yuvscaler(1)

NAME

   yuvscaler  -  UPscales  or DOWNscales a YUV4MPEG2 stream to a specified
   format

SYNOPSIS

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

DESCRIPTION

   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
   format,  as  well  as  widescreen (16:9) format and interlacing. Use of
   yuvscaler was designed to be straightforward.

EXAMPLES

   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
   letterbox_vcd.%d.m1v

   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

OPTIONS

   -I input_keyword

          Specifies  input  processing  options.   Input  options  may  be
          combined 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
          combined 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
          necessary, 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
          anamorphic  video  you  may wish to leave the video unscaled and
          simply specify the approprate format during MPEG  encoding  (see
          mpeg2enc(1)).

          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
          letterboxed 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
          feature!!)

   -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
          specification 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=secam,n=ntsc).

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

   -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
          downscaling

          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
          RATIO_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

AUTHOR

   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:
     mjpeg-users@lists.sourceforge.net

   For more info, see our website at
          http://mjpeg.sourceforge.net/

SEE ALSO

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

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