[FFmpeg-trac] #3785(swscale:closed): SWSCALE: in_range, in_color_matrix, out_range, out_color_matrix incorrect

[FFmpeg]

#3785: SWSCALE: in_range, in_color_matrix, out_range, out_color_matrix incorrect
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             Reporter:  troy_s      |                    Owner:  (none)
                 Type:  defect      |                   Status:  closed
             Priority:  normal      |                Component:  swscale
              Version:  git-master  |               Resolution:  invalid
             Keywords:  range       |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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Comment (by troy_s):

 Great. So FFMPEG now has someone checking bugs who works on one of the
 most fucked up browsers on the planet with respect to pixel management.

 It all makes sense now.

 So here’s a tip; every single RGB colourspace has a set of luminance
 coefficients given by the middle row of the respective normalized
 primaries matrix. Guess what that row corresponds to? That’s right, the Y
 position relative to CIE XYZ. Know what the Y stands for? That’s right...
 that’s luminance.

 So guess where those luminance coefficients are derived from in all YCbCr
 encodings? That’s right... the same CIE XYZ model. So why are they in
 every single YCbCr encoding? Because the Y weights correspond to the RGB
 encoding to optimize the nonlinearly encoded luma plane.

 Unfuck yourself before speaking down to folks who actually know their
 shit.

 I’m 100% open to being wrong and making mistakes, but Jesus fuck man,
 stand the fuck down. There are real issues still present in FFMPEG’s
 colourimetric handling, and making sure it is handling things properly is
 critical.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/3785#comment:25>
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