[MPlayer-dev-eng] DxVA in MPlayer

[Reimar Döffinger]

On Fri, Nov 19, 2010 at 11:39:28PM +0100, Laurent Aimar wrote:
> On Fri, Nov 19, 2010 at 11:11:53PM +0100, Reimar Döffinger wrote:
> > On Fri, Nov 19, 2010 at 10:53:21PM +0100, Laurent Aimar wrote:
> > >  I would think that doing the read back first might be easier as you
> > > would modify less mplayer code (ie the code you need to write would only
> > > touch vd_ffmpeg.c).
> > 
> > "Modify no MPlayer code" IMO absolutely must be the goal for this.
> > Having half a decoder in FFmpeg and the other half in MPlayer without
> > a technical reason is at the very least a maintainance nightmare.
>  FFmpeg current API forces the caller to setup all the data needed for the
> accelerator, that means that for now you need to have specific player code
> to use it (wherever you put it). It's the same for VAAPI/VDPAU. There are
> some patches on the FFmpeg mailing list to start changing that but I haven't
> looked closely at them.
> 
>  Anyway, with DXVA2 API (I think you have the same issue with VAAPI, dunno
> about VDPAU), you cannot completly let FFmpeg initializes everything it needs
> at least in the case when you don't do read back.

This part was about readback code and only about that.
There is no reason whatsoever FFmpeg can't do everything in that case,
in the very worst case it might have to create a renderer, so what?
Obviously it would make sense to make some of those functions also
available in a way that they can be reused for applications that do
not want to do readback.