[mythtv-users] fps drops with DRM sync and bob

Hamish Moffatt hamish at cloud.net.au
Mon Jun 4 14:39:36 UTC 2007


On Sun, Jun 03, 2007 at 10:44:13AM -0400, Doug Larrick wrote:
> Hamish Moffatt wrote:
> > FWIW, switching to audio sync makes things even more entertaining;
> > Now the fps jitters around 25Hz with huge standard deviation.
> 
> Audio as timebase is the normal mode of operation for most folks.  The
> standard deviation is in usec, I believe, not fps, so these are not
> terribly huge standard deviation values.  On my desktop system (which is
> 60 Hz refresh, watching video that's 29.97 Hz refresh) I get std. dev.
> values in the 4000-ish range, which I attribute to the mismatch.
> 
> If you could get your refresh rate to *exactly* 50 Hz I believe these
> would go down even further.
> 
> How does the picture *look* with audio as timebase?
> 
> Also, figuring out how to get realtime priority working would increase
> the timing accuracy independent of the timing method used.  The modern
> method is using pam_limits (/etc/security/limits.conf, rtprio keyword).

Kerneldeint with audio as timebase looks quite fine, though during
movement it's noticeably not as good as bob. I watched for over an hour
with no issues. No shimmering.

Bob with audio as timebase AND realtime priority still loses the plot
after a few seconds, claiming fps values other side of 25 fps and lots
of dropped frames. Also the picture seems to shimmer vertically.


Thanks
Hamish
-- 
Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>


More information about the mythtv-users mailing list