[MPlayer-users] ass subtitles, vo gl and amd video

Reimar Döffinger Reimar.Doeffinger at gmx.de
Mon Sep 23 20:22:54 CEST 2013

On Mon, Sep 23, 2013 at 08:06:12PM +0200, Reimar Döffinger wrote:
> On Mon, Sep 23, 2013 at 05:37:16PM +0300, Nick Koretsky wrote:
> > Hi!
> > 
> > I have a weird problem on my new htpc box that uses a8 cpu build in video
> > with fglrx driver - with vo gl certain ass effects cause extreme slowdowns
> > up to 1-2 frames per second. 
> With which MPlayer version? I think there were some improvements a few
> months ago.
> But yes, frequently changing subtitles can be an issue.
> Sometimes slightly adjusting the size of the subtitles can help,
> but is a bit tricky to do.
> I'll give it a try later, but I don't know if running it on a desktop
> will help much.
> You could try running perf record/perf report.
> There is also the option of trying the OpenSource driver, which has
> the advantage that you can try -vo vdpau which also provides
> full-resolution subtitles but using a completely different approach
> (though VDPAU still is a bit buggy on AMD, even with the latest of
> everything).

Hm, this is none of the usual culprits.
All the CPU time is in glCallList call.
So this time, the texture upload is not the issue.
I have no idea what that would be, all that code is supposed to
do is draw some triangles, switch texture and modify color,
draw some more triangles etc., nothing difficult.
Seems like something bad in the driver with handling these
kind of workloads?
Commenting out the texture changes doesn't make much of a difference,
it seems the issue is just that it is > 1800 elements.
Now, this seems quite crazy so I wonder if there's something wrong
that those subtitles consist of thousands of elements, but it's
not really hard for a GPU, I suspect the driver just doesn't
optimize it at all and punches the data triangle by triangle which
will of course be horrible...

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