[FFmpeg-devel] [PATCH v3] lavc/aomdec: Allow RGB decoding

[Balling]

чт, 10 июн. 2021 г., 20:33 James Zern <jzern at google.com>:

> On Thu, Jun 10, 2021 at 9:26 AM Валерий Заподовников
> <val.zapod.vz at gmail.com> wrote:
> >
> > >This doesn't match the check in libdav1d.c.
> >
> > I do not really care what libdav1d.c does, since it uses internal to AV1
> spec DAV1D_MC_IDENTITY (and frame->colorspace). This should have been a no
> go into FFmpeg, but it was not somehow. FFmpeg can handle all of this in by
> itself, there is no need to use examples from AV1 spec, which are wrong by
> omission: see for yourself.
> https://github.com/FFmpeg/FFmpeg/blob/c8778606b3811da6bd58ca6b73d2446bd430013e/libavcodec/libdav1d.c#L299
> >
>
> It would be better to put this on the list for others to be able to
> comment on.
>
> > This is sRGB definition from AV1, not R'G'B' (or even RGB in case of
> linear transfer) and thus is total garbage. What if the file is tagged with
> DCI-P3 transfer and/or primaries? I am not going to fix libdav1d.c, since
> as I said, it uses internal names and internal deliberations which are
> unacceptable.
> >
> > Again. AV1 spec is really quite hillarious in that part. For example it
> does mention XYZ, but does not check for it anywhere, try Ctrl-F here:
> https://aomediacodec.github.io/av1-spec/av1-spec.pdf
> >
> > Thus I did implement filtering this out too, since FFmpeg does support
> XYZ pixel format (and maybe somebody one day will implement it too).
> >
> > Listen, my patch is correct. AV1 spec is also telling the same, as it
> shows all the possible primaries and transfers. But it only looks into sRGB
> scenario, since your people (Google, etc) were not capable to implement
> normal icc color management, but FFmpeg with mpv can do it and thus no need
> to concentrate on sRGB like your people did. I mean you can fix AV1 spec if
> you want, but IMHO it is correct already, this is color spaces info 101 and
> AV1 is depending on ITU-R H.273.
>


Okay, I will put it into the mailing list.

P.S. Dunno what that guy was thinking. I am not going to inline my comments
any more than I want to. I mean sure I do not top post, but just since this
is just waste of Internet traffic, and so is inlining in most cases (but
right here it is COOL and very needed).

>