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)

MJPEG Tools Team                                  28 April 2004                                  y4mcolorbars(1)