[mythtv] Patch for Via XvMC VLD QMatrix Decoding

Ivor Hewitt ivor at ivor.org
Thu Sep 23 19:22:56 EDT 2004


On Monday 20 Sep 2004 14:42, Isaac Richards wrote:
> On Monday 20 September 2004 10:22 am, Ivor Hewitt wrote:
> > >>However, I was planning on creating a new OSDI44Surface type, to hold
> > >>and handle the OSD in native format instead. I'll let you know if I get
> > >>anywhere.
> > >
> > >That'll be even worse performance - the current blending code is MMX
> > >optimized, and if you change the internal surface format, you'll lose
> > > that.
> >
> > But there would be no blending required to display the final osd, it
> > would be held in I44 format throughout.
> > Of course, it might be a complete non-starter and I've probably
> > overlooked something fundamental... I just thought I'd give it a bash.
>
> You're overlooking the fact that all the images/text are blended into each
> other / the surface.  All of that has been MMX optimized for a YUV420
> internal surface format.
>
But I'm holding the OSD in the ia44 format at all times. so there is no 
blending at all. The OSDTypeXxx::Draw functions render directly into the i44 
format.

Yes they wouldn't be MMX optimised, but they wouldn't be doing all the 
rgb->yuv->ia44 conversions that go on at the moment.

I've hacked together an initial bit of code that seems to work. and without 
doing the yuv blending the osd stutter is gone. I'll keep plugging on and see 
if I can come up with something workable.

Cheers,

-- 
Ivor Hewitt.
http://www.ivor.it - tech | http://www.ivor.org - hedge


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