Question for mpark:
Worked late last night, so I recorded the NASCAR race from 12-1 on my Comcast HD PVR. The pre-race show began in upconverted 16:9, but the audio was WAY out of synch. My receiver reported it as Dolby Pro as opposed to Digital 5.1, and the sound preceded the picture by a good five seconds.
Before the race began, the video format switched to 4:3 (which looked sharper unstretched, especially the text in graphics) and the audio was back in synch.
I haven't watched a lot of the race yet, but I was wondering if you could explain what happened. My guess was that either the 16:9 upconvert had no sound and the audio from the alternate feed didn't match, or that the 16:9 feed had a sever lip-synch problem that forced a switch to the 4:3 signal.
Water over the dam, but I was curious.