[mythtv] new nVidia drivers and XvMC

John Patrick Poet john at BlueSkyTours.com
Sat Jul 10 18:26:32 EDT 2004

John Patrick Poet wrote:

> Daniel Thor Kristjansson wrote:
>> I don't get HDTV at the moment. But I'd love it if someone could test
>> the 1.0-6106 driver with 1080i content I'd appreciate it.
>> In particular there is a new option...
>>        Option "XvmcUsesTextures" "boolean"
>> If enabled the driver uses the 3D engine for compositing instead of
>> video overlays. This may be a solution for our OSD problems...
>> -- Daniel
>> ------------------------------------------------------------------------
> I will compile up a version with XvMC enabled, and try it.  Give me an 
> hour.
> John

With XvMC *disabled*, setting XvmcUsesTextures makes no difference -- as 

With XvMC *enabled*, setting XvmcUsesTextures makes thinks worse -- for me.

Turning on XvMC and XvmcUsesTextures off looks okay, but studders just a 
bit more when any OSD is fading away -- compaired to having XvMC disabled.

With XvMC and XvmcUsesTextures enabled, the reaction to OSD is about the 
same.  The problem is, normal video has a constant studder to it.  The 
studder is very consistant, and very fast.  Like a 30th/sec pause, jump, 
30th/sec pause, jump, etc, etc, etc.  I suppose that it is very 
consitant may be a good sign -- you might be able to tune it somehow to 
fix the problem.

I still get the smoothest playback with XvMC disabled on my 3GHz HT P4.  
Doug's work with OpenGL has helped, as has his suggestions about nice 
levels for X and mythfrontend.  Studders are now very rare.  Any 
studders I get now, are much fewer and much shorter.  It takes a slow, 
close-up pan (say up a mountain) to invoke any kind of skip -- and those 
are not reproduceable.  Makes me think some further tuning of the Linux 
scheduler could help.


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