[FFmpeg-devel] [PATCH] HWAccel infrastructure (take 7.1)

[Reimar Döffinger]

On Tue, Feb 24, 2009 at 06:52:33PM +0100, Michael Niedermayer wrote:
> On Tue, Feb 24, 2009 at 06:08:47PM +0100, Reimar D?ffinger wrote:
> > On Tue, Feb 24, 2009 at 04:58:30PM +0100, Michael Niedermayer wrote:
> > > On Tue, Feb 24, 2009 at 04:24:36PM +0100, Gwenole Beauchesne wrote:
> > > > On Tue, 24 Feb 2009, Michael Niedermayer wrote:
> > > > > the user app can use whatever it needs from AVCodecContext to decide if
> > > > > its accelerator can handle it or not ...
> > > > 
> > > > Then you also nicely break Reimar's recent map tables work since you no 
> > > > longer have any bijection there. And requiring an extra arg (for e.g. 
> > > > codec_id) is not a really clean approach either.
> > > 
> > > comments from reimar as well as comments from you about improving the design
> > > and implementation are welcome
> > 
> > While in MPlayer's current design a per-codec PIX_FMT is not necessary,
> > I do not think the situation is comparable to the per-level PIX_FMT
> > case.
> > The notable differences are
> > 1) levels/profile changing within a file is supported in the software
> > implementation (and such files might be even valid), I do not like a
> > design that would restrict the hardware implementation to be
> > _necessarily_ less powerful.
> 
> changing pix_fmt in the middle of a file is not impossible ...

It is a bit problematic conceptually though, and does it actually work
or would most libavc users probably handle it in a highly exploitable
way?

> [...]
> > Not using per-codec PIX_FMTs seems more likely to me to just complicate
> > things, though I do not know for sure.
> 
> well i have no strong oppinion on this but i dislike the
> half page of code per API X codec X variant (IDCT/MC/VLC)

I just wanted to express my suspicion that this, contrary to the other
case, might just move that half page of code to whoever uses lavc :-)
If there wasn't the issue of public API it's the typical case where I'd
suggest to get it in one way and then see if it can and should be
changed.