[mythtv] 'WriteAudio: buffer underrun' during playback caused bythe scheduler

Tom Lichti tom at redpepperracing.com
Thu Sep 14 14:59:24 UTC 2006

William Prochazka wrote:
> So I am reading this thread I found through Google that sounds just 
> like my issue, come to find out it is an active thread and I just had 
> not check the Dev grou pin a few days ;).  Ok, so I have a P4 3.0HT w/ 
> 1GB of ram and an NVidia FX5200.  I( am trying to output the HD using 
> DVI and the audio passthrough to my receiver.  Like Jan, I am getting 
> no great results.  I have tried using XvMC, but I see a 87-90% CPU 
> usage yet the audio and video are very skippy.  The receiver detects 
> the audio as 3/2 which is fine.  As far as skipping, though, I hear .5 
> sec of audio and the .5 of silence and the video is skipping in-time.  
> Without XvMC, I am getting 99% CPU utilization but only occasional 
> skipping (ie, when there is lots of motion).  Of course if I dare to 
> add in any type of deintelace it gets worse.  I have tried disabling 
> HT thinking it might be a CPU task switching issue (plus HT doesn't 
> really DO that much), real-time priority, and any other tweak I can 
> think of.
If you have 'OpenGL Vsync' enabled in the playback settings, try 
disabling it and see what happens.


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