[FFmpeg-devel] [PATCH][7/8] Add VA API accelerated H.264 decoding (take 4)

[Reimar Döffinger]

On Mon, Feb 09, 2009 at 03:32:46PM +0100, Michael Niedermayer wrote:
> On Mon, Feb 09, 2009 at 11:39:43AM +0100, Gwenole Beauchesne wrote:
> > On Fri, 6 Feb 2009, Michael Niedermayer wrote:
> >> C. as stephen suggested, outputting decoded surfaces
> >
> > I had a look at it when Jean-Michel Pour? asked for it. However, it turns 
> > out this could be rather suboptimal. In particular, there are cases where 
> > NV12 readback might be supported but not YV12. Sure, it doesn't cost that 
> > much to convert both, but it still has some cost.
> 
> i dont understand the problem you describe, If the hardware can only make
> NV12 available and the user app cannot use that convert is needed anyway
> and if a common format is supported that could be used ...
> what am i missing?

IMHO there is no need to support cards that can output only NV12,
converting it to YV12 is trivial to do even for the graphics card and if
a serious need arises NVidia/ATI/whoever should have little problem
implementing it as part of their APIs.