[FFmpeg-devel] [PATCH 1/2] vc1dec: support multiple slices in frame coded images with hwaccel

Hendrik Leppkes h.leppkes at gmail.com
Fri Nov 18 20:42:46 EET 2016

On Fri, Nov 18, 2016 at 6:40 PM, Michael Niedermayer
<michael at niedermayer.cc> wrote:
> On Fri, Nov 18, 2016 at 03:18:27PM +0100, Hendrik Leppkes wrote:
>> On Fri, Nov 18, 2016 at 3:11 PM, Hendrik Leppkes <h.leppkes at gmail.com> wrote:
>> > Based on a patch by Jun Zhao <mypopydev at gmail.com>
>> > ---
>> >  libavcodec/vc1dec.c | 41 +++++++++++++++++++++++++++++++++++++++--
>> >  1 file changed, 39 insertions(+), 2 deletions(-)
>> >
>> As a quick run down on the whole set:
>> - This does fix decoding of frame-coded samples (ie. fate-vc1_sa10091
>> and fate-vc1_sa20021) on NVIDIA using DXVA2, no regressions using
>> DXVA2 are known
>> - This does fix decoding of these samples on Intel GPUs using VAAPI,
>> however it appears to break on AMD using VAAPI. Important to note here
>> however is that this change is matching up with the vaapi spec, and
>> the AMD implementation is more or less hacky.
>> - VDPAU seems to overall be unimpressed and keeps working as before.
>> I hope I summarized the non-DXVA2 cases properly, as I didn't test
>> those personally, but relied on data from Mark Thompson.
>> Despite the breakage of AMD VAAPI decoding, this change appears to be
>> correct in the sense that it matches the VAAPI and DXVA2 specs on how
>> to handle slices and fixes decoding on two different GPUs, using those
>> two APIs.
> can the amd case be detected and the implementation adapted so
> everything works ?

Not really. Lets just let them fix the implementation in mesa, Mark
tells me its generally considered hacky and not very stable/reliable
in the first place.

- Hendrik

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