.	 The default value of borderw is 0.

       bordercolor
	   Set the color to be used for	drawing	border around text. For	the
	   syntax of this option, check	the "Color" section in the ffmpeg-
	   utils manual.

	   The default value of	bordercolor is "black".

       expansion
	   Select how the text is expanded. Can	be either "none", "strftime"
	   (deprecated)	or "normal" (default). See the drawtext_expansion,
	   Text	expansion section below	for details.

       basetime
	   Set a start time for	the count. Value is in microseconds. Only
	   applied in the deprecated strftime expansion	mode. To emulate in
	   normal expansion mode use the "pts" function, supplying the start
	   time	(in seconds) as	the second argument.

       fix_bounds
	   If true, check and fix text coords to avoid clipping.

       fontcolor
	   The color to	be used	for drawing fonts. For the syntax of this
	   option, check the "Color" section in	the ffmpeg-utils manual.

	   The default value of	fontcolor is "black".

       fontcolor_expr
	   String which	is expanded the	same way as text to obtain dynamic
	   fontcolor value. By default this option has empty value and is not
	   processed. When this	option is set, it overrides fontcolor option.

       font
	   The font family to be used for drawing text.	By default Sans.

       fontfile
	   The font file to be used for	drawing	text. The path must be
	   included.  This parameter is	mandatory if the fontconfig support is
	   disabled.

       alpha
	   Draw	the text applying alpha	blending. The value can	be a number
	   between 0.0 and 1.0.	 The expression	accepts	the same variables x,
	   y as	well.  The default value is 1.	Please see fontcolor_expr.

       fontsize
	   The font size to be used for	drawing	text.  The default value of
	   fontsize is 16.

       text_shaping
	   If set to 1,	attempt	to shape the text (for example,	reverse	the
	   order of right-to-left text and join	Arabic characters) before
	   drawing it.	Otherwise, just	draw the text exactly as given.	 By
	   default 1 (if supported).

       ft_load_flags
	   The flags to	be used	for loading the	fonts.

	   The flags map the corresponding flags supported by libfreetype, and
	   are a combination of	the following values:

	   default
	   no_scale
	   no_hinting
	   render
	   no_bitmap
	   vertical_layout
	   force_autohint
	   crop_bitmap
	   pedantic
	   ignore_global_advance_width
	   no_recurse
	   ignore_transform
	   monochrome
	   linear_design
	   no_autohint

	   Default value is "default".

	   For more information	consult	the documentation for the FT_LOAD_*
	   libfreetype flags.

       shadowcolor
	   The color to	be used	for drawing a shadow behind the	drawn text.
	   For the syntax of this option, check	the "Color" section in the
	   ffmpeg-utils	manual.

	   The default value of	shadowcolor is "black".

       shadowx
       shadowy
	   The x and y offsets for the text shadow position with respect to
	   the position	of the text. They can be either	positive or negative
	   values. The default value for both is "0".

       start_number
	   The starting	frame number for the n/frame_num variable. The default
	   value is "0".

       tabsize
	   The size in number of spaces	to use for rendering the tab.  Default
	   value is 4.

       timecode
	   Set the initial timecode representation in "hh:mm:ss[:;.]ff"
	   format. It can be used with or without text parameter.
	   timecode_rate option	must be	specified.

       timecode_rate, rate, r
	   Set the timecode frame rate (timecode only).

       tc24hmax
	   If set to 1,	the output of the timecode option will wrap around at
	   24 hours.  Default is 0 (disabled).

       text
	   The text string to be drawn.	The text must be a sequence of UTF-8
	   encoded characters.	This parameter is mandatory if no file is
	   specified with the parameter	textfile.

       textfile
	   A text file containing text to be drawn. The	text must be a
	   sequence of UTF-8 encoded characters.

	   This	parameter is mandatory if no text string is specified with the
	   parameter text.

	   If both text	and textfile are specified, an error is	thrown.

       reload
	   If set to 1,	the textfile will be reloaded before each frame.  Be
	   sure	to update it atomically, or it may be read partially, or even
	   fail.

       x
       y   The expressions which specify the offsets where text	will be	drawn
	   within the video frame. They	are relative to	the top/left border of
	   the output image.

	   The default value of	x and y	is "0".

	   See below for the list of accepted constants	and functions.

       The parameters for x and	y are expressions containing the following
       constants and functions:

       dar input display aspect	ratio, it is the same as (w / h) * sar

       hsub
       vsub
	   horizontal and vertical chroma subsample values. For	example	for
	   the pixel format "yuv422p" hsub is 2	and vsub is 1.

       line_h, lh
	   the height of each text line

       main_h, h, H
	   the input height

       main_w, w, W
	   the input width

       max_glyph_a, ascent
	   the maximum distance	from the baseline to the highest/upper grid
	   coordinate used to place a glyph outline point, for all the
	   rendered glyphs.  It	is a positive value, due to the	grid's
	   orientation with the	Y axis upwards.

       max_glyph_d, descent
	   the maximum distance	from the baseline to the lowest	grid
	   coordinate used to place a glyph outline point, for all the
	   rendered glyphs.  This is a negative	value, due to the grid's
	   orientation,	with the Y axis	upwards.

       max_glyph_h
	   maximum glyph height, that is the maximum height for	all the	glyphs
	   contained in	the rendered text, it is equivalent to ascent -
	   descent.

       max_glyph_w
	   maximum glyph width,	that is	the maximum width for all the glyphs
	   contained in	the rendered text

       n   the number of input frame, starting from 0

       rand(min, max)
	   return a random number included between min and max

       sar The input sample aspect ratio.

       t   timestamp expressed in seconds, NAN if the input timestamp is
	   unknown

       text_h, th
	   the height of the rendered text

       text_w, tw
	   the width of	the rendered text

       x
       y   the x and y offset coordinates where	the text is drawn.

	   These parameters allow the x	and y expressions to refer each	other,
	   so you can for example specify "y=x/dar".

       Text expansion

       If expansion is set to "strftime", the filter recognizes	strftime()
       sequences in the	provided text and expands them accordingly. Check the
       documentation of	strftime(). This feature is deprecated.

       If expansion is set to "none", the text is printed verbatim.

       If expansion is set to "normal" (which is the default), the following
       expansion mechanism is used.

       The backslash character \, followed by any character, always expands to
       the second character.

       Sequences of the	form "%{...}" are expanded. The	text between the
       braces is a function name, possibly followed by arguments separated by
       ':'.  If	the arguments contain special characters or delimiters (':' or
       '}'), they should be escaped.

       Note that they probably must also be escaped as the value for the text
       option in the filter argument string and	as the filter argument in the
       filtergraph description,	and possibly also for the shell, that makes up
       to four levels of escaping; using a text	file avoids these problems.

       The following functions are available:

       expr, e
	   The expression evaluation result.

	   It must take	one argument specifying	the expression to be
	   evaluated, which accepts the	same constants and functions as	the x
	   and y values. Note that not all constants should be used, for
	   example the text size is not	known when evaluating the expression,
	   so the constants text_w and text_h will have	an undefined value.

       expr_int_format,	eif
	   Evaluate the	expression's value and output as formatted integer.

	   The first argument is the expression	to be evaluated, just as for
	   the expr function.  The second argument specifies the output
	   format. Allowed values are x, X, d and u. They are treated exactly
	   as in the "printf" function.	 The third parameter is	optional and
	   sets	the number of positions	taken by the output.  It can be	used
	   to add padding with zeros from the left.

       gmtime
	   The time at which the filter	is running, expressed in UTC.  It can
	   accept an argument: a strftime() format string.

       localtime
	   The time at which the filter	is running, expressed in the local
	   time	zone.  It can accept an	argument: a strftime() format string.

       metadata
	   Frame metadata. Takes one or	two arguments.

	   The first argument is mandatory and specifies the metadata key.

	   The second argument is optional and specifies a default value, used
	   when	the metadata key is not	found or empty.

       n, frame_num
	   The frame number, starting from 0.

       pict_type
	   A 1 character description of	the current picture type.

       pts The timestamp of the	current	frame.	It can take up to three
	   arguments.

	   The first argument is the format of the timestamp; it defaults to
	   "flt" for seconds as	a decimal number with microsecond accuracy;
	   "hms" stands	for a formatted	[-]HH:MM:SS.mmm	timestamp with
	   millisecond accuracy.  "gmtime" stands for the timestamp of the
	   frame formatted as UTC time;	"localtime" stands for the timestamp
	   of the frame	formatted as local time	zone time.

	   The second argument is an offset added to the timestamp.

	   If the format is set	to "localtime" or "gmtime", a third argument
	   may be supplied: a strftime() format	string.	 By default, YYYY-MM-
	   DD HH:MM:SS format will be used.

       Examples

       o   Draw	"Test Text" with font FreeSerif, using the default values for
	   the optional	parameters.

		   drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf:	text='Test Text'"

       o   Draw	'Test Text' with font FreeSerif	of size	24 at position x=100
	   and y=50 (counting from the top-left	corner of the screen), text is
	   yellow with a red box around	it. Both the text and the box have an
	   opacity of 20%.

		   drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf:	text='Test Text':\
			     x=100: y=50: fontsize=24: fontcolor=yellow@0.2: box=1: boxcolor=red@0.2"

	   Note	that the double	quotes are not necessary if spaces are not
	   used	within the parameter list.

       o   Show	the text at the	center of the video frame:

		   drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h)/2"

       o   Show	the text at a random position, switching to a new position
	   every 30 seconds:

		   drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=if(eq(mod(t\,30)\,0)\,rand(0\,(w-text_w))\,x):y=if(eq(mod(t\,30)\,0)\,rand(0\,(h-text_h))\,y)"

       o   Show	a text line sliding from right to left in the last row of the
	   video frame.	The file LONG_LINE is assumed to contain a single line
	   with	no newlines.

		   drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"

       o   Show	the content of file CREDITS off	the bottom of the frame	and
	   scroll up.

		   drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"

       o   Draw	a single green letter "g", at the center of the	input video.
	   The glyph baseline is placed	at half	screen height.

		   drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"

       o   Show	text for 1 second every	3 seconds:

		   drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:enable=lt(mod(t\,3)\,1):text='blink'"

       o   Use fontconfig to set the font. Note	that the colons	need to	be
	   escaped.

		   drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'

       o   Print the date of a real-time encoding (see strftime(3)):

		   drawtext='fontfile=FreeSans.ttf:text=%{localtime\:%a	%b %d %Y}'

       o   Show	text fading in and out (appearing/disappearing):

		   #!/bin/sh
		   DS=1.0 # display start
		   DE=10.0 # display end
		   FID=1.5 # fade in duration
		   FOD=5 # fade	out duration
		   ffplay -f lavfi "color,drawtext=text=TEST:fontsize=50:fontfile=FreeSerif.ttf:fontcolor_expr=ff0000%{eif\\\\:	clip(255*(1*between(t\\, $DS + $FID\\, $DE - $FOD) + ((t - $DS)/$FID)*between(t\\, $DS\\, $DS +	$FID) +	(-(t - $DE)/$FOD)*between(t\\, $DE - $FOD\\, $DE) )\\, 0\\, 255) \\\\: x\\\\: 2	}"

       o   Horizontally	align multiple separate	texts. Note that max_glyph_a
	   and the fontsize value are included in the y	offset.

		   drawtext=fontfile=FreeSans.ttf:text=DOG:fontsize=24:x=10:y=20+24-max_glyph_a,
		   drawtext=fontfile=FreeSans.ttf:text=cow:fontsize=24:x=80:y=20+24-max_glyph_a

       For more	information about libfreetype, check:
       <http://www.freetype.org/>.

       For more	information about fontconfig, check:
       <http://freedesktop.org/software/fontconfig/fontconfig-user.html>.

       For more	information about libfribidi, check: <http://fribidi.org/>.

   edgedetect
       Detect and draw edges. The filter uses the Canny	Edge Detection
       algorithm.

       The filter accepts the following	options:

       low
       high
	   Set low and high threshold values used by the Canny thresholding
	   algorithm.

	   The high threshold selects the "strong" edge	pixels,	which are then
	   connected through 8-connectivity with the "weak" edge pixels
	   selected by the low threshold.

	   low and high	threshold values must be chosen	in the range [0,1],
	   and low should be lesser or equal to	high.

	   Default value for low is "20/255", and default value	for high is
	   "50/255".

       mode
	   Define the drawing mode.

	   wires
	       Draw white/gray wires on	black background.

	   colormix
	       Mix the colors to create	a paint/cartoon	effect.

	   Default value is wires.

       Examples

       o   Standard edge detection with	custom values for the hysteresis
	   thresholding:

		   edgedetect=low=0.1:high=0.4

       o   Painting effect without thresholding:

		   edgedetect=mode=colormix:high=0

   eq
       Set brightness, contrast, saturation and	approximate gamma adjustment.

       The filter accepts the following	options:

       contrast
	   Set the contrast expression.	The value must be a float value	in
	   range "-2.0"	to 2.0.	The default value is "1".

       brightness
	   Set the brightness expression. The value must be a float value in
	   range "-1.0"	to 1.0.	The default value is "0".

       saturation
	   Set the saturation expression. The value must be a float in range
	   0.0 to 3.0. The default value is "1".

       gamma
	   Set the gamma expression. The value must be a float in range	0.1 to
	   10.0.  The default value is "1".

       gamma_r
	   Set the gamma expression for	red. The value must be a float in
	   range 0.1 to	10.0. The default value	is "1".

       gamma_g
	   Set the gamma expression for	green. The value must be a float in
	   range 0.1 to	10.0. The default value	is "1".

       gamma_b
	   Set the gamma expression for	blue. The value	must be	a float	in
	   range 0.1 to	10.0. The default value	is "1".

       gamma_weight
	   Set the gamma weight	expression. It can be used to reduce the
	   effect of a high gamma value	on bright image	areas, e.g. keep them
	   from	getting	overamplified and just plain white. The	value must be
	   a float in range 0.0	to 1.0.	A value	of 0.0 turns the gamma
	   correction all the way down while 1.0 leaves	it at its full
	   strength. Default is	"1".

       eval
	   Set when the	expressions for	brightness, contrast, saturation and
	   gamma expressions are evaluated.

	   It accepts the following values:

	   init
	       only evaluate expressions once during the filter	initialization
	       or when a command is processed

	   frame
	       evaluate	expressions for	each incoming frame

	   Default value is init.

       The expressions accept the following parameters:

       n   frame count of the input frame starting from	0

       pos byte	position of the	corresponding packet in	the input file,	NAN if
	   unspecified

       r   frame rate of the input video, NAN if the input frame rate is
	   unknown

       t   timestamp expressed in seconds, NAN if the input timestamp is
	   unknown

       Commands

       The filter supports the following commands:

       contrast
	   Set the contrast expression.

       brightness
	   Set the brightness expression.

       saturation
	   Set the saturation expression.

       gamma
	   Set the gamma expression.

       gamma_r
	   Set the gamma_r expression.

       gamma_g
	   Set gamma_g expression.

       gamma_b
	   Set gamma_b expression.

       gamma_weight
	   Set gamma_weight expression.

	   The command accepts the same	syntax of the corresponding option.

	   If the specified expression is not valid, it	is kept	at its current
	   value.

   erosion
       Apply erosion effect to the video.

       This filter replaces the	pixel by the local(3x3)	minimum.

       It accepts the following	options:

       threshold0
       threshold1
       threshold2
       threshold3
	   Limit the maximum change for	each plane, default is 65535.  If 0,
	   plane will remain unchanged.

       coordinates
	   Flag	which specifies	the pixel to refer to. Default is 255 i.e. all
	   eight pixels	are used.

	   Flags to local 3x3 coordinates maps like this:

	       1 2 3
	       4   5
	       6 7 8

   extractplanes
       Extract color channel components	from input video stream	into separate
       grayscale video streams.

       The filter accepts the following	option:

       planes
	   Set plane(s)	to extract.

	   Available values for	planes are:

	   y
	   u
	   v
	   a
	   r
	   g
	   b

	   Choosing planes not available in the	input will result in an	error.
	   That	means you cannot select	"r", "g", "b" planes with "y", "u",
	   "v" planes at same time.

       Examples

       o   Extract luma, u and v color channel component from input video
	   frame into 3	grayscale outputs:

		   ffmpeg -i video.avi -filter_complex 'extractplanes=y+u+v[y][u][v]' -map '[y]' y.avi -map '[u]' u.avi	-map '[v]' v.avi

   elbg
       Apply a posterize effect	using the ELBG (Enhanced LBG) algorithm.

       For each	input image, the filter	will compute the optimal mapping from
       the input to the	output given the codebook length, that is the number
       of distinct output colors.

       This filter accepts the following options.

       codebook_length,	l
	   Set codebook	length.	The value must be a positive integer, and
	   represents the number of distinct output colors. Default value is
	   256.

       nb_steps, n
	   Set the maximum number of iterations	to apply for computing the
	   optimal mapping. The	higher the value the better the	result and the
	   higher the computation time.	Default	value is 1.

       seed, s
	   Set a random	seed, must be an integer included between 0 and
	   UINT32_MAX. If not specified, or if explicitly set to -1, the
	   filter will try to use a good random	seed on	a best effort basis.

       pal8
	   Set pal8 output pixel format. This option does not work with
	   codebook length greater than	256.

   fade
       Apply a fade-in/out effect to the input video.

       It accepts the following	parameters:

       type, t
	   The effect type can be either "in" for a fade-in, or	"out" for a
	   fade-out effect.  Default is	"in".

       start_frame, s
	   Specify the number of the frame to start applying the fade effect
	   at. Default is 0.

       nb_frames, n
	   The number of frames	that the fade effect lasts. At the end of the
	   fade-in effect, the output video will have the same intensity as
	   the input video.  At	the end	of the fade-out	transition, the	output
	   video will be filled	with the selected color.  Default is 25.

       alpha
	   If set to 1,	fade only alpha	channel, if one	exists on the input.
	   Default value is 0.

       start_time, st
	   Specify the timestamp (in seconds) of the frame to start to apply
	   the fade effect. If both start_frame	and start_time are specified,
	   the fade will start at whichever comes last.	 Default is 0.

       duration, d
	   The number of seconds for which the fade effect has to last.	At the
	   end of the fade-in effect the output	video will have	the same
	   intensity as	the input video, at the	end of the fade-out transition
	   the output video will be filled with	the selected color.  If	both
	   duration and	nb_frames are specified, duration is used. Default is
	   0 (nb_frames	is used	by default).

       color, c
	   Specify the color of	the fade. Default is "black".

       Examples

       o   Fade	in the first 30	frames of video:

		   fade=in:0:30

	   The command above is	equivalent to:

		   fade=t=in:s=0:n=30

       o   Fade	out the	last 45	frames of a 200-frame video:

		   fade=out:155:45
		   fade=type=out:start_frame=155:nb_frames=45

       o   Fade	in the first 25	frames and fade	out the	last 25	frames of a
	   1000-frame video:

		   fade=in:0:25, fade=out:975:25

       o   Make	the first 5 frames yellow, then	fade in	from frame 5-24:

		   fade=in:5:20:color=yellow

       o   Fade	in alpha over first 25 frames of video:

		   fade=in:0:25:alpha=1

       o   Make	the first 5.5 seconds black, then fade in for 0.5 seconds:

		   fade=t=in:st=5.5:d=0.5

   fftfilt
       Apply arbitrary expressions to samples in frequency domain

       dc_Y
	   Adjust the dc value (gain) of the luma plane	of the image. The
	   filter accepts an integer value in range 0 to 1000. The default
	   value is set	to 0.

       dc_U
	   Adjust the dc value (gain) of the 1st chroma	plane of the image.
	   The filter accepts an integer value in range	0 to 1000. The default
	   value is set	to 0.

       dc_V
	   Adjust the dc value (gain) of the 2nd chroma	plane of the image.
	   The filter accepts an integer value in range	0 to 1000. The default
	   value is set	to 0.

       weight_Y
	   Set the frequency domain weight expression for the luma plane.

       weight_U
	   Set the frequency domain weight expression for the 1st chroma
	   plane.

       weight_V
	   Set the frequency domain weight expression for the 2nd chroma
	   plane.

	   The filter accepts the following variables:

       X
       Y   The coordinates of the current sample.

       W
       H   The width and height	of the image.

       Examples

       o   High-pass:

		   fftfilt=dc_Y=128:weight_Y='squish(1-(Y+X)/100)'

       o   Low-pass:

		   fftfilt=dc_Y=0:weight_Y='squish((Y+X)/100-1)'

       o   Sharpen:

		   fftfilt=dc_Y=0:weight_Y='1+squish(1-(Y+X)/100)'

       o   Blur:

		   fftfilt=dc_Y=0:weight_Y='exp(-4 * ((Y+X)/(W+H)))'

   field
       Extract a single	field from an interlaced image using stride arithmetic
       to avoid	wasting	CPU time. The output frames are	marked as non-
       interlaced.

       The filter accepts the following	options:

       type
	   Specify whether to extract the top (if the value is 0 or "top") or
	   the bottom field (if	the value is 1 or "bottom").

   fieldhint
       Create new frames by copying the	top and	bottom fields from surrounding
       frames supplied as numbers by the hint file.

       hint
	   Set file containing hints: absolute/relative	frame numbers.

	   There must be one line for each frame in a clip. Each line must
	   contain two numbers separated by the	comma, optionally followed by
	   "-" or "+".	Numbers	supplied on each line of file can not be out
	   of [N-1,N+1]	where N	is current frame number	for "absolute" mode or
	   out of [-1, 1] range	for "relative" mode. First number tells	from
	   which frame to pick up top field and	second number tells from which
	   frame to pick up bottom field.

	   If optionally followed by "+" output	frame will be marked as
	   interlaced, else if followed	by "-" output frame will be marked as
	   progressive,	else it	will be	marked same as input frame.  If	line
	   starts with "#" or ";" that line is skipped.

       mode
	   Can be item "absolute" or "relative". Default is "absolute".

       Example of first	several	lines of "hint"	file for "relative" mode:

	       0,0 - # first frame
	       1,0 - # second frame, use third's frame top field and second's frame bottom field
	       1,0 - # third frame, use	fourth's frame top field and third's frame bottom field
	       1,0 -
	       0,0 -
	       0,0 -
	       1,0 -
	       1,0 -
	       1,0 -
	       0,0 -
	       0,0 -
	       1,0 -
	       1,0 -
	       1,0 -
	       0,0 -

   fieldmatch
       Field matching filter for inverse telecine. It is meant to reconstruct
       the progressive frames from a telecined stream. The filter does not
       drop duplicated frames, so to achieve a complete	inverse	telecine
       "fieldmatch" needs to be	followed by a decimation filter	such as
       decimate	in the filtergraph.

       The separation of the field matching and	the decimation is notably
       motivated by the	possibility of inserting a de-interlacing filter
       fallback	between	the two.  If the source	has mixed telecined and	real
       interlaced content, "fieldmatch"	will not be able to match fields for
       the interlaced parts.  But these	remaining combed frames	will be	marked
       as interlaced, and thus can be de-interlaced by a later filter such as
       yadif before decimation.

       In addition to the various configuration	options, "fieldmatch" can take
       an optional second stream, activated through the	ppsrc option. If
       enabled,	the frames reconstruction will be based	on the fields and
       frames from this	second stream. This allows the first input to be pre-
       processed in order to help the various algorithms of the	filter,	while
       keeping the output lossless (assuming the fields	are matched properly).
       Typically, a field-aware	denoiser, or brightness/contrast adjustments
       can help.

       Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth
       project)	and VIVTC/VFM (VapourSynth project). The later is a light
       clone of	TFM from which "fieldmatch" is based on. While the semantic
       and usage are very close, some behaviour	and options names can differ.

       The decimate filter currently only works	for constant frame rate	input.
       If your input has mixed telecined (30fps) and progressive content with
       a lower framerate like 24fps use	the following filterchain to produce
       the necessary cfr stream:
       "dejudder,fps=30000/1001,fieldmatch,decimate".

       The filter accepts the following	options:

       order
	   Specify the assumed field order of the input	stream.	Available
	   values are:

	   auto
	       Auto detect parity (use FFmpeg's	internal parity	value).

	   bff Assume bottom field first.

	   tff Assume top field	first.

	   Note	that it	is sometimes recommended not to	trust the parity
	   announced by	the stream.

	   Default value is auto.

       mode
	   Set the matching mode or strategy to	use. pc	mode is	the safest in
	   the sense that it won't risk	creating jerkiness due to duplicate
	   frames when possible, but if	there are bad edits or blended fields
	   it will end up outputting combed frames when	a good match might
	   actually exist. On the other	hand, pcn_ub mode is the most risky in
	   terms of creating jerkiness,	but will almost	always find a good
	   frame if there is one. The other values are all somewhere in
	   between pc and pcn_ub in terms of risking jerkiness and creating
	   duplicate frames versus finding good	matches	in sections with bad
	   edits, orphaned fields, blended fields, etc.

	   More	details	about p/c/n/u/b	are available in p/c/n/u/b meaning
	   section.

	   Available values are:

	   pc  2-way matching (p/c)

	   pc_n
	       2-way matching, and trying 3rd match if still combed (p/c + n)

	   pc_u
	       2-way matching, and trying 3rd match (same order) if still
	       combed (p/c + u)

	   pc_n_ub
	       2-way matching, trying 3rd match	if still combed, and trying
	       4th/5th matches if still	combed (p/c + n	+ u/b)

	   pcn 3-way matching (p/c/n)

	   pcn_ub
	       3-way matching, and trying 4th/5th matches if all 3 of the
	       original	matches	are detected as	combed (p/c/n +	u/b)

	   The parenthesis at the end indicate the matches that	would be used
	   for that mode assuming order=tff (and field on auto or top).

	   In terms of speed pc	mode is	by far the fastest and pcn_ub is the
	   slowest.

	   Default value is pc_n.

       ppsrc
	   Mark	the main input stream as a pre-processed input,	and enable the
	   secondary input stream as the clean source to pick the fields from.
	   See the filter introduction for more	details. It is similar to the
	   clip2 feature from VFM/TFM.

	   Default value is 0 (disabled).

       field
	   Set the field to match from.	It is recommended to set this to the
	   same	value as order unless you experience matching failures with
	   that	setting. In certain circumstances changing the field that is
	   used	to match from can have a large impact on matching performance.
	   Available values are:

	   auto
	       Automatic (same value as	order).

	   bottom
	       Match from the bottom field.

	   top Match from the top field.

	   Default value is auto.

       mchroma
	   Set whether or not chroma is	included during	the match comparisons.
	   In most cases it is recommended to leave this enabled. You should
	   set this to 0 only if your clip has bad chroma problems such	as
	   heavy rainbowing or other artifacts.	Setting	this to	0 could	also
	   be used to speed things up at the cost of some accuracy.

	   Default value is 1.

       y0
       y1  These define	an exclusion band which	excludes the lines between y0
	   and y1 from being included in the field matching decision. An
	   exclusion band can be used to ignore	subtitles, a logo, or other
	   things that may interfere with the matching.	y0 sets	the starting
	   scan	line and y1 sets the ending line; all lines in between y0 and
	   y1 (including y0 and	y1) will be ignored. Setting y0	and y1 to the
	   same	value will disable the feature.	 y0 and	y1 defaults to 0.

       scthresh
	   Set the scene change	detection threshold as a percentage of maximum
	   change on the luma plane. Good values are in	the "[8.0, 14.0]"
	   range. Scene	change detection is only relevant in case
	   combmatch=sc.  The range for	scthresh is "[0.0, 100.0]".

	   Default value is 12.0.

       combmatch
	   When	combatch is not	none, "fieldmatch" will	take into account the
	   combed scores of matches when deciding what match to	use as the
	   final match.	Available values are:

	   none
	       No final	matching based on combed scores.

	   sc  Combed scores are only used when	a scene	change is detected.

	   full
	       Use combed scores all the time.

	   Default is sc.

       combdbg
	   Force "fieldmatch" to calculate the combed metrics for certain
	   matches and print them. This	setting	is known as micout in TFM/VFM
	   vocabulary.	Available values are:

	   none
	       No forced calculation.

	   pcn Force p/c/n calculations.

	   pcnub
	       Force p/c/n/u/b calculations.

	   Default value is none.

       cthresh
	   This	is the area combing threshold used for combed frame detection.
	   This	essentially controls how "strong" or "visible" combing must be
	   to be detected.  Larger values mean combing must be more visible
	   and smaller values mean combing can be less visible or strong and
	   still be detected. Valid settings are from "-1" (every pixel	will
	   be detected as combed) to 255 (no pixel will	be detected as
	   combed). This is basically a	pixel difference value.	A good range
	   is "[8, 12]".

	   Default value is 9.

       chroma
	   Sets	whether	or not chroma is considered in the combed frame
	   decision.  Only disable this	if your	source has chroma problems
	   (rainbowing,	etc.) that are causing problems	for the	combed frame
	   detection with chroma enabled. Actually, using chroma=0 is usually
	   more	reliable, except for the case where there is chroma only
	   combing in the source.

	   Default value is 0.

       blockx
       blocky
	   Respectively	set the	x-axis and y-axis size of the window used
	   during combed frame detection. This has to do with the size of the
	   area	in which combpel pixels	are required to	be detected as combed
	   for a frame to be declared combed. See the combpel parameter
	   description for more	info.  Possible	values are any number that is
	   a power of 2	starting at 4 and going	up to 512.

	   Default value is 16.

       combpel
	   The number of combed	pixels inside any of the blocky	by blockx size
	   blocks on the frame for the frame to	be detected as combed. While
	   cthresh controls how	"visible" the combing must be, this setting
	   controls "how much" combing there must be in	any localized area (a
	   window defined by the blockx	and blocky settings) on	the frame.
	   Minimum value is 0 and maximum is "blocky x blockx" (at which point
	   no frames will ever be detected as combed). This setting is known
	   as MI in TFM/VFM vocabulary.

	   Default value is 80.

       p/c/n/u/b meaning

       p/c/n

       We assume the following telecined stream:

	       Top fields:     1 2 2 3 4
	       Bottom fields:  1 2 3 4 4

       The numbers correspond to the progressive frame the fields relate to.
       Here, the first two frames are progressive, the 3rd and 4th are combed,
       and so on.

       When "fieldmatch" is configured to run a	matching from bottom
       (field=bottom) this is how this input stream get	transformed:

	       Input stream:
			       T     1 2 2 3 4
			       B     1 2 3 4 4	 <-- matching reference

	       Matches:		     c c n n c

	       Output stream:
			       T     1 2 3 4 4
			       B     1 2 3 4 4

       As a result of the field	matching, we can see that some frames get
       duplicated.  To perform a complete inverse telecine, you	need to	rely
       on a decimation filter after this operation. See	for instance the
       decimate	filter.

       The same	operation now matching from top	fields (field=top) looks like
       this:

	       Input stream:
			       T     1 2 2 3 4	 <-- matching reference
			       B     1 2 3 4 4

	       Matches:		     c c p p c

	       Output stream:
			       T     1 2 2 3 4
			       B     1 2 2 3 4

       In these	examples, we can see what p, c and n mean; basically, they
       refer to	the frame and field of the opposite parity:

       *<p matches the field of	the opposite parity in the previous frame>
       *<c matches the field of	the opposite parity in the current frame>
       *<n matches the field of	the opposite parity in the next	frame>

       u/b

       The u and b matching are	a bit special in the sense that	they match
       from the	opposite parity	flag. In the following examples, we assume
       that we are currently matching the 2nd frame (Top:2, bottom:2).
       According to the	match, a 'x' is	placed above and below each matched
       fields.

       With bottom matching (field=bottom):

	       Match:		c	  p	      n		 b	    u

				x	x		x	 x	    x
		 Top	      1	2 2	1 2 2	    1 2	2      1 2 2	  1 2 2
		 Bottom	      1	2 3	1 2 3	    1 2	3      1 2 3	  1 2 3
				x	  x	      x	       x	      x

	       Output frames:
				2	   1	      2		 2	    2
				2	   2	      2		 1	    3

       With top	matching (field=top):

	       Match:		c	  p	      n		 b	    u

				x	  x	      x	       x	      x
		 Top	      1	2 2	1 2 2	    1 2	2      1 2 2	  1 2 2
		 Bottom	      1	2 3	1 2 3	    1 2	3      1 2 3	  1 2 3
				x	x		x	 x	    x

	       Output frames:
				2	   2	      2		 1	    2
				2	   1	      3		 2	    2

       Examples

       Simple IVTC of a	top field first	telecined stream:

	       fieldmatch=order=tff:combmatch=none, decimate

       Advanced	IVTC, with fallback on yadif for still combed frames:

	       fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate

   fieldorder
       Transform the field order of the	input video.

       It accepts the following	parameters:

       order
	   The output field order. Valid values	are tff	for top	field first or
	   bff for bottom field	first.

       The default value is tff.

       The transformation is done by shifting the picture content up or	down
       by one line, and	filling	the remaining line with	appropriate picture
       content.	 This method is	consistent with	most broadcast field order
       converters.

       If the input video is not flagged as being interlaced, or it is already
       flagged as being	of the required	output field order, then this filter
       does not	alter the incoming video.

       It is very useful when converting to or from PAL	DV material, which is
       bottom field first.

       For example:

	       ffmpeg -i in.vob	-vf "fieldorder=bff" out.dv

   fifo, afifo
       Buffer input images and send them when they are requested.

       It is mainly useful when	auto-inserted by the libavfilter framework.

       It does not take	parameters.

   find_rect
       Find a rectangular object

       It accepts the following	options:

       object
	   Filepath of the object image, needs to be in	gray8.

       threshold
	   Detection threshold,	default	is 0.5.

       mipmaps
	   Number of mipmaps, default is 3.

       xmin, ymin, xmax, ymax
	   Specifies the rectangle in which to search.

       Examples

       o   Generate a representative palette of	a given	video using ffmpeg:

		   ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv

   cover_rect
       Cover a rectangular object

       It accepts the following	options:

       cover
	   Filepath of the optional cover image, needs to be in	yuv420.

       mode
	   Set covering	mode.

	   It accepts the following values:

	   cover
	       cover it	by the supplied	image

	   blur
	       cover it	by interpolating the surrounding pixels

	   Default value is blur.

       Examples

       o   Generate a representative palette of	a given	video using ffmpeg:

		   ffmpeg -i file.ts -vf find_rect=newref.pgm,cover_rect=cover.jpg:mode=cover new.mkv

   format
       Convert the input video to one of the specified pixel formats.
       Libavfilter will	try to pick one	that is	suitable as input to the next
       filter.

       It accepts the following	parameters:

       pix_fmts
	   A '|'-separated list	of pixel format	names, such as
	   "pix_fmts=yuv420p|monow|rgb24".

       Examples

       o   Convert the input video to the yuv420p format

		   format=pix_fmts=yuv420p

	   Convert the input video to any of the formats in the	list

		   format=pix_fmts=yuv420p|yuv444p|yuv410p

   fps
       Convert the video to specified constant frame rate by duplicating or
       dropping	frames as necessary.

       It accepts the following	parameters:

       fps The desired output frame rate. The default is 25.

       round
	   Rounding method.

	   Possible values are:

	   zero
	       zero round towards 0

	   inf round away from 0

	   down
	       round towards -infinity

	   up  round towards +infinity

	   near
	       round to	nearest

	   The default is "near".

       start_time
	   Assume the first PTS	should be the given value, in seconds. This
	   allows for padding/trimming at the start of stream. By default, no
	   assumption is made about the	first frame's expected PTS, so no
	   padding or trimming is done.	 For example, this could be set	to 0
	   to pad the beginning	with duplicates	of the first frame if a	video
	   stream starts after the audio stream	or to trim any frames with a
	   negative PTS.

       Alternatively, the options can be specified as a	flat string:
       fps[:round].

       See also	the setpts filter.

       Examples

       o   A typical usage in order to set the fps to 25:

		   fps=fps=25

       o   Sets	the fps	to 24, using abbreviation and rounding method to round
	   to nearest:

		   fps=fps=film:round=near

   framepack
       Pack two	different video	streams	into a stereoscopic video, setting
       proper metadata on supported codecs. The	two views should have the same
       size and	framerate and processing will stop when	the shorter video
       ends. Please note that you may conveniently adjust view properties with
       the scale and fps filters.

       It accepts the following	parameters:

       format
	   The desired packing format. Supported values	are:

	   sbs The views are next to each other	(default).

	   tab The views are on	top of each other.

	   lines
	       The views are packed by line.

	   columns
	       The views are packed by column.

	   frameseq
	       The views are temporally	interleaved.

       Some examples:

	       # Convert left and right	views into a frame-sequential video
	       ffmpeg -i LEFT -i RIGHT -filter_complex framepack=frameseq OUTPUT

	       # Convert views into a side-by-side video with the same output resolution as the	input
	       ffmpeg -i LEFT -i RIGHT -filter_complex [0:v]scale=w=iw/2[left],[1:v]scale=w=iw/2[right],[left][right]framepack=sbs OUTPUT

   framerate
       Change the frame	rate by	interpolating new video	output frames from the
       source frames.

       This filter is not designed to function correctly with interlaced
       media. If you wish to change the	frame rate of interlaced media then
       you are required	to deinterlace before this filter and re-interlace
       after this filter.

       A description of	the accepted options follows.

       fps Specify the output frames per second. This option can also be
	   specified as	a value	alone. The default is 50.

       interp_start
	   Specify the start of	a range	where the output frame will be created
	   as a	linear interpolation of	two frames. The	range is [0-255], the
	   default is 15.

       interp_end
	   Specify the end of a	range where the	output frame will be created
	   as a	linear interpolation of	two frames. The	range is [0-255], the
	   default is 240.

       scene
	   Specify the level at	which a	scene change is	detected as a value
	   between 0 and 100 to	indicate a new scene; a	low value reflects a
	   low probability for the current frame to introduce a	new scene,
	   while a higher value	means the current frame	is more	likely to be
	   one.	 The default is	7.

       flags
	   Specify flags influencing the filter	process.

	   Available value for flags is:

	   scene_change_detect,	scd
	       Enable scene change detection using the value of	the option
	       scene.  This flag is enabled by default.

   framestep
       Select one frame	every N-th frame.

       This filter accepts the following option:

       step
	   Select frame	after every "step" frames.  Allowed values are
	   positive integers higher than 0. Default value is 1.

   frei0r
       Apply a frei0r effect to	the input video.

       To enable the compilation of this filter, you need to install the
       frei0r header and configure FFmpeg with "--enable-frei0r".

       It accepts the following	parameters:

       filter_name
	   The name of the frei0r effect to load. If the environment variable
	   FREI0R_PATH is defined, the frei0r effect is	searched for in	each
	   of the directories specified	by the colon-separated list in
	   FREIOR_PATH.	 Otherwise, the	standard frei0r	paths are searched, in
	   this	order: HOME/.frei0r-1/lib/, /usr/local/lib/frei0r-1/,
	   /usr/lib/frei0r-1/.

       filter_params
	   A '|'-separated list	of parameters to pass to the frei0r effect.

       A frei0r	effect parameter can be	a boolean (its value is	either "y" or
       "n"), a double, a color (specified as R/G/B, where R, G,	and B are
       floating	point numbers between 0.0 and 1.0, inclusive) or by a color
       description specified in	the "Color" section in the ffmpeg-utils
       manual),	a position (specified as X/Y, where X and Y are	floating point
       numbers)	and/or a string.

       The number and types of parameters depend on the	loaded effect. If an
       effect parameter	is not specified, the default value is set.

       Examples

       o   Apply the distort0r effect, setting the first two double
	   parameters:

		   frei0r=filter_name=distort0r:filter_params=0.5|0.01

       o   Apply the colordistance effect, taking a color as the first
	   parameter:

		   frei0r=colordistance:0.2/0.3/0.4
		   frei0r=colordistance:violet
		   frei0r=colordistance:0x112233

       o   Apply the perspective effect, specifying the	top left and top right
	   image positions:

		   frei0r=perspective:0.2/0.2|0.8/0.2

       For more	information, see <http://frei0r.dyne.org>

   fspp
       Apply fast and simple postprocessing. It	is a faster version of spp.

       It splits (I)DCT	into horizontal/vertical passes. Unlike	the simple
       post- processing	filter,	one of them is performed once per block, not
       per pixel.  This	allows for much	higher speed.

       The filter accepts the following	options:

       quality
	   Set quality.	This option defines the	number of levels for
	   averaging. It accepts an integer in the range 4-5. Default value is
	   4.

       qp  Force a constant quantization parameter. It accepts an integer in
	   range 0-63.	If not set, the	filter will use	the QP from the	video
	   stream (if available).

       strength
	   Set filter strength.	It accepts an integer in range -15 to 32.
	   Lower values	mean more details but also more	artifacts, while
	   higher values make the image	smoother but also blurrier. Default
	   value is 0 X	PSNR optimal.

       use_bframe_qp
	   Enable the use of the QP from the B-Frames if set to	1. Using this
	   option may cause flicker since the B-Frames have often larger QP.
	   Default is 0	(not enabled).

   gblur
       Apply Gaussian blur filter.

       The filter accepts the following	options:

       sigma
	   Set horizontal sigma, standard deviation of Gaussian	blur. Default
	   is 0.5.

       steps
	   Set number of steps for Gaussian approximation. Defauls is 1.

       planes
	   Set which planes to filter. By default all planes are filtered.

       sigmaV
	   Set vertical	sigma, if negative it will be same as "sigma".
	   Default is "-1".

   geq
       The filter accepts the following	options:

       lum_expr, lum
	   Set the luminance expression.

       cb_expr,	cb
	   Set the chrominance blue expression.

       cr_expr,	cr
	   Set the chrominance red expression.

       alpha_expr, a
	   Set the alpha expression.

       red_expr, r
	   Set the red expression.

       green_expr, g
	   Set the green expression.

       blue_expr, b
	   Set the blue	expression.

       The colorspace is selected according to the specified options. If one
       of the lum_expr,	cb_expr, or cr_expr options is specified, the filter
       will automatically select a YCbCr colorspace. If	one of the red_expr,
       green_expr, or blue_expr	options	is specified, it will select an	RGB
       colorspace.

       If one of the chrominance expression is not defined, it falls back on
       the other one. If no alpha expression is	specified it will evaluate to
       opaque value.  If none of chrominance expressions are specified,	they
       will evaluate to	the luminance expression.

       The expressions can use the following variables and functions:

       N   The sequential number of the	filtered frame,	starting from 0.

       X
       Y   The coordinates of the current sample.

       W
       H   The width and height	of the image.

       SW
       SH  Width and height scale depending on the currently filtered plane.
	   It is the ratio between the corresponding luma plane	number of
	   pixels and the current plane	ones. E.g. for YUV4:2:0	the values are
	   "1,1" for the luma plane, and "0.5,0.5" for chroma planes.

       T   Time	of the current frame, expressed	in seconds.

       p(x, y)
	   Return the value of the pixel at location (x,y) of the current
	   plane.

       lum(x, y)
	   Return the value of the pixel at location (x,y) of the luminance
	   plane.

       cb(x, y)
	   Return the value of the pixel at location (x,y) of the blue-
	   difference chroma plane. Return 0 if	there is no such plane.

       cr(x, y)
	   Return the value of the pixel at location (x,y) of the red-
	   difference chroma plane. Return 0 if	there is no such plane.

       r(x, y)
       g(x, y)
       b(x, y)
	   Return the value of the pixel at location (x,y) of the
	   red/green/blue component. Return 0 if there is no such component.

       alpha(x,	y)
	   Return the value of the pixel at location (x,y) of the alpha	plane.
	   Return 0 if there is	no such	plane.

       For functions, if x and y are outside the area, the value will be
       automatically clipped to	the closer edge.

       Examples

       o   Flip	the image horizontally:

		   geq=p(W-X\,Y)

       o   Generate a bidimensional sine wave, with angle "PI/3" and a
	   wavelength of 100 pixels:

		   geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128

       o   Generate a fancy enigmatic moving light:

		   nullsrc=s=256x256,geq=random(1)/hypot(X-cos(N*0.07)*W/2-W/2\,Y-sin(N*0.09)*H/2-H/2)^2*1000000*sin(N*0.02):128:128

       o   Generate a quick emboss effect:

		   format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2'

       o   Modify RGB components depending on pixel position:

		   geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)'

       o   Create a radial gradient that is the	same size as the input (also
	   see the vignette filter):

		   geq=lum=255*gauss((X/W-0.5)*3)*gauss((Y/H-0.5)*3)/gauss(0)/gauss(0),format=gray

   gradfun
       Fix the banding artifacts that are sometimes introduced into nearly
       flat regions by truncation to 8-bit color depth.	 Interpolate the
       gradients that should go	where the bands	are, and dither	them.

       It is designed for playback only.  Do not use it	prior to lossy
       compression, because compression	tends to lose the dither and bring
       back the	bands.

       It accepts the following	parameters:

       strength
	   The maximum amount by which the filter will change any one pixel.
	   This	is also	the threshold for detecting nearly flat	regions.
	   Acceptable values range from	.51 to 64; the default value is	1.2.
	   Out-of-range	values will be clipped to the valid range.

       radius
	   The neighborhood to fit the gradient	to. A larger radius makes for
	   smoother gradients, but also	prevents the filter from modifying the
	   pixels near detailed	regions. Acceptable values are 8-32; the
	   default value is 16.	Out-of-range values will be clipped to the
	   valid range.

       Alternatively, the options can be specified as a	flat string:
       strength[:radius]

       Examples

       o   Apply the filter with a 3.5 strength	and radius of 8:

		   gradfun=3.5:8

       o   Specify radius, omitting the	strength (which	will fall-back to the
	   default value):

		   gradfun=radius=8

   haldclut
       Apply a Hald CLUT to a video stream.

       First input is the video	stream to process, and second one is the Hald
       CLUT.  The Hald CLUT input can be a simple picture or a complete	video
       stream.

       The filter accepts the following	options:

       shortest
	   Force termination when the shortest input terminates. Default is 0.

       repeatlast
	   Continue applying the last CLUT after the end of the	stream.	A
	   value of 0 disable the filter after the last	frame of the CLUT is
	   reached.  Default is	1.

       "haldclut" also has the same interpolation options as lut3d (both
       filters share the same internals).

       More information	about the Hald CLUT can	be found on Eskil Steenberg's
       website (Hald CLUT author) at
       <http://www.quelsolaar.com/technology/clut.html>.

       Workflow	examples

       Hald CLUT video stream

       Generate	an identity Hald CLUT stream altered with various effects:

	       ffmpeg -f lavfi -i B<haldclutsrc>=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut

       Note: make sure you use a lossless codec.

       Then use	it with	"haldclut" to apply it on some random stream:

	       ffmpeg -f lavfi -i mandelbrot -i	clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv

       The Hald	CLUT will be applied to	the 10 first seconds (duration of
       clut.nut), then the latest picture of that CLUT stream will be applied
       to the remaining	frames of the "mandelbrot" stream.

       Hald CLUT with preview

       A Hald CLUT is supposed to be a squared image of	"Level*Level*Level" by
       "Level*Level*Level" pixels. For a given Hald CLUT, FFmpeg will select
       the biggest possible square starting at the top left of the picture.
       The remaining padding pixels (bottom or right) will be ignored. This
       area can	be used	to add a preview of the	Hald CLUT.

       Typically, the following	generated Hald CLUT will be supported by the
       "haldclut" filter:

	       ffmpeg -f lavfi -i B<haldclutsrc>=8 -vf "
		  pad=iw+320 [padded_clut];
		  smptebars=s=320x256, split [a][b];
		  [padded_clut][a] overlay=W-320:h, curves=color_negative [main];
		  [main][b] overlay=W-320" -frames:v 1 clut.png

       It contains the original	and a preview of the effect of the CLUT: SMPTE
       color bars are displayed	on the right-top, and below the	same color
       bars processed by the color changes.

       Then, the effect	of this	Hald CLUT can be visualized with:

	       ffplay input.mkv	-vf "movie=clut.png, [in] haldclut"

   hflip
       Flip the	input video horizontally.

       For example, to horizontally flip the input video with ffmpeg:

	       ffmpeg -i in.avi	-vf "hflip" out.avi

   histeq
       This filter applies a global color histogram equalization on a per-
       frame basis.

       It can be used to correct video that has	a compressed range of pixel
       intensities.  The filter	redistributes the pixel	intensities to
       equalize	their distribution across the intensity	range. It may be
       viewed as an "automatically adjusting contrast filter". This filter is
       useful only for correcting degraded or poorly captured source video.

       The filter accepts the following	options:

       strength
	   Determine the amount	of equalization	to be applied.	As the
	   strength is reduced,	the distribution of pixel intensities more-
	   and-more approaches that of the input frame.	The value must be a
	   float number	in the range [0,1] and defaults	to 0.200.

       intensity
	   Set the maximum intensity that can generated	and scale the output
	   values appropriately.  The strength should be set as	desired	and
	   then	the intensity can be limited if	needed to avoid	washing-out.
	   The value must be a float number in the range [0,1] and defaults to
	   0.210.

       antibanding
	   Set the antibanding level. If enabled the filter will randomly vary
	   the luminance of output pixels by a small amount to avoid banding
	   of the histogram. Possible values are "none", "weak"	or "strong".
	   It defaults to "none".

   histogram
       Compute and draw	a color	distribution histogram for the input video.

       The computed histogram is a representation of the color component
       distribution in an image.

       Standard	histogram displays the color components	distribution in	an
       image.  Displays	color graph for	each color component. Shows
       distribution of the Y, U, V, A or R, G, B components, depending on
       input format, in	the current frame. Below each graph a color component
       scale meter is shown.

       The filter accepts the following	options:

       level_height
	   Set height of level.	Default	value is 200.  Allowed range is	[50,
	   2048].

       scale_height
	   Set height of color scale. Default value is 12.  Allowed range is
	   [0, 40].

       display_mode
	   Set display mode.  It accepts the following values:

	   parade
	       Per color component graphs are placed below each	other.

	   overlay
	       Presents	information identical to that in the "parade", except
	       that the	graphs representing color components are superimposed
	       directly	over one another.

	   Default is "parade".

       levels_mode
	   Set mode. Can be either "linear", or	"logarithmic".	Default	is
	   "linear".

       components
	   Set what color components to	display.  Default is 7.

       fgopacity
	   Set foreground opacity. Default is 0.7.

       bgopacity
	   Set background opacity. Default is 0.5.

       Examples

       o   Calculate and draw histogram:

		   ffplay -i input -vf histogram

   hqdn3d
       This is a high precision/quality	3d denoise filter. It aims to reduce
       image noise, producing smooth images and	making still images really
       still. It should	enhance	compressibility.

       It accepts the following	optional parameters:

       luma_spatial
	   A non-negative floating point number	which specifies	spatial	luma
	   strength.  It defaults to 4.0.

       chroma_spatial
	   A non-negative floating point number	which specifies	spatial	chroma
	   strength.  It defaults to 3.0*luma_spatial/4.0.

       luma_tmp
	   A floating point number which specifies luma	temporal strength. It
	   defaults to 6.0*luma_spatial/4.0.

       chroma_tmp
	   A floating point number which specifies chroma temporal strength.
	   It defaults to luma_tmp*chroma_spatial/luma_spatial.

   hwupload_cuda
       Upload system memory frames to a	CUDA device.

       It accepts the following	optional parameters:

       device
	   The number of the CUDA device to use

   hqx
       Apply a high-quality magnification filter designed for pixel art. This
       filter was originally created by	Maxim Stepin.

       It accepts the following	option:

       n   Set the scaling dimension: 2	for "hq2x", 3 for "hq3x" and 4 for
	   "hq4x".  Default is 3.

   hstack
       Stack input videos horizontally.

       All streams must	be of same pixel format	and of same height.

       Note that this filter is	faster than using overlay and pad filter to
       create same output.

       The filter accept the following option:

       inputs
	   Set number of input streams.	Default	is 2.

       shortest
	   If set to 1,	force the output to terminate when the shortest	input
	   terminates. Default value is	0.

   hue
       Modify the hue and/or the saturation of the input.

       It accepts the following	parameters:

       h   Specify the hue angle as a number of	degrees. It accepts an
	   expression, and defaults to "0".

       s   Specify the saturation in the [-10,10] range. It accepts an
	   expression and defaults to "1".

       H   Specify the hue angle as a number of	radians. It accepts an
	   expression, and defaults to "0".

       b   Specify the brightness in the [-10,10] range. It accepts an
	   expression and defaults to "0".

       h and H are mutually exclusive, and can't be specified at the same
       time.

       The b, h, H and s option	values are expressions containing the
       following constants:

       n   frame count of the input frame starting from	0

       pts presentation	timestamp of the input frame expressed in time base
	   units

       r   frame rate of the input video, NAN if the input frame rate is
	   unknown

       t   timestamp expressed in seconds, NAN if the input timestamp is
	   unknown

       tb  time	base of	the input video

       Examples

       o   Set the hue to 90 degrees and the saturation	to 1.0:

		   hue=h=90:s=1

       o   Same	command	but expressing the hue in radians:

		   hue=H=PI/2:s=1

       o   Rotate hue and make the saturation swing between 0 and 2 over a
	   period of 1 second:

		   hue="H=2*PI*t: s=sin(2*PI*t)+1"

       o   Apply a 3 seconds saturation	fade-in	effect starting	at 0:

		   hue="s=min(t/3\,1)"

	   The general fade-in expression can be written as:

		   hue="s=min(0\, max((t-START)/DURATION\, 1))"

       o   Apply a 3 seconds saturation	fade-out effect	starting at 5 seconds:

		   hue="s=max(0\, min(1\, (8-t)/3))"

	   The general fade-out	expression can be written as:

		   hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"

       Commands

       This filter supports the	following commands:

       b
       s
       h
       H   Modify the hue and/or the saturation	and/or brightness of the input
	   video.  The command accepts the same	syntax of the corresponding
	   option.

	   If the specified expression is not valid, it	is kept	at its current
	   value.

   hysteresis
       Grow first stream into second stream by connecting components.  This
       makes it	possible to build more robust edge masks.

       This filter accepts the following options:

       planes
	   Set which planes will be processed as bitmap, unprocessed planes
	   will	be copied from first stream.  By default value 0xf, all	planes
	   will	be processed.

       threshold
	   Set threshold which is used in filtering. If	pixel component	value
	   is higher than this value filter algorithm for connecting
	   components is activated.  By	default	value is 0.

   idet
       Detect video interlacing	type.

       This filter tries to detect if the input	frames are interlaced,
       progressive, top	or bottom field	first. It will also try	to detect
       fields that are repeated	between	adjacent frames	(a sign	of telecine).

       Single frame detection considers	only immediately adjacent frames when
       classifying each	frame.	Multiple frame detection incorporates the
       classification history of previous frames.

       The filter will log these metadata values:

       single.current_frame
	   Detected type of current frame using	single-frame detection.	One
	   of: ``tff'' (top field first), ``bff'' (bottom field	first),
	   ``progressive'', or ``undetermined''

       single.tff
	   Cumulative number of	frames detected	as top field first using
	   single-frame	detection.

       multiple.tff
	   Cumulative number of	frames detected	as top field first using
	   multiple-frame detection.

       single.bff
	   Cumulative number of	frames detected	as bottom field	first using
	   single-frame	detection.

       multiple.current_frame
	   Detected type of current frame using	multiple-frame detection. One
	   of: ``tff'' (top field first), ``bff'' (bottom field	first),
	   ``progressive'', or ``undetermined''

       multiple.bff
	   Cumulative number of	frames detected	as bottom field	first using
	   multiple-frame detection.

       single.progressive
	   Cumulative number of	frames detected	as progressive using single-
	   frame detection.

       multiple.progressive
	   Cumulative number of	frames detected	as progressive using multiple-
	   frame detection.

       single.undetermined
	   Cumulative number of	frames that could not be classified using
	   single-frame	detection.

       multiple.undetermined
	   Cumulative number of	frames that could not be classified using
	   multiple-frame detection.

       repeated.current_frame
	   Which field in the current frame is repeated	from the last. One of
	   ``neither'',	``top'', or ``bottom''.

       repeated.neither
	   Cumulative number of	frames with no repeated	field.

       repeated.top
	   Cumulative number of	frames with the	top field repeated from	the
	   previous frame's top	field.

       repeated.bottom
	   Cumulative number of	frames with the	bottom field repeated from the
	   previous frame's bottom field.

       The filter accepts the following	options:

       intl_thres
	   Set interlacing threshold.

       prog_thres
	   Set progressive threshold.

       rep_thres
	   Threshold for repeated field	detection.

       half_life
	   Number of frames after which	a given	frame's	contribution to	the
	   statistics is halved	(i.e., it contributes only 0.5 to its
	   classification). The	default	of 0 means that	all frames seen	are
	   given full weight of	1.0 forever.

       analyze_interlaced_flag
	   When	this is	not 0 then idet	will use the specified number of
	   frames to determine if the interlaced flag is accurate, it will not
	   count undetermined frames.  If the flag is found to be accurate it
	   will	be used	without	any further computations, if it	is found to be
	   inaccurate it will be cleared without any further computations.
	   This	allows inserting the idet filter as a low computational	method
	   to clean up the interlaced flag

   il
       Deinterleave or interleave fields.

       This filter allows one to process interlaced images fields without
       deinterlacing them. Deinterleaving splits the input frame into 2	fields
       (so called half pictures). Odd lines are	moved to the top half of the
       output image, even lines	to the bottom half.  You can process (filter)
       them independently and then re-interleave them.

       The filter accepts the following	options:

       luma_mode, l
       chroma_mode, c
       alpha_mode, a
	   Available values for	luma_mode, chroma_mode and alpha_mode are:

	   none
	       Do nothing.

	   deinterleave, d
	       Deinterleave fields, placing one	above the other.

	   interleave, i
	       Interleave fields. Reverse the effect of	deinterleaving.

	   Default value is "none".

       luma_swap, ls
       chroma_swap, cs
       alpha_swap, as
	   Swap	luma/chroma/alpha fields. Exchange even	& odd lines. Default
	   value is 0.

   inflate
       Apply inflate effect to the video.

       This filter replaces the	pixel by the local(3x3)	average	by taking into
       account only values higher than the pixel.

       It accepts the following	options:

       threshold0
       threshold1
       threshold2
       threshold3
	   Limit the maximum change for	each plane, default is 65535.  If 0,
	   plane will remain unchanged.

   interlace
       Simple interlacing filter from progressive contents. This interleaves
       upper (or lower)	lines from odd frames with lower (or upper) lines from
       even frames, halving the	frame rate and preserving image	height.

		  Original	  Original	       New Frame
		  Frame	'j'	 Frame 'j+1'		 (tff)
		 ==========	 ===========	   ==================
		   Line	0  -------------------->    Frame 'j' Line 0
		   Line	1	   Line	1  ---->   Frame 'j+1' Line 1
		   Line	2 --------------------->    Frame 'j' Line 2
		   Line	3	   Line	3  ---->   Frame 'j+1' Line 3
		    ...		    ...			  ...
	       New Frame + 1 will be generated by Frame	'j+2' and Frame	'j+3' and so on

       It accepts the following	optional parameters:

       scan
	   This	determines whether the interlaced frame	is taken from the even
	   (tff	- default) or odd (bff)	lines of the progressive frame.

       lowpass
	   Enable (default) or disable the vertical lowpass filter to avoid
	   twitter interlacing and reduce moire	patterns.

   kerndeint
       Deinterlace input video by applying Donald Graft's adaptive kernel
       deinterling. Work on interlaced parts of	a video	to produce progressive
       frames.

       The description of the accepted parameters follows.

       thresh
	   Set the threshold which affects the filter's	tolerance when
	   determining if a pixel line must be processed. It must be an
	   integer in the range	[0,255]	and defaults to	10. A value of 0 will
	   result in applying the process on every pixels.

       map Paint pixels	exceeding the threshold	value to white if set to 1.
	   Default is 0.

       order
	   Set the fields order. Swap fields if	set to 1, leave	fields alone
	   if 0. Default is 0.

       sharp
	   Enable additional sharpening	if set to 1. Default is	0.

       twoway
	   Enable twoway sharpening if set to 1. Default is 0.

       Examples

       o   Apply default values:

		   kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0

       o   Enable additional sharpening:

		   kerndeint=sharp=1

       o   Paint processed pixels in white:

		   kerndeint=map=1

   lenscorrection
       Correct radial lens distortion

       This filter can be used to correct for radial distortion	as can result
       from the	use of wide angle lenses, and thereby re-rectify the image. To
       find the	right parameters one can use tools available for example as
       part of opencv or simply	trial-and-error.  To use opencv	use the
       calibration sample (under samples/cpp) from the opencv sources and
       extract the k1 and k2 coefficients from the resulting matrix.

       Note that effectively the same filter is	available in the open-source
       tools Krita and Digikam from the	KDE project.

       In contrast to the vignette filter, which can also be used to
       compensate lens errors, this filter corrects the	distortion of the
       image, whereas vignette corrects	the brightness distribution, so	you
       may want	to use both filters together in	certain	cases, though you will
       have to take care of ordering, i.e. whether vignetting should be
       applied before or after lens correction.

       Options

       The filter accepts the following	options:

       cx  Relative x-coordinate of the	focal point of the image, and thereby
	   the center of the distortion. This value has	a range	[0,1] and is
	   expressed as	fractions of the image width.

       cy  Relative y-coordinate of the	focal point of the image, and thereby
	   the center of the distortion. This value has	a range	[0,1] and is
	   expressed as	fractions of the image height.

       k1  Coefficient of the quadratic	correction term. 0.5 means no
	   correction.

       k2  Coefficient of the double quadratic correction term.	0.5 means no
	   correction.

       The formula that	generates the correction is:

       r_src = r_tgt * (1 + k1 * (r_tgt	/ r_0)^2 + k2 *	(r_tgt / r_0)^4)

       where r_0 is halve of the image diagonal	and r_src and r_tgt are	the
       distances from the focal	point in the source and	target images,
       respectively.

   loop
       Loop video frames.

       The filter accepts the following	options:

       loop
	   Set the number of loops.

       size
	   Set maximal size in number of frames.

       start
	   Set first frame of loop.

   lut3d
       Apply a 3D LUT to an input video.

       The filter accepts the following	options:

       file
	   Set the 3D LUT file name.

	   Currently supported formats:

	   3dl AfterEffects

	   cube
	       Iridas

	   dat DaVinci

	   m3d Pandora

       interp
	   Select interpolation	mode.

	   Available values are:

	   nearest
	       Use values from the nearest defined point.

	   trilinear
	       Interpolate values using	the 8 points defining a	cube.

	   tetrahedral
	       Interpolate values using	a tetrahedron.

   lut,	lutrgb,	lutyuv
       Compute a look-up table for binding each	pixel component	input value to
       an output value,	and apply it to	the input video.

       lutyuv applies a	lookup table to	a YUV input video, lutrgb to an	RGB
       input video.

       These filters accept the	following parameters:

       c0  set first pixel component expression

       c1  set second pixel component expression

       c2  set third pixel component expression

       c3  set fourth pixel component expression, corresponds to the alpha
	   component

       r   set red component expression

       g   set green component expression

       b   set blue component expression

       a   alpha component expression

       y   set Y/luminance component expression

       u   set U/Cb component expression

       v   set V/Cr component expression

       Each of them specifies the expression to	use for	computing the lookup
       table for the corresponding pixel component values.

       The exact component associated to each of the c*	options	depends	on the
       format in input.

       The lut filter requires either YUV or RGB pixel formats in input,
       lutrgb requires RGB pixel formats in input, and lutyuv requires YUV.

       The expressions can contain the following constants and functions:

       w
       h   The input width and height.

       val The input value for the pixel component.

       clipval
	   The input value, clipped to the minval-maxval range.

       maxval
	   The maximum value for the pixel component.

       minval
	   The minimum value for the pixel component.

       negval
	   The negated value for the pixel component value, clipped to the
	   minval-maxval range;	it corresponds to the expression
	   "maxval-clipval+minval".

       clip(val)
	   The computed	value in val, clipped to the minval-maxval range.

       gammaval(gamma)
	   The computed	gamma correction value of the pixel component value,
	   clipped to the minval-maxval	range. It corresponds to the
	   expression
	   "pow((clipval-minval)/(maxval-minval)\,gamma)*(maxval-minval)+minval"

       All expressions default to "val".

       Examples

       o   Negate input	video:

		   lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
		   lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"

	   The above is	the same as:

		   lutrgb="r=negval:g=negval:b=negval"
		   lutyuv="y=negval:u=negval:v=negval"

       o   Negate luminance:

		   lutyuv=y=negval

       o   Remove chroma components, turning the video into a graytone image:

		   lutyuv="u=128:v=128"

       o   Apply a luma	burning	effect:

		   lutyuv="y=2*val"

       o   Remove green	and blue components:

		   lutrgb="g=0:b=0"

       o   Set a constant alpha	channel	value on input:

		   format=rgba,lutrgb=a="maxval-minval/2"

       o   Correct luminance gamma by a	factor of 0.5:

		   lutyuv=y=gammaval(0.5)

       o   Discard least significant bits of luma:

		   lutyuv=y='bitand(val, 128+64+32)'

       o   Technicolor like effect:

		   lutyuv=u='(val-maxval/2)*2+maxval/2':v='(val-maxval/2)*2+maxval/2'

   lut2
       Compute and apply a lookup table	from two video inputs.

       This filter accepts the following parameters:

       c0  set first pixel component expression

       c1  set second pixel component expression

       c2  set third pixel component expression

       c3  set fourth pixel component expression, corresponds to the alpha
	   component

       Each of them specifies the expression to	use for	computing the lookup
       table for the corresponding pixel component values.

       The exact component associated to each of the c*	options	depends	on the
       format in inputs.

       The expressions can contain the following constants:

       w
       h   The input width and height.

       x   The first input value for the pixel component.

       y   The second input value for the pixel	component.

       bdx The first input video bit depth.

       bdy The second input video bit depth.

       All expressions default to "x".

       Examples

       o   Highlight differences between two RGB video streams:

		   lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,0,pow(2,bdx)-1)'

       o   Highlight differences between two YUV video streams:

		   lut2='ifnot(x-y,0,pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1):ifnot(x-y,pow(2,bdx-1),pow(2,bdx)-1)'

   maskedclamp
       Clamp the first input stream with the second input and third input
       stream.

       Returns the value of first stream to be between second input stream -
       "undershoot" and	third input stream + "overshoot".

       This filter accepts the following options:

       undershoot
	   Default value is 0.

       overshoot
	   Default value is 0.

       planes
	   Set which planes will be processed as bitmap, unprocessed planes
	   will	be copied from first stream.  By default value 0xf, all	planes
	   will	be processed.

   maskedmerge
       Merge the first input stream with the second input stream using per
       pixel weights in	the third input	stream.

       A value of 0 in the third stream	pixel component	means that pixel
       component from first stream is returned unchanged, while	maximum	value
       (eg. 255	for 8-bit videos) means	that pixel component from second
       stream is returned unchanged. Intermediate values define	the amount of
       merging between both input stream's pixel components.

       This filter accepts the following options:

       planes
	   Set which planes will be processed as bitmap, unprocessed planes
	   will	be copied from first stream.  By default value 0xf, all	planes
	   will	be processed.

   mcdeint
       Apply motion-compensation deinterlacing.

       It needs	one field per frame as input and must thus be used together
       with yadif=1/3 or equivalent.

       This filter accepts the following options:

       mode
	   Set the deinterlacing mode.

	   It accepts one of the following values:

	   fast
	   medium
	   slow
	       use iterative motion estimation

	   extra_slow
	       like slow, but use multiple reference frames.

	   Default value is fast.

       parity
	   Set the picture field parity	assumed	for the	input video. It	must
	   be one of the following values:

	   0, tff
	       assume top field	first

	   1, bff
	       assume bottom field first

	   Default value is bff.

       qp  Set per-block quantization parameter	(QP) used by the internal
	   encoder.

	   Higher values should	result in a smoother motion vector field but
	   less	optimal	individual vectors. Default value is 1.

   mergeplanes
       Merge color channel components from several video streams.

       The filter accepts up to	4 input	streams, and merge selected input
       planes to the output video.

       This filter accepts the following options:

       mapping
	   Set input to	output plane mapping. Default is 0.

	   The mappings	is specified as	a bitmap. It should be specified as a
	   hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the
	   mapping for the first plane of the output stream. 'A' sets the
	   number of the input stream to use (from 0 to	3), and	'a' the	plane
	   number of the corresponding input to	use (from 0 to 3). The rest of
	   the mappings	is similar, 'Bb' describes the mapping for the output
	   stream second plane,	'Cc' describes the mapping for the output
	   stream third	plane and 'Dd' describes the mapping for the output
	   stream fourth plane.

       format
	   Set output pixel format. Default is "yuva444p".

       Examples

       o   Merge three gray video streams of same width	and height into	single
	   video stream:

		   [a0][a1][a2]mergeplanes=0x001020:yuv444p

       o   Merge 1st yuv444p stream and	2nd gray video stream into yuva444p
	   video stream:

		   [a0][a1]mergeplanes=0x00010210:yuva444p

       o   Swap	Y and A	plane in yuva444p stream:

		   format=yuva444p,mergeplanes=0x03010200:yuva444p

       o   Swap	U and V	plane in yuv420p stream:

		   format=yuv420p,mergeplanes=0x000201:yuv420p

       o   Cast	a rgb24	clip to	yuv444p:

		   format=rgb24,mergeplanes=0x000102:yuv444p

   mestimate
       Estimate	and export motion vectors using	block matching algorithms.
       Motion vectors are stored in frame side data to be used by other
       filters.

       This filter accepts the following options:

       method
	   Specify the motion estimation method. Accepts one of	the following
	   values:

	   esa Exhaustive search algorithm.

	   tss Three step search algorithm.

	   tdls
	       Two dimensional logarithmic search algorithm.

	   ntss
	       New three step search algorithm.

	   fss Four step search	algorithm.

	   ds  Diamond search algorithm.

	   hexbs
	       Hexagon-based search algorithm.

	   epzs
	       Enhanced	predictive zonal search	algorithm.

	   umh Uneven multi-hexagon search algorithm.

	   Default value is esa.

       mb_size
	   Macroblock size. Default 16.

       search_param
	   Search parameter. Default 7.

   midequalizer
       Apply Midway Image Equalization effect using two	video streams.

       Midway Image Equalization adjusts a pair	of images to have the same
       histogram, while	maintaining their dynamics as much as possible.	It's
       useful for e.g. matching	exposures from a pair of stereo	cameras.

       This filter has two inputs and one output, which	must be	of same	pixel
       format, but may be of different sizes. The output of filter is first
       input adjusted with midway histogram of both inputs.

       This filter accepts the following option:

       planes
	   Set which planes to process.	Default	is 15, which is	all available
	   planes.

   minterpolate
       Convert the video to specified frame rate using motion interpolation.

       This filter accepts the following options:

       fps Specify the output frame rate. This can be rational e.g.
	   "60000/1001". Frames	are dropped if fps is lower than source	fps.
	   Default 60.

       mi_mode
	   Motion interpolation	mode. Following	values are accepted:

	   dup Duplicate previous or next frame	for interpolating new ones.

	   blend
	       Blend source frames. Interpolated frame is mean of previous and
	       next frames.

	   mci Motion compensated interpolation. Following options are
	       effective when this mode	is selected:

	       mc_mode
		   Motion compensation mode. Following values are accepted:

		   obmc
		       Overlapped block	motion compensation.

		   aobmc
		       Adaptive	overlapped block motion	compensation. Window
		       weighting coefficients are controlled adaptively
		       according to the	reliabilities of the neighboring
		       motion vectors to reduce	oversmoothing.

		   Default mode	is obmc.

	       me_mode
		   Motion estimation mode. Following values are	accepted:

		   bidir
		       Bidirectional motion estimation.	Motion vectors are
		       estimated for each source frame in both forward and
		       backward	directions.

		   bilat
		       Bilateral motion	estimation. Motion vectors are
		       estimated directly for interpolated frame.

		   Default mode	is bilat.

	       me  The algorithm to be used for	motion estimation. Following
		   values are accepted:

		   esa Exhaustive search algorithm.

		   tss Three step search algorithm.

		   tdls
		       Two dimensional logarithmic search algorithm.

		   ntss
		       New three step search algorithm.

		   fss Four step search	algorithm.

		   ds  Diamond search algorithm.

		   hexbs
		       Hexagon-based search algorithm.

		   epzs
		       Enhanced	predictive zonal search	algorithm.

		   umh Uneven multi-hexagon search algorithm.

		   Default algorithm is	epzs.

	       mb_size
		   Macroblock size. Default 16.

	       search_param
		   Motion estimation search parameter. Default 32.

	       vsbmc
		   Enable variable-size	block motion compensation. Motion
		   estimation is applied with smaller block sizes at object
		   boundaries in order to make the them	less blur. Default is
		   0 (disabled).

       scd Scene change	detection method. Scene	change leads motion vectors to
	   be in random	direction. Scene change	detection replace interpolated
	   frames by duplicate ones. May not be	needed for other modes.
	   Following values are	accepted:

	   none
	       Disable scene change detection.

	   fdiff
	       Frame difference. Corresponding pixel values are	compared and
	       if it satisfies scd_threshold scene change is detected.

	   Default method is fdiff.

       scd_threshold
	   Scene change	detection threshold. Default is	5.0.

   mpdecimate
       Drop frames that	do not differ greatly from the previous	frame in order
       to reduce frame rate.

       The main	use of this filter is for very-low-bitrate encoding (e.g.
       streaming over dialup modem), but it could in theory be used for	fixing
       movies that were	inverse-telecined incorrectly.

       A description of	the accepted options follows.

       max Set the maximum number of consecutive frames	which can be dropped
	   (if positive), or the minimum interval between dropped frames (if
	   negative). If the value is 0, the frame is dropped unregarding the
	   number of previous sequentially dropped frames.

	   Default value is 0.

       hi
       lo
       frac
	   Set the dropping threshold values.

	   Values for hi and lo	are for	8x8 pixel blocks and represent actual
	   pixel value differences, so a threshold of 64 corresponds to	1 unit
	   of difference for each pixel, or the	same spread out	differently
	   over	the block.

	   A frame is a	candidate for dropping if no 8x8 blocks	differ by more
	   than	a threshold of hi, and if no more than frac blocks (1 meaning
	   the whole image) differ by more than	a threshold of lo.

	   Default value for hi	is 64*12, default value	for lo is 64*5,	and
	   default value for frac is 0.33.

   negate
       Negate input video.

       It accepts an integer in	input; if non-zero it negates the alpha
       component (if available). The default value in input is 0.

   nlmeans
       Denoise frames using Non-Local Means algorithm.

       Each pixel is adjusted by looking for other pixels with similar
       contexts. This context similarity is defined by comparing their
       surrounding patches of size pxp.	Patches	are searched in	an area	of rxr
       around the pixel.

       Note that the research area defines centers for patches,	which means
       some patches will be made of pixels outside that	research area.

       The filter accepts the following	options.

       s   Set denoising strength.

       p   Set patch size.

       pc  Same	as p but for chroma planes.

	   The default value is	0 and means automatic.

       r   Set research	size.

       rc  Same	as r but for chroma planes.

	   The default value is	0 and means automatic.

   nnedi
       Deinterlace video using neural network edge directed interpolation.

       This filter accepts the following options:

       weights
	   Mandatory option, without binary file filter	can not	work.
	   Currently file can be found here:
	   https://github.com/dubhater/vapoursynth-nnedi3/blob/master/src/nnedi3_weights.bin

       deint
	   Set which frames to deinterlace, by default it is "all".  Can be
	   "all" or "interlaced".

       field
	   Set mode of operation.

	   Can be one of the following:

	   af  Use frame flags,	both fields.

	   a   Use frame flags,	single field.

	   t   Use top field only.

	   b   Use bottom field	only.

	   tf  Use both	fields,	top first.

	   bf  Use both	fields,	bottom first.

       planes
	   Set which planes to process,	by default filter process all frames.

       nsize
	   Set size of local neighborhood around each pixel, used by the
	   predictor neural network.

	   Can be one of the following:

	   s8x6
	   s16x6
	   s32x6
	   s48x6
	   s8x4
	   s16x4
	   s32x4
       nns Set the number of neurons in	predicctor neural network.  Can	be one
	   of the following:

	   n16
	   n32
	   n64
	   n128
	   n256
       qual
	   Controls the	number of different neural network predictions that
	   are blended together	to compute the final output value. Can be
	   "fast", default or "slow".

       etype
	   Set which set of weights to use in the predictor.  Can be one of
	   the following:

	   a   weights trained to minimize absolute error

	   s   weights trained to minimize squared error

       pscrn
	   Controls whether or not the prescreener neural network is used to
	   decide which	pixels should be processed by the predictor neural
	   network and which can be handled by simple cubic interpolation.
	   The prescreener is trained to know whether cubic interpolation will
	   be sufficient for a pixel or	whether	it should be predicted by the
	   predictor nn.  The computational complexity of the prescreener nn
	   is much less	than that of the predictor nn. Since most pixels can
	   be handled by cubic interpolation, using the	prescreener generally
	   results in much faster processing.  The prescreener is pretty
	   accurate, so	the difference between using it	and not	using it is
	   almost always unnoticeable.

	   Can be one of the following:

	   none
	   original
	   new

	   Default is "new".

       fapprox
	   Set various debugging flags.

   noformat
       Force libavfilter not to	use any	of the specified pixel formats for the
       input to	the next filter.

       It accepts the following	parameters:

       pix_fmts
	   A '|'-separated list	of pixel format	names, such as
	   apix_fmts=yuv420p|monow|rgb24".

       Examples

       o   Force libavfilter to	use a format different from yuv420p for	the
	   input to the	vflip filter:

		   noformat=pix_fmts=yuv420p,vflip

       o   Convert the input video to any of the formats not contained in the
	   list:

		   noformat=yuv420p|yuv444p|yuv410p

   noise
       Add noise on video input	frame.

       The filter accepts the following	options:

       all_seed
       c0_seed
       c1_seed
       c2_seed
       c3_seed
	   Set noise seed for specific pixel component or all pixel components
	   in case of all_seed.	Default	value is 123457.

       all_strength, alls
       c0_strength, c0s
       c1_strength, c1s
       c2_strength, c2s
       c3_strength, c3s
	   Set noise strength for specific pixel component or all pixel
	   components in case all_strength. Default value is 0.	Allowed	range
	   is [0, 100].

       all_flags, allf
       c0_flags, c0f
       c1_flags, c1f
       c2_flags, c2f
       c3_flags, c3f
	   Set pixel component flags or	set flags for all components if
	   all_flags.  Available values	for component flags are:

	   a   averaged	temporal noise (smoother)

	   p   mix random noise	with a (semi)regular pattern

	   t   temporal	noise (noise pattern changes between frames)

	   u   uniform noise (gaussian otherwise)

       Examples

       Add temporal and	uniform	noise to input video:

	       noise=alls=20:allf=t+u

   null
       Pass the	video source unchanged to the output.

   ocr
       Optical Character Recognition

       This filter uses	Tesseract for optical character	recognition.

       It accepts the following	options:

       datapath
	   Set datapath	to tesseract data. Default is to use whatever was set
	   at installation.

       language
	   Set language, default is "eng".

       whitelist
	   Set character whitelist.

       blacklist
	   Set character blacklist.

       The filter exports recognized text as the frame metadata
       "lavfi.ocr.text".

   ocv
       Apply a video transform using libopencv.

       To enable this filter, install the libopencv library and	headers	and
       configure FFmpeg	with "--enable-libopencv".

       It accepts the following	parameters:

       filter_name
	   The name of the libopencv filter to apply.

       filter_params
	   The parameters to pass to the libopencv filter. If not specified,
	   the default values are assumed.

       Refer to	the official libopencv documentation for more precise
       information:
       <http://docs.opencv.org/master/modules/imgproc/doc/filtering.html>

       Several libopencv filters are supported;	see the	following subsections.

       dilate

       Dilate an image by using	a specific structuring element.	 It
       corresponds to the libopencv function "cvDilate".

       It accepts the parameters: struct_el|nb_iterations.

       struct_el represents a structuring element, and has the syntax:
       colsxrows+anchor_xxanchor_y/shape

       cols and	rows represent the number of columns and rows of the
       structuring element, anchor_x and anchor_y the anchor point, and	shape
       the shape for the structuring element. shape must be "rect", "cross",
       "ellipse", or "custom".

       If the value for	shape is "custom", it must be followed by a string of
       the form	"=filename". The file with name	filename is assumed to
       represent a binary image, with each printable character corresponding
       to a bright pixel. When a custom	shape is used, cols and	rows are
       ignored,	the number or columns and rows of the read file	are assumed
       instead.

       The default value for struct_el is "3x3+0x0/rect".

       nb_iterations specifies the number of times the transform is applied to
       the image, and defaults to 1.

       Some examples:

	       # Use the default values
	       ocv=dilate

	       # Dilate	using a	structuring element with a 5x5 cross, iterating	two times
	       ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2

	       # Read the shape	from the file diamond.shape, iterating two times.
	       # The file diamond.shape	may contain a pattern of characters like this
	       #   *
	       #  ***
	       # *****
	       #  ***
	       #   *
	       # The specified columns and rows	are ignored
	       # but the anchor	point coordinates are not
	       ocv=dilate:0x0+2x2/custom=diamond.shape|2

       erode

       Erode an	image by using a specific structuring element.	It corresponds
       to the libopencv	function "cvErode".

       It accepts the parameters: struct_el:nb_iterations, with	the same
       syntax and semantics as the dilate filter.

       smooth

       Smooth the input	video.

       The filter takes	the following parameters:
       type|param1|param2|param3|param4.

       type is the type	of smooth filter to apply, and must be one of the
       following values: "blur", "blur_no_scale", "median", "gaussian",	or
       "bilateral". The	default	value is "gaussian".

       The meaning of param1, param2, param3, and param4 depend	on the smooth
       type. param1 and	param2 accept integer positive values or 0. param3 and
       param4 accept floating point values.

       The default value for param1 is 3. The default value for	the other
       parameters is 0.

       These parameters	correspond to the parameters assigned to the libopencv
       function	"cvSmooth".

   overlay
       Overlay one video on top	of another.

       It takes	two inputs and has one output. The first input is the "main"
       video on	which the second input is overlaid.

       It accepts the following	parameters:

       A description of	the accepted options follows.

       x
       y   Set the expression for the x	and y coordinates of the overlaid
	   video on the	main video. Default value is "0" for both expressions.
	   In case the expression is invalid, it is set	to a huge value
	   (meaning that the overlay will not be displayed within the output
	   visible area).

       eof_action
	   The action to take when EOF is encountered on the secondary input;
	   it accepts one of the following values:

	   repeat
	       Repeat the last frame (the default).

	   endall
	       End both	streams.

	   pass
	       Pass the	main input through.

       eval
	   Set when the	expressions for	x, and y are evaluated.

	   It accepts the following values:

	   init
	       only evaluate expressions once during the filter	initialization
	       or when a command is processed

	   frame
	       evaluate	expressions for	each incoming frame

	   Default value is frame.

       shortest
	   If set to 1,	force the output to terminate when the shortest	input
	   terminates. Default value is	0.

       format
	   Set the format for the output video.

	   It accepts the following values:

	   yuv420
	       force YUV420 output

	   yuv422
	       force YUV422 output

	   yuv444
	       force YUV444 output

	   rgb force packed RGB	output

	   gbrp
	       force planar RGB	output

	   Default value is yuv420.

       rgb (deprecated)
	   If set to 1,	force the filter to accept inputs in the RGB color
	   space. Default value	is 0. This option is deprecated, use format
	   instead.

       repeatlast
	   If set to 1,	force the filter to draw the last overlay frame	over
	   the main input until	the end	of the stream. A value of 0 disables
	   this	behavior. Default value	is 1.

       The x, and y expressions	can contain the	following parameters.

       main_w, W
       main_h, H
	   The main input width	and height.

       overlay_w, w
       overlay_h, h
	   The overlay input width and height.

       x
       y   The computed	values for x and y. They are evaluated for each	new
	   frame.

       hsub
       vsub
	   horizontal and vertical chroma subsample values of the output
	   format. For example for the pixel format "yuv422p" hsub is 2	and
	   vsub	is 1.

       n   the number of input frame, starting from 0

       pos the position	in the file of the input frame,	NAN if unknown

       t   The timestamp, expressed in seconds.	It's NAN if the	input
	   timestamp is	unknown.

       Note that the n,	pos, t variables are available only when evaluation is
       done per	frame, and will	evaluate to NAN	when eval is set to init.

       Be aware	that frames are	taken from each	input video in timestamp
       order, hence, if	their initial timestamps differ, it is a good idea to
       pass the	two inputs through a setpts=PTS-STARTPTS filter	to have	them
       begin in	the same zero timestamp, as the	example	for the	movie filter
       does.

       You can chain together more overlays but	you should test	the efficiency
       of such approach.

       Commands

       This filter supports the	following commands:

       x
       y   Modify the x	and y of the overlay input.  The command accepts the
	   same	syntax of the corresponding option.

	   If the specified expression is not valid, it	is kept	at its current
	   value.

       Examples

       o   Draw	the overlay at 10 pixels from the bottom right corner of the
	   main	video:

		   overlay=main_w-overlay_w-10:main_h-overlay_h-10

	   Using named options the example above becomes:

		   overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10

       o   Insert a transparent	PNG logo in the	bottom left corner of the
	   input, using	the ffmpeg tool	with the "-filter_complex" option:

		   ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output

       o   Insert 2 different transparent PNG logos (second logo on bottom
	   right corner) using the ffmpeg tool:

		   ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output

       o   Add a transparent color layer on top	of the main video; "WxH" must
	   specify the size of the main	input to the overlay filter:

		   color=color=red@.3:size=WxH [over]; [in][over] overlay [out]

       o   Play	an original video and a	filtered version (here with the
	   deshake filter) side	by side	using the ffplay tool:

		   ffplay input.avi -vf	'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'

	   The above command is	the same as:

		   ffplay input.avi -vf	'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'

       o   Make	a sliding overlay appearing from the left to the right top
	   part	of the screen starting since time 2:

		   overlay=x='if(gte(t,2), -w+(t-2)*20,	NAN)':y=0

       o   Compose output by putting two input videos side to side:

		   ffmpeg -i left.avi -i right.avi -filter_complex "
		   nullsrc=size=200x100	[background];
		   [0:v] setpts=PTS-STARTPTS, scale=100x100 [left];
		   [1:v] setpts=PTS-STARTPTS, scale=100x100 [right];
		   [background][left]	    overlay=shortest=1	     [background+left];
		   [background+left][right] overlay=shortest=1:x=100 [left+right]
		   "

       o   Mask	10-20 seconds of a video by applying the delogo	filter to a
	   section

		   ffmpeg -i test.avi -codec:v:0 wmv2 -ar 11025	-b:v 9000k
		   -vf '[in]split[split_main][split_delogo];[split_delogo]trim=start=360:end=371,delogo=0:0:640:480[delogoed];[split_main][delogoed]overlay=eof_action=pass[out]'
		   masked.avi

       o   Chain several overlays in cascade:

		   nullsrc=s=200x200 [bg];
		   testsrc=s=100x100, split=4 [in0][in1][in2][in3];
		   [in0] lutrgb=r=0, [bg]   overlay=0:0	    [mid0];
		   [in1] lutrgb=g=0, [mid0] overlay=100:0   [mid1];
		   [in2] lutrgb=b=0, [mid1] overlay=0:100   [mid2];
		   [in3] null,	     [mid2] overlay=100:100 [out0]

   owdenoise
       Apply Overcomplete Wavelet denoiser.

       The filter accepts the following	options:

       depth
	   Set depth.

	   Larger depth	values will denoise lower frequency components more,
	   but slow down filtering.

	   Must	be an int in the range 8-16, default is	8.

       luma_strength, ls
	   Set luma strength.

	   Must	be a double value in the range 0-1000, default is 1.0.

       chroma_strength,	cs
	   Set chroma strength.

	   Must	be a double value in the range 0-1000, default is 1.0.

   pad
       Add paddings to the input image,	and place the original input at	the
       provided	x, y coordinates.

       It accepts the following	parameters:

       width, w
       height, h
	   Specify an expression for the size of the output image with the
	   paddings added. If the value	for width or height is 0, the
	   corresponding input size is used for	the output.

	   The width expression	can reference the value	set by the height
	   expression, and vice	versa.

	   The default value of	width and height is 0.

       x
       y   Specify the offsets to place	the input image	at within the padded
	   area, with respect to the top/left border of	the output image.

	   The x expression can	reference the value set	by the y expression,
	   and vice versa.

	   The default value of	x and y	is 0.

       color
	   Specify the color of	the padded area. For the syntax	of this
	   option, check the "Color" section in	the ffmpeg-utils manual.

	   The default value of	color is "black".

       eval
	   Specify when	to evaluate  width, height, x and y expression.

	   It accepts the following values:

	   init
	       Only evaluate expressions once during the filter	initialization
	       or when a command is processed.

	   frame
	       Evaluate	expressions for	each incoming frame.

	   Default value is init.

       The value for the width,	height,	x, and y options are expressions
       containing the following	constants:

       in_w
       in_h
	   The input video width and height.

       iw
       ih  These are the same as in_w and in_h.

       out_w
       out_h
	   The output width and	height (the size of the	padded area), as
	   specified by	the width and height expressions.

       ow
       oh  These are the same as out_w and out_h.

       x
       y   The x and y offsets as specified by the x and y expressions,	or NAN
	   if not yet specified.

       a   same	as iw /	ih

       sar input sample	aspect ratio

       dar input display aspect	ratio, it is the same as (iw / ih) * sar

       hsub
       vsub
	   The horizontal and vertical chroma subsample	values.	For example
	   for the pixel format	"yuv422p" hsub is 2 and	vsub is	1.

       Examples

       o   Add paddings	with the color "violet"	to the input video. The	output
	   video size is 640x480, and the top-left corner of the input video
	   is placed at	column 0, row 40

		   pad=640:480:0:40:violet

	   The example above is	equivalent to the following command:

		   pad=width=640:height=480:x=0:y=40:color=violet

       o   Pad the input to get	an output with dimensions increased by 3/2,
	   and put the input video at the center of the	padded area:

		   pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"

       o   Pad the input to get	a squared output with size equal to the
	   maximum value between the input width and height, and put the input
	   video at the	center of the padded area:

		   pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"

       o   Pad the input to get	a final	w/h ratio of 16:9:

		   pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"

       o   In case of anamorphic video,	in order to set	the output display
	   aspect correctly, it	is necessary to	use sar	in the expression,
	   according to	the relation:

		   (ih * X / ih) * sar = output_dar
		   X = output_dar / sar

	   Thus	the previous example needs to be modified to:

		   pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2"

       o   Double the output size and put the input video in the bottom-right
	   corner of the output	padded area:

		   pad="2*iw:2*ih:ow-iw:oh-ih"

   palettegen
       Generate	one palette for	a whole	video stream.

       It accepts the following	options:

       max_colors
	   Set the maximum number of colors to quantize	in the palette.	 Note:
	   the palette will still contain 256 colors; the unused palette
	   entries will	be black.

       reserve_transparent
	   Create a palette of 255 colors maximum and reserve the last one for
	   transparency. Reserving the transparency color is useful for	GIF
	   optimization.  If not set, the maximum of colors in the palette
	   will	be 256.	You probably want to disable this option for a
	   standalone image.  Set by default.

       stats_mode
	   Set statistics mode.

	   It accepts the following values:

	   full
	       Compute full frame histograms.

	   diff
	       Compute histograms only for the part that differs from previous
	       frame. This might be relevant to	give more importance to	the
	       moving part of your input if the	background is static.

	   single
	       Compute new histogram for each frame.

	   Default value is full.

       The filter also exports the frame metadata "lavfi.color_quant_ratio"
       ("nb_color_in / nb_color_out") which you	can use	to evaluate the	degree
       of color	quantization of	the palette. This information is also visible
       at info logging level.

       Examples

       o   Generate a representative palette of	a given	video using ffmpeg:

		   ffmpeg -i input.mkv -vf palettegen palette.png

   paletteuse
       Use a palette to	downsample an input video stream.

       The filter takes	two inputs: one	video stream and a palette. The
       palette must be a 256 pixels image.

       It accepts the following	options:

       dither
	   Select dithering mode. Available algorithms are:

	   bayer
	       Ordered 8x8 bayer dithering (deterministic)

	   heckbert
	       Dithering as defined by Paul Heckbert in	1982 (simple error
	       diffusion).  Note: this dithering is sometimes considered
	       "wrong" and is included as a reference.

	   floyd_steinberg
	       Floyd and Steingberg dithering (error diffusion)

	   sierra2
	       Frankie Sierra dithering	v2 (error diffusion)

	   sierra2_4a
	       Frankie Sierra dithering	v2 "Lite" (error diffusion)

	   Default is sierra2_4a.

       bayer_scale
	   When	bayer dithering	is selected, this option defines the scale of
	   the pattern (how much the crosshatch	pattern	is visible). A low
	   value means more visible pattern for	less banding, and higher value
	   means less visible pattern at the cost of more banding.

	   The option must be an integer value in the range [0,5]. Default is
	   2.

       diff_mode
	   If set, define the zone to process

	   rectangle
	       Only the	changing rectangle will	be reprocessed.	This is
	       similar to GIF cropping/offsetting compression mechanism. This
	       option can be useful for	speed if only a	part of	the image is
	       changing, and has use cases such	as limiting the	scope of the
	       error diffusal dither to	the rectangle that bounds the moving
	       scene (it leads to more deterministic output if the scene
	       doesn't change much, and	as a result less moving	noise and
	       better GIF compression).

	   Default is none.

       new Take	new palette for	each output frame.

       Examples

       o   Use a palette (generated for	example	with palettegen) to encode a
	   GIF using ffmpeg:

		   ffmpeg -i input.mkv -i palette.png -lavfi paletteuse	output.gif

   perspective
       Correct perspective of video not	recorded perpendicular to the screen.

       A description of	the accepted parameters	follows.

       x0
       y0
       x1
       y1
       x2
       y2
       x3
       y3  Set coordinates expression for top left, top	right, bottom left and
	   bottom right	corners.  Default values are "0:0:W:0:0:H:W:H" with
	   which perspective will remain unchanged.  If	the "sense" option is
	   set to "source", then the specified points will be sent to the
	   corners of the destination. If the "sense" option is	set to
	   "destination", then the corners of the source will be sent to the
	   specified coordinates.

	   The expressions can use the following variables:

	   W
	   H   the width and height of video frame.

	   in  Input frame count.

	   on  Output frame count.

       interpolation
	   Set interpolation for perspective correction.

	   It accepts the following values:

	   linear
	   cubic

	   Default value is linear.

       sense
	   Set interpretation of coordinate options.

	   It accepts the following values:

	   0, source
	       Send point in the source	specified by the given coordinates to
	       the corners of the destination.

	   1, destination
	       Send the	corners	of the source to the point in the destination
	       specified by the	given coordinates.

	       Default value is	source.

       eval
	   Set when the	expressions for	coordinates x0,y0,...x3,y3 are
	   evaluated.

	   It accepts the following values:

	   init
	       only evaluate expressions once during the filter	initialization
	       or when a command is processed

	   frame
	       evaluate	expressions for	each incoming frame

	   Default value is init.

   phase
       Delay interlaced	video by one field time	so that	the field order
       changes.

       The intended use	is to fix PAL movies that have been captured with the
       opposite	field order to the film-to-video transfer.

       A description of	the accepted parameters	follows.

       mode
	   Set phase mode.

	   It accepts the following values:

	   t   Capture field order top-first, transfer bottom-first.  Filter
	       will delay the bottom field.

	   b   Capture field order bottom-first, transfer top-first.  Filter
	       will delay the top field.

	   p   Capture and transfer with the same field	order. This mode only
	       exists for the documentation of the other options to refer to,
	       but if you actually select it, the filter will faithfully do
	       nothing.

	   a   Capture field order determined automatically by field flags,
	       transfer	opposite.  Filter selects among	t and b	modes on a
	       frame by	frame basis using field	flags. If no field information
	       is available, then this works just like u.

	   u   Capture unknown or varying, transfer opposite.  Filter selects
	       among t and b on	a frame	by frame basis by analyzing the	images
	       and selecting the alternative that produces best	match between
	       the fields.

	   T   Capture top-first, transfer unknown or varying.	Filter selects
	       among t and p using image analysis.

	   B   Capture bottom-first, transfer unknown or varying.  Filter
	       selects among b and p using image analysis.

	   A   Capture determined by field flags, transfer unknown or varying.
	       Filter selects among t, b and p using field flags and image
	       analysis. If no field information is available, then this works
	       just like U. This is the	default	mode.

	   U   Both capture and	transfer unknown or varying.  Filter selects
	       among t,	b and p	using image analysis only.

   pixdesctest
       Pixel format descriptor test filter, mainly useful for internal
       testing.	The output video should	be equal to the	input video.

       For example:

	       format=monow, pixdesctest

       can be used to test the monowhite pixel format descriptor definition.

   pp
       Enable the specified chain of postprocessing subfilters using
       libpostproc. This library should	be automatically selected with a GPL
       build ("--enable-gpl").	Subfilters must	be separated by	'/' and	can be
       disabled	by prepending a	'-'.  Each subfilter and some options have a
       short and a long	name that can be used interchangeably, i.e. dr/dering
       are the same.

       The filters accept the following	options:

       subfilters
	   Set postprocessing subfilters string.

       All subfilters share common options to determine	their scope:

       a/autoq
	   Honor the quality commands for this subfilter.

       c/chrom
	   Do chrominance filtering, too (default).

       y/nochrom
	   Do luminance	filtering only (no chrominance).

       n/noluma
	   Do chrominance filtering only (no luminance).

       These options can be appended after the subfilter name, separated by a
       '|'.

       Available subfilters are:

       hb/hdeblock[|difference[|flatness]]
	   Horizontal deblocking filter

	   difference
	       Difference factor where higher values mean more deblocking
	       (default: 32).

	   flatness
	       Flatness	threshold where	lower values mean more deblocking
	       (default: 39).

       vb/vdeblock[|difference[|flatness]]
	   Vertical deblocking filter

	   difference
	       Difference factor where higher values mean more deblocking
	       (default: 32).

	   flatness
	       Flatness	threshold where	lower values mean more deblocking
	       (default: 39).

       ha/hadeblock[|difference[|flatness]]
	   Accurate horizontal deblocking filter

	   difference
	       Difference factor where higher values mean more deblocking
	       (default: 32).

	   flatness
	       Flatness	threshold where	lower values mean more deblocking
	       (default: 39).

       va/vadeblock[|difference[|flatness]]
	   Accurate vertical deblocking	filter

	   difference
	       Difference factor where higher values mean more deblocking
	       (default: 32).

	   flatness
	       Flatness	threshold where	lower values mean more deblocking
	       (default: 39).

       The horizontal and vertical deblocking filters share the	difference and
       flatness	values so you cannot set different horizontal and vertical
       thresholds.

       h1/x1hdeblock
	   Experimental	horizontal deblocking filter

       v1/x1vdeblock
	   Experimental	vertical deblocking filter

       dr/dering
	   Deringing filter

       tn/tmpnoise[|threshold1[|threshold2[|threshold3]]], temporal noise
       reducer
	   threshold1
	       larger -> stronger filtering

	   threshold2
	       larger -> stronger filtering

	   threshold3
	       larger -> stronger filtering

       al/autolevels[:f/fullyrange], automatic brightness / contrast
       correction
	   f/fullyrange
	       Stretch luminance to "0-255".

       lb/linblenddeint
	   Linear blend	deinterlacing filter that deinterlaces the given block
	   by filtering	all lines with a "(1 2 1)" filter.

       li/linipoldeint
	   Linear interpolating	deinterlacing filter that deinterlaces the
	   given block by linearly interpolating every second line.

       ci/cubicipoldeint
	   Cubic interpolating deinterlacing filter deinterlaces the given
	   block by cubically interpolating every second line.

       md/mediandeint
	   Median deinterlacing	filter that deinterlaces the given block by
	   applying a median filter to every second line.

       fd/ffmpegdeint
	   FFmpeg deinterlacing	filter that deinterlaces the given block by
	   filtering every second line with a "(-1 4 2 4 -1)" filter.

       l5/lowpass5
	   Vertically applied FIR lowpass deinterlacing	filter that
	   deinterlaces	the given block	by filtering all lines with a "(-1 2 6
	   2 -1)" filter.

       fq/forceQuant[|quantizer]
	   Overrides the quantizer table from the input	with the constant
	   quantizer you specify.

	   quantizer
	       Quantizer to use

       de/default
	   Default pp filter combination ("hb|a,vb|a,dr|a")

       fa/fast
	   Fast	pp filter combination ("h1|a,v1|a,dr|a")

       ac  High	quality	pp filter combination ("ha|a|128|7,va|a,dr|a")

       Examples

       o   Apply horizontal and	vertical deblocking, deringing and automatic
	   brightness/contrast:

		   pp=hb/vb/dr/al

       o   Apply default filters without brightness/contrast correction:

		   pp=de/-al

       o   Apply default filters and temporal denoiser:

		   pp=default/tmpnoise|1|2|3

       o   Apply deblocking on luminance only, and switch vertical deblocking
	   on or off automatically depending on	available CPU time:

		   pp=hb|y/vb|a

   pp7
       Apply Postprocessing filter 7. It is variant of the spp filter, similar
       to spp =	6 with 7 point DCT, where only the center sample is used after
       IDCT.

       The filter accepts the following	options:

       qp  Force a constant quantization parameter. It accepts an integer in
	   range 0 to 63. If not set, the filter will use the QP from the
	   video stream	(if available).

       mode
	   Set thresholding mode. Available modes are:

	   hard
	       Set hard	thresholding.

	   soft
	       Set soft	thresholding (better de-ringing	effect,	but likely
	       blurrier).

	   medium
	       Set medium thresholding (good results, default).

   premultiply
       Apply alpha premultiply effect to input video stream using first	plane
       of second stream	as alpha.

       Both streams must have same dimensions and same pixel format.

   prewitt
       Apply prewitt operator to input video stream.

       The filter accepts the following	option:

       planes
	   Set which planes will be processed, unprocessed planes will be
	   copied.  By default value 0xf, all planes will be processed.

       scale
	   Set value which will	be multiplied with filtered result.

       delta
	   Set value which will	be added to filtered result.

   psnr
       Obtain the average, maximum and minimum PSNR (Peak Signal to Noise
       Ratio) between two input	videos.

       This filter takes in input two input videos, the	first input is
       considered the "main" source and	is passed unchanged to the output. The
       second input is used as a "reference" video for computing the PSNR.

       Both video inputs must have the same resolution and pixel format	for
       this filter to work correctly. Also it assumes that both	inputs have
       the same	number of frames, which	are compared one by one.

       The obtained average PSNR is printed through the	logging	system.

       The filter stores the accumulated MSE (mean squared error) of each
       frame, and at the end of	the processing it is averaged across all
       frames equally, and the following formula is applied to obtain the
       PSNR:

	       PSNR = 10*log10(MAX^2/MSE)

       Where MAX is the	average	of the maximum values of each component	of the
       image.

       The description of the accepted parameters follows.

       stats_file, f
	   If specified	the filter will	use the	named file to save the PSNR of
	   each	individual frame. When filename	equals "-" the data is sent to
	   standard output.

       stats_version
	   Specifies which version of the stats	file format to use. Details of
	   each	format are written below.  Default value is 1.

       stats_add_max
	   Determines whether the max value is output to the stats log.
	   Default value is 0.	Requires stats_version >= 2. If	this is	set
	   and stats_version < 2, the filter will return an error.

       The file	printed	if stats_file is selected, contains a sequence of
       key/value pairs of the form key:value for each compared couple of
       frames.

       If a stats_version greater than 1 is specified, a header	line precedes
       the list	of per-frame-pair stats, with key value	pairs following	the
       frame format with the following parameters:

       psnr_log_version
	   The version of the log file format. Will match stats_version.

       fields
	   A comma separated list of the per-frame-pair	parameters included in
	   the log.

       A description of	each shown per-frame-pair parameter follows:

       n   sequential number of	the input frame, starting from 1

       mse_avg
	   Mean	Square Error pixel-by-pixel average difference of the compared
	   frames, averaged over all the image components.

       mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a
	   Mean	Square Error pixel-by-pixel average difference of the compared
	   frames for the component specified by the suffix.

       psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a
	   Peak	Signal to Noise	ratio of the compared frames for the component
	   specified by	the suffix.

       max_avg,	max_y, max_u, max_v
	   Maximum allowed value for each channel, and average over all
	   channels.

       For example:

	       movie=ref_movie.mpg, setpts=PTS-STARTPTS	[main];
	       [main][ref] psnr="stats_file=stats.log" [out]

       On this example the input file being processed is compared with the
       reference file ref_movie.mpg. The PSNR of each individual frame is
       stored in stats.log.

   pullup
       Pulldown	reversal (inverse telecine) filter, capable of handling	mixed
       hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps
       progressive content.

       The pullup filter is designed to	take advantage of future context in
       making its decisions. This filter is stateless in the sense that	it
       does not	lock onto a pattern to follow, but it instead looks forward to
       the following fields in order to	identify matches and rebuild
       progressive frames.

       To produce content with an even framerate, insert the fps filter	after
       pullup, use "fps=24000/1001" if the input frame rate is 29.97fps,
       "fps=24"	for 30fps and the (rare) telecined 25fps input.

       The filter accepts the following	options:

       jl
       jr
       jt
       jb  These options set the amount	of "junk" to ignore at the left,
	   right, top, and bottom of the image,	respectively. Left and right
	   are in units	of 8 pixels, while top and bottom are in units of 2
	   lines.  The default is 8 pixels on each side.

       sb  Set the strict breaks. Setting this option to 1 will	reduce the
	   chances of filter generating	an occasional mismatched frame,	but it
	   may also cause an excessive number of frames	to be dropped during
	   high	motion sequences.  Conversely, setting it to -1	will make
	   filter match	fields more easily.  This may help processing of video
	   where there is slight blurring between the fields, but may also
	   cause there to be interlaced	frames in the output.  Default value
	   is 0.

       mp  Set the metric plane	to use.	It accepts the following values:

	   l   Use luma	plane.

	   u   Use chroma blue plane.

	   v   Use chroma red plane.

	   This	option may be set to use chroma	plane instead of the default
	   luma	plane for doing	filter's computations. This may	improve
	   accuracy on very clean source material, but more likely will
	   decrease accuracy, especially if there is chroma noise (rainbow
	   effect) or any grayscale video.  The	main purpose of	setting	mp to
	   a chroma plane is to	reduce CPU load	and make pullup	usable in
	   realtime on slow machines.

       For best	results	(without duplicated frames in the output file) it is
       necessary to change the output frame rate. For example, to inverse
       telecine	NTSC input:

	       ffmpeg -i input -vf pullup -r 24000/1001	...

   qp
       Change video quantization parameters (QP).

       The filter accepts the following	option:

       qp  Set expression for quantization parameter.

       The expression is evaluated through the eval API	and can	contain, among
       others, the following constants:

       known
	   1 if	index is not 129, 0 otherwise.

       qp  Sequentional	index starting from -129 to 128.

       Examples

       o   Some	equation like:

		   qp=2+2*sin(PI*qp)

   random
       Flush video frames from internal	cache of frames	into a random order.
       No frame	is discarded.  Inspired	by frei0r nervous filter.

       frames
	   Set size in number of frames	of internal cache, in range from 2 to
	   512.	Default	is 30.

       seed
	   Set seed for	random number generator, must be an integer included
	   between 0 and "UINT32_MAX". If not specified, or if explicitly set
	   to less than	0, the filter will try to use a	good random seed on a
	   best	effort basis.

   readeia608
       Read closed captioning (EIA-608)	information from the top lines of a
       video frame.

       This filter adds	frame metadata for "lavfi.readeia608.X.cc" and
       "lavfi.readeia608.X.line", where	"X" is the number of the identified
       line with EIA-608 data (starting	from 0). A description of each
       metadata	value follows:

       lavfi.readeia608.X.cc
	   The two bytes stored	as EIA-608 data	(printed in hexadecimal).

       lavfi.readeia608.X.line
	   The number of the line on which the EIA-608 data was	identified and
	   read.

       This filter accepts the following options:

       scan_min
	   Set the line	to start scanning for EIA-608 data. Default is 0.

       scan_max
	   Set the line	to end scanning	for EIA-608 data. Default is 29.

       mac Set minimal acceptable amplitude change for sync codes detection.
	   Default is 0.2. Allowed range is "[0.001 - 1]".

       spw Set the ratio of width reserved for sync code detection.  Default
	   is 0.27. Allowed range is "[0.01 - 0.7]".

       mhd Set the max peaks height difference for sync	code detection.
	   Default is 0.1. Allowed range is "[0.0 - 0.5]".

       mpd Set max peaks period	difference for sync code detection.  Default
	   is 0.1. Allowed range is "[0.0 - 0.5]".

       msd Set the first two max start code bits differences.  Default is
	   0.02. Allowed range is "[0.0	- 0.5]".

       bhd Set the minimum ratio of bits height	compared to 3rd	start code
	   bit.	 Default is 0.75. Allowed range	is "[0.01 - 1]".

       th_w
	   Set the white color threshold. Default is 0.35. Allowed range is
	   "[0.1 - 1]".

       th_b
	   Set the black color threshold. Default is 0.15. Allowed range is
	   "[0.0 - 0.5]".

       chp Enable checking the parity bit. In the event	of a parity error, the
	   filter will output 0x00 for that character. Default is false.

       Examples

       o   Output a csv	with presentation time and the first two lines of
	   identified EIA-608 captioning data.

		   ffprobe -f lavfi -i movie=captioned_video.mov,readeia608 -show_entries frame=pkt_pts_time:frame_tags=lavfi.readeia608.0.cc,lavfi.readeia608.1.cc -of	csv

   readvitc
       Read vertical interval timecode (VITC) information from the top lines
       of a video frame.

       The filter adds frame metadata key "lavfi.readvitc.tc_str" with the
       timecode	value, if a valid timecode has been detected. Further metadata
       key "lavfi.readvitc.found" is set to 0/1	depending on whether timecode
       data has	been found or not.

       This filter accepts the following options:

       scan_max
	   Set the maximum number of lines to scan for VITC data. If the value
	   is set to "-1" the full video frame is scanned. Default is 45.

       thr_b
	   Set the luma	threshold for black. Accepts float numbers in the
	   range [0.0,1.0], default value is 0.2. The value must be equal or
	   less	than "thr_w".

       thr_w
	   Set the luma	threshold for white. Accepts float numbers in the
	   range [0.0,1.0], default value is 0.6. The value must be equal or
	   greater than	"thr_b".

       Examples

       o   Detect and draw VITC	data onto the video frame; if no valid VITC is
	   detected, draw "--:--:--:--"	as a placeholder:

		   ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--}:x=(w-tw)/2:y=400-ascent'

   remap
       Remap pixels using 2nd: Xmap and	3rd: Ymap input	video stream.

       Destination pixel at position (X, Y) will be picked from	source (x, y)
       position	where x	= Xmap(X, Y) and y = Ymap(X, Y). If mapping values are
       out of range, zero value	for pixel will be used for destination pixel.

       Xmap and	Ymap input video streams must be of same dimensions. Output
       video stream will have Xmap/Ymap	video stream dimensions.  Xmap and
       Ymap input video	streams	are 16bit depth, single	channel.

   removegrain
       The removegrain filter is a spatial denoiser for	progressive video.

       m0  Set mode for	the first plane.

       m1  Set mode for	the second plane.

       m2  Set mode for	the third plane.

       m3  Set mode for	the fourth plane.

       Range of	mode is	from 0 to 24. Description of each mode follows:

       0   Leave input plane unchanged.	Default.

       1   Clips the pixel with	the minimum and	maximum	of the 8 neighbour
	   pixels.

       2   Clips the pixel with	the second minimum and maximum of the 8
	   neighbour pixels.

       3   Clips the pixel with	the third minimum and maximum of the 8
	   neighbour pixels.

       4   Clips the pixel with	the fourth minimum and maximum of the 8
	   neighbour pixels.  This is equivalent to a median filter.

       5   Line-sensitive clipping giving the minimal change.

       6   Line-sensitive clipping, intermediate.

       7   Line-sensitive clipping, intermediate.

       8   Line-sensitive clipping, intermediate.

       9   Line-sensitive clipping on a	line where the neighbours pixels are
	   the closest.

       10  Replaces the	target pixel with the closest neighbour.

       11  [1 2	1] horizontal and vertical kernel blur.

       12  Same	as mode	11.

       13  Bob mode, interpolates top field from the line where	the neighbours
	   pixels are the closest.

       14  Bob mode, interpolates bottom field from the	line where the
	   neighbours pixels are the closest.

       15  Bob mode, interpolates top field. Same as 13	but with a more
	   complicated interpolation formula.

       16  Bob mode, interpolates bottom field.	Same as	14 but with a more
	   complicated interpolation formula.

       17  Clips the pixel with	the minimum and	maximum	of respectively	the
	   maximum and minimum of each pair of opposite	neighbour pixels.

       18  Line-sensitive clipping using opposite neighbours whose greatest
	   distance from the current pixel is minimal.

       19  Replaces the	pixel with the average of its 8	neighbours.

       20  Averages the	9 pixels ([1 1 1] horizontal and vertical blur).

       21  Clips pixels	using the averages of opposite neighbour.

       22  Same	as mode	21 but simpler and faster.

       23  Small edge and halo removal,	but reputed useless.

       24  Similar as 23.

   removelogo
       Suppress	a TV station logo, using an image file to determine which
       pixels comprise the logo. It works by filling in	the pixels that
       comprise	the logo with neighboring pixels.

       The filter accepts the following	options:

       filename, f
	   Set the filter bitmap file, which can be any	image format supported
	   by libavformat. The width and height	of the image file must match
	   those of the	video stream being processed.

       Pixels in the provided bitmap image with	a value	of zero	are not
       considered part of the logo, non-zero pixels are	considered part	of the
       logo. If	you use	white (255) for	the logo and black (0) for the rest,
       you will	be safe. For making the	filter bitmap, it is recommended to
       take a screen capture of	a black	frame with the logo visible, and then
       using a threshold filter	followed by the	erode filter once or twice.

       If needed, little splotches can be fixed	manually. Remember that	if
       logo pixels are not covered, the	filter quality will be much reduced.
       Marking too many	pixels as part of the logo does	not hurt as much, but
       it will increase	the amount of blurring needed to cover over the	image
       and will	destroy	more information than necessary, and extra pixels will
       slow things down	on a large logo.

   repeatfields
       This filter uses	the repeat_field flag from the Video ES	headers	and
       hard repeats fields based on its	value.

   reverse
       Reverse a video clip.

       Warning:	This filter requires memory to buffer the entire clip, so
       trimming	is suggested.

       Examples

       o   Take	the first 5 seconds of a clip, and reverse it.

		   trim=end=5,reverse

   rotate
       Rotate video by an arbitrary angle expressed in radians.

       The filter accepts the following	options:

       A description of	the optional parameters	follows.

       angle, a
	   Set an expression for the angle by which to rotate the input	video
	   clockwise, expressed	as a number of radians.	A negative value will
	   result in a counter-clockwise rotation. By default it is set	to
	   "0".

	   This	expression is evaluated	for each frame.

       out_w, ow
	   Set the output width	expression, default value is "iw".  This
	   expression is evaluated just	once during configuration.

       out_h, oh
	   Set the output height expression, default value is "ih".  This
	   expression is evaluated just	once during configuration.

       bilinear
	   Enable bilinear interpolation if set	to 1, a	value of 0 disables
	   it. Default value is	1.

       fillcolor, c
	   Set the color used to fill the output area not covered by the
	   rotated image. For the general syntax of this option, check the
	   "Color" section in the ffmpeg-utils manual. If the special value
	   "none" is selected then no background is printed (useful for
	   example if the background is	never shown).

	   Default value is "black".

       The expressions for the angle and the output size can contain the
       following constants and functions:

       n   sequential number of	the input frame, starting from 0. It is	always
	   NAN before the first	frame is filtered.

       t   time	in seconds of the input	frame, it is set to 0 when the filter
	   is configured. It is	always NAN before the first frame is filtered.

       hsub
       vsub
	   horizontal and vertical chroma subsample values. For	example	for
	   the pixel format "yuv422p" hsub is 2	and vsub is 1.

       in_w, iw
       in_h, ih
	   the input video width and height

       out_w, ow
       out_h, oh
	   the output width and	height,	that is	the size of the	padded area as
	   specified by	the width and height expressions

       rotw(a)
       roth(a)
	   the minimal width/height required for completely containing the
	   input video rotated by a radians.

	   These are only available when computing the out_w and out_h
	   expressions.

       Examples

       o   Rotate the input by PI/6 radians clockwise:

		   rotate=PI/6

       o   Rotate the input by PI/6 radians counter-clockwise:

		   rotate=-PI/6

       o   Rotate the input by 45 degrees clockwise:

		   rotate=45*PI/180

       o   Apply a constant rotation with period T, starting from an angle of
	   PI/3:

		   rotate=PI/3+2*PI*t/T

       o   Make	the input video	rotation oscillating with a period of T
	   seconds and an amplitude of A radians:

		   rotate=A*sin(2*PI/T*t)

       o   Rotate the video, output size is chosen so that the whole rotating
	   input video is always completely contained in the output:

		   rotate='2*PI*t:ow=hypot(iw,ih):oh=ow'

       o   Rotate the video, reduce the	output size so that no background is
	   ever	shown:

		   rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none

       Commands

       The filter supports the following commands:

       a, angle
	   Set the angle expression.  The command accepts the same syntax of
	   the corresponding option.

	   If the specified expression is not valid, it	is kept	at its current
	   value.

   sab
       Apply Shape Adaptive Blur.

       The filter accepts the following	options:

       luma_radius, lr
	   Set luma blur filter	strength, must be a value in range 0.1-4.0,
	   default value is 1.0. A greater value will result in	a more blurred
	   image, and in slower	processing.

       luma_pre_filter_radius, lpfr
	   Set luma pre-filter radius, must be a value in the 0.1-2.0 range,
	   default value is 1.0.

       luma_strength, ls
	   Set luma maximum difference between pixels to still be considered,
	   must	be a value in the 0.1-100.0 range, default value is 1.0.

       chroma_radius, cr
	   Set chroma blur filter strength, must be a value in range -0.9-4.0.
	   A greater value will	result in a more blurred image,	and in slower
	   processing.

       chroma_pre_filter_radius, cpfr
	   Set chroma pre-filter radius, must be a value in the	-0.9-2.0
	   range.

       chroma_strength,	cs
	   Set chroma maximum difference between pixels	to still be
	   considered, must be a value in the -0.9-100.0 range.

       Each chroma option value, if not	explicitly specified, is set to	the
       corresponding luma option value.

   scale
       Scale (resize) the input	video, using the libswscale library.

       The scale filter	forces the output display aspect ratio to be the same
       of the input, by	changing the output sample aspect ratio.

       If the input image format is different from the format requested	by the
       next filter, the	scale filter will convert the input to the requested
       format.

       Options

       The filter accepts the following	options, or any	of the options
       supported by the	libswscale scaler.

       See the ffmpeg-scaler manual for	the complete list of scaler options.

       width, w
       height, h
	   Set the output video	dimension expression. Default value is the
	   input dimension.

	   If the value	is 0, the input	width is used for the output.

	   If one of the values	is -1, the scale filter	will use a value that
	   maintains the aspect	ratio of the input image, calculated from the
	   other specified dimension. If both of them are -1, the input	size
	   is used

	   If one of the values	is -n with n > 1, the scale filter will	also
	   use a value that maintains the aspect ratio of the input image,
	   calculated from the other specified dimension. After	that it	will,
	   however, make sure that the calculated dimension is divisible by n
	   and adjust the value	if necessary.

	   See below for the list of accepted constants	for use	in the
	   dimension expression.

       eval
	   Specify when	to evaluate width and height expression. It accepts
	   the following values:

	   init
	       Only evaluate expressions once during the filter	initialization
	       or when a command is processed.

	   frame
	       Evaluate	expressions for	each incoming frame.

	   Default value is init.

       interl
	   Set the interlacing mode. It	accepts	the following values:

	   1   Force interlaced	aware scaling.

	   0   Do not apply interlaced scaling.

	   -1  Select interlaced aware scaling depending on whether the	source
	       frames are flagged as interlaced	or not.

	   Default value is 0.

       flags
	   Set libswscale scaling flags. See the ffmpeg-scaler manual for the
	   complete list of values. If not explicitly specified	the filter
	   applies the default flags.

       param0, param1
	   Set libswscale input	parameters for scaling algorithms that need
	   them. See the ffmpeg-scaler manual for the complete documentation.
	   If not explicitly specified the filter applies empty	parameters.

       size, s
	   Set the video size. For the syntax of this option, check the	"Video
	   size" section in the	ffmpeg-utils manual.

       in_color_matrix
       out_color_matrix
	   Set in/output YCbCr color space type.

	   This	allows the autodetected	value to be overridden as well as
	   allows forcing a specific value used	for the	output and encoder.

	   If not specified, the color space type depends on the pixel format.

	   Possible values:

	   auto
	       Choose automatically.

	   bt709
	       Format conforming to International Telecommunication Union
	       (ITU) Recommendation BT.709.

	   fcc Set color space conforming to the United	States Federal
	       Communications Commission (FCC) Code of Federal Regulations
	       (CFR) Title 47 (2003) 73.682 (a).

	   bt601
	       Set color space conforming to:

	       o   ITU Radiocommunication Sector (ITU-R) Recommendation	BT.601

	       o   ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G

	       o   Society of Motion Picture and Television Engineers (SMPTE)
		   ST 170:2004

	   smpte240m
	       Set color space conforming to SMPTE ST 240:1999.

       in_range
       out_range
	   Set in/output YCbCr sample range.

	   This	allows the autodetected	value to be overridden as well as
	   allows forcing a specific value used	for the	output and encoder. If
	   not specified, the range depends on the pixel format. Possible
	   values:

	   auto
	       Choose automatically.

	   jpeg/full/pc
	       Set full	range (0-255 in	case of	8-bit luma).

	   mpeg/tv
	       Set "MPEG" range	(16-235	in case	of 8-bit luma).

       force_original_aspect_ratio
	   Enable decreasing or	increasing output video	width or height	if
	   necessary to	keep the original aspect ratio.	Possible values:

	   disable
	       Scale the video as specified and	disable	this feature.

	   decrease
	       The output video	dimensions will	automatically be decreased if
	       needed.

	   increase
	       The output video	dimensions will	automatically be increased if
	       needed.

	   One useful instance of this option is that when you know a specific
	   device's maximum allowed resolution,	you can	use this to limit the
	   output video	to that, while retaining the aspect ratio. For
	   example, device A allows 1280x720 playback, and your	video is
	   1920x800. Using this	option (set it to decrease) and	specifying
	   1280x720 to the command line	makes the output 1280x533.

	   Please note that this is a different	thing than specifying -1 for w
	   or h, you still need	to specify the output resolution for this
	   option to work.

       The values of the w and h options are expressions containing the
       following constants:

       in_w
       in_h
	   The input width and height

       iw
       ih  These are the same as in_w and in_h.

       out_w
       out_h
	   The output (scaled) width and height

       ow
       oh  These are the same as out_w and out_h

       a   The same as iw / ih

       sar input sample	aspect ratio

       dar The input display aspect ratio. Calculated from "(iw	/ ih) *	sar".

       hsub
       vsub
	   horizontal and vertical input chroma	subsample values. For example
	   for the pixel format	"yuv422p" hsub is 2 and	vsub is	1.

       ohsub
       ovsub
	   horizontal and vertical output chroma subsample values. For example
	   for the pixel format	"yuv422p" hsub is 2 and	vsub is	1.

       Examples

       o   Scale the input video to a size of 200x100

		   scale=w=200:h=100

	   This	is equivalent to:

		   scale=200:100

	   or:

		   scale=200x100

       o   Specify a size abbreviation for the output size:

		   scale=qcif

	   which can also be written as:

		   scale=size=qcif

       o   Scale the input to 2x:

		   scale=w=2*iw:h=2*ih

       o   The above is	the same as:

		   scale=2*in_w:2*in_h

       o   Scale the input to 2x with forced interlaced	scaling:

		   scale=2*iw:2*ih:interl=1

       o   Scale the input to half size:

		   scale=w=iw/2:h=ih/2

       o   Increase the	width, and set the height to the same size:

		   scale=3/2*iw:ow

       o   Seek	Greek harmony:

		   scale=iw:1/PHI*iw
		   scale=ih*PHI:ih

       o   Increase the	height,	and set	the width to 3/2 of the	height:

		   scale=w=3/2*oh:h=3/5*ih

       o   Increase the	size, making the size a	multiple of the	chroma
	   subsample values:

		   scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"

       o   Increase the	width to a maximum of 500 pixels, keeping the same
	   aspect ratio	as the input:

		   scale=w='min(500\, iw*3/2):h=-1'

       Commands

       This filter supports the	following commands:

       width, w
       height, h
	   Set the output video	dimension expression.  The command accepts the
	   same	syntax of the corresponding option.

	   If the specified expression is not valid, it	is kept	at its current
	   value.

   scale_npp
       Use the NVIDIA Performance Primitives (libnpp) to perform scaling
       and/or pixel format conversion on CUDA video frames. Setting the	output
       width and height	works in the same way as for the scale filter.

       The following additional	options	are accepted:

       format
	   The pixel format of the output CUDA frames. If set to the string
	   "same" (the default), the input format will be kept.	Note that
	   automatic format negotiation	and conversion is not yet supported
	   for hardware	frames

       interp_algo
	   The interpolation algorithm used for	resizing. One of the
	   following:

	   nn  Nearest neighbour.

	   linear
	   cubic
	   cubic2p_bspline
	       2-parameter cubic (B=1, C=0)

	   cubic2p_catmullrom
	       2-parameter cubic (B=0, C=1/2)

	   cubic2p_b05c03
	       2-parameter cubic (B=1/2, C=3/10)

	   super
	       Supersampling

	   lanczos

   scale2ref
       Scale (resize) the input	video, based on	a reference video.

       See the scale filter for	available options, scale2ref supports the same
       but uses	the reference video instead of the main	input as basis.

       Examples

       o   Scale a subtitle stream (b) to match	the main video (a) in size
	   before overlaying

		   'scale2ref[b][a];[a][b]overlay'

   selectivecolor
       Adjust cyan, magenta, yellow and	black (CMYK) to	certain	ranges of
       colors (such as "reds", "yellows", "greens", "cyans", ...). The
       adjustment range	is defined by the "purity" of the color	(that is, how
       saturated it already is).

       This filter is similar to the Adobe Photoshop Selective Color tool.

       The filter accepts the following	options:

       correction_method
	   Select color	correction method.

	   Available values are:

	   absolute
	       Specified adjustments are applied "as-is" (added/subtracted to
	       original	pixel component	value).

	   relative
	       Specified adjustments are relative to the original component
	       value.

	   Default is "absolute".

       reds
	   Adjustments for red pixels (pixels where the	red component is the
	   maximum)

       yellows
	   Adjustments for yellow pixels (pixels where the blue	component is
	   the minimum)

       greens
	   Adjustments for green pixels	(pixels	where the green	component is
	   the maximum)

       cyans
	   Adjustments for cyan	pixels (pixels where the red component is the
	   minimum)

       blues
	   Adjustments for blue	pixels (pixels where the blue component	is the
	   maximum)

       magentas
	   Adjustments for magenta pixels (pixels where	the green component is
	   the minimum)

       whites
	   Adjustments for white pixels	(pixels	where all components are
	   greater than	128)

       neutrals
	   Adjustments for all pixels except pure black	and pure white

       blacks
	   Adjustments for black pixels	(pixels	where all components are
	   lesser than 128)

       psfile
	   Specify a Photoshop selective color file (".asv") to	import the
	   settings from.

       All the adjustment settings (reds, yellows, ...)	accept up to 4 space
       separated floating point	adjustment values in the [-1,1]	range,
       respectively to adjust the amount of cyan, magenta, yellow and black
       for the pixels of its range.

       Examples

       o   Increase cyan by 50%	and reduce yellow by 33% in every green	areas,
	   and increase	magenta	by 27% in blue areas:

		   selectivecolor=greens=.5 0 -.33 0:blues=0 .27

       o   Use a Photoshop selective color preset:

		   selectivecolor=psfile=MySelectiveColorPresets/Misty.asv

   separatefields
       The "separatefields" takes a frame-based	video input and	splits each
       frame into its components fields, producing a new half height clip with
       twice the frame rate and	twice the frame	count.

       This filter use field-dominance information in frame to decide which of
       each pair of fields to place first in the output.  If it	gets it	wrong
       use setfield filter before "separatefields" filter.

   setdar, setsar
       The "setdar" filter sets	the Display Aspect Ratio for the filter	output
       video.

       This is done by changing	the specified Sample (aka Pixel) Aspect	Ratio,
       according to the	following equation:

	       <DAR> = <HORIZONTAL_RESOLUTION> / <VERTICAL_RESOLUTION> * <SAR>

       Keep in mind that the "setdar" filter does not modify the pixel
       dimensions of the video frame. Also, the	display	aspect ratio set by
       this filter may be changed by later filters in the filterchain, e.g. in
       case of scaling or if another "setdar" or a "setsar" filter is applied.

       The "setsar" filter sets	the Sample (aka	Pixel) Aspect Ratio for	the
       filter output video.

       Note that as a consequence of the application of	this filter, the
       output display aspect ratio will	change according to the	equation
       above.

       Keep in mind that the sample aspect ratio set by	the "setsar" filter
       may be changed by later filters in the filterchain, e.g.	if another
       "setsar"	or a "setdar" filter is	applied.

       It accepts the following	parameters:

       r, ratio, dar ("setdar" only), sar ("setsar" only)
	   Set the aspect ratio	used by	the filter.

	   The parameter can be	a floating point number	string,	an expression,
	   or a	string of the form num:den, where num and den are the
	   numerator and denominator of	the aspect ratio. If the parameter is
	   not specified, it is	assumed	the value "0".	In case	the form
	   "num:den" is	used, the ":" character	should be escaped.

       max Set the maximum integer value to use	for expressing numerator and
	   denominator when reducing the expressed aspect ratio	to a rational.
	   Default value is 100.

       The parameter sar is an expression containing the following constants:

       E, PI, PHI
	   These are approximated values for the mathematical constants	e
	   (Euler's number), pi	(Greek pi), and	phi (the golden	ratio).

       w, h
	   The input width and height.

       a   These are the same as w / h.

       sar The input sample aspect ratio.

       dar The input display aspect ratio. It is the same as (w	/ h) * sar.

       hsub, vsub
	   Horizontal and vertical chroma subsample values. For	example, for
	   the pixel format "yuv422p" hsub is 2	and vsub is 1.

       Examples

       o   To change the display aspect	ratio to 16:9, specify one of the
	   following:

		   setdar=dar=1.77777
		   setdar=dar=16/9

       o   To change the sample	aspect ratio to	10:11, specify:

		   setsar=sar=10/11

       o   To set a display aspect ratio of 16:9, and specify a	maximum
	   integer value of 1000 in the	aspect ratio reduction,	use the
	   command:

		   setdar=ratio=16/9:max=1000

   setfield
       Force field for the output video	frame.

       The "setfield" filter marks the interlace type field for	the output
       frames. It does not change the input frame, but only sets the
       corresponding property, which affects how the frame is treated by
       following filters (e.g. "fieldorder" or "yadif").

       The filter accepts the following	options:

       mode
	   Available values are:

	   auto
	       Keep the	same field property.

	   bff Mark the	frame as bottom-field-first.

	   tff Mark the	frame as top-field-first.

	   prog
	       Mark the	frame as progressive.

   showinfo
       Show a line containing various information for each input video frame.
       The input video is not modified.

       The shown line contains a sequence of key/value pairs of	the form
       key:value.

       The following values are	shown in the output:

       n   The (sequential) number of the input	frame, starting	from 0.

       pts The Presentation TimeStamp of the input frame, expressed as a
	   number of time base units. The time base unit depends on the	filter
	   input pad.

       pts_time
	   The Presentation TimeStamp of the input frame, expressed as a
	   number of seconds.

       pos The position	of the frame in	the input stream, or -1	if this
	   information is unavailable and/or meaningless (for example in case
	   of synthetic	video).

       fmt The pixel format name.

       sar The sample aspect ratio of the input	frame, expressed in the	form
	   num/den.

       s   The size of the input frame.	For the	syntax of this option, check
	   the "Video size" section in the ffmpeg-utils	manual.

       i   The type of interlaced mode ("P" for	"progressive", "T" for top
	   field first,	"B" for	bottom field first).

       iskey
	   This	is 1 if	the frame is a key frame, 0 otherwise.

       type
	   The picture type of the input frame ("I" for	an I-frame, "P"	for a
	   P-frame, "B"	for a B-frame, or "?" for an unknown type).  Also
	   refer to the	documentation of the "AVPictureType" enum and of the
	   "av_get_picture_type_char" function defined in libavutil/avutil.h.

       checksum
	   The Adler-32	checksum (printed in hexadecimal) of all the planes of
	   the input frame.

       plane_checksum
	   The Adler-32	checksum (printed in hexadecimal) of each plane	of the
	   input frame,	expressed in the form "[c0 c1 c2 c3]".

   showpalette
       Displays	the 256	colors palette of each frame. This filter is only
       relevant	for pal8 pixel format frames.

       It accepts the following	option:

       s   Set the size	of the box used	to represent one palette color entry.
	   Default is 30 (for a	"30x30"	pixel box).

   shuffleframes
       Reorder and/or duplicate	and/or drop video frames.

       It accepts the following	parameters:

       mapping
	   Set the destination indexes of input	frames.	 This is space or '|'
	   separated list of indexes that maps input frames to output frames.
	   Number of indexes also sets maximal value that each index may have.
	   '-1'	index have special meaning and that is to drop frame.

       The first frame has the index 0.	The default is to keep the input
       unchanged.

       Examples

       o   Swap	second and third frame of every	three frames of	the input:

		   ffmpeg -i INPUT -vf "shuffleframes=0	2 1" OUTPUT

       o   Swap	10th and 1st frame of every ten	frames of the input:

		   ffmpeg -i INPUT -vf "shuffleframes=9	1 2 3 4	5 6 7 8	0" OUTPUT

   shuffleplanes
       Reorder and/or duplicate	video planes.

       It accepts the following	parameters:

       map0
	   The index of	the input plane	to be used as the first	output plane.

       map1
	   The index of	the input plane	to be used as the second output	plane.

       map2
	   The index of	the input plane	to be used as the third	output plane.

       map3
	   The index of	the input plane	to be used as the fourth output	plane.

       The first plane has the index 0.	The default is to keep the input
       unchanged.

       Examples

       o   Swap	the second and third planes of the input:

		   ffmpeg -i INPUT -vf shuffleplanes=0:2:1:3 OUTPUT

   signalstats
       Evaluate	various	visual metrics that assist in determining issues
       associated with the digitization	of analog video	media.

       By default the filter will log these metadata values:

       YMIN
	   Display the minimal Y value contained within	the input frame.
	   Expressed in	range of [0-255].

       YLOW
	   Display the Y value at the 10% percentile within the	input frame.
	   Expressed in	range of [0-255].

       YAVG
	   Display the average Y value within the input	frame. Expressed in
	   range of [0-255].

       YHIGH
	   Display the Y value at the 90% percentile within the	input frame.
	   Expressed in	range of [0-255].

       YMAX
	   Display the maximum Y value contained within	the input frame.
	   Expressed in	range of [0-255].

       UMIN
	   Display the minimal U value contained within	the input frame.
	   Expressed in	range of [0-255].

       ULOW
	   Display the U value at the 10% percentile within the	input frame.
	   Expressed in	range of [0-255].

       UAVG
	   Display the average U value within the input	frame. Expressed in
	   range of [0-255].

       UHIGH
	   Display the U value at the 90% percentile within the	input frame.
	   Expressed in	range of [0-255].

       UMAX
	   Display the maximum U value contained within	the input frame.
	   Expressed in	range of [0-255].

       VMIN
	   Display the minimal V value contained within	the input frame.
	   Expressed in	range of [0-255].

       VLOW
	   Display the V value at the 10% percentile within the	input frame.
	   Expressed in	range of [0-255].

       VAVG
	   Display the average V value within the input	frame. Expressed in
	   range of [0-255].

       VHIGH
	   Display the V value at the 90% percentile within the	input frame.
	   Expressed in	range of [0-255].

       VMAX
	   Display the maximum V value contained within	the input frame.
	   Expressed in	range of [0-255].

       SATMIN
	   Display the minimal saturation value	contained within the input
	   frame.  Expressed in	range of [0-~181.02].

       SATLOW
	   Display the saturation value	at the 10% percentile within the input
	   frame.  Expressed in	range of [0-~181.02].

       SATAVG
	   Display the average saturation value	within the input frame.
	   Expressed in	range of [0-~181.02].

       SATHIGH
	   Display the saturation value	at the 90% percentile within the input
	   frame.  Expressed in	range of [0-~181.02].

       SATMAX
	   Display the maximum saturation value	contained within the input
	   frame.  Expressed in	range of [0-~181.02].

       HUEMED
	   Display the median value for	hue within the input frame. Expressed
	   in range of [0-360].

       HUEAVG
	   Display the average value for hue within the	input frame. Expressed
	   in range of [0-360].

       YDIF
	   Display the average of sample value difference between all values
	   of the Y plane in the current frame and corresponding values	of the
	   previous input frame.  Expressed in range of	[0-255].

       UDIF
	   Display the average of sample value difference between all values
	   of the U plane in the current frame and corresponding values	of the
	   previous input frame.  Expressed in range of	[0-255].

       VDIF
	   Display the average of sample value difference between all values
	   of the V plane in the current frame and corresponding values	of the
	   previous input frame.  Expressed in range of	[0-255].

       YBITDEPTH
	   Display bit depth of	Y plane	in current frame.  Expressed in	range
	   of [0-16].

       UBITDEPTH
	   Display bit depth of	U plane	in current frame.  Expressed in	range
	   of [0-16].

       VBITDEPTH
	   Display bit depth of	V plane	in current frame.  Expressed in	range
	   of [0-16].

       The filter accepts the following	options:

       stat
       out stat	specify	an additional form of image analysis.  out output
	   video with the specified type of pixel highlighted.

	   Both	options	accept the following values:

	   tout
	       Identify	temporal outliers pixels. A temporal outlier is	a
	       pixel unlike the	neighboring pixels of the same field. Examples
	       of temporal outliers include the	results	of video dropouts,
	       head clogs, or tape tracking issues.

	   vrep
	       Identify	vertical line repetition. Vertical line	repetition
	       includes	similar	rows of	pixels within a	frame. In born-digital
	       video vertical line repetition is common, but this pattern is
	       uncommon	in video digitized from	an analog source. When it
	       occurs in video that results from the digitization of an	analog
	       source it can indicate concealment from a dropout compensator.

	   brng
	       Identify	pixels that fall outside of legal broadcast range.

       color, c
	   Set the highlight color for the out option. The default color is
	   yellow.

       Examples

       o   Output data of various video	metrics:

		   ffprobe -f lavfi movie=example.mov,signalstats="stat=tout+vrep+brng"	-show_frames

       o   Output specific data	about the minimum and maximum values of	the Y
	   plane per frame:

		   ffprobe -f lavfi movie=example.mov,signalstats -show_entries	frame_tags=lavfi.signalstats.YMAX,lavfi.signalstats.YMIN

       o   Playback video while	highlighting pixels that are outside of
	   broadcast range in red.

		   ffplay example.mov -vf signalstats="out=brng:color=red"

       o   Playback video with signalstats metadata drawn over the frame.

		   ffplay example.mov -vf signalstats=stat=brng+vrep+tout,drawtext=fontfile=FreeSerif.ttf:textfile=signalstat_drawtext.txt

	   The contents	of signalstat_drawtext.txt used	in the command are:

		   time	%{pts:hms}
		   Y (%{metadata:lavfi.signalstats.YMIN}-%{metadata:lavfi.signalstats.YMAX})
		   U (%{metadata:lavfi.signalstats.UMIN}-%{metadata:lavfi.signalstats.UMAX})
		   V (%{metadata:lavfi.signalstats.VMIN}-%{metadata:lavfi.signalstats.VMAX})
		   saturation maximum: %{metadata:lavfi.signalstats.SATMAX}

   signature
       Calculates the MPEG-7 Video Signature. The filter can handle more than
       one input. In this case the matching between the	inputs can be
       calculated additionally.	 The filter always passes through the first
       input. The signature of each stream can be written into a file.

       It accepts the following	options:

       detectmode
	   Enable or disable the matching process.

	   Available values are:

	   off Disable the calculation of a matching (default).

	   full
	       Calculate the matching for the whole video and output whether
	       the whole video matches or only parts.

	   fast
	       Calculate only until a matching is found	or the video ends.
	       Should be faster	in some	cases.

       nb_inputs
	   Set the number of inputs. The option	value must be a	non negative
	   integer.  Default value is 1.

       filename
	   Set the path	to which the output is written.	If there is more than
	   one input, the path must be a prototype, i.e. must contain %d or
	   %0nd	(where n is a positive integer), that will be replaced with
	   the input number. If	no filename is specified, no output will be
	   written. This is the	default.

       format
	   Choose the output format.

	   Available values are:

	   binary
	       Use the specified binary	representation (default).

	   xml Use the specified xml representation.

       th_d
	   Set threshold to detect one word as similar.	The option value must
	   be an integer greater than zero. The	default	value is 9000.

       th_dc
	   Set threshold to detect all words as	similar. The option value must
	   be an integer greater than zero. The	default	value is 60000.

       th_xh
	   Set threshold to detect frames as similar. The option value must be
	   an integer greater than zero. The default value is 116.

       th_di
	   Set the minimum length of a sequence	in frames to recognize it as
	   matching sequence. The option value must be a non negative integer
	   value.  The default value is	0.

       th_it
	   Set the minimum relation, that matching frames to all frames	must
	   have.  The option value must	be a double value between 0 and	1. The
	   default value is 0.5.

       Examples

       o   To calculate	the signature of an input video	and store it in
	   signature.bin:

		   ffmpeg -i input.mkv -vf signature=filename=signature.bin -map 0:v -f	null -

       o   To detect whether two videos	match and store	the signatures in XML
	   format in signature0.xml and	signature1.xml:

		   ffmpeg -i input1.mkv	-i input2.mkv -filter_complex "[0:v][1:v] signature=nb_inputs=2:detectmode=full:format=xml:filename=signature%d.xml" -map :v -f	null -

   smartblur
       Blur the	input video without impacting the outlines.

       It accepts the following	options:

       luma_radius, lr
	   Set the luma	radius.	The option value must be a float number	in the
	   range [0.1,5.0] that	specifies the variance of the gaussian filter
	   used	to blur	the image (slower if larger). Default value is 1.0.

       luma_strength, ls
	   Set the luma	strength. The option value must	be a float number in
	   the range [-1.0,1.0]	that configures	the blurring. A	value included
	   in [0.0,1.0]	will blur the image whereas a value included in
	   [-1.0,0.0] will sharpen the image. Default value is 1.0.

       luma_threshold, lt
	   Set the luma	threshold used as a coefficient	to determine whether a
	   pixel should	be blurred or not. The option value must be an integer
	   in the range	[-30,30]. A value of 0 will filter all the image, a
	   value included in [0,30] will filter	flat areas and a value
	   included in [-30,0] will filter edges. Default value	is 0.

       chroma_radius, cr
	   Set the chroma radius. The option value must	be a float number in
	   the range [0.1,5.0] that specifies the variance of the gaussian
	   filter used to blur the image (slower if larger). Default value is
	   luma_radius.

       chroma_strength,	cs
	   Set the chroma strength. The	option value must be a float number in
	   the range [-1.0,1.0]	that configures	the blurring. A	value included
	   in [0.0,1.0]	will blur the image whereas a value included in
	   [-1.0,0.0] will sharpen the image. Default value is luma_strength.

       chroma_threshold, ct
	   Set the chroma threshold used as a coefficient to determine whether
	   a pixel should be blurred or	not. The option	value must be an
	   integer in the range	[-30,30]. A value of 0 will filter all the
	   image, a value included in [0,30] will filter flat areas and	a
	   value included in [-30,0] will filter edges.	Default	value is
	   luma_threshold.

       If a chroma option is not explicitly set, the corresponding luma	value
       is set.

   ssim
       Obtain the SSIM (Structural SImilarity Metric) between two input
       videos.

       This filter takes in input two input videos, the	first input is
       considered the "main" source and	is passed unchanged to the output. The
       second input is used as a "reference" video for computing the SSIM.

       Both video inputs must have the same resolution and pixel format	for
       this filter to work correctly. Also it assumes that both	inputs have
       the same	number of frames, which	are compared one by one.

       The filter stores the calculated	SSIM of	each frame.

       The description of the accepted parameters follows.

       stats_file, f
	   If specified	the filter will	use the	named file to save the SSIM of
	   each	individual frame. When filename	equals "-" the data is sent to
	   standard output.

       The file	printed	if stats_file is selected, contains a sequence of
       key/value pairs of the form key:value for each compared couple of
       frames.

       A description of	each shown parameter follows:

       n   sequential number of	the input frame, starting from 1

       Y, U, V,	R, G, B
	   SSIM	of the compared	frames for the component specified by the
	   suffix.

       All SSIM	of the compared	frames for the whole frame.

       dB  Same	as above but in	dB representation.

       For example:

	       movie=ref_movie.mpg, setpts=PTS-STARTPTS	[main];
	       [main][ref] ssim="stats_file=stats.log" [out]

       On this example the input file being processed is compared with the
       reference file ref_movie.mpg. The SSIM of each individual frame is
       stored in stats.log.

       Another example with both psnr and ssim at same time:

	       ffmpeg -i main.mpg -i ref.mpg -lavfi  "ssim;[0:v][1:v]psnr" -f null -

   stereo3d
       Convert between different stereoscopic image formats.

       The filters accept the following	options:

       in  Set stereoscopic image format of input.

	   Available values for	input image formats are:

	   sbsl
	       side by side parallel (left eye left, right eye right)

	   sbsr
	       side by side crosseye (right eye	left, left eye right)

	   sbs2l
	       side by side parallel with half width resolution	(left eye
	       left, right eye right)

	   sbs2r
	       side by side crosseye with half width resolution	(right eye
	       left, left eye right)

	   abl above-below (left eye above, right eye below)

	   abr above-below (right eye above, left eye below)

	   ab2l
	       above-below with	half height resolution (left eye above,	right
	       eye below)

	   ab2r
	       above-below with	half height resolution (right eye above, left
	       eye below)

	   al  alternating frames (left	eye first, right eye second)

	   ar  alternating frames (right eye first, left eye second)

	   irl interleaved rows	(left eye has top row, right eye starts	on
	       next row)

	   irr interleaved rows	(right eye has top row,	left eye starts	on
	       next row)

	   icl interleaved columns, left eye first

	   icr interleaved columns, right eye first

	       Default value is	sbsl.

       out Set stereoscopic image format of output.

	   sbsl
	       side by side parallel (left eye left, right eye right)

	   sbsr
	       side by side crosseye (right eye	left, left eye right)

	   sbs2l
	       side by side parallel with half width resolution	(left eye
	       left, right eye right)

	   sbs2r
	       side by side crosseye with half width resolution	(right eye
	       left, left eye right)

	   abl above-below (left eye above, right eye below)

	   abr above-below (right eye above, left eye below)

	   ab2l
	       above-below with	half height resolution (left eye above,	right
	       eye below)

	   ab2r
	       above-below with	half height resolution (right eye above, left
	       eye below)

	   al  alternating frames (left	eye first, right eye second)

	   ar  alternating frames (right eye first, left eye second)

	   irl interleaved rows	(left eye has top row, right eye starts	on
	       next row)

	   irr interleaved rows	(right eye has top row,	left eye starts	on
	       next row)

	   arbg
	       anaglyph	red/blue gray (red filter on left eye, blue filter on
	       right eye)

	   argg
	       anaglyph	red/green gray (red filter on left eye,	green filter
	       on right	eye)

	   arcg
	       anaglyph	red/cyan gray (red filter on left eye, cyan filter on
	       right eye)

	   arch
	       anaglyph	red/cyan half colored (red filter on left eye, cyan
	       filter on right eye)

	   arcc
	       anaglyph	red/cyan color (red filter on left eye,	cyan filter on
	       right eye)

	   arcd
	       anaglyph	red/cyan color optimized with the least	squares
	       projection of dubois (red filter	on left	eye, cyan filter on
	       right eye)

	   agmg
	       anaglyph	green/magenta gray (green filter on left eye, magenta
	       filter on right eye)

	   agmh
	       anaglyph	green/magenta half colored (green filter on left eye,
	       magenta filter on right eye)

	   agmc
	       anaglyph	green/magenta colored (green filter on left eye,
	       magenta filter on right eye)

	   agmd
	       anaglyph	green/magenta color optimized with the least squares
	       projection of dubois (green filter on left eye, magenta filter
	       on right	eye)

	   aybg
	       anaglyph	yellow/blue gray (yellow filter	on left	eye, blue
	       filter on right eye)

	   aybh
	       anaglyph	yellow/blue half colored (yellow filter	on left	eye,
	       blue filter on right eye)

	   aybc
	       anaglyph	yellow/blue colored (yellow filter on left eye,	blue
	       filter on right eye)

	   aybd
	       anaglyph	yellow/blue color optimized with the least squares
	       projection of dubois (yellow filter on left eye,	blue filter on
	       right eye)

	   ml  mono output (left eye only)

	   mr  mono output (right eye only)

	   chl checkerboard, left eye first

	   chr checkerboard, right eye first

	   icl interleaved columns, left eye first

	   icr interleaved columns, right eye first

	   hdmi
	       HDMI frame pack

	   Default value is arcd.

       Examples

       o   Convert input video from side by side parallel to anaglyph
	   yellow/blue dubois:

		   stereo3d=sbsl:aybd

       o   Convert input video from above below	(left eye above, right eye
	   below) to side by side crosseye.

		   stereo3d=abl:sbsr

   streamselect, astreamselect
       Select video or audio streams.

       The filter accepts the following	options:

       inputs
	   Set number of inputs. Default is 2.

       map Set input indexes to	remap to outputs.

       Commands

       The "streamselect" and "astreamselect" filter supports the following
       commands:

       map Set input indexes to	remap to outputs.

       Examples

       o   Select first	5 seconds 1st stream and rest of time 2nd stream:

		   sendcmd='5.0	streamselect map 1',streamselect=inputs=2:map=0

       o   Same	as above, but for audio:

		   asendcmd='5.0 astreamselect map 1',astreamselect=inputs=2:map=0

   sobel
       Apply sobel operator to input video stream.

       The filter accepts the following	option:

       planes
	   Set which planes will be processed, unprocessed planes will be
	   copied.  By default value 0xf, all planes will be processed.

       scale
	   Set value which will	be multiplied with filtered result.

       delta
	   Set value which will	be added to filtered result.

   spp
       Apply a simple postprocessing filter that compresses and	decompresses
       the image at several (or	- in the case of quality level 6 - all)	shifts
       and average the results.

       The filter accepts the following	options:

       quality
	   Set quality.	This option defines the	number of levels for
	   averaging. It accepts an integer in the range 0-6. If set to	0, the
	   filter will have no effect. A value of 6 means the higher quality.
	   For each increment of that value the	speed drops by a factor	of
	   approximately 2.  Default value is 3.

       qp  Force a constant quantization parameter. If not set,	the filter
	   will	use the	QP from	the video stream (if available).

       mode
	   Set thresholding mode. Available modes are:

	   hard
	       Set hard	thresholding (default).

	   soft
	       Set soft	thresholding (better de-ringing	effect,	but likely
	       blurrier).

       use_bframe_qp
	   Enable the use of the QP from the B-Frames if set to	1. Using this
	   option may cause flicker since the B-Frames have often larger QP.
	   Default is 0	(not enabled).

   subtitles
       Draw subtitles on top of	input video using the libass library.

       To enable compilation of	this filter you	need to	configure FFmpeg with
       "--enable-libass". This filter also requires a build with libavcodec
       and libavformat to convert the passed subtitles file to ASS (Advanced
       Substation Alpha) subtitles format.

       The filter accepts the following	options:

       filename, f
	   Set the filename of the subtitle file to read. It must be
	   specified.

       original_size
	   Specify the size of the original video, the video for which the ASS
	   file	was composed. For the syntax of	this option, check the "Video
	   size" section in the	ffmpeg-utils manual.  Due to a misdesign in
	   ASS aspect ratio arithmetic,	this is	necessary to correctly scale
	   the fonts if	the aspect ratio has been changed.

       fontsdir
	   Set a directory path	containing fonts that can be used by the
	   filter.  These fonts	will be	used in	addition to whatever the font
	   provider uses.

       charenc
	   Set subtitles input character encoding. "subtitles" filter only.
	   Only	useful if not UTF-8.

       stream_index, si
	   Set subtitles stream	index. "subtitles" filter only.

       force_style
	   Override default style or script info parameters of the subtitles.
	   It accepts a	string containing ASS style format "KEY=VALUE" couples
	   separated by	",".

       If the first key	is not specified, it is	assumed	that the first value
       specifies the filename.

       For example, to render the file sub.srt on top of the input video, use
       the command:

	       subtitles=sub.srt

       which is	equivalent to:

	       subtitles=filename=sub.srt

       To render the default subtitles stream from file	video.mkv, use:

	       subtitles=video.mkv

       To render the second subtitles stream from that file, use:

	       subtitles=video.mkv:si=1

       To make the subtitles stream from sub.srt appear	in transparent green
       "DejaVu Serif", use:

	       subtitles=sub.srt:force_style='FontName=DejaVu Serif,PrimaryColour=&HAA00FF00'

   super2xsai
       Scale the input by 2x and smooth	using the Super2xSaI (Scale and
       Interpolate) pixel art scaling algorithm.

       Useful for enlarging pixel art images without reducing sharpness.

   swaprect
       Swap two	rectangular objects in video.

       This filter accepts the following options:

       w   Set object width.

       h   Set object height.

       x1  Set 1st rect	x coordinate.

       y1  Set 1st rect	y coordinate.

       x2  Set 2nd rect	x coordinate.

       y2  Set 2nd rect	y coordinate.

	   All expressions are evaluated once for each frame.

       The all options are expressions containing the following	constants:

       w
       h   The input width and height.

       a   same	as w / h

       sar input sample	aspect ratio

       dar input display aspect	ratio, it is the same as (w / h) * sar

       n   The number of the input frame, starting from	0.

       t   The timestamp expressed in seconds. It's NAN	if the input timestamp
	   is unknown.

       pos the position	in the file of the input frame,	NAN if unknown

   swapuv
       Swap U &	V plane.

   telecine
       Apply telecine process to the video.

       This filter accepts the following options:

       first_field
	   top,	t
	       top field first

	   bottom, b
	       bottom field first The default value is "top".

       pattern
	   A string of numbers representing the	pulldown pattern you wish to
	   apply.  The default value is	23.

	       Some typical patterns:

	       NTSC output (30i):
	       27.5p: 32222
	       24p: 23 (classic)
	       24p: 2332 (preferred)
	       20p: 33
	       18p: 334
	       16p: 3444

	       PAL output (25i):
	       27.5p: 12222
	       24p: 222222222223 ("Euro	pulldown")
	       16.67p: 33
	       16p: 33333334

   threshold
       Apply threshold effect to video stream.

       This filter needs four video streams to perform thresholding.  First
       stream is stream	we are filtering.  Second stream is holding threshold
       values, third stream is holding min values, and last, fourth stream is
       holding max values.

       The filter accepts the following	option:

       planes
	   Set which planes will be processed, unprocessed planes will be
	   copied.  By default value 0xf, all planes will be processed.

       For example if first stream pixel's component value is less then
       threshold value of pixel	component from 2nd threshold stream, third
       stream value will picked, otherwise fourth stream pixel component value
       will be picked.

       Using color source filter one can perform various types of
       thresholding:

       Examples

       o   Binary threshold, using gray	color as threshold:

		   ffmpeg -i 320x240.avi -f lavfi -i color=gray	-f lavfi -i color=black	-f lavfi -i color=white	-lavfi threshold output.avi

       o   Inverted binary threshold, using gray color as threshold:

		   ffmpeg -i 320x240.avi -f lavfi -i color=gray	-f lavfi -i color=white	-f lavfi -i color=black	-lavfi threshold output.avi

       o   Truncate binary threshold, using gray color as threshold:

		   ffmpeg -i 320x240.avi -f lavfi -i color=gray	-i 320x240.avi -f lavfi	-i color=gray -lavfi threshold output.avi

       o   Threshold to	zero, using gray color as threshold:

		   ffmpeg -i 320x240.avi -f lavfi -i color=gray	-f lavfi -i color=white	-i 320x240.avi -lavfi threshold	output.avi

       o   Inverted threshold to zero, using gray color	as threshold:

		   ffmpeg -i 320x240.avi -f lavfi -i color=gray	-i 320x240.avi -f lavfi	-i color=white -lavfi threshold	output.avi

   thumbnail
       Select the most representative frame in a given sequence	of consecutive
       frames.

       The filter accepts the following	options:

       n   Set the frames batch	size to	analyze; in a set of n frames, the
	   filter will pick one	of them, and then handle the next batch	of n
	   frames until	the end. Default is 100.

       Since the filter	keeps track of the whole frames	sequence, a bigger n
       value will result in a higher memory usage, so a	high value is not
       recommended.

       Examples

       o   Extract one picture each 50 frames:

		   thumbnail=50

       o   Complete example of a thumbnail creation with ffmpeg:

		   ffmpeg -i in.avi -vf	thumbnail,scale=300:200	-frames:v 1 out.png

   tile
       Tile several successive frames together.

       The filter accepts the following	options:

       layout
	   Set the grid	size (i.e. the number of lines and columns). For the
	   syntax of this option, check	the "Video size" section in the
	   ffmpeg-utils	manual.

       nb_frames
	   Set the maximum number of frames to render in the given area. It
	   must	be less	than or	equal to wxh. The default value	is 0, meaning
	   all the area	will be	used.

       margin
	   Set the outer border	margin in pixels.

       padding
	   Set the inner border	thickness (i.e.	the number of pixels between
	   frames). For	more advanced padding options (such as having
	   different values for	the edges), refer to the pad video filter.

       color
	   Specify the color of	the unused area. For the syntax	of this
	   option, check the "Color" section in	the ffmpeg-utils manual. The
	   default value of color is "black".

       Examples

       o   Produce 8x8 PNG tiles of all	keyframes (-skip_frame nokey) in a
	   movie:

		   ffmpeg -skip_frame nokey -i file.avi	-vf 'scale=128:72,tile=8x8' -an	-vsync 0 keyframes%03d.png

	   The -vsync 0	is necessary to	prevent	ffmpeg from duplicating	each
	   output frame	to accommodate the originally detected frame rate.

       o   Display 5 pictures in an area of "3x2" frames, with 7 pixels
	   between them, and 2 pixels of initial margin, using mixed flat and
	   named options:

		   tile=3x2:nb_frames=5:padding=7:margin=2

   tinterlace
       Perform various types of	temporal field interlacing.

       Frames are counted starting from	1, so the first	input frame is
       considered odd.

       The filter accepts the following	options:

       mode
	   Specify the mode of the interlacing.	This option can	also be
	   specified as	a value	alone. See below for a list of values for this
	   option.

	   Available values are:

	   merge, 0
	       Move odd	frames into the	upper field, even into the lower
	       field, generating a double height frame at half frame rate.

			------>	time
		       Input:
		       Frame 1	       Frame 2	       Frame 3	       Frame 4

		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444

		       Output:
		       11111			       33333
		       22222			       44444
		       11111			       33333
		       22222			       44444
		       11111			       33333
		       22222			       44444
		       11111			       33333
		       22222			       44444

	   drop_even, 1
	       Only output odd frames, even frames are dropped,	generating a
	       frame with unchanged height at half frame rate.

			------>	time
		       Input:
		       Frame 1	       Frame 2	       Frame 3	       Frame 4

		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444

		       Output:
		       11111			       33333
		       11111			       33333
		       11111			       33333
		       11111			       33333

	   drop_odd, 2
	       Only output even	frames,	odd frames are dropped,	generating a
	       frame with unchanged height at half frame rate.

			------>	time
		       Input:
		       Frame 1	       Frame 2	       Frame 3	       Frame 4

		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444

		       Output:
				       22222			       44444
				       22222			       44444
				       22222			       44444
				       22222			       44444

	   pad,	3
	       Expand each frame to full height, but pad alternate lines with
	       black, generating a frame with double height at the same	input
	       frame rate.

			------>	time
		       Input:
		       Frame 1	       Frame 2	       Frame 3	       Frame 4

		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444

		       Output:
		       11111	       .....	       33333	       .....
		       .....	       22222	       .....	       44444
		       11111	       .....	       33333	       .....
		       .....	       22222	       .....	       44444
		       11111	       .....	       33333	       .....
		       .....	       22222	       .....	       44444
		       11111	       .....	       33333	       .....
		       .....	       22222	       .....	       44444

	   interleave_top, 4
	       Interleave the upper field from odd frames with the lower field
	       from even frames, generating a frame with unchanged height at
	       half frame rate.

			------>	time
		       Input:
		       Frame 1	       Frame 2	       Frame 3	       Frame 4

		       11111<-	       22222	       33333<-	       44444
		       11111	       22222<-	       33333	       44444<-
		       11111<-	       22222	       33333<-	       44444
		       11111	       22222<-	       33333	       44444<-

		       Output:
		       11111			       33333
		       22222			       44444
		       11111			       33333
		       22222			       44444

	   interleave_bottom, 5
	       Interleave the lower field from odd frames with the upper field
	       from even frames, generating a frame with unchanged height at
	       half frame rate.

			------>	time
		       Input:
		       Frame 1	       Frame 2	       Frame 3	       Frame 4

		       11111	       22222<-	       33333	       44444<-
		       11111<-	       22222	       33333<-	       44444
		       11111	       22222<-	       33333	       44444<-
		       11111<-	       22222	       33333<-	       44444

		       Output:
		       22222			       44444
		       11111			       33333
		       22222			       44444
		       11111			       33333

	   interlacex2,	6
	       Double frame rate with unchanged	height.	Frames are inserted
	       each containing the second temporal field from the previous
	       input frame and the first temporal field	from the next input
	       frame. This mode	relies on the top_field_first flag. Useful for
	       interlaced video	displays with no field synchronisation.

			------>	time
		       Input:
		       Frame 1	       Frame 2	       Frame 3	       Frame 4

		       11111	       22222	       33333	       44444
			11111		22222		33333		44444
		       11111	       22222	       33333	       44444
			11111		22222		33333		44444

		       Output:
		       11111   22222   22222   33333   33333   44444   44444
			11111	11111	22222	22222	33333	33333	44444
		       11111   22222   22222   33333   33333   44444   44444
			11111	11111	22222	22222	33333	33333	44444

	   mergex2, 7
	       Move odd	frames into the	upper field, even into the lower
	       field, generating a double height frame at same frame rate.

			------>	time
		       Input:
		       Frame 1	       Frame 2	       Frame 3	       Frame 4

		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444
		       11111	       22222	       33333	       44444

		       Output:
		       11111	       33333	       33333	       55555
		       22222	       22222	       44444	       44444
		       11111	       33333	       33333	       55555
		       22222	       22222	       44444	       44444
		       11111	       33333	       33333	       55555
		       22222	       22222	       44444	       44444
		       11111	       33333	       33333	       55555
		       22222	       22222	       44444	       44444

	   Numeric values are deprecated but are accepted for backward
	   compatibility reasons.

	   Default mode	is "merge".

       flags
	   Specify flags influencing the filter	process.

	   Available value for flags is:

	   low_pass_filter, vlfp
	       Enable vertical low-pass	filtering in the filter.  Vertical
	       low-pass	filtering is required when creating an interlaced
	       destination from	a progressive source which contains high-
	       frequency vertical detail. Filtering will reduce	interlace
	       'twitter' and Moire patterning.

	       Vertical	low-pass filtering can only be enabled for mode
	       interleave_top and interleave_bottom.

   transpose
       Transpose rows with columns in the input	video and optionally flip it.

       It accepts the following	parameters:

       dir Specify the transposition direction.

	   Can assume the following values:

	   0, 4, cclock_flip
	       Rotate by 90 degrees counterclockwise and vertically flip
	       (default), that is:

		       L.R     L.l
		       . . ->  . .
		       l.r     R.r

	   1, 5, clock
	       Rotate by 90 degrees clockwise, that is:

		       L.R     l.L
		       . . ->  . .
		       l.r     r.R

	   2, 6, cclock
	       Rotate by 90 degrees counterclockwise, that is:

		       L.R     R.r
		       . . ->  . .
		       l.r     L.l

	   3, 7, clock_flip
	       Rotate by 90 degrees clockwise and vertically flip, that	is:

		       L.R     r.R
		       . . ->  . .
		       l.r     l.L

	   For values between 4-7, the transposition is	only done if the input
	   video geometry is portrait and not landscape. These values are
	   deprecated, the "passthrough" option	should be used instead.

	   Numerical values are	deprecated, and	should be dropped in favor of
	   symbolic constants.

       passthrough
	   Do not apply	the transposition if the input geometry	matches	the
	   one specified by the	specified value. It accepts the	following
	   values:

	   none
	       Always apply transposition.

	   portrait
	       Preserve	portrait geometry (when	height >= width).

	   landscape
	       Preserve	landscape geometry (when width >= height).

	   Default value is "none".

       For example to rotate by	90 degrees clockwise and preserve portrait
       layout:

	       transpose=dir=1:passthrough=portrait

       The command above can also be specified as:

	       transpose=1:portrait

   trim
       Trim the	input so that the output contains one continuous subpart of
       the input.

       It accepts the following	parameters:

       start
	   Specify the time of the start of the	kept section, i.e. the frame
	   with	the timestamp start will be the	first frame in the output.

       end Specify the time of the first frame that will be dropped, i.e. the
	   frame immediately preceding the one with the	timestamp end will be
	   the last frame in the output.

       start_pts
	   This	is the same as start, except this option sets the start
	   timestamp in	timebase units instead of seconds.

       end_pts
	   This	is the same as end, except this	option sets the	end timestamp
	   in timebase units instead of	seconds.

       duration
	   The maximum duration	of the output in seconds.

       start_frame
	   The number of the first frame that should be	passed to the output.

       end_frame
	   The number of the first frame that should be	dropped.

       start, end, and duration	are expressed as time duration specifications;
       see the Time duration section in	the ffmpeg-utils(1) manual for the
       accepted	syntax.

       Note that the first two sets of the start/end options and the duration
       option look at the frame	timestamp, while the _frame variants simply
       count the frames	that pass through the filter. Also note	that this
       filter does not modify the timestamps. If you wish for the output
       timestamps to start at zero, insert a setpts filter after the trim
       filter.

       If multiple start or end	options	are set, this filter tries to be
       greedy and keep all the frames that match at least one of the specified
       constraints. To keep only the part that matches all the constraints at
       once, chain multiple trim filters.

       The defaults are	such that all the input	is kept. So it is possible to
       set e.g.	 just the end values to	keep everything	before the specified
       time.

       Examples:

       o   Drop	everything except the second minute of input:

		   ffmpeg -i INPUT -vf trim=60:120

       o   Keep	only the first second:

		   ffmpeg -i INPUT -vf trim=duration=1

   unsharp
       Sharpen or blur the input video.

       It accepts the following	parameters:

       luma_msize_x, lx
	   Set the luma	matrix horizontal size.	It must	be an odd integer
	   between 3 and 23. The default value is 5.

       luma_msize_y, ly
	   Set the luma	matrix vertical	size. It must be an odd	integer
	   between 3 and 23. The default value is 5.

       luma_amount, la
	   Set the luma	effect strength. It must be a floating point number,
	   reasonable values lay between -1.5 and 1.5.

	   Negative values will	blur the input video, while positive values
	   will	sharpen	it, a value of zero will disable the effect.

	   Default value is 1.0.

       chroma_msize_x, cx
	   Set the chroma matrix horizontal size. It must be an	odd integer
	   between 3 and 23. The default value is 5.

       chroma_msize_y, cy
	   Set the chroma matrix vertical size.	It must	be an odd integer
	   between 3 and 23. The default value is 5.

       chroma_amount, ca
	   Set the chroma effect strength. It must be a	floating point number,
	   reasonable values lay between -1.5 and 1.5.

	   Negative values will	blur the input video, while positive values
	   will	sharpen	it, a value of zero will disable the effect.

	   Default value is 0.0.

       opencl
	   If set to 1,	specify	using OpenCL capabilities, only	available if
	   FFmpeg was configured with "--enable-opencl". Default value is 0.

       All parameters are optional and default to the equivalent of the	string
       '5:5:1.0:5:5:0.0'.

       Examples

       o   Apply strong	luma sharpen effect:

		   unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=2.5

       o   Apply a strong blur of both luma and	chroma parameters:

		   unsharp=7:7:-2:7:7:-2

   uspp
       Apply ultra slow/simple postprocessing filter that compresses and
       decompresses the	image at several (or - in the case of quality level 8
       - all) shifts and average the results.

       The way this differs from the behavior of spp is	that uspp actually
       encodes & decodes each case with	libavcodec Snow, whereas spp uses a
       simplified intra	only 8x8 DCT similar to	MJPEG.

       The filter accepts the following	options:

       quality
	   Set quality.	This option defines the	number of levels for
	   averaging. It accepts an integer in the range 0-8. If set to	0, the
	   filter will have no effect. A value of 8 means the higher quality.
	   For each increment of that value the	speed drops by a factor	of
	   approximately 2.  Default value is 3.

       qp  Force a constant quantization parameter. If not set,	the filter
	   will	use the	QP from	the video stream (if available).

   vaguedenoiser
       Apply a wavelet based denoiser.

       It transforms each frame	from the video input into the wavelet domain,
       using Cohen-Daubechies-Feauveau 9/7. Then it applies some filtering to
       the obtained coefficients. It does an inverse wavelet transform after.
       Due to wavelet properties, it should give a nice	smoothed result, and
       reduced noise, without blurring picture features.

       This filter accepts the following options:

       threshold
	   The filtering strength. The higher, the more	filtered the video
	   will	be.  Hard thresholding can use a higher	threshold than soft
	   thresholding	before the video looks overfiltered.

       method
	   The filtering method	the filter will	use.

	   It accepts the following values:

	   hard
	       All values under	the threshold will be zeroed.

	   soft
	       All values under	the threshold will be zeroed. All values above
	       will be reduced by the threshold.

	   garrote
	       Scales or nullifies coefficients	- intermediary between (more)
	       soft and	(less) hard thresholding.

       nsteps
	   Number of times, the	wavelet	will decompose the picture. Picture
	   can't be decomposed beyond a	particular point (typically, 8 for a
	   640x480 frame - as 2^9 = 512	> 480)

       percent
	   Partial of full denoising (limited coefficients shrinking), from 0
	   to 100.

       planes
	   A list of the planes	to process. By default all planes are
	   processed.

   vectorscope
       Display 2 color component values	in the two dimensional graph (which is
       called a	vectorscope).

       This filter accepts the following options:

       mode, m
	   Set vectorscope mode.

	   It accepts the following values:

	   gray
	       Gray values are displayed on graph, higher brightness means
	       more pixels have	same component color value on location in
	       graph. This is the default mode.

	   color
	       Gray values are displayed on graph. Surrounding pixels values
	       which are not present in	video frame are	drawn in gradient of 2
	       color components	which are set by option	"x" and	"y". The 3rd
	       color component is static.

	   color2
	       Actual color components values present in video frame are
	       displayed on graph.

	   color3
	       Similar as color2 but higher frequency of same values "x" and
	       "y" on graph increases value of another color component,	which
	       is luminance by default values of "x" and "y".

	   color4
	       Actual colors present in	video frame are	displayed on graph. If
	       two different colors map	to same	position on graph then color
	       with higher value of component not present in graph is picked.

	   color5
	       Gray values are displayed on graph. Similar to "color" but with
	       3rd color component picked from radial gradient.

       x   Set which color component will be represented on X-axis. Default is
	   1.

       y   Set which color component will be represented on Y-axis. Default is
	   2.

       intensity, i
	   Set intensity, used by modes: gray, color, color3 and color5	for
	   increasing brightness of color component which represents frequency
	   of (X, Y) location in graph.

       envelope, e
	   none
	       No envelope, this is default.

	   instant
	       Instant envelope, even darkest single pixel will	be clearly
	       highlighted.

	   peak
	       Hold maximum and	minimum	values presented in graph over time.
	       This way	you can	still spot out of range	values without
	       constantly looking at vectorscope.

	   peak+instant
	       Peak and	instant	envelope combined together.

       graticule, g
	   Set what kind of graticule to draw.

	   none
	   green
	   color
       opacity,	o
	   Set graticule opacity.

       flags, f
	   Set graticule flags.

	   white
	       Draw graticule for white	point.

	   black
	       Draw graticule for black	point.

	   name
	       Draw color points short names.

       bgopacity, b
	   Set background opacity.

       lthreshold, l
	   Set low threshold for color component not represented on X or Y
	   axis.  Values lower than this value will be ignored.	Default	is 0.
	   Note	this value is multiplied with actual max possible value	one
	   pixel component can have. So	for 8-bit input	and low	threshold
	   value of 0.1	actual threshold is 0.1	* 255 =	25.

       hthreshold, h
	   Set high threshold for color	component not represented on X or Y
	   axis.  Values higher	than this value	will be	ignored. Default is 1.
	   Note	this value is multiplied with actual max possible value	one
	   pixel component can have. So	for 8-bit input	and high threshold
	   value of 0.9	actual threshold is 0.9	* 255 =	230.

       colorspace, c
	   Set what kind of colorspace to use when drawing graticule.

	   auto
	   601
	   709

	   Default is auto.

   vidstabdetect
       Analyze video stabilization/deshaking. Perform pass 1 of	2, see
       vidstabtransform	for pass 2.

       This filter generates a file with relative translation and rotation
       transform information about subsequent frames, which is then used by
       the vidstabtransform filter.

       To enable compilation of	this filter you	need to	configure FFmpeg with
       "--enable-libvidstab".

       This filter accepts the following options:

       result
	   Set the path	to the file used to write the transforms information.
	   Default value is transforms.trf.

       shakiness
	   Set how shaky the video is and how quick the	camera is. It accepts
	   an integer in the range 1-10, a value of 1 means little shakiness,
	   a value of 10 means strong shakiness. Default value is 5.

       accuracy
	   Set the accuracy of the detection process. It must be a value in
	   the range 1-15. A value of 1	means low accuracy, a value of 15
	   means high accuracy.	Default	value is 15.

       stepsize
	   Set stepsize	of the search process. The region around minimum is
	   scanned with	1 pixel	resolution. Default value is 6.

       mincontrast
	   Set minimum contrast. Below this value a local measurement field is
	   discarded. Must be a	floating point value in	the range 0-1. Default
	   value is 0.3.

       tripod
	   Set reference frame number for tripod mode.

	   If enabled, the motion of the frames	is compared to a reference
	   frame in the	filtered stream, identified by the specified number.
	   The idea is to compensate all movements in a	more-or-less static
	   scene and keep the camera view absolutely still.

	   If set to 0,	it is disabled.	The frames are counted starting	from
	   1.

       show
	   Show	fields and transforms in the resulting frames. It accepts an
	   integer in the range	0-2. Default value is 0, which disables	any
	   visualization.

       Examples

       o   Use default values:

		   vidstabdetect

       o   Analyze strongly shaky movie	and put	the results in file
	   mytransforms.trf:

		   vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf"

       o   Visualize the result	of internal transformations in the resulting
	   video:

		   vidstabdetect=show=1

       o   Analyze a video with	medium shakiness using ffmpeg:

		   ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1	dummy.avi

   vidstabtransform
       Video stabilization/deshaking: pass 2 of	2, see vidstabdetect for pass
       1.

       Read a file with	transform information for each frame and
       apply/compensate	them. Together with the	vidstabdetect filter this can
       be used to deshake videos. See also
       <http://public.hronopik.de/vid.stab>. It	is important to	also use the
       unsharp filter, see below.

       To enable compilation of	this filter you	need to	configure FFmpeg with
       "--enable-libvidstab".

       Options

       input
	   Set path to the file	used to	read the transforms. Default value is
	   transforms.trf.

       smoothing
	   Set the number of frames (value*2 + 1) used for lowpass filtering
	   the camera movements. Default value is 10.

	   For example a number	of 10 means that 21 frames are used (10	in the
	   past	and 10 in the future) to smoothen the motion in	the video. A
	   larger value	leads to a smoother video, but limits the acceleration
	   of the camera (pan/tilt movements). 0 is a special case where a
	   static camera is simulated.

       optalgo
	   Set the camera path optimization algorithm.

	   Accepted values are:

	   gauss
	       gaussian	kernel low-pass	filter on camera motion	(default)

	   avg averaging on transformations

       maxshift
	   Set maximal number of pixels	to translate frames. Default value is
	   -1, meaning no limit.

       maxangle
	   Set maximal angle in	radians	(degree*PI/180)	to rotate frames.
	   Default value is -1,	meaning	no limit.

       crop
	   Specify how to deal with borders that may be	visible	due to
	   movement compensation.

	   Available values are:

	   keep
	       keep image information from previous frame (default)

	   black
	       fill the	border black

       invert
	   Invert transforms if	set to 1. Default value	is 0.

       relative
	   Consider transforms as relative to previous frame if	set to 1,
	   absolute if set to 0. Default value is 0.

       zoom
	   Set percentage to zoom. A positive value will result	in a zoom-in
	   effect, a negative value in a zoom-out effect. Default value	is 0
	   (no zoom).

       optzoom
	   Set optimal zooming to avoid	borders.

	   Accepted values are:

	   0   disabled

	   1   optimal static zoom value is determined (only very strong
	       movements will lead to visible borders) (default)

	   2   optimal adaptive	zoom value is determined (no borders will be
	       visible), see zoomspeed

	   Note	that the value given at	zoom is	added to the one calculated
	   here.

       zoomspeed
	   Set percent to zoom maximally each frame (enabled when optzoom is
	   set to 2). Range is from 0 to 5, default value is 0.25.

       interpol
	   Specify type	of interpolation.

	   Available values are:

	   no  no interpolation

	   linear
	       linear only horizontal

	   bilinear
	       linear in both directions (default)

	   bicubic
	       cubic in	both directions	(slow)

       tripod
	   Enable virtual tripod mode if set to	1, which is equivalent to
	   "relative=0:smoothing=0". Default value is 0.

	   Use also "tripod" option of vidstabdetect.

       debug
	   Increase log	verbosity if set to 1. Also the	detected global
	   motions are written to the temporary	file global_motions.trf.
	   Default value is 0.

       Examples

       o   Use ffmpeg for a typical stabilization with default values:

		   ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg

	   Note	the use	of the unsharp filter which is always recommended.

       o   Zoom	in a bit more and load transform data from a given file:

		   vidstabtransform=zoom=5:input="mytransforms.trf"

       o   Smoothen the	video even more:

		   vidstabtransform=smoothing=30

   vflip
       Flip the	input video vertically.

       For example, to vertically flip a video with ffmpeg:

	       ffmpeg -i in.avi	-vf "vflip" out.avi

   vignette
       Make or reverse a natural vignetting effect.

       The filter accepts the following	options:

       angle, a
	   Set lens angle expression as	a number of radians.

	   The value is	clipped	in the "[0,PI/2]" range.

	   Default value: "PI/5"

       x0
       y0  Set center coordinates expressions. Respectively "w/2" and "h/2" by
	   default.

       mode
	   Set forward/backward	mode.

	   Available modes are:

	   forward
	       The larger the distance from the	central	point, the darker the
	       image becomes.

	   backward
	       The larger the distance from the	central	point, the brighter
	       the image becomes.  This	can be used to reverse a vignette
	       effect, though there is no automatic detection to extract the
	       lens angle and other settings (yet). It can also	be used	to
	       create a	burning	effect.

	   Default value is forward.

       eval
	   Set evaluation mode for the expressions (angle, x0, y0).

	   It accepts the following values:

	   init
	       Evaluate	expressions only once during the filter
	       initialization.

	   frame
	       Evaluate	expressions for	each incoming frame. This is way
	       slower than the init mode since it requires all the scalers to
	       be re-computed, but it allows advanced dynamic expressions.

	   Default value is init.

       dither
	   Set dithering to reduce the circular	banding	effects. Default is 1
	   (enabled).

       aspect
	   Set vignette	aspect.	This setting allows one	to adjust the shape of
	   the vignette.  Setting this value to	the SAR	of the input will make
	   a rectangular vignetting following the dimensions of	the video.

	   Default is "1/1".

       Expressions

       The alpha, x0 and y0 expressions	can contain the	following parameters.

       w
       h   input width and height

       n   the number of input frame, starting from 0

       pts the PTS (Presentation TimeStamp) time of the	filtered video frame,
	   expressed in	TB units, NAN if undefined

       r   frame rate of the input video, NAN if the input frame rate is
	   unknown

       t   the PTS (Presentation TimeStamp) of the filtered video frame,
	   expressed in	seconds, NAN if	undefined

       tb  time	base of	the input video

       Examples

       o   Apply simple	strong vignetting effect:

		   vignette=PI/4

       o   Make	a flickering vignetting:

		   vignette='PI/4+random(1)*PI/50':eval=frame

   vstack
       Stack input videos vertically.

       All streams must	be of same pixel format	and of same width.

       Note that this filter is	faster than using overlay and pad filter to
       create same output.

       The filter accept the following option:

       inputs
	   Set number of input streams.	Default	is 2.

       shortest
	   If set to 1,	force the output to terminate when the shortest	input
	   terminates. Default value is	0.

   w3fdif
       Deinterlace the input video ("w3fdif" stands for	"Weston	3 Field
       Deinterlacing Filter").

       Based on	the process described by Martin	Weston for BBC R&D, and
       implemented based on the	de-interlace algorithm written by Jim
       Easterbrook for BBC R&D,	the Weston 3 field deinterlacing filter	uses
       filter coefficients calculated by BBC R&D.

       There are two sets of filter coefficients, so called "simple": and
       "complex". Which	set of filter coefficients is used can be set by
       passing an optional parameter:

       filter
	   Set the interlacing filter coefficients. Accepts one	of the
	   following values:

	   simple
	       Simple filter coefficient set.

	   complex
	       More-complex filter coefficient set.

	   Default value is complex.

       deint
	   Specify which frames	to deinterlace.	Accept one of the following
	   values:

	   all Deinterlace all frames,

	   interlaced
	       Only deinterlace	frames marked as interlaced.

	   Default value is all.

   waveform
       Video waveform monitor.

       The waveform monitor plots color	component intensity. By	default
       luminance only. Each column of the waveform corresponds to a column of
       pixels in the source video.

       It accepts the following	options:

       mode, m
	   Can be either "row",	or "column". Default is	"column".  In row
	   mode, the graph on the left side represents color component value 0
	   and the right side represents value = 255. In column	mode, the top
	   side	represents color component value = 0 and bottom	side
	   represents value = 255.

       intensity, i
	   Set intensity. Smaller values are useful to find out	how many
	   values of the same luminance	are distributed	across input
	   rows/columns.  Default value	is 0.04. Allowed range is [0, 1].

       mirror, r
	   Set mirroring mode. 0 means unmirrored, 1 means mirrored.  In
	   mirrored mode, higher values	will be	represented on the left	side
	   for "row" mode and at the top for "column" mode. Default is 1
	   (mirrored).

       display,	d
	   Set display mode.  It accepts the following values:

	   overlay
	       Presents	information identical to that in the "parade", except
	       that the	graphs representing color components are superimposed
	       directly	over one another.

	       This display mode makes it easier to spot relative differences
	       or similarities in overlapping areas of the color components
	       that are	supposed to be identical, such as neutral whites,
	       grays, or blacks.

	   stack
	       Display separate	graph for the color components side by side in
	       "row" mode or one below the other in "column" mode.

	   parade
	       Display separate	graph for the color components side by side in
	       "column"	mode or	one below the other in "row" mode.

	       Using this display mode makes it	easy to	spot color casts in
	       the highlights and shadows of an	image, by comparing the
	       contours	of the top and the bottom graphs of each waveform.
	       Since whites, grays, and	blacks are characterized by exactly
	       equal amounts of	red, green, and	blue, neutral areas of the
	       picture should display three waveforms of roughly equal
	       width/height. If	not, the correction is easy to perform by
	       making level adjustments	the three waveforms.

	   Default is "stack".

       components, c
	   Set which color components to display. Default is 1,	which means
	   only	luminance or red color component if input is in	RGB
	   colorspace. If is set for example to	7 it will display all 3	(if)
	   available color components.

       envelope, e
	   none
	       No envelope, this is default.

	   instant
	       Instant envelope, minimum and maximum values presented in graph
	       will be easily visible even with	small "step" value.

	   peak
	       Hold minimum and	maximum	values presented in graph across time.
	       This way	you can	still spot out of range	values without
	       constantly looking at waveforms.

	   peak+instant
	       Peak and	instant	envelope combined together.

       filter, f
	   lowpass
	       No filtering, this is default.

	   flat
	       Luma and	chroma combined	together.

	   aflat
	       Similar as above, but shows difference between blue and red
	       chroma.

	   chroma
	       Displays	only chroma.

	   color
	       Displays	actual color value on waveform.

	   acolor
	       Similar as above, but with luma showing frequency of chroma
	       values.

       graticule, g
	   Set which graticule to display.

	   none
	       Do not display graticule.

	   green
	       Display green graticule showing legal broadcast ranges.

       opacity,	o
	   Set graticule opacity.

       flags, fl
	   Set graticule flags.

	   numbers
	       Draw numbers above lines. By default enabled.

	   dots
	       Draw dots instead of lines.

       scale, s
	   Set scale used for displaying graticule.

	   digital
	   millivolts
	   ire

	   Default is digital.

       bgopacity, b
	   Set background opacity.

   weave
       The "weave" takes a field-based video input and join each two
       sequential fields into single frame, producing a	new double height clip
       with half the frame rate	and half the frame count.

       It accepts the following	option:

       first_field
	   Set first field. Available values are:

	   top,	t
	       Set the frame as	top-field-first.

	   bottom, b
	       Set the frame as	bottom-field-first.

       Examples

       o   Interlace video using select	and separatefields filter:

		   separatefields,select=eq(mod(n,4),0)+eq(mod(n,4),3),weave

   xbr
       Apply the xBR high-quality magnification	filter which is	designed for
       pixel art. It follows a set of edge-detection rules, see
       <http://www.libretro.com/forums/viewtopic.php?f=6&t=134>.

       It accepts the following	option:

       n   Set the scaling dimension: 2	for "2xBR", 3 for "3xBR" and 4 for
	   "4xBR".  Default is 3.

   yadif
       Deinterlace the input video ("yadif" means "yet another deinterlacing
       filter").

       It accepts the following	parameters:

       mode
	   The interlacing mode	to adopt. It accepts one of the	following
	   values:

	   0, send_frame
	       Output one frame	for each frame.

	   1, send_field
	       Output one frame	for each field.

	   2, send_frame_nospatial
	       Like "send_frame", but it skips the spatial interlacing check.

	   3, send_field_nospatial
	       Like "send_field", but it skips the spatial interlacing check.

	   The default value is	"send_frame".

       parity
	   The picture field parity assumed for	the input interlaced video. It
	   accepts one of the following	values:

	   0, tff
	       Assume the top field is first.

	   1, bff
	       Assume the bottom field is first.

	   -1, auto
	       Enable automatic	detection of field parity.

	   The default value is	"auto".	 If the	interlacing is unknown or the
	   decoder does	not export this	information, top field first will be
	   assumed.

       deint
	   Specify which frames	to deinterlace.	Accept one of the following
	   values:

	   0, all
	       Deinterlace all frames.

	   1, interlaced
	       Only deinterlace	frames marked as interlaced.

	   The default value is	"all".

   zoompan
       Apply Zoom & Pan	effect.

       This filter accepts the following options:

       zoom, z
	   Set the zoom	expression. Default is 1.

       x
       y   Set the x and y expression. Default is 0.

       d   Set the duration expression in number of frames.  This sets for how
	   many	number of frames effect	will last for single input image.

       s   Set the output image	size, default is 'hd720'.

       fps Set the output frame	rate, default is '25'.

       Each expression can contain the following constants:

       in_w, iw
	   Input width.

       in_h, ih
	   Input height.

       out_w, ow
	   Output width.

       out_h, oh
	   Output height.

       in  Input frame count.

       on  Output frame	count.

       x
       y   Last	calculated 'x' and 'y' position	from 'x' and 'y' expression
	   for current input frame.

       px
       py  'x' and 'y' of last output frame of previous	input frame or 0 when
	   there was not yet such frame	(first input frame).

       zoom
	   Last	calculated zoom	from 'z' expression for	current	input frame.

       pzoom
	   Last	calculated zoom	of last	output frame of	previous input frame.

       duration
	   Number of output frames for current input frame. Calculated from
	   'd' expression for each input frame.

       pduration
	   number of output frames created for previous	input frame

       a   Rational number: input width	/ input	height

       sar sample aspect ratio

       dar display aspect ratio

       Examples

       o   Zoom-in up to 1.5 and pan at	same time to some spot near center of
	   picture:

		   zoompan=z='min(zoom+0.0015,1.5)':d=700:x='if(gte(zoom,1.5),x,x+1/a)':y='if(gte(zoom,1.5),y,y+1)':s=640x360

       o   Zoom-in up to 1.5 and pan always at center of picture:

		   zoompan=z='min(zoom+0.0015,1.5)':d=700:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'

       o   Same	as above but without pausing:

		   zoompan=z='min(max(zoom,pzoom)+0.0015,1.5)':d=1:x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)'

   zscale
       Scale (resize) the input	video, using the z.lib library:
       https://github.com/sekrit-twc/zimg.

       The zscale filter forces	the output display aspect ratio	to be the same
       as the input, by	changing the output sample aspect ratio.

       If the input image format is different from the format requested	by the
       next filter, the	zscale filter will convert the input to	the requested
       format.

       Options

       The filter accepts the following	options.

       width, w
       height, h
	   Set the output video	dimension expression. Default value is the
	   input dimension.

	   If the width	or w is	0, the input width is used for the output.  If
	   the height or h is 0, the input height is used for the output.

	   If one of the values	is -1, the zscale filter will use a value that
	   maintains the aspect	ratio of the input image, calculated from the
	   other specified dimension. If both of them are -1, the input	size
	   is used

	   If one of the values	is -n with n > 1, the zscale filter will also
	   use a value that maintains the aspect ratio of the input image,
	   calculated from the other specified dimension. After	that it	will,
	   however, make sure that the calculated dimension is divisible by n
	   and adjust the value	if necessary.

	   See below for the list of accepted constants	for use	in the
	   dimension expression.

       size, s
	   Set the video size. For the syntax of this option, check the	"Video
	   size" section in the	ffmpeg-utils manual.

       dither, d
	   Set the dither type.

	   Possible values are:

	   none
	   ordered
	   random
	   error_diffusion

	   Default is none.

       filter, f
	   Set the resize filter type.

	   Possible values are:

	   point
	   bilinear
	   bicubic
	   spline16
	   spline36
	   lanczos

	   Default is bilinear.

       range, r
	   Set the color range.

	   Possible values are:

	   input
	   limited
	   full

	   Default is same as input.

       primaries, p
	   Set the color primaries.

	   Possible values are:

	   input
	   709
	   unspecified
	   170m
	   240m
	   2020

	   Default is same as input.

       transfer, t
	   Set the transfer characteristics.

	   Possible values are:

	   input
	   709
	   unspecified
	   601
	   linear
	   2020_10
	   2020_12
	   smpte2084
	   iec61966-2-1
	   arib-std-b67

	   Default is same as input.

       matrix, m
	   Set the colorspace matrix.

	   Possible value are:

	   input
	   709
	   unspecified
	   470bg
	   170m
	   2020_ncl
	   2020_cl

	   Default is same as input.

       rangein,	rin
	   Set the input color range.

	   Possible values are:

	   input
	   limited
	   full

	   Default is same as input.

       primariesin, pin
	   Set the input color primaries.

	   Possible values are:

	   input
	   709
	   unspecified
	   170m
	   240m
	   2020

	   Default is same as input.

       transferin, tin
	   Set the input transfer characteristics.

	   Possible values are:

	   input
	   709
	   unspecified
	   601
	   linear
	   2020_10
	   2020_12

	   Default is same as input.

       matrixin, min
	   Set the input colorspace matrix.

	   Possible value are:

	   input
	   709
	   unspecified
	   470bg
	   170m
	   2020_ncl
	   2020_cl
       chromal,	c
	   Set the output chroma location.

	   Possible values are:

	   input
	   left
	   center
	   topleft
	   top
	   bottomleft
	   bottom
       chromalin, cin
	   Set the input chroma	location.

	   Possible values are:

	   input
	   left
	   center
	   topleft
	   top
	   bottomleft
	   bottom
       npl Set the nominal peak	luminance.

       The values of the w and h options are expressions containing the
       following constants:

       in_w
       in_h
	   The input width and height

       iw
       ih  These are the same as in_w and in_h.

       out_w
       out_h
	   The output (scaled) width and height

       ow
       oh  These are the same as out_w and out_h

       a   The same as iw / ih

       sar input sample	aspect ratio

       dar The input display aspect ratio. Calculated from "(iw	/ ih) *	sar".

       hsub
       vsub
	   horizontal and vertical input chroma	subsample values. For example
	   for the pixel format	"yuv422p" hsub is 2 and	vsub is	1.

       ohsub
       ovsub
	   horizontal and vertical output chroma subsample values. For example
	   for the pixel format	"yuv422p" hsub is 2 and	vsub is	1.

VIDEO SOURCES
       Below is	a description of the currently available video sources.

   buffer
       Buffer video frames, and	make them available to the filter chain.

       This source is mainly intended for a programmatic use, in particular
       through the interface defined in	libavfilter/vsrc_buffer.h.

       It accepts the following	parameters:

       video_size
	   Specify the size (width and height) of the buffered video frames.
	   For the syntax of this option, check	the "Video size" section in
	   the ffmpeg-utils manual.

       width
	   The input video width.

       height
	   The input video height.

       pix_fmt
	   A string representing the pixel format of the buffered video
	   frames.  It may be a	number corresponding to	a pixel	format,	or a
	   pixel format	name.

       time_base
	   Specify the timebase	assumed	by the timestamps of the buffered
	   frames.

       frame_rate
	   Specify the frame rate expected for the video stream.

       pixel_aspect, sar
	   The sample (pixel) aspect ratio of the input	video.

       sws_param
	   Specify the optional	parameters to be used for the scale filter
	   which is automatically inserted when	an input change	is detected in
	   the input size or format.

       hw_frames_ctx
	   When	using a	hardware pixel format, this should be a	reference to
	   an AVHWFramesContext	describing input frames.

       For example:

	       buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1

       will instruct the source	to accept video	frames with size 320x240 and
       with format "yuv410p", assuming 1/24 as the timestamps timebase and
       square pixels (1:1 sample aspect	ratio).	 Since the pixel format	with
       name "yuv410p" corresponds to the number	6 (check the enum
       AVPixelFormat definition	in libavutil/pixfmt.h),	this example
       corresponds to:

	       buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1

       Alternatively, the options can be specified as a	flat string, but this
       syntax is deprecated:

       width:height:pix_fmt:time_base.num:time_base.den:pixel_aspect.num:pixel_aspect.den[:sws_param]

   cellauto
       Create a	pattern	generated by an	elementary cellular automaton.

       The initial state of the	cellular automaton can be defined through the
       filename	and pattern options. If	such options are not specified an
       initial state is	created	randomly.

       At each new frame a new row in the video	is filled with the result of
       the cellular automaton next generation. The behavior when the whole
       frame is	filled is defined by the scroll	option.

       This source accepts the following options:

       filename, f
	   Read	the initial cellular automaton state, i.e. the starting	row,
	   from	the specified file.  In	the file, each non-whitespace
	   character is	considered an alive cell, a newline will terminate the
	   row,	and further characters in the file will	be ignored.

       pattern,	p
	   Read	the initial cellular automaton state, i.e. the starting	row,
	   from	the specified string.

	   Each	non-whitespace character in the	string is considered an	alive
	   cell, a newline will	terminate the row, and further characters in
	   the string will be ignored.

       rate, r
	   Set the video rate, that is the number of frames generated per
	   second.  Default is 25.

       random_fill_ratio, ratio
	   Set the random fill ratio for the initial cellular automaton	row.
	   It is a floating point number value ranging from 0 to 1, defaults
	   to 1/PHI.

	   This	option is ignored when a file or a pattern is specified.

       random_seed, seed
	   Set the seed	for filling randomly the initial row, must be an
	   integer included between 0 and UINT32_MAX. If not specified,	or if
	   explicitly set to -1, the filter will try to	use a good random seed
	   on a	best effort basis.

       rule
	   Set the cellular automaton rule, it is a number ranging from	0 to
	   255.	 Default value is 110.

       size, s
	   Set the size	of the output video. For the syntax of this option,
	   check the "Video size" section in the ffmpeg-utils manual.

	   If filename or pattern is specified,	the size is set	by default to
	   the width of	the specified initial state row, and the height	is set
	   to width * PHI.

	   If size is set, it must contain the width of	the specified pattern
	   string, and the specified pattern will be centered in the larger
	   row.

	   If a	filename or a pattern string is	not specified, the size	value
	   defaults to "320x518" (used for a randomly generated	initial
	   state).

       scroll
	   If set to 1,	scroll the output upward when all the rows in the
	   output have been already filled. If set to 0, the new generated row
	   will	be written over	the top	row just after the bottom row is
	   filled.  Defaults to	1.

       start_full, full
	   If set to 1,	completely fill	the output with	generated rows before
	   outputting the first	frame.	This is	the default behavior, for
	   disabling set the value to 0.

       stitch
	   If set to 1,	stitch the left	and right row edges together.  This is
	   the default behavior, for disabling set the value to	0.

       Examples

       o   Read	the initial state from pattern,	and specify an output of size
	   200x400.

		   cellauto=f=pattern:s=200x400

       o   Generate a random initial row with a	width of 200 cells, with a
	   fill	ratio of 2/3:

		   cellauto=ratio=2/3:s=200x200

       o   Create a pattern generated by rule 18 starting by a single alive
	   cell	centered on an initial row with	width 100:

		   cellauto=p=@s=100x400:full=0:rule=18

       o   Specify a more elaborated initial pattern:

		   cellauto=p='@@ @ @@':s=100x400:full=0:rule=18

   coreimagesrc
       Video source generated on GPU using Apple's CoreImage API on OSX.

       This video source is a specialized version of the coreimage video
       filter.	Use a core image generator at the beginning of the applied
       filterchain to generate the content.

       The coreimagesrc	video source accepts the following options:

       list_generators
	   List	all available generators along with all	their respective
	   options as well as possible minimum and maximum values along	with
	   the default values.

		   list_generators=true

       size, s
	   Specify the size of the sourced video. For the syntax of this
	   option, check the "Video size" section in the ffmpeg-utils manual.
	   The default value is	"320x240".

       rate, r
	   Specify the frame rate of the sourced video,	as the number of
	   frames generated per	second.	It has to be a string in the format
	   frame_rate_num/frame_rate_den, an integer number, a floating	point
	   number or a valid video frame rate abbreviation. The	default	value
	   is "25".

       sar Set the sample aspect ratio of the sourced video.

       duration, d
	   Set the duration of the sourced video. See the Time duration
	   section in the ffmpeg-utils(1) manual for the accepted syntax.

	   If not specified, or	the expressed duration is negative, the	video
	   is supposed to be generated forever.

       Additionally, all options of the	coreimage video	filter are accepted.
       A complete filterchain can be used for further processing of the
       generated input without CPU-HOST	transfer. See coreimage	documentation
       and examples for	details.

       Examples

       o   Use CIQRCodeGenerator to create a QR	code for the FFmpeg homepage,
	   given as complete and escaped command-line for Apple's standard
	   bash	shell:

		   ffmpeg -f lavfi -i coreimagesrc=s=100x100:filter=CIQRCodeGenerator@inputMessage=https\\\\\://FFmpeg.org/@inputCorrectionLevel=H -frames:v 1 QRCode.png

	   This	example	is equivalent to the QRCode example of coreimage
	   without the need for	a nullsrc video	source.

   mandelbrot
       Generate	a Mandelbrot set fractal, and progressively zoom towards the
       point specified with start_x and	start_y.

       This source accepts the following options:

       end_pts
	   Set the terminal pts	value. Default value is	400.

       end_scale
	   Set the terminal scale value.  Must be a floating point value.
	   Default value is 0.3.

       inner
	   Set the inner coloring mode,	that is	the algorithm used to draw the
	   Mandelbrot fractal internal region.

	   It shall assume one of the following	values:

	   black
	       Set black mode.

	   convergence
	       Show time until convergence.

	   mincol
	       Set color based on point	closest	to the origin of the
	       iterations.

	   period
	       Set period mode.

	   Default value is mincol.

       bailout
	   Set the bailout value. Default value	is 10.0.

       maxiter
	   Set the maximum of iterations performed by the rendering algorithm.
	   Default value is 7189.

       outer
	   Set outer coloring mode.  It	shall assume one of following values:

	   iteration_count
	       Set iteration cound mode.

	   normalized_iteration_count
	       set normalized iteration	count mode.

	   Default value is normalized_iteration_count.

       rate, r
	   Set frame rate, expressed as	number of frames per second. Default
	   value is "25".

       size, s
	   Set frame size. For the syntax of this option, check	the "Video
	   size" section in the	ffmpeg-utils manual. Default value is
	   "640x480".

       start_scale
	   Set the initial scale value.	Default	value is 3.0.

       start_x
	   Set the initial x position. Must be a floating point	value between
	   -100	and 100. Default value is
	   -0.743643887037158704752191506114774.

       start_y
	   Set the initial y position. Must be a floating point	value between
	   -100	and 100. Default value is
	   -0.131825904205311970493132056385139.

   mptestsrc
       Generate	various	test patterns, as generated by the MPlayer test
       filter.

       The size	of the generated video is fixed, and is	256x256.  This source
       is useful in particular for testing encoding features.

       This source accepts the following options:

       rate, r
	   Specify the frame rate of the sourced video,	as the number of
	   frames generated per	second.	It has to be a string in the format
	   frame_rate_num/frame_rate_den, an integer number, a floating	point
	   number or a valid video frame rate abbreviation. The	default	value
	   is "25".

       duration, d
	   Set the duration of the sourced video. See the Time duration
	   section in the ffmpeg-utils(1) manual for the accepted syntax.

	   If not specified, or	the expressed duration is negative, the	video
	   is supposed to be generated forever.

       test, t
	   Set the number or the name of the test to perform. Supported	tests
	   are:

	   dc_luma
	   dc_chroma
	   freq_luma
	   freq_chroma
	   amp_luma
	   amp_chroma
	   cbp
	   mv
	   ring1
	   ring2
	   all

	   Default value is "all", which will cycle through the	list of	all
	   tests.

       Some examples:

	       mptestsrc=t=dc_luma

       will generate a "dc_luma" test pattern.

   frei0r_src
       Provide a frei0r	source.

       To enable compilation of	this filter you	need to	install	the frei0r
       header and configure FFmpeg with	"--enable-frei0r".

       This source accepts the following parameters:

       size
	   The size of the video to generate. For the syntax of	this option,
	   check the "Video size" section in the ffmpeg-utils manual.

       framerate
	   The framerate of the	generated video. It may	be a string of the
	   form	num/den	or a frame rate	abbreviation.

       filter_name
	   The name to the frei0r source to load. For more information
	   regarding frei0r and	how to set the parameters, read	the frei0r
	   section in the video	filters	documentation.

       filter_params
	   A '|'-separated list	of parameters to pass to the frei0r source.

       For example, to generate	a frei0r partik0l source with size 200x200 and
       frame rate 10 which is overlaid on the overlay filter main input:

	       frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay

   life
       Generate	a life pattern.

       This source is based on a generalization	of John	Conway's life game.

       The sourced input represents a life grid, each pixel represents a cell
       which can be in one of two possible states, alive or dead. Every	cell
       interacts with its eight	neighbours, which are the cells	that are
       horizontally, vertically, or diagonally adjacent.

       At each interaction the grid evolves according to the adopted rule,
       which specifies the number of neighbor alive cells which	will make a
       cell stay alive or born.	The rule option	allows one to specify the rule
       to adopt.

       This source accepts the following options:

       filename, f
	   Set the file	from which to read the initial grid state. In the
	   file, each non-whitespace character is considered an	alive cell,
	   and newline is used to delimit the end of each row.

	   If this option is not specified, the	initial	grid is	generated
	   randomly.

       rate, r
	   Set the video rate, that is the number of frames generated per
	   second.  Default is 25.

       random_fill_ratio, ratio
	   Set the random fill ratio for the initial random grid. It is	a
	   floating point number value ranging from 0 to 1, defaults to	1/PHI.
	   It is ignored when a	file is	specified.

       random_seed, seed
	   Set the seed	for filling the	initial	random grid, must be an
	   integer included between 0 and UINT32_MAX. If not specified,	or if
	   explicitly set to -1, the filter will try to	use a good random seed
	   on a	best effort basis.

       rule
	   Set the life	rule.

	   A rule can be specified with	a code of the kind "SNS/BNB", where NS
	   and NB are sequences	of numbers in the range	0-8, NS	specifies the
	   number of alive neighbor cells which	make a live cell stay alive,
	   and NB the number of	alive neighbor cells which make	a dead cell to
	   become alive	(i.e. to "born").  "s" and "b" can be used in place of
	   "S" and "B",	respectively.

	   Alternatively a rule	can be specified by an 18-bits integer.	The 9
	   high	order bits are used to encode the next cell state if it	is
	   alive for each number of neighbor alive cells, the low order	bits
	   specify the rule for	"borning" new cells. Higher order bits encode
	   for an higher number	of neighbor cells.  For	example	the number
	   6153	= "(12<<9)+9" specifies	a stay alive rule of 12	and a born
	   rule	of 9, which corresponds	to "S23/B03".

	   Default value is "S23/B3", which is the original Conway's game of
	   life	rule, and will keep a cell alive if it has 2 or	3 neighbor
	   alive cells,	and will born a	new cell if there are three alive
	   cells around	a dead cell.

       size, s
	   Set the size	of the output video. For the syntax of this option,
	   check the "Video size" section in the ffmpeg-utils manual.

	   If filename is specified, the size is set by	default	to the same
	   size	of the input file. If size is set, it must contain the size
	   specified in	the input file,	and the	initial	grid defined in	that
	   file	is centered in the larger resulting area.

	   If a	filename is not	specified, the size value defaults to
	   "320x240" (used for a randomly generated initial grid).

       stitch
	   If set to 1,	stitch the left	and right grid edges together, and the
	   top and bottom edges	also. Defaults to 1.

       mold
	   Set cell mold speed.	If set,	a dead cell will go from death_color
	   to mold_color with a	step of	mold. mold can have a value from 0 to
	   255.

       life_color
	   Set the color of living (or new born) cells.

       death_color
	   Set the color of dead cells.	If mold	is set,	this is	the first
	   color used to represent a dead cell.

       mold_color
	   Set mold color, for definitely dead and moldy cells.

	   For the syntax of these 3 color options, check the "Color" section
	   in the ffmpeg-utils manual.

       Examples

       o   Read	a grid from pattern, and center	it on a	grid of	size 300x300
	   pixels:

		   life=f=pattern:s=300x300

       o   Generate a random grid of size 200x200, with	a fill ratio of	2/3:

		   life=ratio=2/3:s=200x200

       o   Specify a custom rule for evolving a	randomly generated grid:

		   life=rule=S14/B34

       o   Full	example	with slow death	effect (mold) using ffplay:

		   ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16

   allrgb, allyuv, color, haldclutsrc, nullsrc,	rgbtestsrc, smptebars,
       smptehdbars, testsrc, testsrc2, yuvtestsrc
       The "allrgb" source returns frames of size 4096x4096 of all rgb colors.

       The "allyuv" source returns frames of size 4096x4096 of all yuv colors.

       The "color" source provides an uniformly	colored	input.

       The "haldclutsrc" source	provides an identity Hald CLUT.	See also
       haldclut	filter.

       The "nullsrc" source returns unprocessed	video frames. It is mainly
       useful to be employed in	analysis / debugging tools, or as the source
       for filters which ignore	the input data.

       The "rgbtestsrc"	source generates an RGB	test pattern useful for
       detecting RGB vs	BGR issues. You	should see a red, green	and blue
       stripe from top to bottom.

       The "smptebars" source generates	a color	bars pattern, based on the
       SMPTE Engineering Guideline EG 1-1990.

       The "smptehdbars" source	generates a color bars pattern,	based on the
       SMPTE RP	219-2002.

       The "testsrc" source generates a	test video pattern, showing a color
       pattern,	a scrolling gradient and a timestamp. This is mainly intended
       for testing purposes.

       The "testsrc2" source is	similar	to testsrc, but	supports more pixel
       formats instead of just "rgb24".	This allows using it as	an input for
       other tests without requiring a format conversion.

       The "yuvtestsrc"	source generates an YUV	test pattern. You should see a
       y, cb and cr stripe from	top to bottom.

       The sources accept the following	parameters:

       color, c
	   Specify the color of	the source, only available in the "color"
	   source. For the syntax of this option, check	the "Color" section in
	   the ffmpeg-utils manual.

       level
	   Specify the level of	the Hald CLUT, only available in the
	   "haldclutsrc" source. A level of "N"	generates a picture of "N*N*N"
	   by "N*N*N" pixels to	be used	as identity matrix for 3D lookup
	   tables. Each	component is coded on a	"1/(N*N)" scale.

       size, s
	   Specify the size of the sourced video. For the syntax of this
	   option, check the "Video size" section in the ffmpeg-utils manual.
	   The default value is	"320x240".

	   This	option is not available	with the "haldclutsrc" filter.

       rate, r
	   Specify the frame rate of the sourced video,	as the number of
	   frames generated per	second.	It has to be a string in the format
	   frame_rate_num/frame_rate_den, an integer number, a floating	point
	   number or a valid video frame rate abbreviation. The	default	value
	   is "25".

       sar Set the sample aspect ratio of the sourced video.

       duration, d
	   Set the duration of the sourced video. See the Time duration
	   section in the ffmpeg-utils(1) manual for the accepted syntax.

	   If not specified, or	the expressed duration is negative, the	video
	   is supposed to be generated forever.

       decimals, n
	   Set the number of decimals to show in the timestamp,	only available
	   in the "testsrc" source.

	   The displayed timestamp value will correspond to the	original
	   timestamp value multiplied by the power of 10 of the	specified
	   value. Default value	is 0.

       For example the following:

	       testsrc=duration=5.3:size=qcif:rate=10

       will generate a video with a duration of	5.3 seconds, with size 176x144
       and a frame rate	of 10 frames per second.

       The following graph description will generate a red source with an
       opacity of 0.2, with size "qcif"	and a frame rate of 10 frames per
       second.

	       color=c=red@0.2:s=qcif:r=10

       If the input content is to be ignored, "nullsrc"	can be used. The
       following command generates noise in the	luminance plane	by employing
       the "geq" filter:

	       nullsrc=s=256x256, geq=random(1)*255:128:128

       Commands

       The "color" source supports the following commands:

       c, color
	   Set the color of the	created	image. Accepts the same	syntax of the
	   corresponding color option.

VIDEO SINKS
       Below is	a description of the currently available video sinks.

   buffersink
       Buffer video frames, and	make them available to the end of the filter
       graph.

       This sink is mainly intended for	programmatic use, in particular
       through the interface defined in	libavfilter/buffersink.h or the
       options system.

       It accepts a pointer to an AVBufferSinkContext structure, which defines
       the incoming buffers' formats, to be passed as the opaque parameter to
       "avfilter_init_filter" for initialization.

   nullsink
       Null video sink:	do absolutely nothing with the input video. It is
       mainly useful as	a template and for use in analysis / debugging tools.

MULTIMEDIA FILTERS
       Below is	a description of the currently available multimedia filters.

   abitscope
       Convert input audio to a	video output, displaying the audio bit scope.

       The filter accepts the following	options:

       rate, r
	   Set frame rate, expressed as	number of frames per second. Default
	   value is "25".

       size, s
	   Specify the video size for the output. For the syntax of this
	   option, check the "Video size" section in the ffmpeg-utils manual.
	   Default value is "1024x256".

       colors
	   Specify list	of colors separated by space or	by '|' which will be
	   used	to draw	channels. Unrecognized or missing colors will be
	   replaced by white color.

   ahistogram
       Convert input audio to a	video output, displaying the volume histogram.

       The filter accepts the following	options:

       dmode
	   Specify how histogram is calculated.

	   It accepts the following values:

	   single
	       Use single histogram for	all channels.

	   separate
	       Use separate histogram for each channel.

	   Default is "single".

       rate, r
	   Set frame rate, expressed as	number of frames per second. Default
	   value is "25".

       size, s
	   Specify the video size for the output. For the syntax of this
	   option, check the "Video size" section in the ffmpeg-utils manual.
	   Default value is "hd720".

       scale
	   Set display scale.

	   It accepts the following values:

	   log logarithmic

	   sqrt
	       square root

	   cbrt
	       cubic root

	   lin linear

	   rlog
	       reverse logarithmic

	   Default is "log".

       ascale
	   Set amplitude scale.

	   It accepts the following values:

	   log logarithmic

	   lin linear

	   Default is "log".

       acount
	   Set how much	frames to accumulate in	histogram.  Defauls is 1.
	   Setting this	to -1 accumulates all frames.

       rheight
	   Set histogram ratio of window height.

       slide
	   Set sonogram	sliding.

	   It accepts the following values:

	   replace
	       replace old rows	with new ones.

	   scroll
	       scroll from top to bottom.

	   Default is "replace".

   aphasemeter
       Convert input audio to a	video output, displaying the audio phase.

       The filter accepts the following	options:

       rate, r
	   Set the output frame	rate. Default value is 25.

       size, s
	   Set the video size for the output. For the syntax of	this option,
	   check the "Video size" section in the ffmpeg-utils manual.  Default
	   value is "800x400".

       rc
       gc
       bc  Specify the red, green, blue	contrast. Default values are 2,	7 and
	   1.  Allowed range is	"[0, 255]".

       mpc Set color which will	be used	for drawing median phase. If color is
	   "none" which	is default, no median phase value will be drawn.

       video
	   Enable video	output.	Default	is enabled.

       The filter also exports the frame metadata "lavfi.aphasemeter.phase"
       which represents	mean phase of current audio frame. Value is in range
       "[-1, 1]".  The "-1" means left and right channels are completely out
       of phase	and 1 means channels are in phase.

   avectorscope
       Convert input audio to a	video output, representing the audio vector
       scope.

       The filter is used to measure the difference between channels of	stereo
       audio stream. A monoaural signal, consisting of identical left and
       right signal, results in	straight vertical line.	Any stereo separation
       is visible as a deviation from this line, creating a Lissajous figure.
       If the straight (or deviation from it) but horizontal line appears this
       indicates that the left and right channels are out of phase.

       The filter accepts the following	options:

       mode, m
	   Set the vectorscope mode.

	   Available values are:

	   lissajous
	       Lissajous rotated by 45 degrees.

	   lissajous_xy
	       Same as above but not rotated.

	   polar
	       Shape resembling	half of	circle.

	   Default value is lissajous.

       size, s
	   Set the video size for the output. For the syntax of	this option,
	   check the "Video size" section in the ffmpeg-utils manual.  Default
	   value is "400x400".

       rate, r
	   Set the output frame	rate. Default value is 25.

       rc
       gc
       bc
       ac  Specify the red, green, blue	and alpha contrast. Default values are
	   40, 160, 80 and 255.	 Allowed range is "[0, 255]".

       rf
       gf
       bf
       af  Specify the red, green, blue	and alpha fade.	Default	values are 15,
	   10, 5 and 5.	 Allowed range is "[0, 255]".

       zoom
	   Set the zoom	factor.	Default	value is 1. Allowed range is "[1,
	   10]".

       draw
	   Set the vectorscope drawing mode.

	   Available values are:

	   dot Draw dot	for each sample.

	   line
	       Draw line between previous and current sample.

	   Default value is dot.

       scale
	   Specify amplitude scale of audio samples.

	   Available values are:

	   lin Linear.

	   sqrt
	       Square root.

	   cbrt
	       Cubic root.

	   log Logarithmic.

       Examples

       o   Complete example using ffplay:

		   ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
				[a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]'

   bench, abench
       Benchmark part of a filtergraph.

       The filter accepts the following	options:

       action
	   Start or stop a timer.

	   Available values are:

	   start
	       Get the current time, set it as frame metadata (using the key
	       "lavfi.bench.start_time"), and forward the frame	to the next
	       filter.

	   stop
	       Get the current time and	fetch the "lavfi.bench.start_time"
	       metadata	from the input frame metadata to get the time
	       difference. Time	difference, average, maximum and minimum time
	       (respectively "t", "avg", "max" and "min") are then printed.
	       The timestamps are expressed in seconds.

       Examples

       o   Benchmark selectivecolor filter:

		   bench=start,selectivecolor=reds=-.2 .12 -.49,bench=stop

   concat
       Concatenate audio and video streams, joining them together one after
       the other.

       The filter works	on segments of synchronized video and audio streams.
       All segments must have the same number of streams of each type, and
       that will also be the number of streams at output.

       The filter accepts the following	options:

       n   Set the number of segments. Default is 2.

       v   Set the number of output video streams, that	is also	the number of
	   video streams in each segment. Default is 1.

       a   Set the number of output audio streams, that	is also	the number of
	   audio streams in each segment. Default is 0.

       unsafe
	   Activate unsafe mode: do not	fail if	segments have a	different
	   format.

       The filter has v+a outputs: first v video outputs, then a audio
       outputs.

       There are nx(v+a) inputs: first the inputs for the first	segment, in
       the same	order as the outputs, then the inputs for the second segment,
       etc.

       Related streams do not always have exactly the same duration, for
       various reasons including codec frame size or sloppy authoring. For
       that reason, related synchronized streams (e.g. a video and its audio
       track) should be	concatenated at	once. The concat filter	will use the
       duration	of the longest stream in each segment (except the last one),
       and if necessary	pad shorter audio streams with silence.

       For this	filter to work correctly, all segments must start at timestamp
       0.

       All corresponding streams must have the same parameters in all
       segments; the filtering system will automatically select	a common pixel
       format for video	streams, and a common sample format, sample rate and
       channel layout for audio	streams, but other settings, such as
       resolution, must	be converted explicitly	by the user.

       Different frame rates are acceptable but	will result in variable	frame
       rate at output; be sure to configure the	output file to handle it.

       Examples

       o   Concatenate an opening, an episode and an ending, all in bilingual
	   version (video in stream 0, audio in	streams	1 and 2):

		   ffmpeg -i opening.mkv -i episode.mkv	-i ending.mkv -filter_complex \
		     '[0:0] [0:1] [0:2]	[1:0] [1:1] [1:2] [2:0]	[2:1] [2:2]
		      concat=n=3:v=1:a=2 [v] [a1] [a2]'	\
		     -map '[v]'	-map '[a1]' -map '[a2]'	output.mkv

       o   Concatenate two parts, handling audio and video separately, using
	   the (a)movie	sources, and adjusting the resolution:

		   movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
		   movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
		   [v1]	[v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]

	   Note	that a desync will happen at the stitch	if the audio and video
	   streams do not have exactly the same	duration in the	first file.

   drawgraph, adrawgraph
       Draw a graph using input	video or audio metadata.

       It accepts the following	parameters:

       m1  Set 1st frame metadata key from which metadata values will be used
	   to draw a graph.

       fg1 Set 1st foreground color expression.

       m2  Set 2nd frame metadata key from which metadata values will be used
	   to draw a graph.

       fg2 Set 2nd foreground color expression.

       m3  Set 3rd frame metadata key from which metadata values will be used
	   to draw a graph.

       fg3 Set 3rd foreground color expression.

       m4  Set 4th frame metadata key from which metadata values will be used
	   to draw a graph.

       fg4 Set 4th foreground color expression.

       min Set minimal value of	metadata value.

       max Set maximal value of	metadata value.

       bg  Set graph background	color. Default is white.

       mode
	   Set graph mode.

	   Available values for	mode is:

	   bar
	   dot
	   line

	   Default is "line".

       slide
	   Set slide mode.

	   Available values for	slide is:

	   frame
	       Draw new	frame when right border	is reached.

	   replace
	       Replace old columns with	new ones.

	   scroll
	       Scroll from right to left.

	   rscroll
	       Scroll from left	to right.

	   picture
	       Draw single picture.

	   Default is "frame".

       size
	   Set size of graph video. For	the syntax of this option, check the
	   "Video size"	section	in the ffmpeg-utils manual.  The default value
	   is "900x256".

	   The foreground color	expressions can	use the	following variables:

	   MIN Minimal value of	metadata value.

	   MAX Maximal value of	metadata value.

	   VAL Current metadata	key value.

	   The color is	defined	as 0xAABBGGRR.

       Example using metadata from signalstats filter:

	       signalstats,drawgraph=lavfi.signalstats.YAVG:min=0:max=255

       Example using metadata from ebur128 filter:

	       ebur128=metadata=1,adrawgraph=lavfi.r128.M:min=-120:max=5

   ebur128
       EBU R128	scanner	filter.	This filter takes an audio stream as input and
       outputs it unchanged. By	default, it logs a message at a	frequency of
       10Hz with the Momentary loudness	(identified by "M"), Short-term
       loudness	("S"), Integrated loudness ("I") and Loudness Range ("LRA").

       The filter also has a video output (see the video option) with a	real
       time graph to observe the loudness evolution. The graphic contains the
       logged message mentioned	above, so it is	not printed anymore when this
       option is set, unless the verbose logging is set. The main graphing
       area contains the short-term loudness (3	seconds	of analysis), and the
       gauge on	the right is for the momentary loudness	(400 milliseconds).

       More information	about the Loudness Recommendation EBU R128 on
       <http://tech.ebu.ch/loudness>.

       The filter accepts the following	options:

       video
	   Activate the	video output. The audio	stream is passed unchanged
	   whether this	option is set or no. The video stream will be the
	   first output	stream if activated. Default is	0.

       size
	   Set the video size. This option is for video	only. For the syntax
	   of this option, check the "Video size" section in the ffmpeg-utils
	   manual.  Default and	minimum	resolution is "640x480".

       meter
	   Set the EBU scale meter. Default is 9. Common values	are 9 and 18,
	   respectively	for EBU	scale meter +9 and EBU scale meter +18.	Any
	   other integer value between this range is allowed.

       metadata
	   Set metadata	injection. If set to 1,	the audio input	will be
	   segmented into 100ms	output frames, each of them containing various
	   loudness information	in metadata.  All the metadata keys are
	   prefixed with "lavfi.r128.".

	   Default is 0.

       framelog
	   Force the frame logging level.

	   Available values are:

	   info
	       information logging level

	   verbose
	       verbose logging level

	   By default, the logging level is set	to info. If the	video or the
	   metadata options are	set, it	switches to verbose.

       peak
	   Set peak mode(s).

	   Available modes can be cumulated (the option	is a "flag" type).
	   Possible values are:

	   none
	       Disable any peak	mode (default).

	   sample
	       Enable sample-peak mode.

	       Simple peak mode	looking	for the	higher sample value. It	logs a
	       message for sample-peak (identified by "SPK").

	   true
	       Enable true-peak	mode.

	       If enabled, the peak lookup is done on an over-sampled version
	       of the input stream for better peak accuracy. It	logs a message
	       for true-peak.  (identified by "TPK") and true-peak per frame
	       (identified by "FTPK").	This mode requires a build with
	       "libswresample".

       dualmono
	   Treat mono input files as "dual mono". If a mono file is intended
	   for playback	on a stereo system, its	EBU R128 measurement will be
	   perceptually	incorrect.  If set to "true", this option will
	   compensate for this effect.	Multi-channel input files are not
	   affected by this option.

       panlaw
	   Set a specific pan law to be	used for the measurement of dual mono
	   files.  This	parameter is optional, and has a default value of
	   -3.01dB.

       Examples

       o   Real-time graph using ffplay, with a	EBU scale meter	+18:

		   ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]"

       o   Run an analysis with	ffmpeg:

		   ffmpeg -nostats -i input.mp3	-filter_complex	ebur128	-f null	-

   interleave, ainterleave
       Temporally interleave frames from several inputs.

       "interleave" works with video inputs, "ainterleave" with	audio.

       These filters read frames from several inputs and send the oldest
       queued frame to the output.

       Input streams must have well defined, monotonically increasing frame
       timestamp values.

       In order	to submit one frame to output, these filters need to enqueue
       at least	one frame for each input, so they cannot work in case one
       input is	not yet	terminated and will not	receive	incoming frames.

       For example consider the	case when one input is a "select" filter which
       always drops input frames. The "interleave" filter will keep reading
       from that input,	but it will never be able to send new frames to	output
       until the input sends an	end-of-stream signal.

       Also, depending on inputs synchronization, the filters will drop	frames
       in case one input receives more frames than the other ones, and the
       queue is	already	filled.

       These filters accept the	following options:

       nb_inputs, n
	   Set the number of different inputs, it is 2 by default.

       Examples

       o   Interleave frames belonging to different streams using ffmpeg:

		   ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi

       o   Add flickering blur effect:

		   select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave

   metadata, ametadata
       Manipulate frame	metadata.

       This filter accepts the following options:

       mode
	   Set mode of operation of the	filter.

	   Can be one of the following:

	   select
	       If both "value" and "key" is set, select	frames which have such
	       metadata. If only "key" is set, select every frame that has
	       such key	in metadata.

	   add Add new metadata	"key" and "value". If key is already available
	       do nothing.

	   modify
	       Modify value of already present key.

	   delete
	       If "value" is set, delete only keys that	have such value.
	       Otherwise, delete key. If "key" is not set, delete all metadata
	       values in the frame.

	   print
	       Print key and its value if metadata was found. If "key" is not
	       set print all metadata values available in frame.

       key Set key used	with all modes.	Must be	set for	all modes except
	   "print" and "delete".

       value
	   Set metadata	value which will be used. This option is mandatory for
	   "modify" and	"add" mode.

       function
	   Which function to use when comparing	metadata value and "value".

	   Can be one of following:

	   same_str
	       Values are interpreted as strings, returns true if metadata
	       value is	same as	"value".

	   starts_with
	       Values are interpreted as strings, returns true if metadata
	       value starts with the "value" option string.

	   less
	       Values are interpreted as floats, returns true if metadata
	       value is	less than "value".

	   equal
	       Values are interpreted as floats, returns true if "value" is
	       equal with metadata value.

	   greater
	       Values are interpreted as floats, returns true if metadata
	       value is	greater	than "value".

	   expr
	       Values are interpreted as floats, returns true if expression
	       from option "expr" evaluates to true.

       expr
	   Set expression which	is used	when "function"	is set to "expr".  The
	   expression is evaluated through the eval API	and can	contain	the
	   following constants:

	   VALUE1
	       Float representation of "value" from metadata key.

	   VALUE2
	       Float representation of "value" as supplied by user in "value"
	       option.

       file
	   If specified	in "print" mode, output	is written to the named	file.
	   Instead of plain filename any writable url can be specified.
	   Filename ``-'' is a shorthand for standard output. If "file"	option
	   is not set, output is written to the	log with AV_LOG_INFO loglevel.

       Examples

       o   Print all metadata values for frames	with key
	   "lavfi.singnalstats.YDIF" with values between 0 and 1.

		   signalstats,metadata=print:key=lavfi.signalstats.YDIF:value=0:function=expr:expr='between(VALUE1,0,1)'

       o   Print silencedetect output to file metadata.txt.

		   silencedetect,ametadata=mode=print:file=metadata.txt

       o   Direct all metadata to a pipe with file descriptor 4.

		   metadata=mode=print:file='pipe\:4'

   perms, aperms
       Set read/write permissions for the output frames.

       These filters are mainly	aimed at developers to test direct path	in the
       following filter	in the filtergraph.

       The filters accept the following	options:

       mode
	   Select the permissions mode.

	   It accepts the following values:

	   none
	       Do nothing. This	is the default.

	   ro  Set all the output frames read-only.

	   rw  Set all the output frames directly writable.

	   toggle
	       Make the	frame read-only	if writable, and writable if read-
	       only.

	   random
	       Set each	output frame read-only or writable randomly.

       seed
	   Set the seed	for the	random mode, must be an	integer	included
	   between 0 and "UINT32_MAX". If not specified, or if explicitly set
	   to "-1", the	filter will try	to use a good random seed on a best
	   effort basis.

       Note: in	case of	auto-inserted filter between the permission filter and
       the following one, the permission might not be received as expected in
       that following filter. Inserting	a format or aformat filter before the
       perms/aperms filter can avoid this problem.

   realtime, arealtime
       Slow down filtering to match real time approximatively.

       These filters will pause	the filtering for a variable amount of time to
       match the output	rate with the input timestamps.	 They are similar to
       the re option to	"ffmpeg".

       They accept the following options:

       limit
	   Time	limit for the pauses. Any pause	longer than that will be
	   considered a	timestamp discontinuity	and reset the timer. Default
	   is 2	seconds.

   select, aselect
       Select frames to	pass in	output.

       This filter accepts the following options:

       expr, e
	   Set expression, which is evaluated for each input frame.

	   If the expression is	evaluated to zero, the frame is	discarded.

	   If the evaluation result is negative	or NaN,	the frame is sent to
	   the first output; otherwise it is sent to the output	with index
	   "ceil(val)-1", assuming that	the input index	starts from 0.

	   For example a value of 1.2 corresponds to the output	with index
	   "ceil(1.2)-1	= 2-1 =	1", that is the	second output.

       outputs,	n
	   Set the number of outputs. The output to which to send the selected
	   frame is based on the result	of the evaluation. Default value is 1.

       The expression can contain the following	constants:

       n   The (sequential) number of the filtered frame, starting from	0.

       selected_n
	   The (sequential) number of the selected frame, starting from	0.

       prev_selected_n
	   The sequential number of the	last selected frame. It's NAN if
	   undefined.

       TB  The timebase	of the input timestamps.

       pts The PTS (Presentation TimeStamp) of the filtered video frame,
	   expressed in	TB units. It's NAN if undefined.

       t   The PTS of the filtered video frame,	expressed in seconds. It's NAN
	   if undefined.

       prev_pts
	   The PTS of the previously filtered video frame. It's	NAN if
	   undefined.

       prev_selected_pts
	   The PTS of the last previously filtered video frame.	It's NAN if
	   undefined.

       prev_selected_t
	   The PTS of the last previously selected video frame.	It's NAN if
	   undefined.

       start_pts
	   The PTS of the first	video frame in the video. It's NAN if
	   undefined.

       start_t
	   The time of the first video frame in	the video. It's	NAN if
	   undefined.

       pict_type (video	only)
	   The type of the filtered frame. It can assume one of	the following
	   values:

	   I
	   P
	   B
	   S
	   SI
	   SP
	   BI
       interlace_type (video only)
	   The frame interlace type. It	can assume one of the following
	   values:

	   PROGRESSIVE
	       The frame is progressive	(not interlaced).

	   TOPFIRST
	       The frame is top-field-first.

	   BOTTOMFIRST
	       The frame is bottom-field-first.

       consumed_sample_n (audio	only)
	   the number of selected samples before the current frame

       samples_n (audio	only)
	   the number of samples in the	current	frame

       sample_rate (audio only)
	   the input sample rate

       key This	is 1 if	the filtered frame is a	key-frame, 0 otherwise.

       pos the position	in the file of the filtered frame, -1 if the
	   information is not available	(e.g. for synthetic video)

       scene (video only)
	   value between 0 and 1 to indicate a new scene; a low	value reflects
	   a low probability for the current frame to introduce	a new scene,
	   while a higher value	means the current frame	is more	likely to be
	   one (see the	example	below)

       concatdec_select
	   The concat demuxer can select only part of a	concat input file by
	   setting an inpoint and an outpoint, but the output packets may not
	   be entirely contained in the	selected interval. By using this
	   variable, it	is possible to skip frames generated by	the concat
	   demuxer which are not exactly contained in the selected interval.

	   This	works by comparing the frame pts against the
	   lavf.concat.start_time and the lavf.concat.duration packet metadata
	   values which	are also present in the	decoded	frames.

	   The concatdec_select	variable is -1 if the frame pts	is at least
	   start_time and either the duration metadata is missing or the frame
	   pts is less than start_time + duration, 0 otherwise,	and NaN	if the
	   start_time metadata is missing.

	   That	basically means	that an	input frame is selected	if its pts is
	   within the interval set by the concat demuxer.

       The default value of the	select expression is "1".

       Examples

       o   Select all frames in	input:

		   select

	   The example above is	the same as:

		   select=1

       o   Skip	all frames:

		   select=0

       o   Select only I-frames:

		   select='eq(pict_type\,I)'

       o   Select one frame every 100:

		   select='not(mod(n\,100))'

       o   Select only frames contained	in the 10-20 time interval:

		   select=between(t\,10\,20)

       o   Select only I-frames	contained in the 10-20 time interval:

		   select=between(t\,10\,20)*eq(pict_type\,I)

       o   Select frames with a	minimum	distance of 10 seconds:

		   select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'

       o   Use aselect to select only audio frames with	samples	number > 100:

		   aselect='gt(samples_n\,100)'

       o   Create a mosaic of the first	scenes:

		   ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v	1 preview.png

	   Comparing scene against a value between 0.3 and 0.5 is generally a
	   sane	choice.

       o   Send	even and odd frames to separate	outputs, and compose them:

		   select=n=2:e='mod(n,	2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h

       o   Select useful frames	from an	ffconcat file which is using inpoints
	   and outpoints but where the source files are	not intra frame	only.

		   ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi

   sendcmd, asendcmd
       Send commands to	filters	in the filtergraph.

       These filters read commands to be sent to other filters in the
       filtergraph.

       "sendcmd" must be inserted between two video filters, "asendcmd"	must
       be inserted between two audio filters, but apart	from that they act the
       same way.

       The specification of commands can be provided in	the filter arguments
       with the	commands option, or in a file specified	by the filename
       option.

       These filters accept the	following options:

       commands, c
	   Set the commands to be read and sent	to the other filters.

       filename, f
	   Set the filename of the commands to be read and sent	to the other
	   filters.

       Commands	syntax

       A commands description consists of a sequence of	interval
       specifications, comprising a list of commands to	be executed when a
       particular event	related	to that	interval occurs. The occurring event
       is typically the	current	frame time entering or leaving a given time
       interval.

       An interval is specified	by the following syntax:

	       <START>[-<END>] <COMMANDS>;

       The time	interval is specified by the START and END times.  END is
       optional	and defaults to	the maximum time.

       The current frame time is considered within the specified interval if
       it is included in the interval [START, END), that is when the time is
       greater or equal	to START and is	lesser than END.

       COMMANDS	consists of a sequence of one or more command specifications,
       separated by ",", relating to that interval.  The syntax	of a command
       specification is	given by:

	       [<FLAGS>] <TARGET> <COMMAND> <ARG>

       FLAGS is	optional and specifies the type	of events relating to the time
       interval	which enable sending the specified command, and	must be	a non-
       null sequence of	identifier flags separated by "+" or "|" and enclosed
       between "[" and "]".

       The following flags are recognized:

       enter
	   The command is sent when the	current	frame timestamp	enters the
	   specified interval. In other	words, the command is sent when	the
	   previous frame timestamp was	not in the given interval, and the
	   current is.

       leave
	   The command is sent when the	current	frame timestamp	leaves the
	   specified interval. In other	words, the command is sent when	the
	   previous frame timestamp was	in the given interval, and the current
	   is not.

       If FLAGS	is not specified, a default value of "[enter]" is assumed.

       TARGET specifies	the target of the command, usually the name of the
       filter class or a specific filter instance name.

       COMMAND specifies the name of the command for the target	filter.

       ARG is optional and specifies the optional list of argument for the
       given COMMAND.

       Between one interval specification and another, whitespaces, or
       sequences of characters starting	with "#" until the end of line,	are
       ignored and can be used to annotate comments.

       A simplified BNF	description of the commands specification syntax
       follows:

	       <COMMAND_FLAG>  ::= "enter" | "leave"
	       <COMMAND_FLAGS> ::= <COMMAND_FLAG> [(+|"|")<COMMAND_FLAG>]
	       <COMMAND>       ::= ["["	<COMMAND_FLAGS>	"]"] <TARGET> <COMMAND>	[<ARG>]
	       <COMMANDS>      ::= <COMMAND> [,<COMMANDS>]
	       <INTERVAL>      ::= <START>[-<END>] <COMMANDS>
	       <INTERVALS>     ::= <INTERVAL>[;<INTERVALS>]

       Examples

       o   Specify audio tempo change at second	4:

		   asendcmd=c='4.0 atempo tempo	1.5',atempo

       o   Specify a list of drawtext and hue commands in a file.

		   # show text in the interval 5-10
		   5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
			    [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';

		   # desaturate	the image in the interval 15-20
		   15.0-20.0 [enter] hue s 0,
			     [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
			     [leave] hue s 1,
			     [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';

		   # apply an exponential saturation fade-out effect, starting from time 25
		   25 [enter] hue s exp(25-t)

	   A filtergraph allowing to read and process the above	command	list
	   stored in a file test.cmd, can be specified with:

		   sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue

   setpts, asetpts
       Change the PTS (presentation timestamp) of the input frames.

       "setpts"	works on video frames, "asetpts" on audio frames.

       This filter accepts the following options:

       expr
	   The expression which	is evaluated for each frame to construct its
	   timestamp.

       The expression is evaluated through the eval API	and can	contain	the
       following constants:

       FRAME_RATE
	   frame rate, only defined for	constant frame-rate video

       PTS The presentation timestamp in input

       N   The count of	the input frame	for video or the number	of consumed
	   samples, not	including the current frame for	audio, starting	from
	   0.

       NB_CONSUMED_SAMPLES
	   The number of consumed samples, not including the current frame
	   (only audio)

       NB_SAMPLES, S
	   The number of samples in the	current	frame (only audio)

       SAMPLE_RATE, SR
	   The audio sample rate.

       STARTPTS
	   The PTS of the first	frame.

       STARTT
	   the time in seconds of the first frame

       INTERLACED
	   State whether the current frame is interlaced.

       T   the time in seconds of the current frame

       POS original position in	the file of the	frame, or undefined if
	   undefined for the current frame

       PREV_INPTS
	   The previous	input PTS.

       PREV_INT
	   previous input time in seconds

       PREV_OUTPTS
	   The previous	output PTS.

       PREV_OUTT
	   previous output time	in seconds

       RTCTIME
	   The wallclock (RTC) time in microseconds. This is deprecated, use
	   time(0) instead.

       RTCSTART
	   The wallclock (RTC) time at the start of the	movie in microseconds.

       TB  The timebase	of the input timestamps.

       Examples

       o   Start counting PTS from zero

		   setpts=PTS-STARTPTS

       o   Apply fast motion effect:

		   setpts=0.5*PTS

       o   Apply slow motion effect:

		   setpts=2.0*PTS

       o   Set fixed rate of 25	frames per second:

		   setpts=N/(25*TB)

       o   Set fixed rate 25 fps with some jitter:

		   setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'

       o   Apply an offset of 10 seconds to the	input PTS:

		   setpts=PTS+10/TB

       o   Generate timestamps from a "live source" and	rebase onto the
	   current timebase:

		   setpts='(RTCTIME - RTCSTART)	/ (TB *	1000000)'

       o   Generate timestamps by counting samples:

		   asetpts=N/SR/TB

   settb, asettb
       Set the timebase	to use for the output frames timestamps.  It is	mainly
       useful for testing timebase configuration.

       It accepts the following	parameters:

       expr, tb
	   The expression which	is evaluated into the output timebase.

       The value for tb	is an arithmetic expression representing a rational.
       The expression can contain the constants	"AVTB" (the default timebase),
       "intb" (the input timebase) and "sr" (the sample	rate, audio only).
       Default value is	"intb".

       Examples

       o   Set the timebase to 1/25:

		   settb=expr=1/25

       o   Set the timebase to 1/10:

		   settb=expr=0.1

       o   Set the timebase to 1001/1000:

		   settb=1+0.001

       o   Set the timebase to 2*intb:

		   settb=2*intb

       o   Set the default timebase value:

		   settb=AVTB

   showcqt
       Convert input audio to a	video output representing frequency spectrum
       logarithmically using Brown-Puckette constant Q transform algorithm
       with direct frequency domain coefficient	calculation (but the transform
       itself is not really constant Q,	instead	the Q factor is	actually
       variable/clamped), with musical tone scale, from	E0 to D#10.

       The filter accepts the following	options:

       size, s
	   Specify the video size for the output. It must be even. For the
	   syntax of this option, check	the "Video size" section in the
	   ffmpeg-utils	manual.	 Default value is "1920x1080".

       fps, rate, r
	   Set the output frame	rate. Default value is 25.

       bar_h
	   Set the bargraph height. It must be even. Default value is "-1"
	   which computes the bargraph height automatically.

       axis_h
	   Set the axis	height.	It must	be even. Default value is "-1" which
	   computes the	axis height automatically.

       sono_h
	   Set the sonogram height. It must be even. Default value is "-1"
	   which computes the sonogram height automatically.

       fullhd
	   Set the fullhd resolution. This option is deprecated, use size, s
	   instead. Default value is 1.

       sono_v, volume
	   Specify the sonogram	volume expression. It can contain variables:

	   bar_v
	       the bar_v evaluated expression

	   frequency, freq, f
	       the frequency where it is evaluated

	   timeclamp, tc
	       the value of timeclamp option

	   and functions:

	   a_weighting(f)
	       A-weighting of equal loudness

	   b_weighting(f)
	       B-weighting of equal loudness

	   c_weighting(f)
	       C-weighting of equal loudness.

	   Default value is 16.

       bar_v, volume2
	   Specify the bargraph	volume expression. It can contain variables:

	   sono_v
	       the sono_v evaluated expression

	   frequency, freq, f
	       the frequency where it is evaluated

	   timeclamp, tc
	       the value of timeclamp option

	   and functions:

	   a_weighting(f)
	       A-weighting of equal loudness

	   b_weighting(f)
	       B-weighting of equal loudness

	   c_weighting(f)
	       C-weighting of equal loudness.

	   Default value is "sono_v".

       sono_g, gamma
	   Specify the sonogram	gamma. Lower gamma makes the spectrum more
	   contrast, higher gamma makes	the spectrum having more range.
	   Default value is 3.	Acceptable range is "[1, 7]".

       bar_g, gamma2
	   Specify the bargraph	gamma. Default value is	1. Acceptable range is
	   "[1,	7]".

       bar_t
	   Specify the bargraph	transparency level. Lower value	makes the
	   bargraph sharper.  Default value is 1. Acceptable range is "[0,
	   1]".

       timeclamp, tc
	   Specify the transform timeclamp. At low frequency, there is trade-
	   off between accuracy	in time	domain and frequency domain. If
	   timeclamp is	lower, event in	time domain is represented more
	   accurately (such as fast bass drum),	otherwise event	in frequency
	   domain is represented more accurately (such as bass guitar).
	   Acceptable range is "[0.002,	1]". Default value is 0.17.

       basefreq
	   Specify the transform base frequency. Default value is
	   20.01523126408007475, which is frequency 50 cents below E0.
	   Acceptable range is "[10, 100000]".

       endfreq
	   Specify the transform end frequency.	Default	value is
	   20495.59681441799654, which is frequency 50 cents above D#10.
	   Acceptable range is "[10, 100000]".

       coeffclamp
	   This	option is deprecated and ignored.

       tlength
	   Specify the transform length	in time	domain.	Use this option	to
	   control accuracy trade-off between time domain and frequency	domain
	   at every frequency sample.  It can contain variables:

	   frequency, freq, f
	       the frequency where it is evaluated

	   timeclamp, tc
	       the value of timeclamp option.

	   Default value is "384*tc/(384+tc*f)".

       count
	   Specify the transform count for every video frame. Default value is
	   6.  Acceptable range	is "[1,	30]".

       fcount
	   Specify the transform count for every single	pixel. Default value
	   is 0, which makes it	computed automatically.	Acceptable range is
	   "[0,	10]".

       fontfile
	   Specify font	file for use with freetype to draw the axis. If	not
	   specified, use embedded font. Note that drawing with	font file or
	   embedded font is not	implemented with custom	basefreq and endfreq,
	   use axisfile	option instead.

       font
	   Specify fontconfig pattern. This has	lower priority than fontfile.
	   The : in the	pattern	may be replaced	by | to	avoid unnecessary
	   escaping.

       fontcolor
	   Specify font	color expression. This is arithmetic expression	that
	   should return integer value 0xRRGGBB. It can	contain	variables:

	   frequency, freq, f
	       the frequency where it is evaluated

	   timeclamp, tc
	       the value of timeclamp option

	   and functions:

	   midi(f)
	       midi number of frequency	f, some	midi numbers: E0(16), C1(24),
	       C2(36), A4(69)

	   r(x), g(x), b(x)
	       red, green, and blue value of intensity x.

	   Default value is "st(0, (midi(f)-59.5)/12); st(1,
	   if(between(ld(0),0,1), 0.5-0.5*cos(2*PI*ld(0)), 0));	r(1-ld(1)) +
	   b(ld(1))".

       axisfile
	   Specify image file to draw the axis.	This option override fontfile
	   and fontcolor option.

       axis, text
	   Enable/disable drawing text to the axis. If it is set to 0, drawing
	   to the axis is disabled, ignoring fontfile and axisfile option.
	   Default value is 1.

       csp Set colorspace. The accepted	values are:

	   unspecified
	       Unspecified (default)

	   bt709
	       BT.709

	   fcc FCC

	   bt470bg
	       BT.470BG	or BT.601-6 625

	   smpte170m
	       SMPTE-170M or BT.601-6 525

	   smpte240m
	       SMPTE-240M

	   bt2020ncl
	       BT.2020 with non-constant luminance

       cscheme
	   Set spectrogram color scheme. This is list of floating point	values
	   with	format "left_r|left_g|left_b|right_r|right_g|right_b".	The
	   default is "1|0.5|0|0|0.5|1".

       Examples

       o   Playing audio while showing the spectrum:

		   ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a]	showcqt	[out0]'

       o   Same	as above, but with frame rate 30 fps:

		   ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a]	showcqt=fps=30:count=5 [out0]'

       o   Playing at 1280x720:

		   ffplay -f lavfi 'amovie=a.mp3, asplit [a][out1]; [a]	showcqt=s=1280x720:count=4 [out0]'

       o   Disable sonogram display:

		   sono_h=0

       o   A1 and its harmonics: A1, A2, (near)E3, A3:

		   ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
				    asplit[a][out1]; [a] showcqt [out0]'

       o   Same	as above, but with more	accuracy in frequency domain:

		   ffplay -f lavfi 'aevalsrc=0.1*sin(2*PI*55*t)+0.1*sin(4*PI*55*t)+0.1*sin(6*PI*55*t)+0.1*sin(8*PI*55*t),
				    asplit[a][out1]; [a] showcqt=timeclamp=0.5 [out0]'

       o   Custom volume:

		   bar_v=10:sono_v=bar_v*a_weighting(f)

       o   Custom gamma, now spectrum is linear	to the amplitude.

		   bar_g=2:sono_g=2

       o   Custom tlength equation:

		   tc=0.33:tlength='st(0,0.17);	384*tc / (384 /	ld(0) +	tc*f /(1-ld(0))) + 384*tc / (tc*f / ld(0) + 384	/(1-ld(0)))'

       o   Custom fontcolor and	fontfile, C-note is colored green, others are
	   colored blue:

		   fontcolor='if(mod(floor(midi(f)+0.5),12), 0x0000FF, g(1))':fontfile=myfont.ttf

       o   Custom font using fontconfig:

		   font='Courier New,Monospace,mono|bold'

       o   Custom frequency range with custom axis using image file:

		   axisfile=myaxis.png:basefreq=40:endfreq=10000

   showfreqs
       Convert input audio to video output representing	the audio power
       spectrum.  Audio	amplitude is on	Y-axis while frequency is on X-axis.

       The filter accepts the following	options:

       size, s
	   Specify size	of video. For the syntax of this option, check the
	   "Video size"	section	in the ffmpeg-utils manual.  Default is
	   "1024x512".

       mode
	   Set display mode.  This set how each	frequency bin will be
	   represented.

	   It accepts the following values:

	   line
	   bar
	   dot

	   Default is "bar".

       ascale
	   Set amplitude scale.

	   It accepts the following values:

	   lin Linear scale.

	   sqrt
	       Square root scale.

	   cbrt
	       Cubic root scale.

	   log Logarithmic scale.

	   Default is "log".

       fscale
	   Set frequency scale.

	   It accepts the following values:

	   lin Linear scale.

	   log Logarithmic scale.

	   rlog
	       Reverse logarithmic scale.

	   Default is "lin".

       win_size
	   Set window size.

	   It accepts the following values:

	   w16
	   w32
	   w64
	   w128
	   w256
	   w512
	   w1024
	   w2048
	   w4096
	   w8192
	   w16384
	   w32768
	   w65536

	   Default is "w2048"

       win_func
	   Set windowing function.

	   It accepts the following values:

	   rect
	   bartlett
	   hanning
	   hamming
	   blackman
	   welch
	   flattop
	   bharris
	   bnuttall
	   bhann
	   sine
	   nuttall
	   lanczos
	   gauss
	   tukey
	   dolph
	   cauchy
	   parzen
	   poisson

	   Default is "hanning".

       overlap
	   Set window overlap. In range	"[0, 1]". Default is 1,	which means
	   optimal overlap for selected	window function	will be	picked.

       averaging
	   Set time averaging. Setting this to 0 will display current maximal
	   peaks.  Default is 1, which means time averaging is disabled.

       colors
	   Specify list	of colors separated by space or	by '|' which will be
	   used	to draw	channel	frequencies. Unrecognized or missing colors
	   will	be replaced by white color.

       cmode
	   Set channel display mode.

	   It accepts the following values:

	   combined
	   separate

	   Default is "combined".

       minamp
	   Set minimum amplitude used in "log" amplitude scaler.

   showspectrum
       Convert input audio to a	video output, representing the audio frequency
       spectrum.

       The filter accepts the following	options:

       size, s
	   Specify the video size for the output. For the syntax of this
	   option, check the "Video size" section in the ffmpeg-utils manual.
	   Default value is "640x512".

       slide
	   Specify how the spectrum should slide along the window.

	   It accepts the following values:

	   replace
	       the samples start again on the left when	they reach the right

	   scroll
	       the samples scroll from right to	left

	   fullframe
	       frames are only produced	when the samples reach the right

	   rscroll
	       the samples scroll from left to right

	   Default value is "replace".

       mode
	   Specify display mode.

	   It accepts the following values:

	   combined
	       all channels are	displayed in the same row

	   separate
	       all channels are	displayed in separate rows

	   Default value is combined.

       color
	   Specify display color mode.

	   It accepts the following values:

	   channel
	       each channel is displayed in a separate color

	   intensity
	       each channel is displayed using the same	color scheme

	   rainbow
	       each channel is displayed using the rainbow color scheme

	   moreland
	       each channel is displayed using the moreland color scheme

	   nebulae
	       each channel is displayed using the nebulae color scheme

	   fire
	       each channel is displayed using the fire	color scheme

	   fiery
	       each channel is displayed using the fiery color scheme

	   fruit
	       each channel is displayed using the fruit color scheme

	   cool
	       each channel is displayed using the cool	color scheme

	   Default value is channel.

       scale
	   Specify scale used for calculating intensity	color values.

	   It accepts the following values:

	   lin linear

	   sqrt
	       square root, default

	   cbrt
	       cubic root

	   log logarithmic

	   4thrt
	       4th root

	   5thrt
	       5th root

	   Default value is sqrt.

       saturation
	   Set saturation modifier for displayed colors. Negative values
	   provide alternative color scheme. 0 is no saturation	at all.
	   Saturation must be in [-10.0, 10.0] range.  Default value is	1.

       win_func
	   Set window function.

	   It accepts the following values:

	   rect
	   bartlett
	   hann
	   hanning
	   hamming
	   blackman
	   welch
	   flattop
	   bharris
	   bnuttall
	   bhann
	   sine
	   nuttall
	   lanczos
	   gauss
	   tukey
	   dolph
	   cauchy
	   parzen
	   poisson

	   Default value is "hann".

       orientation
	   Set orientation of time vs frequency	axis. Can be "vertical"	or
	   "horizontal". Default is "vertical".

       overlap
	   Set ratio of	overlap	window.	Default	value is 0.  When value	is 1
	   overlap is set to recommended size for specific window function
	   currently used.

       gain
	   Set scale gain for calculating intensity color values.  Default
	   value is 1.

       data
	   Set which data to display. Can be "magnitude", default or "phase".

       rotation
	   Set color rotation, must be in [-1.0, 1.0] range.  Default value is
	   0.

       The usage is very similar to the	showwaves filter; see the examples in
       that section.

       Examples

       o   Large window	with logarithmic color scaling:

		   showspectrum=s=1280x480:scale=log

       o   Complete example for	a colored and sliding spectrum per channel
	   using ffplay:

		   ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1];
				[a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]'

   showspectrumpic
       Convert input audio to a	single video frame, representing the audio
       frequency spectrum.

       The filter accepts the following	options:

       size, s
	   Specify the video size for the output. For the syntax of this
	   option, check the "Video size" section in the ffmpeg-utils manual.
	   Default value is "4096x2048".

       mode
	   Specify display mode.

	   It accepts the following values:

	   combined
	       all channels are	displayed in the same row

	   separate
	       all channels are	displayed in separate rows

	   Default value is combined.

       color
	   Specify display color mode.

	   It accepts the following values:

	   channel
	       each channel is displayed in a separate color

	   intensity
	       each channel is displayed using the same	color scheme

	   rainbow
	       each channel is displayed using the rainbow color scheme

	   moreland
	       each channel is displayed using the moreland color scheme

	   nebulae
	       each channel is displayed using the nebulae color scheme

	   fire
	       each channel is displayed using the fire	color scheme

	   fiery
	       each channel is displayed using the fiery color scheme

	   fruit
	       each channel is displayed using the fruit color scheme

	   cool
	       each channel is displayed using the cool	color scheme

	   Default value is intensity.

       scale
	   Specify scale used for calculating intensity	color values.

	   It accepts the following values:

	   lin linear

	   sqrt
	       square root, default

	   cbrt
	       cubic root

	   log logarithmic

	   4thrt
	       4th root

	   5thrt
	       5th root

	   Default value is log.

       saturation
	   Set saturation modifier for displayed colors. Negative values
	   provide alternative color scheme. 0 is no saturation	at all.
	   Saturation must be in [-10.0, 10.0] range.  Default value is	1.

       win_func
	   Set window function.

	   It accepts the following values:

	   rect
	   bartlett
	   hann
	   hanning
	   hamming
	   blackman
	   welch
	   flattop
	   bharris
	   bnuttall
	   bhann
	   sine
	   nuttall
	   lanczos
	   gauss
	   tukey
	   dolph
	   cauchy
	   parzen
	   poisson

	   Default value is "hann".

       orientation
	   Set orientation of time vs frequency	axis. Can be "vertical"	or
	   "horizontal". Default is "vertical".

       gain
	   Set scale gain for calculating intensity color values.  Default
	   value is 1.

       legend
	   Draw	time and frequency axes	and legends. Default is	enabled.

       rotation
	   Set color rotation, must be in [-1.0, 1.0] range.  Default value is
	   0.

       Examples

       o   Extract an audio spectrogram	of a whole audio track in a 1024x1024
	   picture using ffmpeg:

		   ffmpeg -i audio.flac	-lavfi showspectrumpic=s=1024x1024 spectrogram.png

   showvolume
       Convert input audio volume to a video output.

       The filter accepts the following	options:

       rate, r
	   Set video rate.

       b   Set border width, allowed range is [0, 5]. Default is 1.

       w   Set channel width, allowed range is [80, 8192]. Default is 400.

       h   Set channel height, allowed range is	[1, 900]. Default is 20.

       f   Set fade, allowed range is [0.001, 1]. Default is 0.95.

       c   Set volume color expression.

	   The expression can use the following	variables:

	   VOLUME
	       Current max volume of channel in	dB.

	   PEAK
	       Current peak.

	   CHANNEL
	       Current channel number, starting	from 0.

       t   If set, displays channel names. Default is enabled.

       v   If set, displays volume values. Default is enabled.

       o   Set orientation, can	be "horizontal"	or "vertical", default is
	   "horizontal".

       s   Set step size, allowed range	s [0, 5]. Default is 0,	which means
	   step	is disabled.

   showwaves
       Convert input audio to a	video output, representing the samples waves.

       The filter accepts the following	options:

       size, s
	   Specify the video size for the output. For the syntax of this
	   option, check the "Video size" section in the ffmpeg-utils manual.
	   Default value is "600x240".

       mode
	   Set display mode.

	   Available values are:

	   point
	       Draw a point for	each sample.

	   line
	       Draw a vertical line for	each sample.

	   p2p Draw a point for	each sample and	a line between them.

	   cline
	       Draw a centered vertical	line for each sample.

	   Default value is "point".

       n   Set the number of samples which are printed on the same column. A
	   larger value	will decrease the frame	rate. Must be a	positive
	   integer. This option	can be set only	if the value for rate is not
	   explicitly specified.

       rate, r
	   Set the (approximate) output	frame rate. This is done by setting
	   the option n. Default value is "25".

       split_channels
	   Set if channels should be drawn separately or overlap. Default
	   value is 0.

       colors
	   Set colors separated	by '|' which are going to be used for drawing
	   of each channel.

       scale
	   Set amplitude scale.

	   Available values are:

	   lin Linear.

	   log Logarithmic.

	   sqrt
	       Square root.

	   cbrt
	       Cubic root.

	   Default is linear.

       Examples

       o   Output the input file audio and the corresponding video
	   representation at the same time:

		   amovie=a.mp3,asplit[out0],showwaves[out1]

       o   Create a synthetic signal and show it with showwaves, forcing a
	   frame rate of 30 frames per second:

		   aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]

   showwavespic
       Convert input audio to a	single video frame, representing the samples
       waves.

       The filter accepts the following	options:

       size, s
	   Specify the video size for the output. For the syntax of this
	   option, check the "Video size" section in the ffmpeg-utils manual.
	   Default value is "600x240".

       split_channels
	   Set if channels should be drawn separately or overlap. Default
	   value is 0.

       colors
	   Set colors separated	by '|' which are going to be used for drawing
	   of each channel.

       scale
	   Set amplitude scale.

	   Available values are:

	   lin Linear.

	   log Logarithmic.

	   sqrt
	       Square root.

	   cbrt
	       Cubic root.

	   Default is linear.

       Examples

       o   Extract a channel split representation of the wave form of a	whole
	   audio track in a 1024x800 picture using ffmpeg:

		   ffmpeg -i audio.flac	-lavfi showwavespic=split_channels=1:s=1024x800	waveform.png

   sidedata, asidedata
       Delete frame side data, or select frames	based on it.

       This filter accepts the following options:

       mode
	   Set mode of operation of the	filter.

	   Can be one of the following:

	   select
	       Select every frame with side data of "type".

	   delete
	       Delete side data	of "type". If "type" is	not set, delete	all
	       side data in the	frame.

       type
	   Set side data type used with	all modes. Must	be set for "select"
	   mode. For the list of frame side data types,	refer to the
	   "AVFrameSideDataType" enum in libavutil/frame.h. For	example, to
	   choose "AV_FRAME_DATA_PANSCAN" side data, you must specify
	   "PANSCAN".

   spectrumsynth
       Sythesize audio from 2 input video spectrums, first input stream
       represents magnitude across time	and second represents phase across
       time.  The filter will transform	from frequency domain as displayed in
       videos back to time domain as presented in audio	output.

       This filter is primarily	created	for reversing processed	showspectrum
       filter outputs, but can synthesize sound	from other spectrograms	too.
       But in such case	results	are going to be	poor if	the phase data is not
       available, because in such cases	phase data need	to be recreated,
       usually its just	recreated from random noise.  For best results use
       gray only output	("channel" color mode in showspectrum filter) and
       "log" scale for magnitude video and "lin" scale for phase video.	To
       produce phase, for 2nd video, use "data"	option.	Inputs videos should
       generally use "fullframe" slide mode as that saves resources needed for
       decoding	video.

       The filter accepts the following	options:

       sample_rate
	   Specify sample rate of output audio,	the sample rate	of audio from
	   which spectrum was generated	may differ.

       channels
	   Set number of channels represented in input video spectrums.

       scale
	   Set scale which was used when generating magnitude input spectrum.
	   Can be "lin"	or "log". Default is "log".

       slide
	   Set slide which was used when generating inputs spectrums.  Can be
	   "replace", "scroll",	"fullframe" or "rscroll".  Default is
	   "fullframe".

       win_func
	   Set window function used for	resynthesis.

       overlap
	   Set window overlap. In range	"[0, 1]". Default is 1,	which means
	   optimal overlap for selected	window function	will be	picked.

       orientation
	   Set orientation of input videos. Can	be "vertical" or "horizontal".
	   Default is "vertical".

       Examples

       o   First create	magnitude and phase videos from	audio, assuming	audio
	   is stereo with 44100	sample rate, then resynthesize videos back to
	   audio with spectrumsynth:

		   ffmpeg -i input.flac	-lavfi showspectrum=mode=separate:scale=log:overlap=0.875:color=channel:slide=fullframe:data=magnitude -an -c:v	rawvideo magnitude.nut
		   ffmpeg -i input.flac	-lavfi showspectrum=mode=separate:scale=lin:overlap=0.875:color=channel:slide=fullframe:data=phase -an -c:v rawvideo phase.nut
		   ffmpeg -i magnitude.nut -i phase.nut	-lavfi spectrumsynth=channels=2:sample_rate=44100:win_func=hann:overlap=0.875:slide=fullframe output.flac

   split, asplit
       Split input into	several	identical outputs.

       "asplit"	works with audio input,	"split"	with video.

       The filter accepts a single parameter which specifies the number	of
       outputs.	If unspecified,	it defaults to 2.

       Examples

       o   Create two separate outputs from the	same input:

		   [in]	split [out0][out1]

       o   To create 3 or more outputs,	you need to specify the	number of
	   outputs, like in:

		   [in]	asplit=3 [out0][out1][out2]

       o   Create two separate outputs from the	same input, one	cropped	and
	   one padded:

		   [in]	split [splitout1][splitout2];
		   [splitout1] crop=100:100:0:0	   [cropout];
		   [splitout2] pad=200:200:100:100 [padout];

       o   Create 5 copies of the input	audio with ffmpeg:

		   ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT

   zmq,	azmq
       Receive commands	sent through a libzmq client, and forward them to
       filters in the filtergraph.

       "zmq" and "azmq"	work as	a pass-through filters.	"zmq" must be inserted
       between two video filters, "azmq" between two audio filters.

       To enable these filters you need	to install the libzmq library and
       headers and configure FFmpeg with "--enable-libzmq".

       For more	information about libzmq see: <http://www.zeromq.org/>

       The "zmq" and "azmq" filters work as a libzmq server, which receives
       messages	sent through a network interface defined by the	bind_address
       option.

       The received message must be in the form:

	       <TARGET>	<COMMAND> [<ARG>]

       TARGET specifies	the target of the command, usually the name of the
       filter class or a specific filter instance name.

       COMMAND specifies the name of the command for the target	filter.

       ARG is optional and specifies the optional argument list	for the	given
       COMMAND.

       Upon reception, the message is processed	and the	corresponding command
       is injected into	the filtergraph. Depending on the result, the filter
       will send a reply to the	client,	adopting the format:

	       <ERROR_CODE> <ERROR_REASON>
	       <MESSAGE>

       MESSAGE is optional.

       Examples

       Look at tools/zmqsend for an example of a zmq client which can be used
       to send commands	processed by these filters.

       Consider	the following filtergraph generated by ffplay

	       ffplay -dumpgraph 1 -f lavfi "
	       color=s=100x100:c=red  [l];
	       color=s=100x100:c=blue [r];
	       nullsrc=s=200x100, zmq [bg];
	       [bg][l]	 overlay      [bg+l];
	       [bg+l][r] overlay=x=100 "

       To change the color of the left side of the video, the following
       command can be used:

	       echo Parsed_color_0 c yellow | tools/zmqsend

       To change the right side:

	       echo Parsed_color_1 c pink | tools/zmqsend

MULTIMEDIA SOURCES
       Below is	a description of the currently available multimedia sources.

   amovie
       This is the same	as movie source, except	it selects an audio stream by
       default.

   movie
       Read audio and/or video stream(s) from a	movie container.

       It accepts the following	parameters:

       filename
	   The name of the resource to read (not necessarily a file; it	can
	   also	be a device or a stream	accessed through some protocol).

       format_name, f
	   Specifies the format	assumed	for the	movie to read, and can be
	   either the name of a	container or an	input device. If not
	   specified, the format is guessed from movie_name or by probing.

       seek_point, sp
	   Specifies the seek point in seconds.	The frames will	be output
	   starting from this seek point. The parameter	is evaluated with
	   "av_strtod",	so the numerical value may be suffixed by an IS
	   postfix. The	default	value is "0".

       streams,	s
	   Specifies the streams to read. Several streams can be specified,
	   separated by	"+". The source	will then have as many outputs,	in the
	   same	order. The syntax is explained in the ``Stream specifiers''
	   section in the ffmpeg manual. Two special names, "dv" and "da"
	   specify respectively	the default (best suited) video	and audio
	   stream. Default is "dv", or "da" if the filter is called as
	   "amovie".

       stream_index, si
	   Specifies the index of the video stream to read. If the value is
	   -1, the most	suitable video stream will be automatically selected.
	   The default value is	"-1". Deprecated. If the filter	is called
	   "amovie", it	will select audio instead of video.

       loop
	   Specifies how many times to read the	stream in sequence.  If	the
	   value is 0, the stream will be looped infinitely.  Default value is
	   "1".

	   Note	that when the movie is looped the source timestamps are	not
	   changed, so it will generate	non monotonically increasing
	   timestamps.

       discontinuity
	   Specifies the time difference between frames	above which the	point
	   is considered a timestamp discontinuity which is removed by
	   adjusting the later timestamps.

       It allows overlaying a second video on top of the main input of a
       filtergraph, as shown in	this graph:

	       input -----------> deltapts0 -->	overlay	--> output
						   ^
						   |
	       movie --> scale--> deltapts1 -------+

       Examples

       o   Skip	3.2 seconds from the start of the AVI file in.avi, and overlay
	   it on top of	the input labelled "in":

		   movie=in.avi:seek_point=3.2,	scale=180:-1, setpts=PTS-STARTPTS [over];
		   [in]	setpts=PTS-STARTPTS [main];
		   [main][over]	overlay=16:16 [out]

       o   Read	from a video4linux2 device, and	overlay	it on top of the input
	   labelled "in":

		   movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over];
		   [in]	setpts=PTS-STARTPTS [main];
		   [main][over]	overlay=16:16 [out]

       o   Read	the first video	stream and the audio stream with id 0x81 from
	   dvd.vob; the	video is connected to the pad named "video" and	the
	   audio is connected to the pad named "audio":

		   movie=dvd.vob:s=v:0+#0x81 [video] [audio]

       Commands

       Both movie and amovie support the following commands:

       seek
	   Perform seek	using "av_seek_frame".	The syntax is: seek
	   stream_index|timestamp|flags

	   o   stream_index: If	stream_index is	-1, a default stream is
	       selected, and timestamp is automatically	converted from
	       AV_TIME_BASE units to the stream	specific time_base.

	   o   timestamp: Timestamp in AVStream.time_base units	or, if no
	       stream is specified, in AV_TIME_BASE units.

	   o   flags: Flags which select direction and seeking mode.

       get_duration
	   Get movie duration in AV_TIME_BASE units.

SEE ALSO
       ffmpeg(1), ffplay(1), ffprobe(1), ffserver(1), libavfilter(3)

AUTHORS
       The FFmpeg developers.

       For details about the authorship, see the Git history of	the project
       (git://source.ffmpeg.org/ffmpeg), e.g. by typing	the command git	log in
       the FFmpeg source directory, or browsing	the online repository at
       <http://source.ffmpeg.org>.

       Maintainers for the specific components are listed in the file
       MAINTAINERS in the source code tree.

							     FFMPEG-FILTERS(1)

NAME | DESCRIPTION | FILTERING INTRODUCTION | GRAPH | FILTERGRAPH DESCRIPTION | TIMELINE EDITING | AUDIO FILTERS | AUDIO SOURCES | AUDIO SINKS | VIDEO FILTERS | VIDEO SOURCES | VIDEO SINKS | MULTIMEDIA FILTERS | MULTIMEDIA SOURCES | SEE ALSO | AUTHORS

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