[mythtv] Prebuffering pauses with svn 8250 and PVR-250

[Bob Cottingham]

All of the prebuffering pause tickets seem to involve either DVB or
PVR-350 tv-out, however I am still seeing frequent issues with my
PVR-250. I left LiveTV on last night to see how it would do and when I
woke up it was still working. Great, however, when I checked the logs
it contained a nearly endless stream of prebuffering pause messages
for the previous shows.  Shows either played fine or didn't play at
all. For example, I got prebuffering pauses from 3 to 3:30, then it
appears to have played fine until 5am, then continuous prebuffering
pauses until 7am (it was a 2 hr long show), then it was fine again. 
There were also mpeg2 errors, however they don't always correlate to
prebuffer pauses.  Here are some snippets from the logs:

2005-12-13 00:52:43.153 Video timing method: SGI OpenGL
[mpeg2video @ 0xb75ec2f0]invalid cbp at 37 0
[mpeg2video @ 0xb75ec2f0]Warning MVs not available
[mpeg2video @ 0xb75ec2f0]skipped MB in I frame at 24 1
[mpeg2video @ 0xb75ec2f0]Warning MVs not available
[mpeg2video @ 0xb75ec2f0]invalid cbp at 1 21
[mpeg2video @ 0xb75ec2f0]Warning MVs not available
[mpeg2video @ 0xb75ec2f0]skipped MB in I frame at 22 0
2005-12-13 03:00:06.605 Invalid file handle when opening
/var/mythtv/tv/1043_20051213030001.mpg.  4 retries remaining.
[mpeg2video @ 0xb75ec2f0]invalid mb type in I Frame at 12 10
[mpeg2video @ 0xb75ec2f0]skipped MB in I frame at 27 0
2005-12-13 03:00:10.614 NVP: prebuffering pause
2005-12-13 03:00:12.098 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:13.600 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:14.167
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 4 seconds for
data to become available, waiting again...
2005-12-13 03:00:15.102 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:16.602 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:18.104 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:18.168
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 4 seconds for
data to become available, waiting again...
2005-12-13 03:00:19.606 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:21.107 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:22.169
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 4 seconds for
data to become available, waiting again...
2005-12-13 03:00:22.609 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:24.110 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:25.611 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:26.170
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 4 seconds for
data to become available, waiting again...
2005-12-13 03:00:27.113 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:28.615 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:30.115 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:30.171
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 4 seconds for
data to become available, waiting again...
2005-12-13 03:00:31.617 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:33.119 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:34.172
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 4 seconds for
data to become available, waiting again...
2005-12-13 03:00:34.620 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:36.122 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:37.623 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:38.173
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 4 seconds for
data to become available, waiting again...
2005-12-13 03:00:39.124 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:40.626 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:42.128 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:42.175
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 4 seconds for
data to become available, waiting again...
2005-12-13 03:00:42.175
RingBuf(/var/mythtv/tv/1043_20051213030001.mpg): Waited 14 seconds for
data to become available, aborting
2005-12-13 03:00:43.639 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:00:45.132 NVP: Prebuffer wait timed out 10 times.

(repeats until 03:30)

2005-12-13 03:30:03.718 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:30:05.205 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:30:06.429 Invalid file handle when opening
/var/mythtv/tv/1043_20051213033003.mpg.  4 retries remaining.
2005-12-13 03:30:06.707 NVP: Prebuffer wait timed out 10 times.
2005-12-13 03:30:06.930 Invalid file handle when opening
/var/mythtv/tv/1043_20051213033003.mpg.  3 retries remaining.
2005-12-13 03:30:07.432 Invalid file handle when opening
/var/mythtv/tv/1043_20051213033003.mpg.  2 retries remaining.
2005-12-13 03:30:07.938 Invalid file handle when opening
/var/mythtv/tv/1043_20051213033003.mpg.  1 retries remaining.
2005-12-13 03:30:08.209 NVP: Prebuffer wait timed out 10 times.
[mpeg2video @ 0xb75ec2f0]ac-tex damaged at 30 25
[mpeg2video @ 0xb75ec2f0]invalid mb type in I Frame at 36 0
2005-12-13 05:00:05.188 Invalid file handle when opening
/var/mythtv/tv/1043_20051213050000.mpg.  4 retries remaining.
2005-12-13 05:00:05.726 Invalid file handle when opening
/var/mythtv/tv/1043_20051213050000.mpg.  3 retries remaining.
2005-12-13 05:00:05.901 NVP: prebuffering pause
[mpeg2video @ 0xb75ec2f0]ac-tex damaged at 1 1
2005-12-13 05:00:06.489 NVP: prebuffering pause
2005-12-13 05:00:07.969 NVP: Prebuffer wait timed out 10 times.
2005-12-13 05:00:09.471 NVP: Prebuffer wait timed out 10 times.

(repeats until 07:00 when it the next program comes on)

I was able to rewind to before 07:00 and it played fine, however.
In the mythbackend log, the only thing I noticed was a few of these lines:

Preview Error: Previewer file '/var/mythtv/tv/1043_20051213040000.mpg'
is not valid.

They occurred at 1:30, 3:30, 4:00 and 7:00. Only one correspond to a
file that mythfrontend had prebuffer pauses with.

I would greatly appreciate any help with this.  Should I create a
ticket or get backtraces?

Thanks,
Bob C