[mythtv] Re: Another data point for the new XvMC stuff

Daniel Kristjansson danielk at cat.nyu.edu
Tue May 3 03:20:19 UTC 2005


On Mon, 2005-05-02 at 20:04 -0700, Mark Frey wrote:

> Okay, looks like things aren't quite ideal for me yet. With the sync to
> vblank off I get unpleasant tearing on playback. Should having sync to
> vblank on be causing problems with XvMC?

Sync to vblank causing problems isn't something I've heard of. Can you
toggle OpenGL VSync (you may need to recompile with it enabled), and
tell me if it makes any difference.

> In answer to Daniel's questions:
> My fx5200 is fanless and running fine (glxgears == 3000, AGP is on, mtrr
> is compiled into the kernel: is there anything special I should do with
> mtrr?)

If you are getting 3000fps with GLX gears you should be ok.

> Extra Audio Buffering is on.
> dmesg output is fine, no complaints there.
> I guess I can roll back to 6629, but 7167 actually seem to work well for
> me. I will try tomorrow and see if it makes a difference.

Try the OGL VSync toggle first. If that prevents the tearing I can
disable sync to vblank when VSync is being used, and put some help text
along with XvMC suggesting the use of OGL VSync.

> Without XvMC I can play back 720p programs with about 75% processor
> usage, but I need XvMC to play back 1080i completely smoothly.

I used to have the same problem before I upgraded my home PC, I'm hoping
I'll be able to reuse the my old PC as a HDTV frontend soon...

-- Daniel



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