[mythtv-users] Playback problem -- random short pauses

[Kenneth Emerson]

I am replying back to my original post.  I have been trying to watch
carefully when these pauses occur and, while it isn't 100%, the pauses seem
to correspond to problems with the audio and occasionally with video.  In
addition, the problems with the audio also seem to correspond to recordings
and/or commflag jobs starting/stopping (of which the devs seem to be aware).
 I see one of the two following errors in the frontend log when the pause
occurs:

2011-04-11 22:01:20.870 Player(c): Waited 100ms for video buffers
AAAAAAAAAAAAAAAAA

and

2011-04-11 21:59:47.729 ALSA, Error: WriteAudio: buffer underrun

The buffer underrun is more prevalent on my system.  I do not know if these
errors are causing the pause to occur or are just a side effect (as
originally posted, I have seen pauses with no error messages in the frontend
log).  My system is a combined FE/BE quad-core system with 4GB RAM.  The OS
is a RAID1 (md) on one partition on each of four drives (1TB each). My
recordings are on a different partition on the same four drives configured
as RAID5.  My database is on its on separate drive.  I limit the number of
simultaneous MythTV jobs to two.  The majority of my recordings are MPEG2
with, maybe, 20% coming from my HD-PVR (H.264) which seems to require much
more time to commflag than the MPEG2 files.  Below is a typical log from my
frontend when playing a recording (removed mythweather cruft):

2011-04-11 21:40:06.059 TV: Attempting to change from None to
WatchingPreRecorded
2011-04-11 21:40:07.013 AFD Warning: ScanATSCCaptionStreams() called with no
PMT
2011-04-11 21:40:07.013 AFD: Opened codec 0x9b52a140, id(MPEG2VIDEO)
type(Video)
2011-04-11 21:40:07.013 AFD: codec MP2 has 2 channels
2011-04-11 21:40:07.013 AFD: Opened codec 0xac37f800, id(MP2) type(Audio)
2011-04-11 21:40:07.123 AO: Opening audio device
'iec958:CARD=External,DEV=0' ch 6(2) sr 48000 sf signed 16 bit reenc 0
2011-04-11 21:40:07.133 AudioPlayer: Enabling Audio
2011-04-11 21:40:07.169 Clearing OpenGL painter cache.
2011-04-11 21:40:07.236 VDPAU: Created 2 output surfaces.
2011-04-11 21:40:07.236 VDPAU: Created VDPAU render device 1920x1080
2011-04-11 21:40:07.264 Player(c): Forcing decode extra audio option on
(Video method requires it).
2011-04-11 21:40:07.298 [mpegvideo_vdpau @ 0x1c3eb40]warning: first frame is
no keyframe
2011-04-11 21:40:07.300 [mpegvideo_vdpau @ 0x1c3eb40]warning: first frame is
no keyframe
2011-04-11 21:40:07.332 Player(c): Video timing method: USleep with busy
wait
2011-04-11 21:40:07.332 TV: Changing from None to WatchingPreRecorded
2011-04-11 21:40:07.356 ScreenSaverX11Private: DPMS Deactivated 1
2011-04-11 21:40:07.356 Player(c): Failed to enable deinterlacing
2011-04-11 21:40:07.358 VDPAU: Added 2 output surfaces (total 4, max 4)
2011-04-11 21:40:20.648 AFD Warning: ScanATSCCaptionStreams() called with no
PMT
2011-04-11 21:44:28.923 PlaybackBox: Ignoring PREVIEW_SUCCESS, item no
longer on screen.
2011-04-11 21:45:03.839 PlaybackBox: Ignoring PREVIEW_SUCCESS, item no
longer on screen.
2011-04-11 21:48:08.822 [mpegvideo_vdpau @ 0x1c3eb40]warning: first frame is
no keyframe
2011-04-11 21:52:23.436 [mpegvideo_vdpau @ 0x1c3eb40]warning: first frame is
no keyframe
2011-04-11 21:52:23.438 [mpegvideo_vdpau @ 0x1c3eb40]warning: first frame is
no keyframe
2011-04-11 21:59:14.835 TV: ASK_RECORDING 8 29 0 0 hasrec: 0 haslater: 0
2011-04-11 21:59:47.425 PlaybackBox: Ignoring PREVIEW_SUCCESS, item no
longer on screen.
2011-04-11 21:59:47.729 ALSA, Error: WriteAudio: buffer underrun
 <<<<<<<<<<<<<<<<<< pause occurred here
2011-04-11 22:00:52.083 [mpegvideo_vdpau @ 0x1c3eb40]warning: first frame is
no keyframe
2011-04-11 22:01:02.602 [mpegvideo_vdpau @ 0x1c3eb40]warning: first frame is
no keyframe
2011-04-11 22:01:04.012 [mp2 @ 0x1c3eb40]incomplete frame
2011-04-11 22:01:04.012 AFD Error: Unknown audio decoding error
2011-04-11 22:01:04.198 Marking recording as watched using offset 4 minutes
2011-04-11 22:01:04.198 TV: Attempting to change from WatchingPreRecorded to
None
2011-04-11 22:01:04.205 VDPAU Painter: Clearing VDPAU painter cache.
2011-04-11 22:01:04.223 Trying 1920x1080 0.000 Hz
2011-04-11 22:01:04.224 SwitchToGUI: Switched to 1920x1080 0.000 Hz
2011-04-11 22:01:04.279 TV: Changing from WatchingPreRecorded to None
2011-04-11 22:01:04.280 ScreenSaverX11Private: DPMS Reactivated 1
2011-04-11 22:01:04.286 TV: Attempting to change from None to None

-- Ken E.
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