[MPlayer-dev-eng] Removal of backing store

[Reimar Doeffinger]

On Fri, Aug 22, 2008 at 02:01:20AM +0200, Stephane Marchesin wrote:
> - most importantly, backing store prevents from using a real hardware
> overlay (as opposed to blitter/texture adapters) because this forces
> window redirection. You then have to fallback to using the blitter
> port, which is a lot slower than a native hardware overlay.
> Also FWIW, neither vlc nor xine (with its xine-ui frontend) enable
> backing store, as seen in the following files/places:
> http://git.videolan.org/?p=vlc.git;a=blob;f=modules/gui/skins2/x11/x11_window.cpp;h=03ec09fe978a3e048ff1e32f52be9b9ce9cd738a;hb=HEAD
> http://xine.cvs.sourceforge.net/xine/xine-ui/src/xitk/videowin.c?revision=1.237&view=markup
> (look for XCreateWindow calls in both)

There must be some things missing in your description, first I _know_ MPlayer
never ended up using the blitter for me, which is obvious due to
1) vsync working (at least when manually choosing a non-overlay port vsync is not supported)
2) performance being better much better than with any other method

Actually, your last numbers with the binary nvidia drivers seem 
This was tested with a NVidia TNT2. And the situation when using the
xvidix drivers is basically the same for what I can tell.
I am not generally opposed to it, but so far my summary of the situation would be
"nouveau drivers behave stupidly when backing store is enabled, so disable
it in MPlayer so nouveau does not need to be fixed".
I guess your opinion is that nouveau is behaving as it should, but without
arguments it is a weak position to change code that has worked well for many
years and nobody might truly no what kind of effects changing it might really
have (e.g. does disabling backing store not mean that MPlayer will have to redraw
the window each time it is moved instead of possibly using 2D acceleration
during the moving? If so, this might cause flickering).

Greetings,
Reimar Doeffinger