Preston Crow wrote:
On Tue, 2005-11-08 at 17:14 +1000, ffrr wrote:
I chased video glitches from my DVB setup for ages, and with a lot of
help from the list, I finally nailed it. It was the Si 3112 SATA
controller chip doing nasties on the PCI bus and corrupting the mpeg
stream from the DVB card.
This would correlate with your observation that it is worse with system
load, in particular disk access.
I have two hard drives. If I simply cat /dev/dvb/adapter0/dvr0 to a
file on the SATA drive, I get some glitches. If I do the same to a file
on the PATA drive, I get tons of glitches. If I do it to a ram disk, I
get a perfect recording.
But is your linux system running from the SATA drive? If so, it is
still being used - maybe by all sorts of background processes at the
same time. Booting from SATA drives, and putting the DVB data on an IDE
drive did not cure the glitches for me. Your ram disk experience is
interesting, but I think it may have worked because it was so very fast.
So it doesn't look like it's the SATA chipset doing something nasty. In
fact, the SATA drive, being on a faster bus, gives me a better recording
than the PATA drive. This makes it look more like my original theory of
being an issue that can be solved in the DVB driver. Of course, it
could be the SATA chipset or anything else on the PCI bus, but if
something were corrupting the DVB traffic, wouldn't it also corrupt
other traffic, like disk I/O?
As per my other message (just sent) it did indeed cause disk problems
initially. That chipset is just rubbish! It sounds like your BIOS
already copes with the timing problem, as my BIOS update did, but with
the same unfortunate result for the DVB data stream.
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