[FFmpeg-devel] [PATCH] avcodec: add Actimagine VX video decoder

[Florian Nouwt]

Alright, I'll just convert to rgb then. Both the windows codec and the ds
decoder decode the subsampling by simply duplicating the u/v samples within
a 2x2 block (no interpolation). Should I do that too? Or would
interpolation be preferred? As far as I was able to see the windows codec
takes the average of 2x2 blocks to create the subsampled data.

Op ma 15 mrt. 2021 23:35 schreef Hendrik Leppkes <h.leppkes at gmail.com>:

> On Mon, Mar 15, 2021 at 10:55 PM Florian Nouwt <fnouwt2 at gmail.com> wrote:
> >
> > Now that I think about it, it might not be possible to an accurate
> > straightforward conversion to regular yuv because of the subsampling.
> The u
> > and v cannot just linearly be scaled to line up with the required values
> > for regular yuv. That would mean the output would have to be in rgb
> format.
> > It wouldn't really be an issue, but not the most elegant solution.
> Wouldn't
> > it be possible to support these alternative coefficients in libswscale or
> > so? I suppose that would still give issues with applications that have
> > their own conversion algorithms.
> >
>
> I don't think a single game codec warrants creating an entirely new
> pixel format for, unless it has a concrete independent definition and
> is used outside of this codec as well.
> Otherwise, the conversion logic looks rather straight forward and
> relatively cheap, and should probably just output RGB (either packed
> or planar, whichever is easier). It does remind me a bit of YCgCo, but
> with different  formulas unfortunately.
>
> - Hendrik
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