[mythtv-users] Stuttering in DVD menus

[Richard]

Hi,

Most of the DVDs I've tried recently suffer from stuttering audio/video 
in the menus.  It only seems to affect animated menus and only when 
VDPAU is used for playback.  OpenGL works fine but that gives me other 
issues watching recordings so I'd rather not use OpenGL.

I've tried ripping a DVD to ISO and playing it back from the local hard 
drive to make sure it wasn't some sort of issue with the DVD itself but 
it doesn't help.

Starting mythfrontend with -v audio,playback gives lots of errors:

2012-09-19 21:29:38.611274 I  AO: enc(0), passthru(0), features (LPCM) 
configured_channels(2), 2 channels supported(1) max_channels(2)
2012-09-19 21:29:38.611282 I  AO: Audio processing enabled
2012-09-19 21:29:38.611294 I  AO: Opening audio device 
'plughw:CARD=PCH,DEV=0' ch 2(2) sr 48000 sf signed 32 bit reenc 0
2012-09-19 21:29:38.611300 I  ALSA: OpenDevice plughw:CARD=PCH,DEV=0
2012-09-19 21:29:38.611507 I  ALSA: SetParameters(format=10, channels=2, 
rate=48000, buffer_time=500000, period_time=4)
2012-09-19 21:29:38.611753 I  ALSA: Buffer size range from 32 to 8192
2012-09-19 21:29:38.611760 I  ALSA: Period size range from 16 to 4096
2012-09-19 21:29:38.611796 I  ALSA: Buffer time = 170666 us
2012-09-19 21:29:38.611850 I  ALSA: Period time = 4 periods
2012-09-19 21:29:38.611996 I  ALSA: Buffer size = 8192 | Period size = 2048
2012-09-19 21:29:38.612032 I  AO: Audio fragment size: 8192
2012-09-19 21:29:38.612037 I  AO: Software volume enabled
2012-09-19 21:29:38.645069 I  AO: Audio Stretch Factor: 1
2012-09-19 21:29:38.645109 I  AO: Ending Reconfigure()
2012-09-19 21:29:38.645196 I  AO: kickoffOutputAudioLoop: pid = 5820
2012-09-19 21:29:38.645215 I  AO: OutputAudioLoop: Play Event
2012-09-19 21:29:38.784646 I  AFD: Key frame distance changed from 15 to 11.
2012-09-19 21:29:38.875333 I  Player(0): Video is 4.82812 frames ahead 
of audio,
                         doubling video frame interval to slow down.
2012-09-19 21:29:38.995329 I  Player(0): Video is 6.19607 frames ahead 
of audio,
                         doubling video frame interval to slow down.
2012-09-19 21:29:39.057410 I  ALSA: WriteAudio: buffer underrun
2012-09-19 21:29:39.115321 I  Player(0): Video is 6.72205 frames ahead 
of audio,
                         doubling video frame interval to slow down.
2012-09-19 21:29:39.235328 I  Player(0): Video is 6.62278 frames ahead 
of audio,
                         doubling video frame interval to slow down.



I don't get stuttering playing back recordings (whether HD or SD) nor in 
the actual film itself - only in animated DVD menus.

Does anyone have any ideas what the root cause of the problem could be?

To my untrained eye, it doesn't seem to be a video decoding problem as 
the video is waiting for the audio to catch up.  Obviously Myth has to 
sync video to audio but why should VDPAU cause sync problems only in 
animated DVD menus?

As always, I'd be very grateful for any hints or ideas.

Richard.