[mythtv-users] Stuttering in DVD menus

Richard peper03 at yahoo.com
Mon Nov 12 10:44:39 UTC 2012

On 11/11/12 02:01, Richard wrote:
> the conditions are true whilst in the menu.  Commenting out the
> 'IsInDiscMenuOrStillFrame' condition improves things, but it still isn't
> right.
> If I set the deinterlace mode to None, the problem seems to go away.
> Re-enabling one of the deinterlace modes usually seems to introduce the
> problem again, but often not immediately.  That feels like some sort of
> load problem, but I'm not sure where the load is coming from because the
> rest of the DVD will play fine at Advanced x2 but just selecting 'One
> Field' deinterlacing is enough to cause problems in the menu.
> Why does VDPAU decoding require additional buffering anyway?  Can I turn
> on any more logging?  I tried 'playback,timestamp' but that produces so
> much that I've no idea what to look for (or even whether what I'm after
> is even in there).
> Could this have anything to do with the interleaving of video and audio
> frames?  It seems that only video frames are buffered and as soon as a
> non-video frame appears, a video frame is processed from the buffer.  If
> the ratio of video to non-video frames were too low, could that not
> potentially cause issues?

Answering myself, it seems I was on the right track.  I found another 
location in the same file that was calling 'IsInDiscMenuOrStillFrame' 
after processing an audio frame.  This prevented the loop in another 
method from buffering enough video frames.  Whether everything played 
smoothly then really depended on the ratio of video to non-video frames.

I've created a ticket (http://code.mythtv.org/trac/ticket/11233) and 
attached a patch to it.


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