y4mcolorbars

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 pos‐        sible, 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 inte‐             ger 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 pat‐             tern:              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  out‐             put  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 bot‐        tom-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.  How‐        ever, 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:          [e-mail]         For more info, see our website at               http://mjpeg.sourceforge.net        mjpegtools(1), mpeg2enc(1), y4mscaler(1), yuv2lav(1), yuvplay(1)