|-n num||Output a total of num output frames. [default: 1]|
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]|
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
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
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%
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).
Set verbosity level.
0 - warnings and errors only.
1 - add informative messages, too. [default]
2 - add chatty debugging message, too.
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
First, its not clear to the author (who hasnt 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.
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:
For more info, see our website at http://mjpeg.sourceforge.net
|MJPEG Tools Team||Y4MCOLORBARS (1)||28 April 2004|