[FFmpeg-trac] #3026(avfilter:new): support vectorscope graticule in histogram color modes

FFmpeg trac at avcodec.org
Fri Oct 4 06:19:48 CEST 2013


#3026: support vectorscope graticule in histogram color modes
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               Reporter:  dericed      |                  Owner:
                   Type:  enhancement  |                 Status:  new
               Priority:  normal       |              Component:  avfilter
                Version:  git-master   |               Keywords:  histogram
             Blocked By:               |               Blocking:
Reproduced by developer:  0            |  Analyzed by developer:  0
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 Summary of the enhancement request:

 A vectorscope graticule overlay option would allow for easier measurements
 and readings when using the color and color2 modes of the histogram filter
 and allow for the emulation of some broadcast equipment. An example of a
 vectorscope graticule overlay for NTSC is here
 http://upload.wikimedia.org/wikipedia/commons/7/7b/Vectorscope_graticule.png.

 A very rough un-aligned example can be produce via:

 ffmpeg -i Vectorscope_graticule.png -f lavfi -i smptebars -filter_complex
 "[0:v]scale=-1:256[a];[1:v]histogram=mode=color,transpose=cclock[b];[b][a]overlay[c]"
 -map "[c]"

 Slightly better looking and aligned to center, but still unaligned at
 color points.

 ffmpeg -i Vectorscope_graticule.png -f lavfi -i smptebars -filter_complex
 "[0:v]null[a];[1:v]histogram=mode=color,transpose=cclock,scale=680:680,negate[b];[b][a]overlay=24:44[c]"
 -map "[c]" -f nut -c:v rawvideo - | ffplay -

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/3026>
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