[FFmpeg-devel] [PATCH 1/3] avfilter: Add support for colour range as a link parameter

[Nicolas George]

Philip Langdale (2018-02-21):
> Negotiation is part of Paul's larger changeset, and will be a useful
> feature. My change is still a strict improvement over the current state
> of the world - where range is not propagated at all, regardless of
> compatibility. In those situations where negotiation is required, the
> status quo will essentially continue, with the range value not
> accurately reflecting the frame contents.

I am not comfortable with what you write here.

I am afraid that adding negotiation on top of this would be more work
than adding negotiation on top of the current code.

I am also afraid that an incorrect value is worse than an unspecified
one.

But it all depends on what filters and codecs actually do with the color
range, and that I do not know.

Could you perhaps make a little summary of that issue: where the color
range comes from, which filters and encoders do not care, which ones
only work with one, which ones do something special with it? Maybe as a
longer doxy comment for enum AVColorRange in libavutil/pixfmt.h?


(Also, my mail contained "reply-to: ffmpeg-devel"; please heed it in the
future.)

Regards,

-- 
  Nicolas George
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