[FFmpeg-trac] #10767(documentation:new): Bad documentation on chroma-derived-nc and friends

[FFmpeg]

#10767: Bad documentation on chroma-derived-nc and friends
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             Reporter:  Mingye Wang  |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
                                     |  documentation
              Version:  git-master   |               Resolution:
             Keywords:  colorspace   |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by Mingye Wang):

 Yes, I get that. But the thing is, the user-facing documentation in the
 texinfo pages is worse than the programmer-facing document in pixfmt.h.
 (Have you clicked the link "what pixfmt says"? Because that goes right to
 the line for {{{AVCOL_SPC_CHROMA_DERIVED_NCL }}} in pixfmt.h.)

 For {{{chroma-derived-nc}}}, texinfo says "Chroma-derived NCL", while
 pixfmt says "Chromaticity-derived non-constant luminance system". That's
 much better.

 For {{{color_range}}} {{{mpeg}}}, texinfo says {{{MPEG (219*2^(n-8))}}},
 while pixfmt very carefully tells you {{{(219 * E + 16) * 2^(n-8)}}} for
 luma and {{{(224 * E + 128) * 2^(n-8)}}} for chroma. That's not only
 better, but also more correct.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10767#comment:5>
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