On Tue, May 21, 2002 at 04:03:00PM +0200, Justin Schoeman wrote:
> Kevin Liao wrote:
> > Hi,
> >
> > I am using a video capture card with four BT878A and one INTEL PCI bridge on
> > it. Each video input channel is connected to one BT878A respectively. I am
> > trying to capture video data from all four channels and compress them to
> > JPEG files at the same time. But sometimes I will get some annoying line
> > noise (as indicated by red circle in the attached file). Does anyone know
> > it's hardware's or software's issue? Is there anyway to avoid this? Thanks!
> >
>
> This is a PCI problem. The Bt878's are not getting PCI bus access
> quickly enough, and are dropping data. You can try playing with the PCI
> bus latency settings in the bios, or through the module options of later
> versions of bttv.
Well, but with the option of the module you are only setting the latency of
the Bt878 (right?). If so and you have a IDE oder network card with high
latency settings you have still a problem!
I have the same problem (but much heavier!) with a bt848a (card=39). I can
only run at 384x288. With higher settings (e.g. 640x480) I have many
white horizontal lines (as above) and after some minutes the computer
gets crazy (gcc do not work, complety hang and so on).
I have played with setpci (setpci -v -d *:* latency_timer=1)
(I tried all values 0,1,8,30,64,255 and more ...)
changed my cards in the slots (and was able to get the interrupt 5 for
the 848 only! :-) but all that did not help.
Any idea what I can do to improve it?
replace the grabber card (maybe it is damaged?)
change the board? (currently: Athlon 800, VIA VT8363/8365 [KT133/KM133], 2000)
change the grabber chip? (does a 878 work better as a 848?)
change the VGA card? (the nVidia GeForce2 MX works better as a Riva 128)
change what else (i tried USB webcams, but the results are much worse)?
kernel: 2.4.17xfs and bttv-0.7.92
btw. I have the same problems if I run windows. So I guess
it is hardware related (not solveable by software).
After some days of fiddling I am out of ideas, hope you can get me some hints.
Matthias
