Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
yuvscaler(1)		      MJPEG tools manual		  yuvscaler(1)

       yuvscaler  -  UPscales  or DOWNscales a YUV4MPEG2 stream	to a specified

       yuvscaler [-I  input_keyword]  [-M  mode_keyword]  [-O  output_keyword]
       [-n p|s|n] [-v 0-2] [-h]

       yuvscaler is a general (UP or DOWN) scaling utility that	is provided to
       allow conversion	 between  different  video  formats.  It  reads	 in  a
       YUV4MPEG2  format  stream from stdin (such as that produced by lav2yuv)
       and outputs such	stream to stdout (e.g. to be  consumed	by  mpeg2enc).
       The most	common use of yuvscaler	is to generate input suitable for MPEG
       encoding	to VCD or SVCD formats using mpeg2enc(1).

       yuvscaler will automatically take into account PAL/SECAM	and NTSC  for-
       mat,  as	well as	widescreen (16:9) format and interlacing. Use of yuvs-
       caler was designed to be	straightforward.

       VCD encoding:
       lav2yuv my-file.avi | yuvscaler -O VCD |	mpeg2enc -f 1 -o vcd.%d.m1v

       SVCD encoding:
       lav2yuv my-file.qt | yuvscaler -O SVCD |	mpeg2enc -f 4 -o svcd.%d.m2v

       Encoding	anamorphic 16:9	as letterboxed VCD:
       lav2yuv my-ana16-9.eli |	yuvscaler -M WIDE2VCD |	mpeg2enc -f 1 -o  let-

       Encoding	anamorphic 16:9	as letterboxed SVCD:
       lav2yuv	my-ana16-9.eli | yuvscaler -M WIDE2STD -O SVCD | mpeg2enc -f 4
       -o letterbox_svcd.%d.m2v

       Encoding	anamorphic 16:9	as letterboxed DVD:
       lav2yuv my-ana16-9.eli |	yuvscaler -M WIDE2STD -O DVD | mpeg2enc	 -f  8
       -o letterbox_dvd.%d.m2v

       -I input_keyword

	      Specifies	 input	processing options.  Input options may be com-
	      bined by using multiple -I flags.	Possible input_keywords	are:

	      USE_WidthxHeight+WidthOffset+HeightOffset	 to  select  a	useful
	      area  of	the  input  frame  (all	 multiple  of  2,  Height  and
	      HeightOffset multiple of 4 if interlaced), the rest of the image
	      being discarded

	      ACTIVE_WidthxHeight+WidthOffset+HeightOffset to select an	active
	      area  of	the  input  frame  (all	 multiple  of  2,  Height  and
	      HeightOffset multiple of 4 if interlaced), the rest of the image
	      being made black

       -M mode_keyword

	      Sets the scaling mode options.  Scaling mode options can be com-
	      bined by giving several -M flags.	 Possible  are:

	      BICUBIC  - to use	the (Mitchell-Netravalli) high-quality bicubic
	      upsacling	and/or downscaling algorithm

	      RESAMPLE - to use	a classical  resampling	 algorithm  -only  for
	      downscaling-  that  goes much faster than	bicubic. For coherence
	      reason, yuvscaler	will use RESAMPLE if only downscaling is  nec-
	      essary, BICUBIC if not.

	      WIDE2STD - convert widescreen anamorphic (16:9) input video into
	      letterboxed (4:3), generating necessary black lines.  Note  that
	      for MPEG applications if your player can properly	decode anamor-
	      phic video you may wish to leave the video unscaled  and	simply
	      specify	the   approprate  format  during  MPEG	encoding  (see

	      RATIO_WidthIn_WidthOut_HeightIn_HeightOut	to  specified  scaling
	      ratios  of WidthIn/WidthOut for width and	HeightIN/HeightOut for
	      height to	be applied to the useful area. The output frames  that
	      result  from scaling can have a different	format than the	output
	      format specified using -O	options(s).  In	this  case,  yuvscaler
	      automatically  generate necessary	black lines and	columns	and/or
	      skips necessary lines and	columns	to center the scaled image  in
	      the output frame.

	      WIDE2VCD	to scale anamorphic widescreen (16:9) frames into let-
	      terboxed VCD format (equivalent to -M WIDE2STD -O	VCD).

	      FASTVCD to transcode full	sized frames to	VCD (equivalent	to  -M
	      RATIO_2_1_2_1 -O VCD, see	below).

	      FAST_WIDE2VCD  to	 transcode full-sized anamorphic (16:9)	frames
	      to letter-boxed VCD (equivalent to -M WIDE2STD -M	 RATIO_2_1_2_1
	      -O VCD, see below).

	      NO_HEADER	to suppress stream header generation on	output

	      MMX  to use MMX functions	for BICUBIC scaling (experimental fea-

       -O output_keyword

	      Sets the output frame format options.  Output format options can
	      be  combined  by	giving	several	 -O flags.  By default,	output
	      frames size will be the same as input frame sizes,  as  well  as
	      output frames interlacing	if coherent with output	keyword	speci-
	      fication which prevails, top_first if not.

	      MONOCHROME to generate monochrome	frames on output.  Chrominance
	      information  for the scaled pixels is set	neutral	(white).  MPEG
	      encoding of black	and white video	will be	both  inefficient  and
	      show annonying chrominance artifacts unless this is done.

	      VCD  to  generate	VCD compliant frames on	output (taking care of
	      PAL and NTSC standards). Non-interlaced output.

	      SVCD to generate SVCD compliant frames on	output (taking care of
	      PAL and NTSC standards). Top-field-first interlaced frames.

	      DVD  to  generate	DVD compliant frames on	output (taking care of
	      PAL and NTSC standards). Top-field-first interlaced frames.

	      SIZE_WidthxHeight	to generate frames  of	size  WidthxHeight  on
	      output (multiple of 4)

	      If VCD, SVCD or DVD keywords are not used, output	interlacing is
	      taken of the same	type as	input. By default, output frames  size
	      will be the same as input	frame size.

       -n p|s|n
	      (usually	not  necessary)	 if  norm could	not be determined from
	      data flux, specifies the OUTPUT norm for	VCD/SVCD  (p=pal,s=se-

       -v 0|1|2
	      Specifies	 the  degree  of  verbosity: 0=quiet, 1=normal,	2=ver-

       -h     Prints a summary of command line syntax.

       Note: The most useful downscaling ratios	are  handled  using  dedicated
       optimised scaling routines. They	are:

	      RATIO_WidthIn_WidthOut_2_1  => Full-sized	frame to VCD downscal-

	      RATIO_3_2_1_1 => Full-sized frame	to SVCD	downscaling

	      RATIO_1_1_4_3 => WIDE2STD	downscaling mode

	      RATIO_WidthIn_WidthOut_1_1 => downscaling	only  concerns	width,
	      not height

	      RATIO_1_1_HeightIn_HeightOut   =>	  downscaling	only  concerns
	      height, not width

	      RATIO_2_1_2_1 => FASTVCD,	slightly width distorted  (real	 ratio
	      45 to 22)	but faster full-sized frame to VCD downscaling (-M RA-
	      TIO_2_1_2_1 -O VCD)

	      RATIO_WidthIn_WidthOut_8_3 => specific to	 WIDE2VCD  downscaling
	      (-M WIDE2STD -O VCD)

	      RATIO_2_1_8_3  =>	 specific to (slighly distorted) FAST_WIDE2VCD
	      downscaling (-M WIDE2STD -M RATIO_2_1_2_1	-O VCD)

	      RATIO_1_1_1_1 => copy useful  input  part	 of  possible  several
	      files into output	frames

       This man	page was written by Xavier Biquard et al.
       If  you	have  questions, remarks, problems or you just want to contact
       the developers, the main	mailing	list for the MJPEG-tools is:

       For more	info, see our website at

       mjpegtools(1), lavpipe(1), lav2yuv(1) mpeg2enc(1)

MJPEG Tools Team	       26 Septembre 2001		  yuvscaler(1)


Want to link to this manual page? Use this URL:

home | help