[mythtv] waiting for prebuffer...

Fri Sep 24 21:13:50 EDT 2004

Hi Doug,

I mentioned a while back that I occationally get short pauses while 
watching a show.  You asked for the output from mythfrontend, and I 
finally took the time to record it.  Here is a sample:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2004-09-24 19:04:38 Changing from None to WatchingPreRecorded
2004-09-24 19:04:38 Using realtime prio2r004i-0t9y-.2
4 19:04:38 Not in the running state, state=2
2004-09-24 19:04:38 Not in the running state, state=2
2004-09-24 19:04:38 Not in the running state, state=2
2004-09-24 19:04:38 Not in the running state, state=2
2004-09-24 19:04:38 Not in the running state, state=2
2004-09-24 19:04:38 Using deinterlace method bobdeint
2004-09-24 19:04:38 nVidiaVideoSync: VBlank ioctl did not work, 
unimplemented in this driver?
2004-09-24 19:04:39 DRMVideoSync: Could not open device /dev/dri/card0, 
No such device or address
2004-09-24 19:04:39 Using audio as timebase
2004-09-24 19:04:39 Video timing method: SGI OpenGL
2004-09-24 19:04:39 Refresh rate: 16683, frame interval: 33366
2004-09-24 19:04:39 waiting for prebuffer...
2004-09-24 19:04:39 prebuffer wait timed out..
2004-09-24 19:04:39 waiting for prebuffer...
2004-09-24 19:04:39 A/V diverged by 5.54457 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 9.73296 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 12.6869 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 14.6627 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 15.9271 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 16.4784 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 16.712 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 16.6699 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 16.3986 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:39 A/V diverged by 15.9704 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 15.4244 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 14.7751 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 13.8986 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 13.0239 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 12.1356 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 11.2296 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 10.3328 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 9.41296 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 8.51328 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 7.59126 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 6.51762 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 5.48013 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 4.47722 frames, extending frame to 
keep audio in sync
2004-09-24 19:04:40 A/V diverged by 3.49278 frames, extending frame to 
keep audio in sync
'video_output' mean = '41240.26', std. dev. = '14537.52', fps = '24.25'
avsync_delay: -40, avsync_avg: -36, warpfactor: 0.9, warpfactor_avg: 
0.00504102
'video_output' mean = '33262.04', std. dev. = '569.34', fps = '30.06'
avsync_delay: -32, avsync_avg: -26, warpfactor: 0.9, warpfactor_avg: 
0.0100043
'video_output' mean = '33263.05', std. dev. = '402.12', fps = '30.06'
avsync_delay: -22, avsync_avg: -17, warpfactor: 0.9, warpfactor_avg: 
0.0149401
'video_output' mean = '33248.74', std. dev. = '676.80', fps = '30.08'
avsync_delay: -14, avsync_avg: -8, warpfactor: 0.9, warpfactor_avg: 
0.0198485
'video_output' mean = '33270.36', std. dev. = '511.66', fps = '30.06'
avsync_delay: -5, avsync_avg: 3, warpfactor: 0.9, warpfactor_avg: 0.0247296
'video_output' mean = '33253.96', std. dev. = '394.78', fps = '30.07'
avsync_delay: 25, avsync_avg: 17, warpfactor: 0.9, warpfactor_avg: 0.0295837
'video_output' mean = '33262.15', std. dev. = '482.17', fps = '30.06'
avsync_delay: 32, avsync_avg: 26, warpfactor: 0.9, warpfactor_avg: 0.0344109
'video_output' mean = '33263.53', std. dev. = '584.49', fps = '30.06'
avsync_delay: 44, avsync_avg: 36, warpfactor: 0.9, warpfactor_avg: 0.0392113
2004-09-24 19:05:09 A/V diverged by 3.12962 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:09 prebuffering pause
2004-09-24 19:05:09 waiting for prebuffer...
2004-09-24 19:05:09 prebuffer wait timed out..
2004-09-24 19:05:09 waiting for prebuffer...
2004-09-24 19:05:09 prebuffer wait timed out..
2004-09-24 19:05:09 waiting for prebuffer...
2004-09-24 19:05:09 prebuffer wait timed out..
2004-09-24 19:05:09 waiting for prebuffer...
2004-09-24 19:05:09 prebuffer wait timed out..
2004-09-24 19:05:09 waiting for prebuffer...
2004-09-24 19:05:10 A/V diverged by 3.87571 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:10 A/V diverged by 4.1955 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:10 A/V diverged by 4.17311 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:10 A/V diverged by 3.9765 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:10 A/V diverged by 3.58179 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:10 A/V diverged by 3.06096 frames, extending frame to 
keep audio in sync
'video_output' mean = '43265.78', std. dev. = '73894.34', fps = '23.11'
avsync_delay: -40, avsync_avg: -35, warpfactor: 0.9, warpfactor_avg: 
0.0439851
2004-09-24 19:05:13 prebuffering pause
2004-09-24 19:05:13 waiting for prebuffer...
2004-09-24 19:05:13 prebuffer wait timed out..
2004-09-24 19:05:13 waiting for prebuffer...
2004-09-24 19:05:14 prebuffer wait timed out..
2004-09-24 19:05:14 A/V diverged by 3.21606 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:14 A/V diverged by 3.64083 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:14 A/V diverged by 3.73464 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:14 A/V diverged by 3.56522 frames, extending frame to 
keep audio in sync
2004-09-24 19:05:14 A/V diverged by 3.16091 frames, extending frame to 
keep audio in sync
'video_output' mean = '38421.93', std. dev. = '31166.80', fps = '26.03'
avsync_delay: -4, avsync_avg: -7, warpfactor: 0.9, warpfactor_avg: 0.0487324
'video_output' mean = '33402.87', std. dev. = '1466.76', fps = '29.94'
avsync_delay: -16, avsync_avg: -13, warpfactor: 0.9, warpfactor_avg: 
0.0534534
'video_output' mean = '33259.18', std. dev. = '425.19', fps = '30.07'
avsync_delay: -12, avsync_avg: -6, warpfactor: 0.9, warpfactor_avg: 
0.0581482
'video_output' mean = '33262.11', std. dev. = '418.99', fps = '30.06'
avsync_delay: 0, avsync_avg: 5, warpfactor: 0.9, warpfactor_avg: 0.062817
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The pauses happen when the log says "prebuffering pause"/"prebuffer wait 
timed out..".

I have seperate backend/frontend machines connected via gigabit 
ethernet.  The backend machine's load is usually arround 0.3 if I am 
watching and recording at the same time.

Does "prebuffering pause" indicate that the backend is not sending data 
to the frontend quick enough?

Thanks,

John