[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 16:18:27 EET 2016

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.

- Hendrik

More information about the ffmpeg-devel mailing list