[MPlayer-dev-eng] Removal of backing store

[Vladimir Mosgalin]

Hi Stephane Marchesin!

 On 2008.08.24 at 14:23:41 +0200, Stephane Marchesin wrote next:

> > Yes, obviously. It does exactly like it should. If I force overlay
> > instead of default textured video xv port, it gives funny effects in
> > compiz - effects operate on blue window, not on video. Not that it
> > matters much, since when you don't make window transparent or move it or
> > switch tasks you can watch video without any problems.
> 
> But you have to use the textured adapter, which is a performance loss.

Why do I have to?

> It might not matter to you, but I've found the hw overlay to be the

It matters to me. Like I said, textured video it's really slow with
compiz; that's why I use video overlay.

> No intel doesn't manage overlay usage, they basically don't make you

Eh? They provide both xv adaptors.

> use the overlay adapter. As I said before, intel uses textured video
> by default for everyone, at the expense of speed.

It's only a matter of preference.. Modern intel cards don't have overlay
anyway, so by default it's textured video for everyone - not that it
stops users from using overlay if their cards actually supports it.

> No, intel uses the textured adapter by default and the hw overlay
> adapter comes second, so people don't use it. In the end, the result

Questionable sentence.. Either it matters for them or it doesn't. If it
does, I guess they'll be able to find a solution.

> for intel is that their video playback is slower.

Only if you use compiz. Hey, the world isn't perfect. Either video
playback is slower, but follows the effects, or it's fast, but interacts
badly with complex stuff in compiz. There's simply no other choice.
Intel people picked first choice, maybe because users complained about
overlay + compiz troubles, but they don't stop people from using second
choice if all they desire is video output speed.

> Now if intel wanted to improve the speed, they could put the overlay
> adapter as default, and make it fallback to the textured adapter when
> the window is redirected. However, mplayer would prevent this by

And what would be the reason? Like I said, without compiz, there's no
speed difference between overlay & textured video, with compiz there is.
Falling back to very slow method only when using compiz doesn't seem
like a good idea; in that case, textured video must be used always. Also
it isn't a good idea because if user wants to use hw overlay, it should
be allowed to do so even in compiz environment.

And what would happen with that fallback if compiz starts & stops when
video is running? Right now, without fallback you can run compiz when
playing back video both thought overlay and textured video. In second
case, mplayer starts eating more cpu; in first case, nothing changes.

> making it fallback all the time (because of the backing store flag).

Argh. Just why? Backing store flag doesn't prevent mplayer from using
either hw overlay or textured video with or without compiz. If they
decide to make automatic fallback, which I wouldn't like because of the
reasons above, how backing store flag could harm it if right now it
works in any combination?

> models don't), r100->r300 (that is up to X800) and i810 -> i915 (there

Well my 945 certainly has it..

-- 

Vladimir