[FFmpeg-trac] #3236(avfilter:new): lut3d video filter swaps color channels

[FFmpeg]

#3236: lut3d video filter swaps color channels
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             Reporter:  FredTester  |                     Type:  defect
               Status:  new         |                 Priority:  normal
            Component:  avfilter    |                  Version:  2.1.1
             Keywords:              |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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 In detail:
 I compared the colors of the input video with those of the output video.
 In the output the red channel is displaying the blue input values and the
 blue channel is displaying the red values.

 For example, yellow (green+red) becomes cyan (green+blue) in the output.
 Objects that where red with a tint of blue are now blue with a tint of
 red.
 Only green objects have kept their color.

 This seems to be independent of the LUT file. I tested .cube files
 generated by:
 - Davinci Resolve 9
 - Red Giant LUTBuddy
 - Briz LUT Converter
 They all had the same issue.

 Sample command line:
 ffmpeg.exe -y -v 9 -loglevel 99 -i lut3d-channel-bug_input-video.avi -vf
 lut3d=file=lut3d-channel-bug_CineStyle_S-Curve.cube:interp=trilinear -f
 avi -vcodec libxvid -qscale:v 2 -acodec pcm_s16le -ar 48000 -ac 2 lut3d-
 channel-bug_output-video.avi

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Ticket URL: <https://trac.ffmpeg.org/ticket/3236>
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