[mythtv-users] Mythtv 0.24 Acer Revo ALSA WriteAudio buffer underruns

[pnetherwood at email.com]

Hi

Since upgrading to 0.24 my Acer R3600 Revo's have been stuttering on 
playback. It was all fine 0.23. It noticed in the logs it was 
mentioning failing to do a preview which always seemed to occur at the 
same time as the buffer underruns. Below is a snippet from my log:

2010-12-25 20:10:48.104 AO: Opening audio device 
'hdmi:CARD=NVidia,DEV=0' ch 2(2) sr 48000 sf signed 16 bit reenc 0
2010-12-25 20:10:48.107 AudioPlayer: Enabling Audio
2010-12-25 20:10:49.555 VDPAU: Created 2 output surfaces.
2010-12-25 20:10:49.555 VDPAU: Version 1
2010-12-25 20:10:49.555 VDPAU: Information NVIDIA VDPAU Driver Shared 
Library  256.44  Thu Jul 29 01:59:12 PDT 2010
2010-12-25 20:10:49.555 VDPAU: Created VDPAU render device 1280x720
2010-12-25 20:10:49.737 Player(0): Forcing decode extra audio option on 
(Video method requires it).
2010-12-25 20:10:49.978 Player(0): Video timing method: USleep with 
busy wait
2010-12-25 20:10:49.979 TV: Changing from None to WatchingPreRecorded
2010-12-25 20:10:50.056 VDPAU: Added 2 output surfaces (total 4, max 4)
2010-12-25 20:10:50.183 ALSA, Error: WriteAudio: buffer underrun
2010-12-25 20:36:07.118 ALSA, Error: WriteAudio: buffer underrun
2010-12-25 20:36:07.914 ALSA, Error: WriteAudio: buffer underrun
2010-12-25 20:36:08.517 ALSA, Error: WriteAudio: buffer underrun
2010-12-25 20:36:09.644 PlaybackBox: Ignoring PREVIEW_SUCCESS, item no 
longer on screen.
2010-12-25 20:36:12.526 ALSA, Error: WriteAudio: buffer underrun

Anyone know why its trying to do a preview in the middle of a playback? 
I did notice an old setting in my settings table relating to previews 
called "PlaybackPreview" which I set from 1 to 0 with no effect. 
Probably a relic from 0.21 when previews worked but with no effect.

I also seem to get the problem when it appears to be waiting for video 
buffers:

2010-12-25 21:10:05.245 ALSA, Error: WriteAudio: buffer underrun
2010-12-25 21:10:05.427 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA
2010-12-25 21:10:05.438 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA
2010-12-25 21:10:05.444 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA
2010-12-25 21:10:05.454 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA
2010-12-25 21:10:05.558 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA
2010-12-25 21:10:05.564 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA
2010-12-25 21:10:05.580 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA
2010-12-25 21:10:05.684 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA
2010-12-25 21:10:05.700 Player(0): Waited 100ms for video buffers 
AAAAAAdAAAADLLAAA

Unfortunately -v audio didn't add any extra infor at teh time of the 
buffer underruns.
I'm not sure if these are related or two separate problems. My ALSA 
device is: hdmi:CARD=NVidia,DEV=0. I have also tried using ALSA:default 
and changing the buffer size my .asoundrc file which didn't help much. 
I have also tried increasing by VDPAU buffer size to 32 in the filter 
settings with no effect. I'm using version fixes/0.24 [f3ddc58]. My 
alsa version is 1.0.22.1

Any thoughts?

Paul