[mythtv] Horrible screetching sound in live tv audio

[Jason Tackaberry]

I've mentioned this in an earlier email and on IRC, but I've done some
more investigating and have new information.

Details on my system is here:
   http://lists.snowman.net/pipermail/mythtv-dev/2003-April/008653.html
	
Fairly regularly (but not consistently every time), when going into
watch live tv, after a few seconds of stuttering video and out-of-sync
audio, I will hear a horribly loud screetching sound from my sound
card.  Invariably if I hit escape, and go back into watch tv, it works
fine.  Playback of previously recorded video has so far always worked
fine.  When this happens, I will see on the frontend console "Audio
buffer overflow, audio data lost!"

I have tried 3 different sound cards (Sound Blaster Live! (emu10k1),
Creative Ensoniq (es1371), and on-board audio on my motherboard
(via82xx)).  I have tried drivers for both ALSA and OSS.  In all six
cases, the I have the same problem.

I have tried having putting the line-in on one sound card, and playing
back through another sound card (i.e. not use full-duplex).  Same
problem.

I have tried both Red Hat Linux 9's kernel (2.4.20-8 and 2.4.20-9) as
well as my own compiled kernel with HZ=1024 with the preempt patch. 
Same problem with both kernels.

I have recorded a sample of what I'm hearing for your listening
pleasure.  WARNING: TURN YOUR VOLUME DOWN!  It gets very loud very
suddenly. :)
	http://sault.org/~tack/screetch.ogg
 
I previously reported that MythTV 0.8 didn't have this problem, but I
was wrong.  I reverted again and was able to reproduce it.

I welcome any suggestions.  I'm happy to provide more info or try some
other things.

Cheers,
Jason.

-- 
Jason Tackaberry  ::  tack at auc.ca  :: 705-949-2301 x330 
Academic Computing Support Specialist
Information Technology Services
Algoma University College  ::  www.auc.ca