[FFmpeg-devel] [RFC] DXVA2 decoding and FFmpeg

Stefano Sabatini stefasab at gmail.com
Mon May 18 13:26:56 CEST 2015

On Mon, May 18, 2015 at 1:17 PM, Hendrik Leppkes <h.leppkes at gmail.com>

> On Mon, May 18, 2015 at 12:37 PM, Stefano Sabatini <stefasab at gmail.com>
> wrote:

> >
> > I have a first hackish patch, performed some tests and I got some
> > significant performance gains, on my iCore5 with Intel Graphics HD4000 I
> > have now the same performance as the software decoder using DXVA2 for
> > decoding a H.264 1920x1080 video, but using only a single thread. The
> patch
> > as is is a hack, since I had to modify the compilation flags to enable
> > assembly compilation in the ffmpeg_dxva2.c file. I should probably create
> > an optimized copy function in libavutil, comments are welcome.
> FWIW, I never saw any benefits from using a small cache over simply
> copying directly to the destination memory, that could potentially
> simplify this a bit.

> And yeah, its a huge hack, we don't want new inline assembly.

The sanest approach is probably to add a function to libavutil. The
optimized copy would then be accessible to third-party library users, with
no assembly hacks involved.

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