[mythtv] [patch] turn off OpenGL vsync by default

[Doug Larrick]

Hamish Moffatt wrote:
> Doug, I tried your GLX-sync patches and didn't find quite the result I
> was expecting. It compiled OK though (I have latest CVS and enabled
> OpenGL sync in settings.pro). 

I have not tried this code for TV out, only for RGB output.  If you take 
a look at the code you'll see what I added is really very little, and 
any bugs are (unfortunately) likely to be in the driver.

All I can suggest is to debug the same way I've worked on this, which is 
to dump a bunch of timings to a file and analyze how (un)even the frame 
cadence is, how close it is to the proper framerate, and where the 
delays seem to be coming from.  I need to do some more of this myself 
(HDTV playback is still not silky smooth) so if I come up with something 
suitable for public consumption maybe I'll send in a patch.

> Theoretical question; I think that since I have an interlaced source,
> and an interlaced output device (analog TV), I don't need deinterlacing
> and video sync (as in the experimental A/V sync feature) should be all I
> need to prevent jagged edges (mice teeth). Is that correct?

I would say that, in an ideal world, this is correct.  Are you going to 
see occasional combing if Myth's video sync skips a beat?  Probably.

-Doug
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