[mythtv-users] Audio Buffer Underruns with XvMC and HD in 0.20

Christopher Rodd christopher.rodd at gmail.com
Sat Sep 16 18:19:05 UTC 2006

I get the following output when I try to watch HD recordings or live HDTV:

>XvMC: picture structure FRAME
>2006-09-16 13:15:55.520 Connected to database 'mythconverg' at host:
>2006-09-16 13:15:55.625 Video timing method: USleep with busy wait
>2006-09-16 13:15:55.643 VideoOutputXv Error: ProcessFrameXvMC: Failed to
get OSD lock
>2006-09-16 13:15: 55.643 VideoOutputXv Error: ProcessFrameXvMC: Failed to
get OSD lock
>2006-09-16 13:16:03.954 WriteAudio: buffer underrun
>2006-09-16 13:16:03.997 WriteAudio: buffer underrun
>and a lot more buffer underrun errors.
>I tried to see if I could modify the source to increase the amount of
"extra audio buffering" but I couldn't find where to >change that.

>Thanks to anyone who can help me.

Hi Randall,

I'm getting the same thing since 0.20 as you.  I was running svn from a week
or so before 0.20 came out without any real problems.  Then on upgrade to
0.20 final all my NEW recordings from WB/CW/whatever it's called now produce
these WriteAudio warnings but, curiously, HD recordings from the major
broadcast networks (Fox/ABC/NBC/CBS) don't.  Recordings made previous to
0.20 final play back without any real issue (any channel).  My setup is a
little different than yours:

Athlon XP 3000
1Gb ram
GeForce 6600
Nvidia 1.0.8774 drivers.

(i've compiled 0.20 release.  no RPMs here)

I'm using XvMC with OpenGL Vsync and CPU usage is generally in the 60-90%
range when viewing HD material (this is normal for me).   There doesn't seem
to be any CPU spike when I get the WriteAudio underruns.  And I also have
the Extra Audio buffering enables.  No deinterlace either.

I'd be happy to provide any debug output that is necessary to diagnose the

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