OpenGL video performance

Michel Dänzer michel at
Wed Apr 25 22:58:12 PDT 2012

On Mit, 2012-04-25 at 18:34 +0200, Greg G. wrote: 
> Background: for some time now I've repeatedly trying to get my HD3200 
> equipped mythtv box to use the OpenGL renderer. While things have gotten 
> *much* better in the course of the last 1.5 years, I still find that Xv 
> rendering is much more "real-time", meaning that when I use a proper 
> deinterlacer (hard requirement) with Xv I get smooth rendering with no 
> judder at all. WithOpenGL it's pretty jerky. My test case is to play 
> some piece of recording from a news channel with a horizontal scoll text 
> (like stock prices), this way you see even slight hickups. Note I'm not 
> even talking about h.264 output (which is, btw, also great on Xv), but 
> merely SD material.
> I'm using Ubuntu and the fabulous oibaf drivers, and KMS. Myth is 
> configured to use real-time priorities. "Top" shows that there is ample 
> CPU time. Blanking method is DRM.

What are the other options for 'blanking method' (I assume that's
related to sync to vertical blank)? Do any of them work better?

Otherwise we'd need to see the Xorg.0.log file and the output of dmesg
and glxinfo.

Earthling Michel Dänzer           |         
Libre software enthusiast         |          Debian, X and DRI developer

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