yuvscaler; man page

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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  for‐
       mat,  as well as widescreen (16:9) format and interlacing. Use of yuvs‐
       caler 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  let‐
       terbox_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 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


              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
              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 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‐
              ture!!)



       -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
              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=ver‐
              bose/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 downscal‐
              ing

              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





MJPEG Linux Square             26 Septembre 2001                  yuvscaler(1)
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