[mythtv] 2019-devel: lipsync drift

[John Pilkington]

Yesterday and today I have become aware of lipsync drift during 
continuous playback.  Restarting and stepping forward to the same point 
restores good playback.

This is using 'Normal' decoding, shown on the later page as ffmpeg & 
opengl or 'Standard', HQ Deinterlacers with no options ticked.

Current build b8e27f103, first suspected in ca1453f5, for el7

Seen both with and without AVSync2

DVB-T recordings.  They have been processed using Project-X, which may 
insert extra audio frames to maintain sync, but I've been using that for 
years.  I suppose the most obvious suspect is ca1453f, but I'm not sure 
that it's active with my settings.

John P