[mythtv] Jittery sound - ALSA / AC97

Brett Buckingham mythtv-dev@snowman.net
Fri, 27 Dec 2002 08:32:40 -0500


>Try lowering the volume on the PCM.  On my SBLive, if I have PCM all the
>way up I get ticking, and chirping noises.  Lowering it to 75-85 helped.

Thanks for the suggestion, but I tried that, and all sorts of other fiddling 
with the mixer, to no avail.  The sound clipping sounded to me like ALSA was 
repeatedly overrunning a buffer, resulting in intermittent clipped sound.

Occasionally (only somewhat repeatably), I'd get a repeating message to stderr 
saying "ran out of free AUDIO buffers :-(".  I tried to play with the buffer 
size setting (and the full duplex setting) in the KDE control center, but 
that completely toasted MythTV.  Even after restoring all of the KDE settings 
to their defaults and rebooting (!) MythTV was hosed (hung, no error to 
stderr).

In frustration, I went out to a boxing day sale and picked up a Soundblaster 
Live!.

Finally, after about 4 full days struggling trying to get MythTV to work, it 
finally works!!  Awesome system, guys.

[I tried for 2 days patching / recompiling XFree86, only to discover that my 
ATI AIW Radeon wasn't fully v4l compliant, and wouldn't work with MythTV.  I 
bought an ATI TV Wonder, which solved the video problem, then, after 2 more 
days of futzing with the on-board sound, I bought the Soundblaster Live! to 
solve the audio problem.  Only cost me a couple of hundred bucks to get a 
PVR!  Wait - maybe I could have just bought a TiVo...  Oh well.]

I'd be happy to update the FAQ with this info.  Is there a FAQ maintainer, or 
should I just submit this to CVS?

Brett