[mythtv] Funky 720p playback

[Bill Cizek]

A few weeks ago I noticed playback problems on some of ABC's 720p programs.

The symptoms are jerky playback, out of sync audio, and incorrect 
program length
(an hour long program will be displayed as 45 minutes in the OSD).

The frontend log shows a bunch of lines like
     'video_output' mean = '22090.37', std. dev. = '7938.94', fps = '45.27'
     'video_output' mean = '22820.35', std. dev. = '8543.71', fps = '43.82'

Interspersed with dozens of messages:
      "NVP: Video is xxx frames ahead of audio."

If I watch the recorded video in mplayer I get the same audio problem and
constant warnings like this:

     Warning! FPS changed 47.952 -> 59.940  (-11.988010) [7]   2%  5.7% 9 0
     A:75362.5 V:75362.4 A-V:  0.021 ct:  0.189 1399/1353 45%  2%  5.6% 9 0
     demux_mpg: 24000/1001fps progressive NTSC content detected, 
switching framerate.
     A:75362.5 V:75362.4 A-V:  0.045 ct:  0.191 1401/1354 44%  2%  5.6% 9 0
     demux_mpg: 30000/1001fps NTSC content detected, switching framerate.
     Warning! FPS changed 47.952 -> 59.940  (-11.988010) [7]   2%  5.6% 9 0
     A:75362.8 V:75362.8 A-V: -0.004 ct:  0.195 1418/1366 44%  2%  5.4% 9 0
     demux_mpg: 24000/1001fps progressive NTSC content detected, 
switching framerate.

This started at the end of January using recent SVN. It's on ABC in Chicago.
The only thing I found on the web is 
http://forum.videohelp.com/topic344584.html ,
which implies ABC did something to new program episodes.  Unfortunately 
my depth of
knowledge on this topic is quite shallow.

My questions:

Has anyone else noticed this?
Is this something that is wrong with the broadcast or should the player 
be able to handle it?

Just curious.  It's been a long time since I've had any non-trivial 
problems in MythTV --
It's been rock solid.

-Bill