NAME

       y4mcolorbars - Create a YUV4MPEG2 stream containing a colorbar test pattern

SYNOPSIS

       y4mcolorbars [options]

DESCRIPTION

       y4mcolorbars  creates  a  YUV4MPEG2  stream  consisting  entirely  of  frames containing a
       colorbar test pattern.  The pattern attempts to reproduce  the  standard  SMPTE  EG-1-1990
       colorbar  test  signal  as  faithfully  as  possible,  given the constraints of the Y'CbCr
       colorspace.

       Output is to stdout to facilitate piping to other MJPEG tools.

OPTIONS

       y4mcolorbars accepts the following options:

       -n num
            Output a total of 'num' output frames. [default: 1]

       -F n:d
            Set framerate encoded in output stream, as an exact integer ratio.  Common rates are:
             24000:1001 - NTSC 3:2 pulldown converted film
                   24:1 - native film
                   25:1 - PAL/SECAM
             30000:1001 - NTSC video [default]
                   50:1 - PAL field rate
             60000:1001 - NTSC field rate

       -W w Set frame width. [default: 720]

       -H h Set frame height. [default: 480]

       -A n:d
            Set pixel aspect ratio encoded in output stream, as an exact integer  ratio.   Common
            ratios are:
                 1:1  - square pixels (e.g. computer graphics)
                10:11 - CCIR-601 NTSC [default]
                59:54 - CCIR-601 PAL

       -I x Set  interlacing mode, used to interpret the PPM image(s), and also encoded in output
            stream.
             p - progressive, non-interlaced [default]
             t - top/upper-field-first interlaced
             b - bottom/lower-field-first interlaced

       -Q n Data to place in the "-I/+Q" patches in the bottom row of the pattern:
             0 -  -I and +Q at 20% (20IRE)  [default]
             1 -  -I and +Q at 50% (50IRE)
             2 -  +Cb and +Cr at 100%

       -S mode
            Set chroma subsampling mode.
                   444 - 4:4:4 (no subsampling) [default]
               420jpeg - 4:2:0 JPEG/MPEG-1, interstitial cositing
              420mpeg2 - 4:2:0 MPEG-2, horizontal cositing

            The supported subsampled modes use a lousy subsampling filter; better results will be
            achieved  by passing the default 4:4:4 output to a scaler which supports subsampling,
            such as y4mscaler(1).

       -v [0,1,2]
            Set verbosity level.
             0 -  warnings and errors only.
             1 -  add informative messages, too. [default]
             2 -  add chatty debugging message, too.

EXAMPLES

       To create  and  display  200  frames  of  colorbars  corresponding  to  a  top-field-first
       interlaced 4:3 NTSC source:

            y4mcolorbars -n 200 -It -S 420jpeg | yuvplay

       To  create  and  display  200  frames  of  colorbars corresponding to a bottom-field-first
       interlaced 4:3 PAL source:

            y4mcolorbars -n 200 -H 576 -F 25:1 -A 59:54 -Ib | yuvplay

BUGS

       First, it's not clear to the author (who hasn't actually ever  seen  the  SMPTE  EG-1-1990
       document  itself)  what the absolute excursion of the -I and +Q regions is supposed to be;
       however, the phase is correct, and that should be the critical feature.  Second, the PLUGE
       bars,  of  -4 and +4 IRE, can never be precisely synthesized --- the Y' digital space maps
       [16,235] over the full luma excursion, but the full luma excursion in analog space depends
       on  whether or not 7.5 IRE NTSC setup is being used by whatever device eventually produces
       the analog output.  However, the difference is within 1-bit of Y' accuracy anyway.

AUTHOR

       This man page was written by Matt Marjanovic.
       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), mpeg2enc(1), y4mscaler(1), yuv2lav(1), yuvplay(1)