[FFmpeg-trac] #9491(avfilter:new): ass/subtitle filter incorectly handles colorspaces

FFmpeg trac at avcodec.org
Mon Nov 1 14:39:53 EET 2021

#9491: ass/subtitle filter incorectly handles colorspaces
             Reporter:  alwinramirus  |                    Owner:  (none)
                 Type:  defect        |                   Status:  new
             Priority:  normal        |                Component:  avfilter
              Version:  git-master    |               Resolution:
             Keywords:  ass           |               Blocked By:
             Blocking:                |  Reproduced by developer:  0
Analyzed by developer:  0             |
Comment (by alwinramirus):

 Yes I know that those are RGB values.
 This was my guess as to what happens since the resulting rectangle is
 drawn with the color (0, 206, 0) instead of (0, 245, 0) which is what
 happens if you go RGB --BT.601--> YCbCr --BT.709--> RGB.

 Looking at the code it seems like drawutils.c#L163-L165 converts the RGB
 values to YCbCr with BT.601.
Ticket URL: <https://trac.ffmpeg.org/ticket/9491#comment:4>
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