[mythtv-users] Adventures in HDTV - Notes from the trenches

Jesse Guardiani jesse at wingnet.net
Mon Dec 19 09:38:35 EST 2005

Matt Mossholder wrote:
> On Mon, 2005-12-19 at 07:53 -0500, Doug Larrick wrote:
>> Matt Mossholder wrote:
>> >     Here are a few links to other people experiencing the VBlank
>> > problem. Basically, if I have VBlank enabled, and play back video
>> > content with Xv, the system hangs. On further inspection it isn't
>> > limited to DVI...
>> > 
>> > http://www.nvnews.net/vbulletin/showthread.php?t=56384
>> > <http://www.nvnews.net/vbulletin/showthread.php?t=56384&highlight=xvideo+vblank <http://www.nvnews.net/vbulletin/showthread.php?t=56384&highlight=xvideo+vblank>>
>> If I'm understanding correctly, if (in nvidia-settings) "X Server XVideo
>> Settings -> Video Texture Adaptor -> Sync to VBlank" is checked, it
>> hangs?  Then don't do that!  Instead, to avoid tearing, uncheck that
>> setting, and make sure MythTV is using OpenGL vsync.  This is the *only*
>> way to get tearing-free, stutter-free playback out of MythTV, because
>> it's one of only two video timing methods (the other working only with
>> ancient nVidia drivers, like 4xxx) that measures when the vertical
>> retrace happens.
>> -Doug
> Doug,
>     Thanks for pointing out that I am an idiot ;) I had been assuming 
> that the reason that Myth wasn't using opengl-vsync, even though I had 
> compiled in the support,  was because of the Sync to Vblank settings 
> in nvidia-settings. Your prompting made me take another look, and 
> realize that the version of 0.18.1 that I have is missing the defines 
> to enable OpenGL VBlank syning. Compiling now... and crossing my 
> fingers :)

Is that a configure option? Wondering if it's on by default in Gentoo's
0.18.1 when compiled with nVidia support.

Jesse Guardiani
Programmer/Sys Admin
jesse at wingnet.net

More information about the mythtv-users mailing list