[mythtv] playback framerate vs screen refresh.

[Debabrata Banerjee]

I just updated this wiki with a discovery about HDTV playback problems, it's 
a livelock situation that I believe anyone will run into when the frame rate 
comes up against the vertical refresh. 
http://www.mythtv.org/wiki/NVidiaProprietaryDriver#Choppy_video.2FHigh_CPU_Usage

I think what needs to happen is that the output frames need to get dropped 
if it gets too far behind, I don't see any other way to make a generic 
solution that works for everyone. Unless the playback timing can come from 
the video driver itself??? The modelines seem to change between driver 
updates, forget about the dozens or more of available chipsets. Perhaps this 
is better suited for the ffmpeg list, but haven't had much time to dig into 
how the playback path works. However this is a bigger problem for mythtv 
because we will get NTSC/ATSC video that runs into this more often than not, 
versus 25fps or other for file players.

-Debabrata