[mythtv-users] Playback causes recording stream corruption

[Ben Rigby]

Hi,

I've recently upgraded to 0.19 (via atrpms) on my FC3 myth box and run
into a problem. The problem might not be new, or necessarily causes by
0.19 but it does seem to be exacerbated by it.

My problem is that watching a recording (or Live TV) seems to cause
some sort of corruption in any recordings being made. When the myth
box is not in use for playback, and recordings are near perfect (very
occasional video or audio artifacts). When a recording is made while
I'm watching it or something else previously recorded, then there are
significant artifacts. Often the recording is completely unwatchable
for sections lasting up to 3 minutes. The corruption definitely seems
to be occuring on the recording side of things, not the playback side
of things beacuse I can go back later and play it again and the same
corruption will occur.

The box is an Athlon 64 3000+ with 512 MB RAM in a shuttle case with
an Nforce3-250 based MB. CPU usage stays around 20% when recording and
playing back at once. Recordings are SDTV via a DVICO FusionHDTV DVB-T
Lite. Playback is via a geforce 5200 using s-video out.

I ran the mythbackend with -v record and have attached the log file.
At the start of the file you can see the output I get when trying to
record while playing back a file (in this case it was Live TV so I was
playing back the same time). These messages continue for as long as I
record. Here's a snippet of what I get:

2006-03-28 17:23:31.095 DVBRec(0): Packet dropped due to uncorrectable error.
2006-03-28 17:23:31.095 DVBRec(0): Packet dropped due to uncorrectable error.
2006-03-28 17:23:31.095 DVBRec(0): Packet dropped due to uncorrectable error.
2006-03-28 17:23:31.095 DVBRec(0): PID 0x200 discontinuity detected
2006-03-28 17:23:31.095 DVBRec(0): PID 0x28b discontinuity detected
2006-03-28 17:23:31.111 DVBRec(0): PID 0x28a discontinuity detected
2006-03-28 17:23:31.112 DVBRec(0): Packet dropped due to uncorrectable error.
2006-03-28 17:23:31.112 DVBRec(0): Packet dropped due to uncorrectable error.
2006-03-28 17:23:31.112 DVBRec(0): Packet dropped due to uncorrectable error.
2006-03-28 17:23:31.112 DVBRec(0): Packet dropped due to uncorrectable error.
2006-03-28 17:23:31.112 DVBRec(0): PID 0x200 discontinuity detected
2006-03-28 17:23:31.112 DVBRec(0): PID 0x28a discontinuity detected

At the bottom of the log is the output from a recording while I'm not
watching anything. The recording starts at 8pm and finishes at 8:45pm
in the log. There are 0 of these messages above and the recording is
pretty much perfect.

Has anyone seen this before? Can anyone tell me what might be causing
this? I'm not sure what other information to provide, but will do my
best to provide anything that might help.

Thanks,

Ben
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