[AG-TECH] System freezes sending video on Linux w/ IVC-200 capture card

[Andrew Ford]

Hi,

For a while now we've been seeing hard freezes (ie, trying to kill the X
server does nothing) on one of our Linux machines when it tries to send
video via an IVC-200 cap card. It tends to occur more frequently when the
load is heavier - attempting to send 2 or more 720x480 mpeg4 or h.264
streams causes it to freeze within 5-10 minutes, 4 h.261 videos make it
freeze in about half an hour, and 2 261 videos makes it last about 2 days.
dmesg and /var/log/messages don't give any clues. Other types of load don't
seem to cause freezes, and I ran memtest86 overnight with no errors.
Originally the machine was Ubuntu 8.04 64-bit, then 8.10 64-bit, then 8.10
32-bit, and the problem was seen in all 3. In all cases it was running the
UQ-provided AG 3.2beta with the stock VideoProducer services. I know there
was a bttv driver deadlock issue in kernels pre-2.6.24, but this is running
kernel 2.6.27 so that shouldn't be the problem.

Also when sending video on that machine occasionally the stream would start
to flicker, flashing an old frame alternating with the current output of the
camera. Has anyone seen either of these issues before?

Thanks,
--Andrew
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