[mythtv-users] MythTV 0.24 and vsync on Nvidia / Fedora 14 / RPMFusion

[George Mari]

On 11/27/2010 10:12 PM, Mark Kendall wrote:
> On 28 November 2010 12:04, George Mari<george_mythusers at mari1938.org>  wrote:
>> On 11/27/2010 06:50 PM, Jarod Wilson wrote:
>> OK, thanks for that, Jarod.
>> - it's still using USleep for video timing. :-(
>>
>> Any other information I could provide to help troubleshoot?
>
> George
>
> There is no OpenGL Vsync in the Mythtv code anymore - so you simply
> cannot get the "SGI OpenGL" timing method whatever you try - and there
> is no such thing as 'XVideo Sync to vblank timing method'. It does not
> exist.
>

I understand this part, at least the part about the OpenGL timing method 
going away - I read that in the description of the changeset that Jimmy 
linked to earlier in the thread.

>> From you've already posted, your video driver supports XVideo sync to
> video blank as a method of preventing tearing of video playback. This
> will also ensure that 'USleep with busy wait' will give you exactly
> the same playback quality as you had previously.
>

OK, this part I didn't understand.  I mis-understood and thought that 
the OpenGL timing method was replaced by some kind of XVideo timing 
method.  I was expecting to see a message in the log along the lines of:

Video timing method: XVideo sync to vblank

For years, my experience has been that OpenGL sync had given me good 
results, and USleep or RTC had given not-so-good results.  So when I 
experienced sub-par playback after upgrading to 0.24, and noticed USleep 
being used for timing, and learned earlier in the thread that OpenGL 
timing was removed, I was thinking I need to tweak the frontend 
configuration to use whatever replaced OpenGL for timing, and get away 
from USleep or RTC.

I think I've got it now - thanks everyone for your explanations.  I'll 
look elsewhere for whatever is causing my playback issues.