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MJPEG tools(MJPEG Linux	Square)		       MJPEG tools(MJPEG Linux Square)

       MJPEG  HOWTO  -	An  introduction  to  the MJPEG-toolsPraschinger Bern-
       hardv2.00MJPEG capture/editting/replay and MPEG	encoding  toolset  de-


       I wrote this things down, because I had many sheets with	notes on them.
       This should be some kind	of summary of collected	knowledge over a  long
       period  of time.	 Andrew	Stevens	helped with encoding and VCD knowledge
       and hints.

       Mjpegtools is a set of programs that can	do recording, playback,	 edit-
       ing and eventual	MPEG compression of audio and video under Linux.

       Although	 primarily  intended  for  use	with capture / playback	boards
       based on	the Zoran ZR36067 MJPEG	codec chip mjpegtools  can  easily  be
       used  to	 process and compress MJPEG video streams captured using xawtv
       using simple frame-buffer devices.

       The HOWTO for the tools intended	to give	 an  an	 introduction  to  the
       MJPEG-tools  and	the creation of	MPEG 1/2 videos. VCD, SVCD and DVD and
       the transcoding of existing mpeg	streams.

       For more	information about the programs	read  the  corresponding  man-

       Achtung es gibt auch eine deutsche Version bei:

       There  is also a	manpage	of this	text. You can read it with "man	mjpeg-
       tools" if installed.  We	also have a info version you should be able to
       read it with info

       The  text  version of this text is available via	cvs. You should	get it
       with the	tarball	or the precompiled package (RPM	and deb).

       In the following	picture	you see	the typical workflow when you record a
       video, cut it afterwards	and encode it. In the picture you also see the
       connections to other programs. These parts are in grey.	The  parts  in
       blue can	be done	with the mjpegtools.

       Video encoding workflow

       Unsorted	list of	useful Hints

       You  have  to compile and install the mjpeg_play	package, for this read
       the README & INSTALL.real  an  follow  the  hints  from	the  configure
       script.	 If  you do not	want to	compile	it, you	can download the mjpeg
       .RPM or .DEB package at Sourceforge, or if available use	the  one  that
       comes with your distribution.

       There  is  a script in the scripts/ directory. This script is something
       that shows you a	way it can be done. It	also  creates  (under  certain
       circumstances) videos that look quite good. Better videos you will only
       get by tuning the parameters.

       If you use a Linux kernel from the 2.4 series you will usually have  to
       load  the  drivers  for the Buz or DC10 or LML33	cards. You have	to run
       the update script providing as option the name of your card  you	 have.
       The  script  is	usually	 in  /usr/src/driver-zoran/.  The zoran	kernel
       driver below the	kernel 2.4.4 do	not work.  You have to use the	driver
       available from:

       In  the	2.6.  Linux kernel is the driver for the zoran cards included,
       you just	need to	make sure that it is loaded correct. If	you have a x64
       machine	and  an	kernel that is newer than 2.6.30 we'd be happy to hear
       that you	are able to record from	the zoran based	card. I'm not soure if
       that combination	works.

       The  driver  for	 the  Matrox  Marvel card also works, more information
       about it:

       If you compile the tools	on a P6	based  computer	 (PPro,	 P-II,	P-III,
       P-4,  Athlon,Duron)  then  never	try to let them	run on a P5 based com-
       puter (Pentium, Pentium-MMX, K6,	K6-x, Cyrix, Via, Winchip). You'll get
       a  "illegal  instruction"  and the program won't	work. That is the same
       for the newer CPU as well. If you use specific optimizations  be	 aware
       of them.

       If  lav2yuv dumps core then one possible	cause is no dv support was in-
       cluded. To enable it make sure that libdv is installed on  the  system.
       This  will be necessary if you are using	a digital camera (or analog to
       DV converter such as the	Canopus	ADVC100	and converting the dv avi for-
       mat into	the MPEG format.

       Start  xawtv  to	see if you get an picture. If you want to use HW-play-
       back of the recorded streams you	have to	start xawtv (any  TV  applica-
       tion  works) once to get	the streams played back. You should also check
       the settings of your mixer in the sound	card.  If  you	use  v4l2  you
       should give mplayer a try to watch the picture

       If  you	compile	the tools on a platform	other than Linux not all tools
       will work.   Mjpegtools on a OS/X system	for example will not have  V4L
       (video4linux) capability.

       Never  try to stop or start the TV application when lavrec runs.	If you
       start or	stop the TV application	lavrec will stop  recording,  or  your
       computer	could get "frozen". This is a problem of v4l (video4linux).

       This  problem  is  solved with v4l2. If you use v4l2 you	can record the
       video and stop and start	the tv application  whenever  you  want.   But
       v4l2  is	 currently  (7.	 Jan. 2003) only supported for the zoran based
       cards (BUZ, DC10,  DC10+,  LML33)  if  you  use	the  CVS  driver  from  tagged with ZORAN_VIDEODEV_2.  And	this driver only works
       with the	2.4.20 kernel and the 2.5.* development	kernel.

       One last	thing about the	data you get before we start:

       Audio: (	Samplerate * Channels *	Bitsize	) / (8 * 1024)
       CD Quality:(44100 Samples/sec * 2 Chanels * 16 Bit) / (8	* 1024)=172,2 kB/sec

       The 8 * 1024 convert the	value from bit/sec to kByte/sec

       Video: (width * height *	framerate * quality ) /	(200 * 1024)
       PAL HALF	Size : (352 * 288 * 25 * 80) / (200 * 1024) = 990 kB/sec
       PAL FULL	size : (720 * 576 * 25 * 80) / (200 * 1024) = 4050 kB/sec
       NTSC HALF size: (352 * 240 * 30 * 80) / (200 * 1024) = 990 kB/sec
       NTSC FULL size: (720 * 480 * 30 * 80) / (200 * 1024) = 4050 kB/sec

       The 1024	converts the Bytes to kBytes. Not every	card  can  record  the
       size  mentioned.	 The Buz and Marvel G400 for example can only record a
       size of 720x576 when using -d 1,	the DC10 records  a  size  of  384x288
       when using -d 2.

       When  you  add audio and	video datarate this is what your hard disk has
       to be able to write constantly  streaming,  else	 you  will  have  lost

       If  you	want  to play with the --mjpeg-buffer-size. Remember the value
       should be at least big enough that one frame fits in it.	 The  size  of
       one  frame  is:	(width * height	* quality ) / (200 * 1024) = kB	If the
       buffer is too small the rate calculation	doesn't	 match	any  more  and
       buffer overflows	can happen. The	maximum	value is 512kB.

       How video works and the difference between the video types is explained

       There you also find how to create MPEG Still Images for VCD/SVCD.

       A good description of DV	(Digital Video)	can be found here:

Some books we found usefull
       written in English:

       Digital Video and HDTV by Charles Poyton	(ISBN 1-55860-792-7)

       Digital Video Compression by Peter Symes	(ISBN 0-07-142487-3)

       Video Demystified by Keith Jack (ISBN 1-878707-56-6)

       written in German:

       Fernsehtechnik von Rudolf Maeusl	(ISBN 3-7785-2374-0)

       Professionelle Videotechnik - analoge und digitale  Grundlagen  von  U.
       Schmidt (ISBN 3-540-43974-9)

       Digitale	Film- und Videotechnik von U. Schmidt (ISBN 3-446-21827-0)

       If you know some	other really good book about that, write us!

       Recording videos

lavrec examples
       Recording with lavrec looks like	this:

       > lavrec	-f a -i	P -d 2 record.avi

       Should start recording now,

       -f a

       use AVI as output format,

       -i P

       use as input source the SVHS-In with PAL	format,

       -d 2

       the size	of the pictures	are half size (352x288)


       name of the created file.

       Recording is finished by	pressing Ctrl-C	(on German Keyboards: Strg-C).
       Sometimes using -f A instead of -f a might be necessary

       Other example:

       > lavrec	-f q -i	n -d 1 -q 80 -s	-l 80 -R l -U record.avi

       Should start recording now,

       -f q

       use Quicktime as	output format,

       -i n

       use Composite-In	with NTSC format,

       -d 1

       record pictures with full size (640x480)

       -q 80

       set the quality to 80% of the captured image


       use stereo mode (default	mono)

       -l 80

       set the recording level to 80% of the max during	recording

       -R l

       set the recording source	to Line-In


       With this lavrec	uses the read instead of mmap for  recording  this  is
       needed if your sound card does not support the mmap for recording.

       Setting	the  mixer does	not work with every sound card.	 If you	record
       with 2 different	settings and both  recordings  are  equally  loud  you
       should setup the	mixer with a mixer program.  After that	you should use
       the -l -1 option	when you record	using lavrec

       The size	of the image depends on	the card you use.  At full size	(-d 1)
       you  get	 these image sizes: BUZ	and LML33: 720x576, the	DC10 and DC30:

       Other example:

       > lavrec	-w -f a	-i S -d	2 -l -1	record%02d.avi

       Should start recording,


       Waits for user confirmation to start (press enter)

       -f a

       use AVI as output format,

       -i S

       use SECAM SVHS-Input (SECAM Composite recording is also possible: -i s)

       -d 2

       the size	of the pictures	are half size

       -l -1

       do not touch the	mixer settings


       Here lavrec creates the first file named	record00.avi  after  the  file
       has  reached  a	size  of  1.6GB	 (after	about 20 Minutes recording) it
       starts a	new sequence named record01.avi	and so on till	the  recording
       is  stopped or the disk is full.	 With the release of the 1.9.0 Version
       mjpegtools is able to handle AVI	files larger than 2GB. So that	option
       is present for compatibility.

       Other example:

       > lavrec	-f a -i	t -q 80	-d 2 -C	europe-west:SE20 test.avi

       Should start recording now,

       -f a

       use AVI as output format,

       -i t

       use tuner input,

       -q 80

       set the quality to 80% of the captured image

       -d 2

       the size	of the pictures	are half size (352x288)


       choose TV channels, and the corresponding -it and -iT (video source: TV
       tuner) can currently be used on the Marvel  G200/G400  and  the	Matrox
       Millenium  G200/G400 with Rainbow Runner	extension (BTTV-Support	is un-
       der construction). For more information on how to  make	the  TV	 tuner
       parts of	these cards work, see the Marvel/Linux project on:

       Last example:

       >  lavrec  -f a -i p -g 352x288 -q 80 -s	-l 70 -R l --software-encoding

       The two new options are -g 352x288, which sets the size of the video to
       be  recorded  when using	--software-encoding, this enables the software
       encoding	of the recorded	images.	With this option you can  also	record
       from  a	bttv  based card. The processor	load is	high. This option only
       works for generic video4linux  cards  (such  as	the  brooktree-848/878
       based cards), it	doesn't	work for zoran-based cards.

Other recording	hints
       All  lavtools  accept  a	 file description like file*.avi so you	do not
       have to name each file but that is a posibility.

       Note: More options are described	in the man-page,  but  with  this  you
       should be able to get started.

       Here  are  some hints for sensible settings. Turn the quality to	80% or
       more for	-d 2 capture. At full resolution as low	as  40%	 seems	to  be
       visually	 "perfect".  -d	2 is already better than VHS video (a *lot*!).
       For a Marvel you	should not set the quality higher  than	 50  when  you
       record  at  full	 size (-d 1). If you use higher	settings (-q 60) it is
       more likely that	you will encounter problems. Higher settings will  re-
       sult  in	 framedrops.   If  you're aiming to create VCD's then there is
       little to be gained recording at	full resolution	as you need to	reduce
       to -d 2 resolution later	anyway.

       you  can	 record	 at other sizes	than the obvious -d 1/2/4. You can use
       combinations where you use halve	 horizontal  size  and	full  vertical
       size:  -d  21.	This  would record for NTSC at a size of 352x480. This
       helps if	you want to create SVCDs, scaling the 352 Pixles put to	480 is
       not  that visible for the eye as	if you would use the other combination
       -d 12.  Where you have the full horzontal resolution and	half  vertical
       this Version will have a	size of	720x288	for NTSC

Some information about the typical lavrec output while recording
       0.06.14:22 int: 00040 lst:0 ins:0 del:0 ae:0 td1=0.014 td2=0.029

       The  first  part	shows the time lavrec is recording.  int: the interval
       between two frames. lst:	the number of lost frames. ins	and  del:  are
       the number of frames inserted and deleted for sync correction. ae: num-
       ber of audio errors.  td1 and td2 are the audio/video time-difference.

       (int) frame interval should be around 33	(NTSC) or 40  (PAL/SECAM).  If
       it  is  very  different,	 you'll	likely get a bad recording and/or many
       lost frames

       (lst) lost frames are bad and mean that something is not	 working  very
       well  during  recording	(too  slow  HD,	 too  high CPU usage, ...) Try
       recording with a	greater	decimation and possibly	a lower	quality.

       (ins, del) inserted OR deleted frames of	them are normal	 ->  sync.  If
       you  have many lost AND inserted	frames,	you're asking too much of your
       machine.	 Use less demanding options or try a different sound card.

       (ae) audio errors are never good. Should	be 0

       (td1, td2) time differenceis always floating around 0, unless sync cor-
       rection is disabled (--synchronization!=2, 2 is default).

Notes about "interlace field order - what can go wrong and how to fix it"
       Firstly,	what does it mean for interlace	field order to be wrong?

       The  mjpegtools	image  processing chain	is frame-oriented. Since it is
       video material that is captured each frame comprised  of	 a  top	 field
       (the  0th, 2nd, 4th and so lines) and a bottom field (the 1st, 3rd, 5th
       and so on lines).

       There are three bad things that can happen with fields

       This is really only an issue for	movies in PAL video  where  each  film
       frame  is  sent	as  a  pair of fields. These can be sent top or	bottom
       field first and sadly it's not always the same, though bottom-first ap-
       pears to	be usual. If you capture with the wrong	field order (you start
       capturing each frame with a bottom rather than a	top or vice versa) the
       frames  of  the	movie get split	*between* frames in the	stream.	Played
       back on a TV where each field is	displayed on its own this is harmless.
       The  sequence of	fields played back is exactly the same as the sequence
       of fields broadcast. Unfortunately, playing back	on a Computer  monitor
       where both fields of a frame appear at once it looks *terrible* because
       each frame is effectively mixing	two moments 1/25sec apart in time.

       The two fields can simply be swapped somehow so that top	gets treat  as
       bottom  and bottom treat	as top.	Juddering and "slicing"	is the result.
       This occasionally seems to happen due to	hardware glitches in the  cap-
       ture card.

       Somewhere in capturing/processing the *order* in	time of	the two	fields
       in each frame can get mislabeled	somehow. This is not good as it	 means
       that  when  playback eventually takes place a field containing an image
       sampled earlier in time comes after  an	image  sampled	later.	 Weird
       "juddering" effects are the results.

       How can I recognize if I	have one of these Problems ?

       This  can  be  hard to spot. If you have	mysteriously flickery pictures
       during playback try encoding a snippet  with  the  reverse  field-order
       forced (see below). If things improve you know what the problem was and
       what the	solution is!

       The two fields can simply be swapped somehow so that top	gets treat  as
       bottom  and bottom treat	as top.	Juddering and "slicing"	is the result.
       This occasionally seems to happen due to	hardware glitches in the  cap-
       ture card. That problem looks like that:

       Interlacing problem

       Somewhere in capturing/processing the *order* in	time of	the two	fields
       in each frame can get mislabeled	somehow. This is not good as it	 means
       that  when  playback eventually takes place a field containing an image
       sampled earlier in time comes after an image sampled later. Weird "jud-
       dering" effects are the result.

       If  you	use glav or lavplay be sure that you also use the -F/--flicker
       option. This disables some things that improve the picture.

       If you want to look at the video	you can	also use yuvplay:

       > lav2yuv | ... | yuvplay

       If there	is a field order problem you should see	it with	yuvplay.

       How can you fix it?

       To fix this one the fields need to be "shifted" through the frames. Use
       yuvcorrect's  -T	 BOTT_FORWARD/TOP_FORWARD  to shift the	way fields are
       allocated to frames. You	can find out the current field	order  for  an
       MJPEG  file  by	looking	at the first few lines of debug	output from: >
       lav2yuv -v 2 the_mjpeg_file > /dev/null Or re-record  exchanging	 -f  a
       for -F A	or vice-versa.

       This  isn't  too	 bad  either. Use a tool that simply swaps the top and
       bottom fields a	second	time.  yuvcorrect  can	do  this  use  the  -T

       Is  easy	 to fix. Either	tell a tool someplace to relabel the fields or
       simply tell the player to play back in swapped order (the latter	can be
       done "indirectly" by telling mpeg2enc when encoding to reverse the flag
       (-z b|t)	that tells the decoder which field order to use.

       In order	to determine exactly what  type	 of  interlacing  problem  you
       have, you need to extract some frames from the recorded stream and take
       a look at them:

       > mkdir pnm
       > lav2yuv -f 40 video.avi | y4mtoppm | pnmsplit - pnm/image%d.pnm
       > rm pnm/image?.pnm
       > cd pnm
       > xv

       First we	create a directory where we store the images. The  lav2yuv  -f
       40 writes only the first	40 frames to stdout. The program y4mtoppm con-
       verts the frames	to pnm images and the pnmsplit splits the picture into
       two  frames  in	the picture to two single pictures. Then we remove the
       first 10	images because pnmsplit	does not support the  %0xd  numbering.
       Without	a  leading zero	in the number, the files will be sorted	in the
       wrong order, leading to confusing playback.

       Use your	favorite graphic program (xv for example)  to  view  the  pic-
       tures.  As each picture only contain one	field out of two they will ap-
       pear scaled vertically. If you look at the pictures you should see  the
       movie slowly advancing.

       If you have a film you should always see	2 pictures that	are nearly the
       same (because the film frame is split into two field for	 broadcasting)
       after each other.  You can observe this easily if you have comb effects
       when you	pause the film because both fields will	be  displayed  at  the
       same  time.  The	 two pictures that belong together should have an even
       number and the following	odd number. So if you take a look on pictures:
       4  and  5 are nearly identical, 5 and 6 differ (have movement), 6 and 7
       identical, 7 and	8 differ , ....

       To fix this problem you have to use  yuvcorrect's  -T  BOTT_FORWARD  or
       TOP_FORWARD.  You  can  also  have  the	problem	 that  the field order
       (top/bottom) is still wrong. You	may have to use	 yuvcorrect  a	second
       time with -M LINE_SWITCH, or use	the mpeg2enc -z	(b|t) option.

       To  see	if  you	guessed	correctly extract the frames again and reorder
       them using yuvcorrect:

       > lav2yuv -f 40 video.avi | yuvcorrect -T OPTION	| y4mtoppm |  pnmsplit
       - pnm/image%d.pnm

       Where "OPTION" is what you think	will correct the problem.  This	is for
       material	converted from film. Material produced directly	for TV is  ad-
       dressed below.

       Hey, what about NTSC movies ?

       Movies are broadcast in NTSC using "3:2"	pulldown which means that half
       the capture frames contain fields from 1	movie frame  and  half	fields
       from 2 frames. To undo this effect for efficient	MPEG encoding you need
       to use yuvkineco.

       If you have an interlaced source	like a TV camera you have a frame con-
       sists  of  two  fields  that  are recorded at different points in time.
       Spotting	the problem here is harder. You	need to	find something	moving
       horizontally  from  the left to the right. When you extract the fields,
       the thing should	move in	small steps from the left to  the  right,  not
       one   large  step  forward,  small  step	 back,	large  forward,	 small
       back......  You have to use the same options mentioned aboth to correct
       the problem.

       Do  not expect that the field order is always the same (top- or bottom-
       first) It may change between the	channels, between the  films,  and  it
       may  even  change within	a film.	If it changes constant you may have to
       encode with the mpeg2enc	-I 1 or	even -I	2.

       You can only have this problems if you record at	full size !!!

       Creating	videos from other sources

       Here are	some hints and descriptions of how to create the  videos  from
       other sources like images and other video types.

       You might also be interested in taking a	look at	the Transcoding	of ex-
       isting MPEG-2 section.

Creating videos	from images
       You can use jpeg2yuv to create a	yuv stream from	separate JPEG  images.
       This  stream  is	 sent to stdout, so that it can	either be saved	into a
       file, encoded directly to a mpeg	video using mpeg2enc or	used for  any-
       thing else.

       Saving an yuv stream can	be done	like this:

       > jpeg2yuv -f 25	-I p -j	image%05d.jpg >	result.yuv

       Creates	the file result.yuv containing the yuv video data with 25 FPS.
       The -f option is	used to	set the	frame rate.  Note  that	 image%05d.jpg
       means  that the jpeg files are named image00000.jpg, image00001.jpg and
       so on. (05 means	five digits, 04	means four digits, etc.) The -I	 p  is
       needed  for specifing the interlacing. You have to check	which type you
       have.  If you don't have	interlacing just choose	p for progressive

       If you want to encode a mpeg video directly from	 jpeg  images  without
       saving a	separate video file type:

       > jpeg2yuv -f 25	-I p -j	image%05d.jpg |	mpeg2enc -o mpegfile.m1v

       Does  the same as above but saves a mpeg	video rather than a yuv	video.
       See mpeg2enc section for	details	on how to use mpeg2enc.

       You can also use	yuvscaler between jpeg2yuv and mpeg2enc. If  you  want
       to create a SVCD	from your source images:

       >  jpeg2yuv -f 25 -I p -j image%05d.jpg | yuvscaler -O SVCD |  mpeg2enc
       -f 4 -o video.m2v

       You can use the -b option to set	the number of the image	to start with.
       The  number of images to	be processed can be specified with the -n num-
       ber. For	example, if your first image is	image01.jpg  rather  than  im-
       age00.jpg and you only want 60 images to	be processed type:

       >jpeg2yuv -b 1 -f 25 -I p -n 60 -j image*.jpg | yuv2lav -o stream_with-

       Adding the sound	to the stream then:

       > lavaddwav stream_without_sound.avi sound.wav stream_with_sound.avi

       For ppm input there is the ppmtoy4m util. There is a manpage  for  ppm-
       toy4m that should be consulted for additional information.

       To create a mpeg	video try this:

       >cat *.ppm | ppmtoy4m -o	75 -n 60 -F 25:1 | mpeg2enc -o output.m1v

       cat  each  *.ppm	file to	ppmtoy4m. There	the first 75 frames (pictures)
       are ignored and next 60 are encoded by mpeg2enc to output.m1v. You  can
       run  it	without	 the  -o and -n	option.	The -F	options	sets the frame
       rate, default is	NTSC (30000:1001), for PAL you have to use -F 25:1.

       Other picture formats can also be used if there is a converter to ppm.

       >ls *.tga | xargs -n1 tgatoppm |	ppmtoy4m | yuvplay

       A list of filenames (ls *.tga) is given	to  xargs  that	 executes  the
       tgatoppm	 with  one (-n 1) argument per call, and feeds the output into
       ppmtoy4m.  This time the	video is only shown on the screen.  The	 xargs
       is only needed if the converter (tgatoppm) can only operate on a	single
       image at	a time.

       If you want to use the ImageMagick 'convert' tool (a Swiss Army	Knife)

       >convert	*.gif ppm:- | ppmtoy4m | yuvplay

       That  means take	all '.jpg' images in directory,	convert	to PPM format,
       pipe to stdout, then to ppmtoy4m	for conversion to y4m ....

Decoding streams with mplayer
       Decoding	the streams with mplayer is a nice way of bringing every video
       that  mplayer can play back to something	you can	edit or	encode to mpeg
       with mjpegtools.	This method has	been tested with  mplayer  1.0rc2  and
       should work with	newer versions

       >mkfifo stream.yuv

       >cat stream.yuv | yuv2lav -o mjpeg_wo.avi &

       >mplayer	-nosound -noframedrop -vo yuv4mpeg anyfile.mpg

       >mplayer	-vo null -ao pcm:file=anyfile.wav anyfile.mpg

       Now you have an example of a mjpeg encoded AVI without sound. The sound
       will be in anyfile.wav. You can choose if you want to add the sound  to
       the AVI with lavaddwav and edit the file	before encoding.

       You  can	 also  use instead of yuv2lav, mpeg2enc	or any other tool from
       the mjpeg tools so your command might also look like that:

       > cat stream.yuv	| yuvdenoise | yuvscaler -O SVCD | mpeg2enc  -f	 4  -o

       cat  the	 wav  file  into  mp2enc  to  encode  it to MP2	audio. The -vo
       yuv4mpeg	option works well with other  input  types  mentioned  in  the
       mplayer documentation.

Decoding MPEG-2	streams	with mpeg2dec
       You  can	 decode	 mpeg2 streams with the	patched	mpeg2dec version which
       creates yuv streams. You	can pipe that into any other  mjpegtools  pro-
       gram.   Or  you	use  a	mpeg2dec  version  directly  from the libmpeg2
       project and use the output mode pgmpipe.	With the pgmtoy4m program  you
       can convert that	pgm output back	to yuv.

       If  you	ask yourself why there is a patched version and	pgmtoy4m.  The
       answer is that the patch	for yuv	output was sent	several	times  to  the
       libmpeg2	 developers  but  was  never  included.	  Now we have two ways
       around that problem. Decoding looks like	this:

       > mpeg2dec -s -o	 pgmpipe  ANYTS.VOB  |	pgmtoy4m  -i  t	 -a  10:11  -r
       30000:1001 | mpeg2enc -f	8 newvideo.m2v

       You  can	 decode	 the audio as described	in the Transcoding of existing
       MPEG-2 Section.

Other things to	know
       If you have Transport streams from your DVB card, or Satelite  Receiver
       you  might  want	 to  demultiplex  or cut them. A nice tool for that is
       Project X available from:

       You can process the streams afterwards as you would do  with  any  mpeg
       movie  or  demultiplexed	 audio	video.	So the Transcoding of existing
       MPEG-2 section of this document will be of interest.Checking if record-
       ing was successful

       You can use lavplay or glav. IMPORTANT: NEVER try to run	xawtv and lav-
       play or glav with hardware playback, it will  not  work.	 For  software
       playback	it works fine.

       >lavplay	-p S record.avi

       You  should see the recorded video and hear the sound. But the decoding
       of the video is done by the CPU which will place	a heavy	 load  on  the
       system.	The advantage of this method is	you don't need xawtv.

       The better way:

       >lavplay	-p H record.avi

       The  video  is  decoded	and played by the hardware. The	system load is
       very low.  This will play it back on-screen using the  hardware	rather
       than software decoding.

       You might also try:

       > lavply	-p C record.avi

       Which  will  play it back using the hardware but	to the video output of
       the card.

       > glav record.avi

       Does the	same as	lavplay	but you	have an	nice GUI. The options for glav
       and lavplay are nearly the same.	Using no option	SW playback is used.

       Using hardware playback a signal	for the	Composite and SVHS OUT is gen-
       erated so you can view the movie	on your	TV.

       > lav2yuv test.eli | yuvplay

       Is a other way to get the video without sound. You can use yuvplay once
       in  the	encoding command. When you use yuvplay in the encoding command
       you see the changes made	by filters and scaling.	You can	 also  use  it
       for slow-motion debugging.

       NOTE: After loading the driver's	you have to start xawtv	to set up some
       things lavplay and glav do not, but they	are  needed  for  HW-Playback.
       Don't forget to close xawtv !!

       NOTE2:  Do  not	try to send glav an lavplay into background, wont work
       correct !!!

       NOTE3: SECAM playback is	now (12.3.2001)	only  in  monochrome  but  the
       recording and encoding is done right.

       NOTE4:Bad  cables  may  reduce  the  quality of the image. Normally you
       can't see this but when there is	text you might notice a	small  shadow.
       When you	see this you should change the cable.

       Coming  soon:  There is a tool which makes recoding videos very simple:
       Linux Studio. You can download it at:

       Edit the	video

Edit with glav
       Most tasks can be easily	done by	 glav.	Like  deleting	parts  of  the
       video, cut paste	and copy parts of the videos.

       glav button description

       The  modifications  should be saved because glav	does not destructively
       edit the	video. This means that the original video  is  left  untouched
       and  the	 modifications	are kept in an extra "Edit List" file readable
       with a text editor. These files can be used as an input	to  the	 other
       lavtools	programs such as lav2wav, lav2yuv, lavtrans.

       If you want to cut off the beginning and	the end	of the stream mark the
       beginning and the and, and use the "save	select"	button.	The edit  list
       file  is	 than  used  as	input for the lavtools.	If you want to split a
       recorded	video to some smaller parts simply select the parts  and  then
       save each part to a different listfile.

       You  can	see all	changes	to the video and sound NOW and you do not need
       to recalculate anything.

       If you want to get a "destructive" version of your edited video use:

       > lavtrans -o short_version.avi -f a editlist.eli


       specifies the output name

       -f a

       specifies the output format (AVI	for example)


       is the list file	where the modifications	are described.	 You  generate
       the list	file with the "save all" or "save select" buttons in glav.

Unify videos
       > lavtrans -o stream.qt -f q record_1.avi record_2.avi ... record_n.avi


       specifies the outputfile	name

       -f q

       specifies the output format, quicktime in this case

       This is usually not needed. Keep	in your	mind that there	is a 2GB file-
       size-limit on 32Bit systems with	an older glibc.	Usually	not a  problem
       these days

Separate sound
       > lavtrans -o sound.wav -f w stream.avi

       Creates a wav file with the sound of the	stream.avi Maybe needed	if you
       want to remove noise or if you want to convert it to another sound for-

       Another way to split the	sound is:

       > lav2wav editlist.eli >sound.wav

Separate images
       >mkdir jpg; lavtrans -o jpg/image%05d.jpg -f i stream.avi

       First  create the directory "jpg". Then lavtrans	will create single JPG
       images in the jpg directory from	the stream.avi file. The files will be
       named: image00000.jpg, image00001.jpg ....

       The  jpg	 images	 created  contain  the	whole picture. But if you have
       recorded	at full	size the images	are  stored  interlaced.  Usually  the
       picture viewers show only the first field in the	jpg file.

       If you want to have the image in	a single file you can use that version

       > lav2yuv -f 1 stream.avi | y4mtoppm -L >file.pnm

       If you want to split the	fields into single files use that:

       >  lav2yuv -f 5 ../stream.avi | y4mtoppm	| pnmsplit - image%d.pnm

       Maybe  interesting  if  you  need sample	images and do not want to play
       around with grabbing a single image.

Creating movie transitions
       Thanks to Philipp Zabel's lavpipe we can	now  make  simple  transitions
       between movies or combine multiple layers of movies.

       Philipp wrote this HOWTO	on how to make transitions:

       Let's  assume simple this scene:	We have	two input videos intro.avi and and	want to	make intro.avi	transition  into
       with  a	duration of one	second (that is	25 frames for PAL or 30	frames
       for NTSC).

       Intro.avi and have to be of	 the  same  format  (the  same
       frame  rate  and	resolution). In	this example they are both 352x288 PAL
       files. intro.avi	contains 250 frames and  is  1000	frames

       Therefore our output file will contain:

       the first 225 frames of intro.avi

       a  25  frame  transition	containing the last 25 frames of intro.avi and
       the first 25 frames of

       the last	975 frames of

       We could	get the	last 25	frames of intro.avi by calling:

       >lav2yuv	-o 225 -f 25 intro.avi

       -o 255, the offset, tells lav2yuv to begin with frame # 225 and
	-f 25 makes it output 25 frames	from there on.

       Another possibility (because negative  offsets  are  counted  from  the

       > lav2yuv -o -25	intro.avi

       And the first 25	frames of

       > lav2yuv -f 25

       -o defaults to an offset	of zero

       But  we need to combine the two streams with lavpipe. So	the call would

       > lavpipe "lav2yuv -o 255 -f 25 intro.avi" "lav2yuv -f 25"

       The output of this is a raw yuv stream  that  can  be  fed  into	 tran-

       transist.flt  needs to be informed about	the duration of	the transition
       and the opacity of the second stream at the beginning and at the	end of
       the transition:

       -o num

       opacity of second input at the beginning	[0-255]

       -O num

       opacity of second input at the end [0-255]

       -d num

       duration	of transition in frames

       An opacity of 0 means that the second stream is fully transparent (only
       stream one visible), at 255 stream two is fully opaque.

       In our case the correct call (transition	from stream  1	to  stream  2)
       would be:

       > transist.flt -o 0 -O 255 -d 25

       The  -s and -n parameters equate	to the -o and -f parameters of lav2yuv
       and are only needed if anybody wants to render only a  portion  of  the
       transition  for whatever	reason.	Please note that this only affects the
       weighting calculations -	none of	the input is really skipped.   If  you
       use  the	 skip parameter	(-s 30,	for example) you also need to skip the
       first 30	frames in lav2yuv (-o 30) in order to get the expected result.
       If  you	didn't	understand this	send an	email to the authors or	simply
       ignore -s and -n. The whole procedure will eventually be	automated.

       Now we want to compress the yuv stream with yuv2lav:

       > yuv2lav -f a -q 80 -o transition.avi

       Reads the yuv stream from stdin and outputs an avi  file	 (-f  a)  with
       compressed jpeg frames of quality 80.

       Now we have the whole command for creating a transition:

       > ypipe "lav2yuv	-o 255 -f 25 intro.avi"	"lav2yuv -f 25" |
       transist.flt -o 0 -O 255	-d 25 |	yuv2lav	-f a -q	80 -o transition.avi

       The resulting video can be written as a LAV Edit	 List  (a  plain  text
       file) containing	the following lines:

       LAV Edit	List
       0 0 224
       1 0 24
       2 25 999

       This  file  can	be  fed	 into glav or lavplay, or you can pipe it into
       mpeg2enc	with lav2yuv or	combine	the whole stuff	into one single	 mjpeg
       file with lavtrans or lav2yuv|yuv2lav.

       Converting the stream to	MPEG or	DIVx videos

       First there is some general description in the encoding process and af-
       terwards	there is a detailed description	of some	commonly  used	output

       If  you	want a one command conversation	to mpeg	videos try lav2mpeg in
       the scripts directory

       The encoding with the lav2mpeg script looks like	this for mpeg1 output:

       >lav2mpeg -a 160	-b 2110	-d 320x240 -m mpeg1 -o output.mpg file.eli

       Will create a mpeg1 with	videobitrate of	2110kBit/sec and  audiobitrate
       of 160 kBit/sec

       at a resolution of 320x240

       Or for the generation of	mpeg2 output:

       lav2mpeg	-o mpeg2 -O output.mpg file.eli

       Will  create a mpeg2 with default bitrate in same resolution as the in-
       put resolution

       Better results can be accomplished, however, by trying various  options
       and find	out which ones work best for you. These	are discussed below.

       The  creation  of  MPEG-1 movies	is explained with more examples	and in
       greater detail because most of the things that can be used  for	MPEG-1
       also work for the other output formats

       For  the	 creation  of  of  VCD/SVCD  Stills  sequences (-f 6 / -f 7 in
       mpeg2enc) you should see:

       Still sequences are needed for the creation of menus in	VCD/SVCD.  The
       creation	of menus is described in the doku of vcdimager.

Creating sound
       MPEG-1  videos  need MPEG-1-Layer2 (MP2)	sound files. For MPEG-2	videos
       you can use MPEG-1-Layer2 and MPEG1-Layer3 (MP3). MP3 audio is  not  an
       offically  valid	 audio	format but many	VCD players will recognize it.
       MP3 audio is not	valid for DVDs.	 You should stick to MP2 because  many
       of the MPEG-2 players (DVD Player for example, usually the Windows Ver-
       sions have  great  problems  with  this	too)  are  not	able  to  play
       MPEG2-Video and MP3 sound.

       mp2enc is a MP2 Audio encoder. The toolame encoder is also able to pro-
       duce an MP2 file. Toolame is much faster	than mp2enc but	 toolame  does
       not  peform  resampling (48000 to 44100 samples/second).	 Many hardware
       players will play SVCDs using 48000 rate	audio.	For MP3	 creation  I'm
       be sure you have	an encoder.


       > lav2wav stream.avi | mp2enc -o	sound.mp2

       This  creates  a	mpeg sound file	out of the stream.avi with 224kBit/sec
       bitrate and a sample rate of 48kHz.  If	you  audio  file  has  44.1kHz
       mp2enc  resamples  the  audio  to  create a 48kHz output. If you	want a
       44.1kHz output sample rate you have to add -r 44100 to the mp2enc  com-


       > cat sound.wav | mp2enc	-v 2 -V	-o sound.mp2

       This  creates  a	VCD (-V	bitrate=224, stereo, sampling rate:44100) com-
       patible output from the wav file.

       With -v 2 mp2enc	is more	verbose, while encoding	you see	the number  of
       sec of audio already encoded.

       You can test the	output with:

       > plaympeg sound.mp2

       NOTE:  plaympeg is a MPEG-1 Player for Linux, you can use other players
       as wellr. For audio testing you can also	use mpg123. For	both audio and
       video  playing there are	the universal player like VLC mplayer and oth-

Converting video
       Creating	MPEG-1 and MPEG-2 videos.

       Normally	the first video	you create is not the best. For	optimal	 qual-
       ity/size	you need to play with the bitrate, search radius, noise	filter
       .... The	options	of mpeg2enc are	described in the manpage of mpeg2enc.


       lav2yuv stream.avi stream1.avi |	mpeg2enc -o video.m1v

       This creates an	video  file  with  the	default	 constant  bitrate  of
       1152kBit/sec.  This is the bitrate you need if you want to create VCDs.
       You can specify more files and also use the placeholder	%nd.  Where  n
       describes  the number. By default mpeg2enc assumes that you want	to en-
       code a not interlaced video to Mpeg-1. If you want  to  encode  a  full
       size video with interlacing that	command	above will fail.


       > lav2yuv streami%02d.avi | mpeg2enc -b 1500 -r 16 -o video.m1v

       mpeg2enc	 creates  a  video with	a bitrate of 1500kBit/s	uses an	search
       radius of 16. That means	when trying to find similar 16*16  macroblocks
       of  pixels  between  frames the encoder looks up	to 16 pixels away from
       the current position of each block. It looks twice as far when  compar-
       ing frames 1 frame apart	and so on. Reasonable values are 16 or 24. The
       default is 16 so	adding the option here is useless.  Lower  values  (0,
       8),  improve the	encoding speed but you get lower quality (more visible
       artifacts) while	higher values (24, 32) improve the quality at the cost
       of the speed. With the file description of stream%02d.avi all files are
       processed that match this pattern with 00, 01....


       Using yuvscaler one can now also	scale the video	 before	 encoding  it.
       This  can be useful for users with a DC10 or DC10+ cards	which captures
       at -d 1 768x576 or -d 2 384x288 (PAL/SECAM) or -d 1 640x480 (NTSC).

       You get a full description of all commands by reading  the  manpage  or

       >yuvscaler -h


       > lav2yuv stream.avi | yuvscaler	-O VCD | mpeg2enc -o video.m1v

       This  will  scale the stream to VCD size	which for PAL/SECAM is 352x288
       and for NTSC is 352x240.	The scaled yuvstream is	encoded	to MPEG-1.

       It can also do SVCD scaling to 480x480 (NTSC) or	480x576	(PAL/SECAM):

       > lav2yuv stream.avi | yuvscaler	-O  SVCD  -M  BICUBIC  |  mpeg2enc  -o

       The  mode keyword (-M) forces yuvscaler to use the higher quality bicu-
       bic algorithms for downscaling and not the default resample algorithms.
       Upscaling is always done	using the bicubic algorithm.


       > lav2yuv stream.avi | yuvscaler	-I USE_450x340+20+30 -O	SIZE_320x200 |
       mpeg2enc	-o video.m1v

       Here we only use	a part of the input and	specify	a  nonstandard	output

       NOTE: yuvscaler can set a active	area, and set everything else to black
       using:  -I  ACTIVE_WidthxHeight+WidthOffset+HeightOffset	 High  quality
       scaling:	y4mscaler

       y4mscaler  has been arround for quite some time.	But it was for a quite
       long time a extra tool you needed to compile. There is a	 comprehensive
       manpage	explaining all the details, there also a lot fo	helpful	infor-
       mation on the website:

       One unique feature is that is it	able to	change	the  subsampling,  and
       Choma  Modes.  And  you can choose the scaler kernels, depending	on the
       source that can help a lot.


       > cat raw.yuv | y4mscaler -O infer=CLIP -O preset=DVD -O	sar=PAL_Wide |
       mpeg2enc	video.m1v

       In  this	 example  y4mscaler will take the input	stream and scale it to
       the coresponding	PAL size. The sar option tell to scale is  to  a  wide
       format  (16:9).	The infer=clip option will tells y4mscaler that	it can
       clip the	top and	bottom bars away to scale it to	the resulting size.


       > mpeg2dec -o pgmpipe deluxe.m2v	|  pgmtoy4m -x 420jpeg -r 25:1 -i t  |
       y4mscaler   -I  sar=64:36  -I  active=344x476+100+48  -O	 preset=DVD  |
       mpeg2enc	-f 8 video.m1v

       This is a more the job for y4mscaler.  We have a	weird PAL MPEG	source
       format  with  544x576  pixels  in a wide	screen 16:9 format, that makes
       black bars all around the original 4:3 image.  This command scales  the
       image up	to a original 4:3 size,	and takes just the interesting center.
       The SAR is the sample aspect ratio get lost somewhere so	we specify  it
       in  the	beginning.  So it is specified again, than you tell y4mscaller
       the active size of the picture it shall use to  scale  up.  The	active
       keyword	is treated different in	y4mscaler and yuvscaler.  The DVD is a
       preset for the output format  you  want.	 From  the  stream  parameters
       y4mscaler  knows	 that it is a PAL stream and the output	parameters. If
       you wanted a 16:9 output	you would have to use the keyword: DVD_WIDE.

       Testing is done by:

       > mplayer video.m1v

       NOTE:These are only examples. There are more options you	can  use.  You
       can  use	 most  of them together	to create high quality videos with the
       lowest possible bitrate.

       NOTE2:The higher	you set	the search radius the  longer  the  conversion
       will take. In general the more options used the longer encoding takes.

       NOTE3:MPEG-1  was not designed to be a VBR (variable bitrate stream) !!
       So if you encode	with -q	15 mpeg2enc sets the  maximal  bitrate	-b  to
       1152. If	you want a VBR MPEG-1 you have to set -b very high (2500).

       NOTE4:Maybe you should give better names	than video.mpg.	A good idea is
       to  use	the  options  as  part	 of   the   filename   (for   example:
       video_b1500_r16_41_21.m1v).   Another  possibility  is  to call all the
       layer 2 audio files ".mp2" all the MPEG-1 video files  ".m1v"  and  all
       MPEG-2  video  files  ".m2v" Easy to see	what's happening then. Reserve
       .mpg for	multiplexed MPEG-1/2 streams.

Putting	the streams together

       > mplex sound.mp2 video.m1v -o my_video.m1v

       Puts the	sound.mp2 and the video.m1v stream together to my_video.mpg

       Now you can use your preferred MPEG player and watch  it.  All  players
       (gtv  for  example)  based  on  the SMPEG library work well for MPEG-1.
       Other players (which can	play MPEG-2 as well  as	 MPEG-1	 movies)  are:
       xmovie, xine, and MPlayer VLC, to name some.

       NOTE: If	you have specified the -S option for mpeg2enc mplex will auto-
       matically split the files if there is  in  the  output  filename	 a  %d
       (looks  like:  -o test%d.mpg) The files generated this way are separate
       stand-alone MPEG	steams!

       NOTE2: xine might have a	problem	with seeking through videos.   mplayer
       has  a  problem	with the "seek backward/forward" with variable bitrate
       streams because it goes forward in the file the amount of  data	for  a
       constant	 bitrate  stream. That amount might be significantly more than
       10 seconds or one minute	(those are the amount mplayer seeks  for  each
       press  of  the  arrow keys). So don't wonder if it seeks	much more time
       forward or backward than	you expect.

       Variable	bit-rate multiplexing: Remember	to tell	mplex you're  encoding
       VBR  (-V	 option)  as  well  as	mpeg2enc (see the example scripts). It
       *could* auto-detect but it is not working yet. You should tell mplex  a
       video  buffer  size  at	least  as  large  as  the one you specified to
       "mpeg2enc" Sensible numbers for MPEG-1 might be a ceiling  bit-rate  of
       2800Kbps, a quality ceiling (quantization floor)	of 6 and a buffer size
       of 400K.


       > mplex -V -r 1740 audio.mp2 video_vbr.m1v -o vbr_stream.mpg

       Here we multiplex a variable bitrate stream. mplex  is  a  single  pass
       multiplexer so it can't detect the maximal bitrate and we have to spec-
       ify it. The data	rate for the output stream is: audio  bitrate  +  peak
       videobitrate + 1-2% for mplex information. If audio (-b 224) is 224kBit
       and the video is	1500kBit (encoded with -b 1500 -q 9) then we have 1724
       * 1.01 or about 1740kBit.


       > plaympeg my_video.mpg


       > mplayer my_video.mpg

Creating MPEG-1	Videos
       For  MPEG-1  videos you can use MP2 audio and MPEG-1 video. A subset of
       MPEG-1 movies are VCD's.	You can	use VBR	 (Variable  BitRate)  for  the
       Video (although VCDs are	almost always use CBR video) but the Audio has
       to be CBR (Constant BitRate).

       MPEG-1 is recommended for picture sizes	up  to	352x288	 for  PAL  and
       352x240	for  NTSC for larger sizes MPEG-2 is the better	choice.	 There
       is no exact resolution where MPEG-1 is better  than  MPEG-2.   Just  to
       make soure, MPEG-1 can't	handle interlaced sources. If you video	is in-
       terlaced	you need MPEG-2	to get it proper encoded.

       MPEG-1 Audio creation Example

       > lav2wav editlist.eli |	mp2enc -r 44100	-o sound.mp2

       You can save some bits by telling mp2enc	to use a lower bitrate (-b op-
       tion)  like  160	 or  192 kBit/s.  The -r 44100 option forces mp2enc to
       generate	a 44.1kHz audio	file.

       > lav2wav editlist.eli |	mp2enc -b 128 -m -o sound.mp2

       This creates a mono output with an bitrate of 128kBit/sec bitrate.  The
       input  this  time  is the editlistfile (can have	any name) created with
       glav so all changes you made in glav are	direct	processed  and	handed
       over  to	 mp2enc.  You do NOT have to create an edited stream with lav-
       trans to	get it converted properly.

       MPEG-1 Video creation example

       > lav2yuv editlist.eli |	mpeg2enc -b 2000 -r 24 -q 6 -o video.m1v

       mpeg2enc	 creates  an  video  with  an  bitrate	 of   2000kBit/s   (or
       2048000Bit/s)  but  the	-q  flag  activates the	variable bitrate and a
       quality factor of 6. It uses a search radius of 24.

       Explanation:when	mpeg2enc is invoked without the	'q'  flag  it  creates
       "constantbit-rate"  MPEG	streams. Where (loosely	speaking) the strength
       of compression (and hence picture quality) is adjusted to  ensure  that
       on  average  each  frame	 of  video has exactly the specified number of
       bits. Such constant bit-rate streams are	needed	for  broadcasting  and
       for  low-cost  hardware	like DVD and VCD players which use slow	fixed-
       speed player hardware.

       Obviously this is fairly	inefficient as it means	inactive scenes	use up
       bits  that could	better be "spent" on rapidly changing scenes.  Setting
       the 'q' flag tells mpeg2enc to generate variable	bit-rate streams.  For
       such  streams the bit-rate specified is simply the maximum permissible.
       The 'q' parameter specifies the minimum degree of compression to	be ap-
       plied  by specifying how	exactly	picture	information is recorded. Typi-
       cally 'q' would be set so that quiet scenes would  use  less  than  the
       specified maximum (around 6 or 8) but fast moving scenes	would still be
       bit-rate	limited. For archival purposes setting a maximum bit-rate high
       enough  never to	be reached (e.g. 10Mbps) and a q of 2 or 3 are reason-
       able choices.


       > lav2yuv stream.avi | yuvscaler	-I ACTIVE_352x240+0+24 |  mpeg2enc  -b
       1152 -r 16 -4 1 -2 1 -o video.m1v

       Usually there is	at the top and at the bottom a nearly black border and
       a lot of	bandwidth is used for something	you do not like. The yuvscaler
       -I  ACTIVE  option sets everything that is not in the described area to
       black but the imagesize (352x288) is not	changed.  So you have  a  real
       black  border  the  encoder only	uses a few bits	for encoding them. You
       are still compatible with the VCD's format in this example.  To	deter-
       mine the	active window extract one frame	to the jpeg format:

       > lavtrans -f i -i 100 -o frame.jpg test.avi

       Than  use your favorite graphic display program to determine the	active
       size.  The -4 1 and -2 1	options	improves the  quality  about  10%  but
       conversion is slower.

       At the size of 352x288 (1/2 PAL size created when using the -d 2	option
       when  recording)	 the  needed  bitrate  is/should  be  between  1000  -
       1500kBit/s.  For	NTSC it	should be about	the same, because the image is
       smaller but there are more frames per second than in PAL.

       Anyways,	the major factor is quality of the original and	the degree  of
       filtering.  Poor	 quality  unfiltered material typically	needs a	higher
       rate to avoid visible artifacts.	 If you	want to	reduce bit-rate	 with-
       out  annoying  artifacts	when compressing broadcast material you	should
       try one (or more) of the	noise filters.


       > lav2yuv stream.avi | mpeg2enc -b 1500 -n s -g 6 -G 20 -P -o video.m1v

       Here the	stream.avi will	be encoded with:

       -b 1500

       a Bitrate of 1500kBit/sec

       -n s

       the input Video norm is forced to SECAM


       This ensures that 2 B frames appear between adjacent I/P	 frames.  Sev-
       eral  common MPEG-1 decoders can't handle streams that do not have 2 B-
       frames between I/P frames

       -g 6 -G 20

       the encoder can dynamically change the group-of-pictures	 size  to  re-
       flect  scene  changes.  This is done by setting a maximum GOP (-G flag)
       size larger than	the minimum (-g	flag).	For VCDs sensible values might
       be a minimum of 9 and a maximum of 15.  For SVCD	9 and 15 would be good
       values. If you only want	to play	it back	on SW player you can use other
       min-max values.


       >  lav2yuv stream*.avi |	mpeg2enc -b 1500 -r 16 -4 1 -2 1 -S 630	-B 260
       -o video_n1_1500_r16_41_21_S630_B240.m1v

       lav2yuv processes all the stream	files. Then mpeg2enc is	given some op-
       tions  that make	the encoded stream look	nicer. Using -S	630 means that
       mpeg2enc	marks the stream so that mplex generates a  new	 stream	 every
       630MB.  One important thing is the use of the -B	option which specifies
       the non-video (audio and	mplex information) bitrate. The	 -B  value  of
       260  should  be	fine for audio with 224kBit and	mplex information. For
       further information take	a look at the encoding scripts in the  scripts

       MPEG-1 Multiplexing Example


	>mplex sound.mp2 video.m1v -o my_video.mpg

       Puts  the  sound.mp2 and	the video.m1v stream together to my_video.mpg.
       It only works that easy if you have CBR (the -q	option	was  not  used
       with mpeg2enc).


       mplex -V	-r 1740	audio.mp2 video_vbr.m1v	-o vbr_stream.mpg

       Here we multiplex a variable bitrate stream. mplex is now a single pass
       multiplexer so it can't detect the maximal bitrate and we have to spec-
       ify  it.	 The  data rate	for the	output stream is: audio	bitrate	+ peak
       videobitrate + 1-2% for	mplex  information.  If	 audio	(-b  224)  has
       224kBit,	 video	has  1500kBit  (was encoded with -b 1500 -q 9) then we
       have 1724 * 1.01	or about 1740kBit.

Creating MPEG-2	Videos
       MPEG-2 is recommended for sources with a	greater	picture	 than  352x240
       for NTSC	and 352x288 for	PAL. MPEG-2 can	also handle interlaced sources
       like recording from TV at full resolution.

       MPEG-2 allows the usage of mpeg layer 3 (mp3) sound.  So	 you  can  use
       your  favorite  mp3encoder for the creation of the sound.  However, MP3
       audio is	not valid for DVDs.  It	is best	to use MP2  (Layer  2)	audio.
       The audio can also be a VBR stream.

       MPEG-2  is  usually a VBR stream. MPEG-2	creation with optimization re-
       quires a	lot of CPU power.  A film with the double resolution is	NOT  4
       times  larger than an MPEG-1 stream. Depending on your quality settings
       it will be about	1.5 up to 3 times larger than the MPEG-1 stream	at its
       lower resolution.MPEG-2 audio creation example

       > lav2wav editlist.eli |	mp2enc -o sound.mp2

       You can save some bits by telling mp2enc	to use a lower bitrate (-b op-
       tion) like 160 or 192 kBit/s. You might want to add -r  44100  so  that
       mpeg2enc	generates 44.1kHz sampling rate	audio.	I hope I don't need to
       explain the usage of an MP3 Encoder.  But you should not	 use  all  the
       fancy options that are available.MPEG-2 Video creation example

       > lav2yuv editlist.eli |	mpeg2enc -f 3 -b 3000 -q 9 -o video.m2v

       A  very	simple example for MPEG-2 Video.  The most important option is
       the -f 3. That tells mpeg2enc that it should create  a  MPEG-2  stream.
       Because	it is a	generic	MPEG-2 you have	to use the -b bitrate options.
       And should use the -q option because you	usually	want  a	 space	saving
       VBR  stream.  When  using  VBR streams the -b option tells mpeg2enc the
       maximum bitrate that can	be used. The  -q  option  tell	mpeg2enc  what
       quality the streams should have.	 The bitrate has an upper bound	of the
       value specified by -b.

       > lav2yuv editlist.eli |	mpeg2enc -f 3 -4 1 -2 1	-q7 -b 4500 -V 300  -P
       -g 6 -G 18 -I 1 -o video.m2v

       This  will generate a higher quality MPEG-2 stream because the -4 1 and
       -2 1 options were used.	With -b	4500 -q	7 you tell mpeg2enc the	 maxi-
       mal  bitrate  and the quality factor.  -V is the	video buffer size used
       for decoding the	stream.	For SW playback	it can be much higher than the
       default.	Dynamic	GOP is set with	-g and -G.  A larger GOP size can help
       reduce the bit-rate required for	a given	quality	but very  large	 sizes
       can  introduce  artifacts  due to DCT/iDCT accumulated rounding errors.
       The -P option also ensures that 2 B frames appear between adjacent  I/P
       frames.	The -I 1 option	tells mpeg2enc that the	source is a interlaced
       material	like videos. There is (time consuming) interlaced motion  com-
       pensation  logic	 present in mpeg2enc.  Mpeg2enc	will use that logic if
       the size	of the frames you encode is larger than	the VCD	size for  your
       TV Norm.

       If  you	deinterlacing  the  movie  with	yuvdeinterlace you should tell
       mpeg2enc	that it	does not need to do motion estimation  for  interlaced
       material.  You  have to use the -I 0 option of mpeg2enc to say that the
       frames are already deinterlaced.	 This will save	a lot of time when en-
       coding.	If you don't use -I 0 it will not cause	problems, the encoding
       will just take longer.

       You can also use	scaling	an options that	optimize (denoise) the	images
       to  get	smaller	streams.  These	options	are explained in detail	in the
       following sections.Which	values should be used for VBR Encoding?

       The -q option controls the minimum quantization of the  output  stream.
       Quantization controls the precision with	which image information	is en-
       coded. The lower	the value the better the image quality.	 Values	 below
       4 are extremes and should only be used if you know what you are doing

       Usually	you  have to set up a maximum bitrate with the -b option.  The
       tricky task is to set a value for the -q	option and the -b option  that
       produces	a nice movie without using too much bandwidth and does not in-
       troduce too many	artifacts.

       A quality factor	should be chosen that way that	the  mplex  output  of
       Peak bit-rate and average bit-rate differ by about 20-25%.  If the dif-
       ference is very small (less than	< 10%) it is likely that you will  be-
       gin  to	see artifacts in high motion scenes.  The most common cause of
       the average rate	being too close	(or equal)  to	the  maximum  rate  is
       wrong  value  for  the  maximal bitrate or a quality factor that	is too

       A combination that will produce more artifacts than you can count is  a
       SVCD with a maximal video bitrate of 2500kBit and a quality factor of 1
       or 2.  For SVCD with a video limit of 2500kBit a	quality	factor of 7-11
       fits  quite good	(8 is the default). If you use filter programs or have
       a very good source like digital TV, DVD like material or	rendered  pic-
       tures  you  can use a quality factor of 6 when creating SVCDs.  If your
       SVCD/DVD	player supports	non-standard bitrates  you  can	 increase  the
       bitrate above the standard maximum of 2788 kBit/sec (video plus audio).
       When using a higher bitrate and quality factor action scenes will  look
       much better but of course the playing time of the disc will be less.

       The  same  (7-11)  quality factor for a full size picture and a top bi-
       trate of	3500 to	4000 kBit will produce few artifacts.

       For SVCD/DVD you	can expect a result like the one described if the max-
       imal bitrate is not set too low:

	  q <= 6 real sharp pictures, and good quality
	  q <= 8 good quality
	  q >= 10 average quality
	  q >= 11 not that good
	  q >= 13 here even still sequences might look blocky

       Encoding	destination TV (interlaced) or Monitor (progressive)

       MPEG-2  supports	interlaced data	in addition to the progressive format.
       A MPEG-2	movie can be interlaced	or  progressive.  It  depends  on  the
       source (film or broadcast) and on the viewing device.

       If  you	encode	a film both fields should be the same. Deinterlace the
       stream with yuvdeinterlace, or if you have a high quality  source,  and
       don't  need to use the denoiser with yuvcorrect -T NOT_INTERLACED. Also
       set the mpeg2enc	interlace-mode (-I) option to 0. This means that there
       is  no  interlacing.   We do not	really need deinterlacing here because
       there is	no motion between the fields of	the frame.  We	only  need  to
       unite the two fields into a single progressive frame.

       This movie should play back an any device (TV or	Monitor) without prob-

       If you have an interlaced source	(broadcast) you	can encode it  as  in-
       terlaced	stream.	Or deinterlace the stream and encode it	as progressive
       stream. If you deinterlace it with yuvdeinterlace  you  will  lose  de-
       tails.	But if you plan	to play	the recorded stream on your DVD	player
       and your	TV it would not	be wise	to perform deinterlacing.  If you only
       want  to	 play it back on the Monitor (progressive display) the picture
       looks better when playing it back if it is deinterlaced.	If the	player
       you  use	 can do	deinterlacing it does not matter if your encoded video
       has interlaced frames or	progressive frames.

       If you plan to deinterlace the stream you can only  do  this  with  yu-
       vdeinterlace  and set the mpeg2enc -I 0.	If you do not want to deinter-
       lace the	stream you do not need to set any special option (do  not  use
       yuvdeinterlace and mpeg2enc -I 0)

       If  you like to pause the stream	and look on the	still you should dein-
       terlace.	Because	then the image is flicker free when pausing.

       If you have a film (progressive)	with parts from	 a  broadcast  (inter-
       laced)  mixed  together	(like in a documentary where some parts	from a
       speaker are recorded interlaced and other parts are filmed) you have to
       choose between good film	sequences with average still images or average
       looking film sequences with good	still images.

       For good	film with average stills do not	deinterlace.  For average film
       sequences  with	good stills then deinterlace (using yuvdeinterlace and
       mpeg2enc	-I 0).MPEG-2 Multiplexing example

       > mplex -f 3 -b 300 -r 4750 -V audio.mp3	video.m2v -o final.mpg

       Now both	streams	(a mp3 audio and a mpeg2 video)	are multiplex  into  a
       single  stream  (final.mpg).  You  have	to use the -f 3	option to tell
       mplex the output	format.	You also have to add the  -b  decoder  buffers
       size  option  with  the	same value used	when encoding the video. -r is
       that rate of video + audio +1-2%	of mplex information.

       The -Voption tells that your source for mplexing	is a  VBR  stream.  If
       you  don't  use	this  option mplex creates something like a CBR	stream
       with the	bitrate	you have told it with the -r  option.	These  streams
       are usually get BIG.

Creating Video CDs (VCDs)
       VCD  is	a constrained version of MPEG-1	video.	VCD format was defined
       by Philips. The goal was	to use a single	speed CD-drive and other cheap
       hardware	 (not  flexible)  to  have  a cheap HW-Player. Because of that
       there are limitations for video and audio used to make a	VCD.  The  bi-
       trate for video is 1152kBit and 224kBit/sec MP2 audio.  You are not al-
       lowed to	use the	-q option, dynamic GOP sizes and the video  buffer  is
       limited	to 46kB.  The image size is limited to 352x240 for NTSC, an to
       352x288 for PAL.

       If you have no VCD (only) player	and you	plan to	use  your  DVD	player
       then  it	 is quite possible that	the DVD	player will be flexible	enough
       to allow	higher bitrates, dynamic GOP sizes, larger video buffer	and so
       onVCD Audio creation Example

       > lav2wav stream.avi | mp2enc -V	-o sound.mp2

       -V  force  VCD  2.0  compatible	output.	 There the audio samplerate is
       fixed to	44.1kHz. And  you can choose the audio bitrate for mono	 audio
       to  be  64,  96 or 192kBit/sec. If you have stereo audio	you can	choose
       128, 192, 224 or	384kBit/sec.  For hardware players, you	 should	 stick
       to 44.1 224kBps Stereo layer 2 Audio.VCD	Video creation Example

       >  lav2yuv  stream.avi  |  yuvscaler  -O	 VCD  |	mpeg2enc -f 1 -r 16 -o

       For VCD compatible output the -f	1 sets	all  options  in  mpeg2enc  as
       needed.	It seems that many VCD players (Avex for example) are not able
       to play MPEG streams that are encoded with a search radius greater than
       16 so do	not use	the -r option to override the default of 16.

       >  lav2yuv  streams.eli	|  mpeg2enc -f 1 -4 1 -2 1 -S 630 -B 260 -P -o

       Using '-S 630' means that mpeg2enc marks	the stream so that mplex  gen-
       erates  a new stream every 630MB. One important thing is	the use	of the
       -B option which specifies the non-video (audio and  mplex  information)
       bitrate.	 The -B	value of 260 should be fine for	audio with 224kBit and
       mplex information. For further information take a look at the  encoding
       scripts in the scripts directory. The multiplexed streams should	easily
       fit on a	650MB CD.

       The default value (-B) is 700MB for the video. mpeg2enc marks automati-
       cally  every  stream at that size if the	-B option is not used to set a
       different value.	 If you	have a CD where	you can	write more data	 (per-
       haps  as	 much  as  800MB)  you	have to	set the	-S option or otherwise
       mpeg2enc	will mark the stream at	700  MB,  and  mplex  will  split  the
       stream there.  Which is almost certainly	not what you want.

       VCD Multiplexing	Example

       > mplex -f 1 sound.mp2 video.mpg	-o vcd_out.mpg

       The  -f	1  option  turns on a lot of weird stuff that otherwise	has no
       place in	a respectable multiplexer!Creating the CD

       The multiplexed streams have to be  converted  to  an  VCD  compatible.
       This is done by vcdimager

       > vcdimager testvideo.mpg

       Creates	a  videocd.bin,	the data file, and a videocd.cue which is used
       as control file for cdrdao.

       You use cdrdao to burn the image. Cdrdao	is yet	another	 fine  Source-
       forge project which is found at:	Notes

       For  MPEG-1  encoding a typical (45 minute running time)	show or	90 odd
       minute movie from an analog broadcast a	constant  bit-rate  of	around
       1800  kBit/sec should be	ideal. The resulting files are around 700M for
       45 minutes which	fits nicely as a raw XA	MODE2 data track  on  a	 CD-R.
       For  pure  digital  sources  (DTV  or DVD streams and similar) VCD 1152
       works fine.

       Note: If	you encode VBR MPEG-1 (-q) remember the	Hardware was  probably
       not  designed  to  do  the playback because it is not in	the specifica-
       tions. If it works be very happy. I've noticed that it helps  when  you
       have  an	MPEG-1 stream to tell vcdimager	that it	is an SVCD.  vcdimager
       complains (but only with	a warning and  not  a  fatal  error)  but  you
       should  be  able	to burn	it. This could convince	the player to use dif-
       ferent routines in its firmware and play	it back	correct	but  there  is
       no guarantee of that.Storing MPEGs

       If you record the data as XA mode 2 tracks you can fit appreciably more
       on a CD (at the expense of error	 correction/detection).	 You  can  use
       vcdimager to do this and	vcdxrip	(part of the vcdimager package)	to ex-
       tract ("rip") the resulting files. For better Quality  there  are  SVCD
       and XVCD	and DVD.

       Currently  SVCD	is  fully supported with a pre-set format in mplex and
       tools to	create disks. MPEG streams that	can be played  by  DVD	player
       hardware	and software can readily produced using	mpeg2enc/mplex

       If your player doesn't support SVCD you may well	find it	can handle VCD
       streams that have much higher than standard bit-rates. Often as much as
       2500kBit/sec  is	 possible.  The	several	brands of DVD players can also
       play wildly out of spec SVCD and	VCD discs.  With higher	bit-rates  and
       good  quality  source  material	it  is worth trying mpeg2enc's -h flag
       which produce a stream that is as sharp as the limits of	the VCD	 stan-
       dard permits.

       However,	 if  your player supports it and you have the patience for the
       longer encoding times SVCD is a much better alternative.	Using  a  more
       efficient  MPEG	format	SVCD  more than	doubles	VCD's resolution while
       typically producing files that are less than twice as big.

Creating SVCD
       Super Video CD (SVCD) is	an enhancement to Video	CD that	was  developed
       by  a  Chinese  government-backed  committee  of	 manufacturers and re-
       searchers.  The final SVCD spec was announced  in  September  1998.   A
       good explanation	of the SVCD format from	Philips	can be found here: .

       Record  at full TV resolution (means: -d	1 for PAL this is 720x576) The
       resolution is for NTSC is 480x480 of PAL	480x576, so you	know  why  you
       should record at	full size.SVCD Audio creation Example

       > lav2wav stream.avi | mp2enc -V	-e -o sound.mp2

       The  SVCD  specifications permit	a much wider choice of audio rates, it
       is not necessary	to use 224 kBit/sec. Any audio rate between 32 and 384
       kBit/sec	is permitted. The audio	may be VBR (Variable Bit Rate).	The -e
       enables the CRC error protection	for the	audio. The CRC has to  be  en-
       abled  to  be  SVCD  standard  compliant	but it seems that most players
       don't pay attention to the CRC information. The CRC information need  2
       bytes per Audio frame

       The approximate frame length formula for	MPEG-1 layer-II	is:

       (frame length in	bytes) = 144 * (byte rate) / (sample rate)

       If  you have the	typical	VCD settings the CRC data needs	about 0,27% of
       the whole data. In the worst case where you have	 a  MONO  32k  Bitrate
       stream the CRC data needs 1,92%.SVCD Video creation example

       >  lav2yuv  stream.avi |	yuvscaler -O SVCD | mpeg2enc -f	4 -q 7 -I 1 -V
       200 -o video.m2v

       -f 4

       sets the	options	for mpeg2enc to	SVCD

       -q 7

       tell mpeg2enc to	generate a variable bitrate stream

       -I 1

       tell mpeg2enc to	assume that the	original signal	 is  field  interlaced
       video  where  the  odd rows of pixels are sampled a half	frame interval
       after the even ones in each frame. The -I  0  (progressive  output  (no
       field pictures))	option will also work for PAL

       You  can	use lower bitrates but the SVCD	standard limits	total bit-rate
       (audio and video) to 2788800 Bit/sec. So	with 224Kbps audio  and	 over-
       head  2550  may	already	be marginally too tight. Since the SVCD	format
       permits any audio rate between 32 and 384 kBit/sec you can save	a  few
       bits/sec	by using 192k audio (or	for non-musical	material 160k).

       SVCD  supports  variable	 bitrate (VBR),	because	MPEG-2 is usually VBR,
       but with	the top	video bitrate limit of 2500kBit/sec.  With  the	 -f  4
       flag  the  encoder also sets dynamic GOP	with a low limit of -g 6 and a
       high limit of -G	18. This saves a few bits/sec and improves the picture
       quality during scene changes.  When encoding with -f 4 mpeg2enc ignores
       the video bitrate (-b) and search radius	(-r) options. If you use -f  5
       you have	to specify the bitrate and other options to mpeg2enc.

       Another	possibility  for  movies  in  PAL (European style 25 frames/50
       fields per sec) video is:

       > lav2yuv stream.avi | yuvscaler	-O SVCD	| mpeg2enc -f 4	-I 0 -V	300 -o

       Movies are shot on film at 24 frames/sec. For PAL broadcast the film is
       simply shown slightly "too fast"	at 25 frame/sec	(much to the  pain  of
       people  with an absolute	pitch sense of pitch). The -I 0	flag turns off
       the tedious calculations	needed to  compensate  for  field  interlacing
       giving much faster encoding.

       Unfortunately,  movies  broadcast in NTSC (US style 30 frames/60	fields
       sec) video this will produce very poor compression. The "pulldown" sam-
       pling used to produce 60	fields a second	from a 24 frame	a second movie
       means half the frames in	an NTSC	*are* field interlaced.

       Don't forget the	-S and -B options mentioned above. You want the	stream
       to fit on a CD don't you	?SVCD multiplexing example

       > mplex -f 4 -b 300 -r 2750 sound.mp2 video.m2v -o svcd_out.mpg

       -f 4

       tells mplex to mplex a SVCD

       -r 2750

       is the calculated Audio + Video Bitrate + 1-2% multiplex	information

       -b 300

       is  the buffer available	on the playback	device (the same value as used
       for the video encoding (mpeg2enc's -V option).  SVCD creating the CD


       > vcdimager -t svcd testvideo.mpg

       Creates a videocd.bin, the data file, and a videocd.cue which  is  used
       as control file for cdrdao.

       Use cdrdao to burn the image as mentioned earlier.

       NOTE:If	you  want  to build "custom" VCD/SVCD you will need to use the
       mplex -f	2 and -f 5 switches.

       NOTE:The	VCD and	SVCD stuff may work on your HW player  or  not.	 There
       are  many reports that it works quite well. Don't be worried if it does
       not work. Nor am	I responsible for unusable CDs.	("coasters")

Creating DVD's
       This statement was correct a few	years ago: Everything in this  section
       is  new.	 The limitations I mention here	might not exist	in the current
       version.	 Currently (Dec. 2007) DVD creating is working.

       You need	obviously a DVD	writer.	I did own a Ricoh DVD+RW  that	works,
       and  I  know  of	 a  DVD-RAM writer that	is able	to to burn DVD-R. That
       disks also work with a DVD-Player. Now most DVD writers ar able to burn
       both  media  +  and -, so that should not be a problem any more.	 Which
       programs	you use	for burning depends on the DVD writer drive.

       For the creation	and writing of the VOB,	IFO and	BUP files we  use  dv-
       dauthor.	 Aviable from Sourceforge (you might have guessed it) .DVD Au-
       dio creation example

       > lav2wav stream.eli | mp2enc -o	sound.mp2

       The sample rate has to be 48kHz.	The mp2enc does	create	by  default  a
       sample rate of 48kHz. If	it is not a 48kHz mp2enc will resample the au-
       dio to get the sample rate.  If the audio is recorded at	48kHz then  no
       resampling  is  needed  and toolame can be used for the encoding	(it is
       faster than mp2enc).  DVD Video creation	example

       > lav2yuv stream.eli | mpeg2enc -f 8 -o video.m2v

       -f 8

       This sets the options correctly for a MPEG-2 video  that	 is  compliant
       with  the DVD standard.	The maximum bitrate is set to 7500kBps and the
       video buffer size is set	to 230KB. The default quality factor is	set to
       8.   mpeg2enc sets currenty no automatic	sequence length	as it does for

       The other options to get	a low bitrate and high quality stream can also
       be used to override the default settings	mentioned above.  You can also
       use yuvdenoise to increase the picture quality if  the  input  data  is
       noisy  (from a VHS tape for example).  A	typical	command	will look like

       lav2yuv moby.eli	| yuvdenoise | mpeg2enc	-f 8 -q	7 -4 1 -2 1 -P -I 0 -N
       -o video_DVD.m2vDVD multiplexing	example

       > mplex -f 8 sound.mp2 video.m2v	-o my_dvdlikestream.mpg

       -f 8

       Here again we specify that we want to have DVD like MPEG	stream.	 mplex
       cannot do all the fancy things allowed for  a  DVD,  but	 it  is	 close
       enough that the HW-DVD players accept it.


       there we	specify	the output filename.  DVD creation example

       This  topic  will be covered by the documentation of the	dvdauthor pro-
       gram.  For questions please see In general it will work like this:

       >  dvdauthor   -o   output/   stream1.mpg   stream2.mpg	 ...   my_dvd-
       likestream.mpg; dvdauthor -T -o output/

       You will	get a directory	with AUDIO_TS and VIDEO_TS directories.	 Burn-
       ing the data from the disk to a DVD+-R/+-RW writer would	be  done  like

       growisofs -Z /dev/scd2 -dvd-video mydvd/

       If you own a DVD+RW/+R drive a good place for more information is:

       page.  You  also	need a version of the cdrtools with dvd-video support.
       The cdrtools 1.11a27 is known to	work but newer versions	already	exist.

       For other writers the commands to write a DVD will  be  different.  You
       can  get	 some  more  information in the	dvdauthor package. There is no
       guarantee that it will work at all !!!

Creating DIVX Videos

       Another way of creating DIVX is the program mencoder which is from  the
       mplayer	project.   .   For more	information about mencoder please read
       mencoder/mplayer	help and documents. A first and	a second pass give  at
       the  end	 of  pass  hints for bitrate which can be used for encoding to
       specific	size (650 MB, 700 MB and 800 MB). The script  uses
       this  information  if provided (for short streams it is omitted by men-
       coder).	Look for parameter preferedSize	in the script.	You  can  also
       specify	other parameters used for encoding with	encoderParam option in
       the script. For a description of	the usable parameters take a  look  in
       the mplayer/mencoder manual.

       The  outputfilename  is that name of your input file (first option) but
       with the	extension avi. If the size of file is less then	 specified  by
       preferedSize  it's  because  the	 source	 was  of very high quality (no
       noise) and the specified	bitrate	was higher than	required.  You usually
       get  700MB for 1.5 hour film at half image size with bitrate around 900
       that means for divx good	quality	(assuming good quality source material
       of course).

       The script does a 3 step	encoding:

       1st step	- audio	encoding

       2nd step	- first	video pass

       3rd step	- second video pass

       The mplayer/mencoder documentation deprecates the use of	the 3 pass en-
       coding method (it can cause A/V sync problems) and recommends  the  use
       of the 2	pass method.   The mencoder/mplayer documentation is extensive
       and has many helpful hints (and a bitrate calculator in the TOOLS/  di-

       For  encoding  use  the fast ffmpeg (lavc) codec. It gives nice results
       together	with high good performance. For	audio encoding	mp3  is	 used.
       For encoding of all parts it uses unix pipes. This mean that you	DO NOT
       need additional space on	your hard drive	where all  glav	 manipulations
       will be done. For audio encoding	the script uses	a FIFO queue.

       If you want to tweak the	script for your	own needs use these hints:

       Output of 1st step is file called frameno.avi with encoded audio

       2nd   step  is  using  frameno.avi  and	output	is  text  file	called
       lavc_stats.txt with timing informations

       3rd step	is using  frameno.avi  and  lavc_stats.txt  for	 encoding  the
       stream to the output file movie2.avi

       If you want change only video bitrate keep the file frameno.avi comment
       out the 1st step	encoding and repeate 2nd and 3rd step. Dont forget  to
       remove the line where the frameno.avi is	removed.

       Optimizing the stream

       Using  filters  helps to	increase the image quality of constant bitrate
       (CBR) video streams. With VBR (variable bit rate) video the filesize is


       > lav2yuv stream.avi | yuvmedianfilter |	mpeg2enc -o video.m1v

       Here the	yuvmedianfilter	program	is used	to improve the image. This re-
       moves some of low frequence noise in the	images.	It  also  softens  the
       image  a	 little.  It  takes  a	center pointer and averages the	pixels
       around it that fall within the specified	threshold.  It	then  replaces
       the center pixel	with this new value.  You can also use the -r (radius)
       option for an other search radius.

       NOTE:a radius greater than the default value of 2 is horrendously slow!

       yuvmedianfilter has separate settings for luma and chroma. You can con-
       trol the	search radius and the trigger threshold	independently.	If you
       use a threshold of 0 then filtering is disabled	(-t  0	disables  luma
       filtering, -T 0 disables	chroma filtering).

       >  lav2yuv  stream.avi  |  yuvmedianfilter -r 3 -t 4 -T 0 | mpeg2enc -o

       This example uses a search radius of 3 pixels for the luma, a threshold
       of  4  (the default is 2), and disables filtering for the chroma	compo-
       nents.	Sometimes, depending on	the source material, median  filtering
       of the chroma can cause a slight	color shift towards green.   Filtering
       on the luma component (disabling	the chroma filtering) is the  solution
       to that problem.


       > lav2yuv stream.avi | yuvdenoise | mpeg2enc -o video.m1v

       Now we are using	yuvdenoise to improve the image. The filter mainly re-
       duces color and luminance-noise and flickering due to phase errors  but
       is also effective at removing speckles.

       yuvdenoise  denoises interlaced if the input is interlaced.  You	can of
       course change the denoiser threshold (-g/t).  Creating a	 black	border
       can  lower  the	bitrate	of the encoded stream because pure black areas
       compress	much better than noise (captures from analog sources  such  as
       VHS  and	8mm usually have several lines at the time and bottom that are
       very noisy). For	this you can use the scaler.

       yuvdenoise uses a different approach to filter the noise.  More	infor-
       mation  about  how  yuvdenoise works as well as descriptions of its op-
       tions are found in the manpage.

       If you have a high quality source you should lower the filter to	levels
       like  that:  -g	0,255,255  -t  2,2,2.  You might also use the mpeg2enc
       -h/--keep-hf option. That option	tells mpeg2enc to keep	as  much  high
       frequency information as	possible.   Using -h will greatly increase the
       bitrate (filesize).  If the bitrate is too close	to  the	 maximum  (set
       with -b)	the encoder will have to decrease the quality to avoid exceed-
       ing the maximum bitrate.

       A builtin filter	in mpeg2enc is the -N/--reduce-HF option.  This	option
       is not really filter in the usual sense.	 Rather	it changes how exactly
       the high	frequency information is encoded.  Often the high frequency is
       noise.  You also	have high frequencies on sharp borders or transitions.
       The -N option can have values between 0.0 and 2.0 where 0.0 does	 noth-
       ing  (disables  the  high  frequency quantizer boost) and 2.0 gives the
       maximum quantization boost.  The	value to use depends  on  the  desired
       output  quality and filesize.  Values of	-N less	than 0.5 are very sub-
       tle while a value of 1.0	will achieve a good  balance  between  bitrate
       reduction  and output quality.	Using -N values	above 1.5 will notice-
       ably reduce the sharpness of the	output picture and are	normally  used
       only for	poor quality sources (VHS tapes	for example).

       Using  yuvmedianfilter's	 capability  to	only filter the	chroma (-T) is
       moderately effective at reducing	noise in dark scenes without softening
       the  image  during  normal (brighter) scenes.   Median filtering	of the
       luma (-t) will produce a	lower bitrate but can  cause  loss  of	detail
       (softening).   Chroma  only  medianfiltering is less agressive and is a
       good choice to use in combination with yuvdenoise.

       Combining the filters yuvdenoise, yuvmedianfilter and the  mpeg2enc  -N
       option gives a very fine	degree of control over the bitrate (filesize).
       The reduction (or increase) in the bitrate depends on the source	 mate-
       rial and	the exact encoding/filter options used.	 So we can give	no ex-
       act numbers how much each option	and combination	will reduce the	 file-
       size, only guidelines.

       Usually you should use the -N option in a range from 0.5	to 1.5.	 Below
       0.5 it does not reduce the bitrate very much (but does preserve	sharp-
       ness).	At 1.5 and higher you will notice a softening in the video and
       possibly	artifacts (halo/ringing) around	edges of objects  (text/subti-
       tles especially).  If you combine the filters you should	use yuvdenoise
       and maybe afterwards yuvmedianfilter.  Maybe yuvmedianfilter even after
       scaling.	  Having  yuvmedianfilter in the chain does not	reduce the bi-
       trate that much.	 Often the use of yuvdenoise is	enough.	 The  yuvmedi-
       anfilter	 helps much if you have	low quality sources, and not that much
       if you already have a rather good quality.  When	you combine the	filter
       and  option  you	will very likely reduce	the filesize to	about the half
       of the filesize without using the options and programs.

       In general aggressive filtering will produce smaller files  (lower  bi-
       trate)  but  reduce the quality (details) of the	picture.  Less aggres-
       sive filtering/processing will  preserve	 more  detail  but  result  in
       larger files.


       > lav2yuv stream.avi | yuvkineco	-F 1 | mpeg2enc	-o video.m1v

       yuvkineco  is  used  for	 NTSC  sources.	 It does the conversation from
       30000.0/1001.0 (about 29.97) fps	to 24000.0/1001.0 (about 23.976)  fps,
       you  can	 call  it  "reverse  2-3 pulldown" more	info about this	in the
       README.2-3pulldown. yuvkineco does only remove NTSC specific problems.

       If you want to improve the image	you should also	use yuvdenoise:

       > lav2yuv stream.avi | yuvkineco	| yuvdenoise | mpeg2enc	-o video.m1v


       > lav2yuv stream.avi | yuvycsnoise | mpeg2enc -o	video.m1v

       yuvycsnoise is also used	for NTSC and is	specialized for	NTSC Y/C sepa-
       ration  noise.  If video	capture	hardware has only a poor Y/C separator
       then at vertical	stripes	(especially red/blue) noises appear which seem
       checker	flag  and bright/dark invert per 1 frame.  yuvycsnoise reduces
       noises of  this	type.  You  can	 also  use  different  thresholds  for
       luma/chroma  and	the optimizing method.	This filter is not needed with
       working with DV (Digital	Video) data.

       yuvycsnoise works only correct when we have NTSC	with:

       full height (480	lines)

       full motion captured (29.97 fps)

       captured	with poor Y/C separator	hardware

       For more	information about  the	yuvkineco  and	yuvycsnoise  read  the
       README in the yuvfilters	directory.

       If you want to experiment to determine the optimal settings for the de-
       noiser, scaler and so on	replace	the mpeg2enc  with  yuvplay.   yuvplay
       plays back the yuv frames so you	can see	if the options you have	chosen
       are making the thing better or worse.

       A command would look like this:

       > lav2yuv stream.eli | yuvdenoise -options | yuvscaler -options	|  yu-

       If you want to know how much each tool lowers the average bitrate.  You
       can use this table to see what you can expect if	you have a  full  size
       video  and  want	 to create a DVD with a	qality factor of 5 and the al-
       lowed maximal bitrate of	8500kb/sec.

       no denoising : 8300 kb/s	(mostly	hitting	the upper bound)

       yuvenoise : 7700	kb/s

       mpeg2enc	--reduce-hf : 7400 kb/s

       yuvdenoise + yuvmedianfilter : 6000 kb/s

       yuvdenoise + mpeg2enc --reduce-hf : 4900	kb/s

       all of the above	: 3600 kb/s

       While -N|--reduce-hf or yuvdenoise alone	is only	a modest  improvement,
       together	 they  reduce  the bitrate substantially.  There is not	really
       much visible difference between using yuvdenoise	alone  and  yuvdenoise
       with  mpeg2enc --reduce-hf. The usefull values are between 0.0 and 1.5.
       Where you can say that the higher the quality factor you	want, the less
       this option improves. At	a quality factor 4 you save using -N 1.0 about
       1%. If you want a quality factor	of 9 and use the -N 1.0	you might save
       up  to  40%. But	you might save less, that depends on the video you en-

       If you ask yourself why not alyways use all of the above	filters?   The
       answers	are  that  the image softens (loss of detail) and the encoding
       time increases.	Most of	the filters each require about the same	amount
       of time as mpeg2enc needs for encoding the video.

       If  you	have  very high	quality	material and want to keep every	detail
       you should try to use the mpeg2enc --keep-hf|-h on the other hand.

       Note: The bitrate reduction you have depends on the material and	on the
       noise of	the images.

       A  other	 interresting  mpeg2enc	option is the -E|--unit-coeff-elim op-
       tion. This option is disabled by	default. If you	enable it,  a  special
       "unit  coefficient  elimination"	 algorithm,  is	applied	to the encoded
       picture blocks.	 Basically this	proceedure forces  blocks  of  a  type
       that  do	not carry much information (but	use many bits to encode) to be
       skipped.	A negative value examines the base (DC)	as well	as the AC  co-
       efficients.  A positive value means that	only texture (AC) coefficients
       are examined and	possibly zeroed.  The recommended values lies  between
       -20  and	+20. You usually can expect that you have a 5% decreased file-
       size. The amount	the bitrate is	reduced	 can  vary  considerably,  the
       range spans from	not really noticable up	to 20%.

       If  you	think a	other quantization matrice will	help use the -K|--cus-
       tom-quant-matrices option. You can try out your	own  quanitsation  ma-
       trice  or use another builtin than the default.	You can	choose between
       kvcd, tmpgenc, hi-res, and your own. Using -K usually  makes  the  file
       smaller	except	the  hi-res  option  (that  makes  files  considerably
       larger).	Exact guidelines are hard to give, sometime a other  quanitsa-
       tion  matrix  saves  almost  nothing, and the next time up to 20%. More
       than 20%	is very	unlikely, 10-15% at a moderate qualityfactor (-q 8-10)
       are likely.  The	higher the qualiy the less it saves, at	a quality fac-
       tor of 4-6 the reduction	in bitrate may only be 5%

       One thing to keep in mind is that the unit coefficient elimination  and
       the  quantization  matrix option	are decreasing the bitrate while main-
       taining the same	visual quality.	  At this point	you can	chose  to  use
       the  smaller  file to increase the amount of video that will fit	on the
       disc media or you could chose to	increase the quality even more by low-
       ering the -q value by 1 and make	a larger (but higher quality) file.

Scaling	and offset correction
       The basic scaling is described in the Converting	video section

       The  scaling  takes  a part of the picture and scales it	to a larger or
       smaller size. The scaling is done by yuvscaler:

       lav2yuv test.eli	| yuvscaler -I USE_400x400+50+100 | yuvplay

       Here we only take part of the picture and scale it up to	 the  size  of
       the original frame.  But	yuvscaler also changes the pixel aspect	ratio.
       That means when you look	at the stream using yuvplay it	looks  like  a
       square in our example.  After scaling, if the sample (pixel) aspect ra-
       tio were	not changed, the video would not display with the  proper  as-
       pect  ratio.   Yuvscaler	compensates by adjusting the sample aspect ra-
       tio.  If	you have a interlaced video, the height	and HeightOffset  have
       to  be  a  multiple  by	4  if the video	is interlaced. Else the	values
       (width, height, widthoffset, heightoffset) have to be a multiple	of 2.

       A problem that cannot be	solved easily with scaling is when the picture
       is not centered horizontal. On one side you have	no black pixels	and on
       the other you have 30 for example. Scaling is here is the  wrong	 solu-
       tion.   y4mshift	is the perfect solution	because	it can shift the image
       to the left or right.

       lav2yuv test.eli	| y4mshift -n 20 | mpeg2enc -f 3  -b  4000  -q	10  -o

       That will shift the image 20 pixels to the right. If you	use a negative
       the image is shift to the left. You have	to use a even number. The  in-
       serted pixels are set to	black.

       Some  might  wonder  why	the image is not centered and there is a black
       border around the image when you	view what you have recorded. The  rea-
       son for the black border	is in history of the CRT (Cathode Ray Tube) TV
       technology.  The	history	of the TV standard s a very interesting	 story
       but that	topic is described in other (large) books.

       The  TV	does  not  show	the full picture. A part of the	picture	is not
       shown because the TV sets overscan (sometimes as	much as	10%  but  more
       common  today  is  5%).	But when you capture the video with a card you
       see the whole image including the border	that TVs lose due to overscan-
       ning.   A  horizontal  offset  is  usually not a	problem	of the capture
       card. It	is a problem when the film is broadcast	and not	well  synchro-
       nized  with  the	image.	This means that	the scan of the	source not ex-
       actly synchronized with the carrier signal, you wont see	that on	TV.

Frame rate conversion
       Ever needed to convert the framerate from PAL to	NTSC or	the other  di-
       rection	around ? Or something much simpler like	converting the framer-
       ate from	24FPS to 24000:1001 for	conversation from a film frame rate to
       a valid NTSC frame rate.

       Than  yuvfps  is	 your  program.	It can lower the framerate by dropping
       frames or create	a higher framerate by replicating frames. If you  have
       a  wrong	 framerate in the header you can only change the header	of the
       YUV stream and not modify the stream.

       Because the frames are only  replicated	(copied)  you  should  denoise
       first  and then change the framerate and	scale at als last step.	If you
       have a interlaced source	you should also	deinterlace  before  changeing
       the framerate. If you create a higher frame rate	it is very likely that
       you will	have weird flickers when you play it back. If you convert  PAL
       to  NTSC	 (30000:1001 FPS about 29,97 FPS) the frame rate will lower by
       about the factor	480/576	(NTSC lines / PAL lines).  If  you  lower  the
       frame  rate  from  PAL to NTSC (at 24000:1001) or NTSC FILM (24FPS) the
       bitrate will be about (480 Lines	* 24 FPS) / (576 Lines *  25FPS).   If
       you  change  the	 frame	rate before denoising the yuvdenoise will have
       problems	finding	the noise across the frames and	 the  needed  bandwith
       will slightly increase.


       >  lav2yuv  video.eli  |	 yuvfps	 -r  30000:1001	 | yuvscaler -O	SVCD |
       mpeg2enc	-f 4 -o	video_ntsc_svcd.m2v

       This is a example to convert the	source video to	a NTSC	video  running
       at 30000:1001 FPS (or about 29,97FPS) at	SVCD size.


       >  lav2yuv video.eli | yuvdenoise | yuvfps -r 24000:1001	| yuvscaler -O
       SIZE_720x480 | mpeg2enc -f 3 -b 4000 -q 7 -o video_ntsc.m2v

       This example shows how you should use the tools.	Denoise	first and than
       change the framerate and	in the last step change	the image size.

       It can happen that yuvscaler or mpeg2enc	do not detect the TV norm cor-
       rect. If	that happens you have to add the norm option -n	n/p/s  to  the
       program that chooses the	wrong norm.

       If  you	know that the header tells the wrong framerate,	you can	simply
       change the framerate of the yuv header this way:

       > lav2yuv video.eli | yuvfps -r 25:1 -c | mpeg2enc -f 3 -b 4000 -q 7 -o

       You  need  the -c option. To tell yuvfps	that it	only should change the
       header of the stream. With the -r 25:1 you tell yuvfps the  frame  rate
       it  should write	into the header. In your example the PAL frame rate of
       25 FPS. You always have to use the fractional form.

       If you know that	the header is wrong, and you need a  different	output
       bitrate you can do this in a single step:

       >   lav2yuv   video.eli	|  yuvfps  -s  24:1  -r	 25:1  |  mpeg2enc  -o
       video.m1vTranscoding of existing	MPEG-2

       For transcoding existing	MPEG-2 streams from digital TV cards or	DVD  a
       lower  data-rate	 than  for broadcast will give good results.  Standard
       VCD 1152	kbps typically works just fine for MPEG-1. The	difference  is
       in  the	Signal/Noise  ratio  of	 the original. The noise in the	analog
       stuff makes it much harder to compress.

       You will	also need to manually adjust the audio delay  offset  relative
       to  video  when multiplexing. Very often	around 150ms delay seems to do
       the trick.

       You have	to download the	ac3dec and mpeg2dec  packages.	You  can  find
       them  at	their homepage:	mpeg2dec ( ) and ac3dec.  For decoding the au-
       dio streams mpg123 and mplayer can be very helpfull.  You also need sox
       and toolame.

       In the scripts directory	there is a mpegtranscode script	that does most
       of the work.

       So transcoding looks like this:

       > mjpegtranscode	-V -o vcd_stream mpeg2src.mpg


       set's the options so that a VCD compatible stream is generated

       -o vcd_stream

       a vcd_stream.m1v	(video)	and vcd_stream.mp2 (audio) is created


       specifies the source stream

       The script prints also something	like this:

       > SYNC 234 mSec

       You will	need to	adjust the audio/video startup delays when  multiplex-
       ing  to	ensure	audio and video	are synchronized.  The exact delay (in
       milliseconds) that you need to pass to mplex to synchronize  audio  and
       video using the "-v"" is	printed	by the extract_a52 tool	labeled	"SYNC"
       when run	with the "s" flag. This	is the value th	mjpegtranscode	script
       prints out after	the SYNC word.

       Then you	need to	multiplex them like this:

       > mplex -f 1 -O 234 vcd_stream.mp2 vcd_stream.m1v -o lowrate.mpg

       -f 1

       Mux format is set to VCD

       -O 234

       Video  timestamp	 offset	 in  mSec,  generated  by the mjpegtranscoding
       script, there negative values are allowed

       vcd_stream.mp2 &	vcd_stream.m1v

       generated files by the script


       the VCD compatible output stream

       Here we have a SVCD (MPEG-2 video) example:

       > mjpegtranscode	-S -o svcd_stream mpeg2src.mpg

       You have	to multiplex it	with:

       > mplex -f 4 -O 234 svcd_stream.mp2 svcd_stream.m2v -o lowrate.mpg

       Problem:	There is sometimes a problem with NTSC and  VCD	 playback  be-
       cause  movies may be recoded with 3:2 pulldown NTSC with	60 fields/sec.
       mpeg2dec	is designed for	playback on computers and generates the	origi-
       nal  24frames/sec  bitrate.  If	you  encode the	video now 30frames/sec
       video is	created. This video is now much	too short for the encoded  au-

       The transcoding can be made to work but it must be done manually:

       >  mpeg2dec -s -o pgmpipe mpeg2src.mpg |	pgmtoy4m -a 59:54 -r 25:1 -i t
       | mpeg2enc -I 0 -f 4 -q 9 -V 230	-p -P -o svcd_stream.m2v

       The -p tells mpeg2enc to	generate header	flags for  3:2	pull  down  of
       24fps  movie.  It  may also work	if you do not add the -p flag.	You do
       not need	the -p flag when transcoding to	VCD format because it  is  not
       supported in mpeg1.

If you want to do every	step on	your own it will look something	like this
       Extracting Audio:

       >  cat  test2.mpg  |  extract_a52  -  -s	 |  ac3dec -o wav -p sound.wav

       One of the first	lines showed contains the label	"SYNC" you have	to use
       this time later when multiplexing. The 2>/dev/null redirects the	output
       of ac3dec to /dev/null.	In the next step you generate the  mpeg	 audio

       > cat sound.wav | mp2enc	-V -v 2	-o audio.mp2


       forces VCD format, the sampling rate is converted to 44.1kHz from 48kHz

       -v 2

       unnecessary  but	if you use it mp2enc tells you how many	seconds	of the
       audio file are already encoded.


       Specifies the output file.

       cat test2.mpg | extract_a52  -  -s  |  ac3dec  -o  wav  |  sox  -t  wav
       /dev/stdin -t wav -r 44100 /dev/stdout |	toolame	-p 2 -b	224 /dev/stdin

       One of the first	lines again output contains  the  label	 "SYNC".   You
       have  to	 use  this time	(referred to as	"SYNC_value" below) when doing
       the multiplexing.

       For VCD creation	use:

       > mpeg2dec -s -o	pgmpipe	test2.mpg | pgmtoy4m -a	59:54 -r 25:1 -i  t  |
       mpeg2enc	-s -o video_vcd.m1v



       tells mpeg2dec to use program stream demultiplexer

       -o pgmpipe

       the output format of the	pictures, suitable for pgmtoy4m

       Mplex with:

       > mplex -f 1 -O SYNC_value audio.mp2 video_vcd.m1v -o vcd_stream.mpg

       -f 1

       generates an VCD	stream

       -O SYNC_value

       the value mentioned above

       For SVCD	creation use:

       >  mpeg2dec  -s	-o  mpeg2src.mpg  |  pgmtoy4m -a 59:54 -r 25:1 -i t  |
       mpeg2enc	-f 4 -q	9 -V 230 -o video_svcd.mpg

       -q 9

       Quality factor for the stream (VBR stream) (default q: 12)

       -V 230

       Target video buffer size	in KB


       Output file

       Mplex with:

       > mplex -f 4 -b 230 audio.mp2 video_svcd	-o svcd_stream.mpg

       -f 4

       generate	an SVCD	stream

       -b 200

       Specify the video buffer	size by	the playback device.

       For other video output formats this might work:

       > mpeg2dec -s -o	pgmpipe	test2.mpg | pgmtoy4m -a	59:54 -r 25:1 -i  t  |
       yuvscaler   -O	SIZE_320x200   -O   NOT_INTERLACED   |	 mpeg2enc   -o

       If you want to edit mpeg	streams	this also works	but in a slightly dif-
       ferent  way.  For  demultiplexing  you  can use bbdmux from the bbtools
       package.	Splits out either video	or audio very cleanly.	You can't  get
       it  any more from the homepage from Brent Beyler, it can	still be found
       when you	search for it  using  that  keywords  "	 bbtools  linux	 -suse
       -blackbox". Currenty it can be found at:

       First run:

       > bbdmux	myvideo.mpg

       You should get something	like this:

       Found stream id 0xE0 = Video Stream 0
       Found stream id 0xC0 = MPEG Audio Stream	0
       Found stream id 0xBE = Padding Stream

       Extract audio with:

       > bbdmux	myvideo.mpg 0xC0 audio.mp1

       Convert it to wav:

       > mpg123	-w audio.wav audio.m1v

       Extract video with:

       > bbdmux	myvideo.mpg 0xE0 video.m1v

       Converting video	to an mjpeg avi	stream:

       >  mpeg2dec  -o	pgmpipe	 video.m1v  | pgmtoy4m -a 59:54	-r 25:1	-i t |
       yuv2lav -f a -o test.avi

       Then adding the sound to	the avi:

       > lavaddwav test.avi audio.wav final.avi

       If the source video has already the size	of the	target	video  use  -o
       YUV.  Using  YUVh  makes	the video the half size!  The rest can be done
       just like editing and encoding other streams.  If you have videos  with
       ac3 sound you only have to adapt	the commands above.

       Extracting Audio:

       >  cat  test2.mpg  |  extract_a52  -  -s	 |  ac3dec  -o	wav 2>dev/null

       Extract video and adding	the audio in a single step :

       > mpeg2dec -s -o	pgmpipe	| pgmtoy4m -a 59:54 -r 25:1 -i t  |  yuvscaler
       -O VCD |	yuv2lav	-f a -q	85 -w sound.wav	-o test.avi

       NOTE:You	 need much disk	space. 1GB of video has	a size of about	2GB at
       SVCD format and of course disk space is needed  for  some  temp	files.
       Converting the video to mjpeg also takes	some time.  On my Athlon 500 I
       never get more than 6-7 Frames a	second.	 You loose quality  each  time
       you convert a stream into an other format! Trading Quality/Speed

       If  absolute  quality  is  your	objective  a modest improvement	can be
       achieved	using the -4 and  -2  flags.   These  control  how  ruthlessly
       mpeg2enc	 discards  bad	looking	 matches  between sections of adjacent
       frames during the early stages of the search when it  is	 working  with
       4*4  and	 2*2 clusters of pixels	rather than individual pixels. Setting
       -4 1 -2 1 maximizes quality. -4 4 -2 4 maximizes	speed. Note  that  be-
       cause the statistical criteria mpeg2enc uses for	discarding bad looking
       matches are usually fairly reliable the increase/decrease in quality is
       modest (but noticeable).

       Reducing	 the radius of the search for matching sections	of images also
       increases speed.	However	due to the way the search algorithm works  the
       search  radius is in effect rounded to the nearest multiple of 8.  Fur-
       thermore	on modern CPU's	the speed gained by reducing the radius	 below
       16  is not large	enough to make the marked quality reduction worthwhile
       for most	applications.

Creating streams to be played from disk	using Software players
       Usually MPEG player software is much more flexible  than	 the  hardware
       built  into  DVD	 and VCD players. This flexibility allows for signifi-
       cantly better compression to be achieved	for  the  same	quality.   The
       trick is	to generate video streams that use big video buffers (500KB or
       more) and variable bitrate encoding (the	-f /  -q  flag	to  mpeg2enc).
       Software	players	will often also	correctly play back the	more efficient
       MPEG layer 3 (yes, "MP3"	audio format.  A good MP3  encoder  like  lame
       will  produce  results  comparable  to layer 2 at 224Kbps at 128Kbps or
       160Kbps.SMP and distributed Encoding

       Distributed encoding is a quite dark theory for the typical Machine  in
       2013.   So  most	users can safely skip that point. SMP Encoding is more
       interresting for	the average computer

       The degree to which mpeg2enc tries to split work	 between  concurrently
       executing threads is controlled by the -M or --multi-thread [0..32] op-
       tion. This optimizes mpeg2enc for the specified number of CPUs. By  de-
       fault  (-M 1) mpeg2enc runs with	just a little multi-threading: reading
       of frames happens concurrently with compression.	This is	done to	 allow
       encoding	 pipelines  that are split across several machines (see	below)
       to work efficiently without the need for	 special  buffering  programs.
       If  you are encoding on a single-CPU machine where RAM is tight you may
       find turning off	 multithreading	 altogether  by	 setting  -M  0	 works
       slightly	more efficiently.

       For SMP machines	with two ore more processors you can speed up mpeg2enc
       by setting the number of	concurrently executing encoding	threads's  you
       wish  to	 utilize  (e.g.	-M 2). Setting -M 2 or -M 3 on a 2-way machine
       should allow you	to speed up encoding by	around 80%.   Values  above  3
       are accepted but	have very little effect	even on	4 cpu systems.

       If  you	have  a	real fast SMP machine (currently 1.Aug.03) like	a dual
       Athlon MP 2600 or something similar the -M 2 and	 the  filtering	 might
       not  keep both (or more)	 CPU's busy. The use of	the buffer or bfr pro-
       gram with a 10-20MB buffer helps	to keep	both CPUs busy.

       Obviously if your encoding pipeline contains several  filtering	stages
       it  is  likely  that you	can keep two or	more CPU's busy	simultaneously
       even without using -M. Denoising	using yuvdenoise or yuvmedianfilter is
       particular  demanding  and uses almost as much processing power as MPEG

       It you more than	one computer you can also split	the encoding  pipeline
       between	computers using	the standard 'rsh' or 'rcmd' remote shell exe-
       cution commands.	For example, if	you have two computers:

       > rsh machine1 lav2yuv "mycapture.eli | yuvscaler -O SVCD | yuvdenoise"
       | mpeg2enc -f 4 -o mycapture.m2vi

       Here  the  computer where you execute the command is doing the MPEG en-
       coding and "machine1" is	the machine that is decoding scaling  and  de-
       noising the captured video.

       Obviously,  for	this  to  work "machine1" has to be able to access the
       video and the computer where the	command	is executed has	to have	 space
       for the encoded video. In practice, it is usually well worth setting up
       network file-storage using "NFS"	or other packages if you are going  to
       do  stuff  like	this.  If you have three computers you can take	this a
       stage further, one computer could do the	decoding and scaling, the next
       could do	denoising and the third	could do MPEG encoding:

       > rsh machine1 "lav2yuv mycapture.eli | yuvscaler -O SVCD" | yuvdenoise
       | rsh machine3 mpeg2enc -f 4 -o mycapture.m2v

       NOTE:How	the remote command executions are set up so that the  data  is
       sent  direct from the machine that produces it to the machine that con-
       sumes it.

       In practice for this to be worthwhile the network you are using must be
       fast  enough  to	avoid becoming a bottleneck. For Pentium-III class ma-
       chines or above you will	need a 100Mbps Ethernet.

       For really fast machines	a switched 100MBps Ethernet (or	 better!)  may
       be  needed.Setting up the rshd ("Remote Shell Daemon" needed for	rsh to
       do its work and configuring "rsh" is beyond the scope of	this document,
       but its a standard package and should be	easily installed and activated
       on any Linux or BSD distribution.

       Be aware	that this is potentially a security issue so use with care  on
       machines	that are visible to outside networks!Interoperability

       Quicktime  files	 capturing  using  lavrec  can	be edited using	Broad-
       cast2000.  But Broadcast2000 is not available any more  on  heroinewar-
       rior.   mjpeg AVI files captured	using the streamer tool	from the xawtv
       package can be edited and compressed and	played	back  using  software.
       Hardware	 playback is not possible for such files due to	limitations in
       the Zoran hardware  currently  supported.  Videos  recorded  with  Nup-
       pelVideo	can also be processed with the mjpeg tools.

       If  you	have  a	 Macintosh  (MAC) and want to use the mjpeg tools look

       MPEG files produced using the tools are know to play back correctly on:

       dxr2 (hardware decoder card)





       MPEG-1 only: gtv

       MS Media	player version 6 and 7 and later version

       severals	Software based DVD Player

       To find out what	you HW-player (most of the time	 DVD  player)  can  do
       take a look at:

       It seems	that the MS Media player likes MPEG-1 streams more if you have
       used -f 1 when multiplexing.

       If you have any problems	or suggestions feel free to mail me  (Bernhard
       Praschinger): There is a	lot of stuff added from	the HINTS which	Andrew
       Stevens created.	Wolfgang Goeller and Steven  M.	 Schultz  checked  the
       document	for bugs and spelling mistakes.

       And  to	the  people  who  have helped me with program descriptions and
       hints, thanks

       The mjpeg homepage is at:

       vcdimager  is aviable at:

       cdrdao	is aviable at:

       Linux Video Studio is aviable at:

       The lavtools:
       jpeg2yuv(1), lav2wav(1),	lav2yuv(1), lavpipe(1),	lavplay(1), lavrec(1),
       lavtrans(1), lavinfo(1),	mp2enc(1), mpeg2enc(1),	mplex(1), ppmtoy4m(1),
       pnmtoy4m(1),  yuv2lav(1),  yuvdenoise(1),  yuvkineco(1),	 yuvmedianfil-
       ter(1),	  yuvplay(1),	 yuvfps(1),    yuvscaler(1),   yuvycsnoise(1),
       y4mblack(1),  y4mcolorbars(1),  y4mdenoise(1),  y4mhist(1),   y4minter-
       lace(1),	y4mshift(1), y4mstabilizer(1), y4mtopnm(1).  y4mtoppm(1).

       Tools without a man page: lavaddwaw, glav

			      MJPEG tools manuaMJPEG tools(MJPEG Linux Square)

Some books we found usefull | lavrec examples | Other recording hints | Some information about the typical lavrec output while recording | Notes about "interlace field order - what can go wrong and how to fix it" | Creating videos from images | Decoding streams with mplayer | Decoding MPEG-2 streams with mpeg2dec | Other things to know | Edit with glav | Unify videos | Separate sound | Separate images | Creating movie transitions | Creating sound | Converting video | Putting the streams together | Creating MPEG-1 Videos | Creating MPEG-2 Videos | Creating Video CDs (VCDs) | Creating SVCD | Creating DVD's | Creating DIVX Videos | Scaling and offset correction | Frame rate conversion | If you want to do every step on your own it will look something like this | Creating streams to be played from disk using Software players | SEE ALSO

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