[mythtv-users] OpenGL render problems with radeon and 0.24.1

dargllun dargllun at googlemail.com
Fri Jun 10 15:49:15 UTC 2011

On 10.06.2011 03:22, Mark Kendall wrote:
> Coincidentally, I spent some time a couple of days ago on that ticket.
> I slotted my HD4550 into a couple of boxes to test AMD/ATI OpenGL
> issues. While I couldn't get the proprietary driver to install on
> either box, the radeon driver worked perfectly on both machines.
> One box is now quite old and the most up to date driver package I
> could get still had a couple of issues with OpenGL 2.0 support (which
> is not yet needed by default). On my master backend, using the very
> latest radeon version, everything I could test with it MythTV wise
> worked as expected. I then forced it to use the latest builds from the
> xorg-edgers ppa and enabled Gallium - and again, no obvious issues.
> So all told, while I was expecting a day of grief, I ended up being
> pleasantly surprised:)
> That said, there is still a significant performance issue with the
> OpenGL video renderer. While the MythtTV code uses a different
> approach to other players (and I would expect slightly higher CPU
> usage), there is a difference of 20-30% cpu utilisation across
> different platforms and using different GPU hardware. At this point I
> still don't know what is causing it, though I'm fairly sure the key
> factor is Qt; we rely quite heavily on the underlying Qt OpenGL
> support and somewhere it is causing a problem.

I also gave it another go last night, and had to confirm that the 
rendering is *very* much corrupted at this point. I have to say however 
that I'm using the latest&greatest xorg-edgers packages. There were a 
great many r600g commits during the last week which may have broken some 

Can you describe what exactly "pleasantly surprised" means? Did you have 
a stable real-time rendering? Did you you any deinterlacers? Leaving the 
massive corruption aside for a moment, which may have other causes, I 
seem to get good performance without deint, but a bad one when using 
kernel(2x). (I'm using this one for Xv which, there, gives great results).

Thanks for the hint on the Qt/OpenGL thing, that would surely explain a 
lot (for example that mplayer -vo gl works fine.

Thanks for your continued help. I almost thought this communinity is 
entirely pwned by Nvidia... :-)


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