[FFmpeg-devel] video corruption using h264 hw decoders

Michael Niedermayer michaelni at gmx.at
Fri Oct 28 22:06:25 CEST 2011


On Fri, Oct 28, 2011 at 07:01:05PM +0200, Rainer Hochecker wrote:
> >avcodec_align_dimensions2 tells you the correct dimensions (well, mostly
> >for decoding with FFmpeg, but works just as well for that).
> >And as you see from the changed patch, that means that the height has to
> >basically be rounded up to a multiple of 32.
> 
> I have tried avcodec_align_dimensions2. It introduces corruption on a
> gt220 which was fine before.
> Expanding the video surface in horizontal direction will always result
> into corruption.
> We are able to duplicate this issue with dxva decoder.
> 

> Why do you think the size of a video surface should not match the
> original coded size of a frame?

Iam not sure what statement from whom you refer to, but the sizes
must be large enough to cover all writes to the surface and the
linesizes must be sufficiently aligned to allow SIMD code to function
at full speed. That is not just SIMD from the software decoder when
used but also possible filters a user application might want to
apply to the output afterwards

If you need some croping details exported, this can be done though i
do not understand why you have this need and everyone else seems not
to have it.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No human being will ever know the Truth, for even if they happen to say it
by chance, they would not even known they had done so. -- Xenophanes
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