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

Christoph Willing c.willing at uq.edu.au
Thu Mar 26 01:58:07 CDT 2009

On 26/03/2009, at 3:34 AM, Andrew Ford wrote:

> 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?


I just installed a 32bit Ubuntu 8.10 on the UQVislab node's video  
capture machine. I've been running 2x mpeg4 streams and an h261 stream  
for over two hours. I just powered the machine down to confirm it is  
actually an IVC-200G card (it is). After the restart, I've now  
configured it to run with 3x mpeg4 streams. These are full PAL streams  
704x576. Its been running for nearly 10 minutes now - will leave it  
running overnight (in the APAG lobby, if you want to check on them)  
and report back. Based on the previous successful 2 hour test, I think  
this 3 large streams test will be OK too.

You could try reseating the card - maybe some dust or contact  
oxidation is creating some bad effect? Do you have any similar capture  
cards lying around you could temporarily replace the IVC with? That  
may indicate whether you have a card fault or machine/OS fault.


Christoph Willing                       +61 7 3365 8316
QCIF Access Grid Manager
University of Queensland

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