[mythtv] AVSync Problem on entering recorded playback

[Stephen Williams]

I'm only seeing this with recorded content, live TV works fine. Also
this is only with SD content, not pushing the box at all (less than
50% CPU usage and no prepuffering pauses).

Haven't noticed audio/video slowdown then speed up again. Not sure why
you'd be seeing that, the video speed should be constant when using
video as timebase unless AV get more than 3 frames out of sync.

It's definitely a problem with MythTV directly, from the debugging
i've done the AVSync code is clearly failing. Done a bit of code
review of that area and there's quite a lot of undocumented 'magic'
going on, especially with the audio 'warpfactor' calculation. I'll
keep digging and see if it can't be improved.

Stephen