[FFmpeg-devel] [PATCH 01/24] avcodec: add color_range to AVCodec struct

Paul B Mahol onemda at gmail.com
Wed May 2 14:51:11 EEST 2018

On 5/2/18, Nicolas George <george at nsup.org> wrote:
> Vittorio Giovara (2018-05-01):
>> Well no, let's step back a little.
>> First of all there is no stigma about adding fields to AVCodecContext,
>> in fact, the more, the merrier, right?
>> Secondly, there _is_ concern about adding a field to AVCodec (not avctx),
>> since is a delicate point of entry, and very sensitive to ABI (which in
>> fact
>> was broken in the first iteration of this patch).
>> Finally, I immensely disagree that this is a good API at all, just
>> throwing
>> fields to structure is rarely a good approach to anything. On a separate
>> note
>> I also disagree that color_range (despite its importance) is an
>> "essential
>> property of images", at least not any more than the other color
>> propeties:
>> it is simply being noticed because there are special purpose enum values,
>> but
>> that doesn't mean that the other properties will work "just fine".
>> Because
>> they don't.
>> The transfer characteristics for example is a much more impactful and
>> delicate property that can affect the the color of the image in a much
>> more profund way than color range.
>> Similar arguments could be made for primaries and matrix.
>> As much as you may hate hear it, this proposed filtering system does
>> *not*
>> belong to neither lavfi, lavf or lavc, but rather to the scaling library.
>> Unfortunately the one used by default, swscale, is a monster spaghetti
>> code
>> and too difficult to work around. That however should not affect the
>> design
>> of APIs used in the other libraries: if swscale is not suited anymore for
>> its job it should be replaced, you shouldn't be adding workarounds to
>> AVCodec.
> Thanks for taking the time to express the reservations. I fully agree
> with what you wrote.

Patches and actual proposals are better than agreeing of some written
text that glorifies status quo.

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