[mythtv-users] Getting lots of jitter with version 0.24

Justin Johnson justin.johnson3 at gmail.com
Mon Nov 22 23:23:10 UTC 2010


On Sun, Nov 14, 2010 at 4:06 PM, Justin Johnson
<justin.johnson3 at gmail.com> wrote:
> On Sat, Nov 13, 2010 at 8:25 PM, Kevin Ross <kevin at familyross.net> wrote:
>>
>> Unfortunately, no I haven't.  I haven't had time to try to diagnose the
>> problem, so I've just been putting up with it.  I wonder how many other
>> HD-PVR users are observing the same.
>
> I've investigated this a little further, after having a couple
> recordings take place. I only see the jitter in LiveTV on progressive
> scan video, my recordings are fine. In fact, if I enter livetv, I
> observe the jitter. If I then hit the record button, then play the
> same recording from the recording list, the jitter is gone. I've
> confirmed this in the logs as well as visually.
> It looks like the framerate in LiveTV is being detected as 25fps, and
> the display is set to match. But the video is actually 30fps and so
> the display is at the wrong refresh rate. If I force the display rate
> to 60Hz then it displays fine, of course 24fps content is wrong.
> So, the question is, why does myth incorrectly detect the framerate of
> progressive content in LiveTV only?
> As a temporary workaround, I've removed the 50Hz modeline from
> xorg.conf and the issue is fixed. Since I don't plan on watching any
> PAL content, I don't think this should be a problem, but it would be
> nice if it were fixed in the future.
>
> --Justin Johnson
>

OK, I lied, this does not work around the issue, at least not fully. I
still see the same behavior when playing back at 1.5x (I like to watch
most shows sped up, it dramatically decreases the amount of time in
front of the tv). Again, only with progressive content. Mythfrontend
drops a number of frames every 0.02 seconds, which causes significant
stutter. Any ideas for troubleshooting, users?

--Justin Johnson


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