[mythtv] Could not find codec paramters, a few more tidbits

[thor]

To anyone else who is trying to work their way through this:

	av_find_stream_info does go through it's for(;;) loop a few times, but 
eventually dies on:

		if (is->iformat->read_packet(ic, pkt) < 0)

	... so ... read_packet() is returning something less than 0. 

	Also, this is clearly a PVR-x50 problem. I have one myth box with a PVR-250 
and a bttv (defined in that order). If I manage to get the 250 tied up with a 
recording job, I can go in and out of Live on the bttv with absolutely no 
problem.

	This leads me to suspect that something about fairly recent (last 72 hours?) 
versions of ivtv are interacting with fairly recent versions of libmythtv 
(last 72 hours?) in a way that generates av streams that libavcodec pukes on. 

	Anyone have confirming or dissenting evidence?

- thor