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

Mark Thompson sw at jkqxz.net
Sun Nov 20 17:20:43 EET 2016

On 18/11/16 14:18, 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.

Yes, the mesa driver was subverting the API to make it work before (and it may not even have been deliberate).

Retested, patch LGTM: this is definitely a positive change even with that regression.

I'll add looking at the mesa driver to my todo list, it should certainly be fixed there rather than in lavc.


- Mark

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