[Libav-user] Hardware decoding via libva

faeem faeem.ali at gmail.com
Sat Dec 22 13:15:07 CET 2012


On 22/12/2012 02:53, Carl Eugen Hoyos wrote:
> faeem <faeem.ali at ...> writes:
>
> I know of two examples, the va-api code in vlc and the code in a patch 
> for MPlayer, see for example 
> http://thread.gmane.org/gmane.comp.video.mplayer.devel/61734/focus=61744 
> [...] 
Thanks. I'll be looking into those examples ASAP.

>>    // FIXME use direct rendering
>>
>> I need to know how to fix that FIXME.
> This is not related to va-api at all.
I selected that //FIXME because it specified "direct rendering", which I 
took to mean "handled by the GPU". It seems I was mistaken there.

My conceptual understanding of va-api thus far, within the ffmpeg 
framework, is that libavcodec will read an encoded video frame, then use 
va-api and the GPU to perform decoding of that frame instead of 
performing decoding in software.

The end result will probably be a frame in YUV. I'll need to run the YUV 
to RGB conversion on each frame if I'm running OpenGL and this will 
still be CPU intensive. I would benefit from the hardware frame decoding 
though, and that alone should make a significant difference.

Is this correct?

Faeem



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