[MPlayer-users] ssa/ass rendering uses lots of cpu with -vo gl

[Reimar Döffinger]

On Sun, May 01, 2011 at 07:29:44PM +0400, Vladimir Mosgalin wrote:
> Now what's so funny about this - if mplayer plays this video in window,
> load is like 15% without subtitles and no more than 20% even when having
> subtitles both on top and bottom. And I mean playing in same resolution
> as in fullscreen, i.e. resizing window, or using -xy or other means to
> make graphics card render at same resolution as it would've rendered in
> fullscreen.

Well, drivers and/or compositing Window managers will often switch to
a different mode when switching into fullscreen mode.
You could try playing with -fsmode or capturing a CPU usage trace with
e.g. the "perf" tool (by comparing for running with and without fullscreen
the issue should become quite obvious) but this very much sounds like a bug
completely outside of MPlayer's control.
I have often had issues with crappy 3D drivers and switching in/out of
fullscreen, but usually it's just a matter of it being slow for maybe half
a second and then returning back to normal or at worst it working after
switching in/out of fullscreen multiple time. Btw. also on Windows, so
obviously fullscreen switching is rather badly tested everywhere.

> But it's done after unsharp filter; if using gl
> sharpening, this kind of noise becomes noticable and annoying, so I have
> to reduce numbers, having noise=5uah:5uah.

I had wanted to add noise to -vo gl for that reason, but it's
really tricky (and will probably always be suboptimal) and
I haven't really had time and motivation so far.