[mythtv-users] 720p HD content from WPVI in Philly periodic a/v sync issues

Byron Poland wpoland at gmail.com
Tue Dec 15 02:02:57 UTC 2009

On Mon, Dec 14, 2009 at 6:15 PM, Taylor Ralph <tralph11 at yahoo.com> wrote:
>> Is there any way to disable the DRM timing method (or
>> enable the
>> Usleep one) without modifying the code?
> The only way to do this without modifying the code is use a video card that doesn't support DRM. :) Let's first try to get your video to work with DRM. It seems the vsync methods, DRM or OpenGL, which use the hardware retrace to reach the next trigger has issues. I've attached a new patch for you to try out.
>> Are you going to submit this patch for possible inclusion
>> upstream?
>> it makes unwatchable recordings watchable for me.  I
>> appreciate your
>> effort, and time.
> Yes, I'll probably create a ticket in the next day or two.
> Please let us know if the new patch helps at all when using DRM or OpenGL vsync.
> --
> Taylor

This patch worked well with the sample recording on my system using
DRM vsync.  I didn't notice any offensive a/v sync errors.  Thought I
notices a couple ghost-like frames but I'm not sure.

Here's the log:  http://dl.dropbox.com/u/2386241/patch-v5-DRM.log.gz

opengl vsync didn't seem to work on my mac-mini install, even when
enabled it defaulted to DRM.  Previously it would run opengl vsync, as
all my testing as been on this machine.  I'll definitely try to
compile on my other frontend, with different hardware and report back
with an update as to whether opengl vsync is working.


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