I would like to use the ASUS Pundit-R or the Pundit P1-PH1 to build a
portable multi-camera DVR. I know there are some relatively inexpensive
COTS products, but there are some additional functions I would like to
be able to perform with this DVR that are not available on the low-end
units.
Question: Does anyone know of any conflicts with the Pundit and video
capture cards?
Also you if you have any experience or opinions on the Pundit, please
share.
Thanks.
I think my first questions would have more to do with your
operational experience with the video capture card. Have
you ever tested the video capture card with some number
of cameras, on some other motherboard ? Did you run into
issues ? Why would choosing just about the smallest
motherboard you could find, in the form of the Pundit,
help with these issues ?
I've seen a couple of quad input camera cards. One had a
single BT848/BT878, and functioned as a multiplexer. In
other words, you could never "look" at more than one
camera at a time. Such a camera card is suitable for
a security system, where samples are taken from the
cameras, in sequential turn. It can never use more than
about ~20+MB/sec of PCI bus bandwidth.
There is a second card I saw, which had four BT848/BT878
type chips on it, and a PCI-PCI bridge (a HINT chip).
That kind of card can simultaneously record from four
cameras. A posting I found in Google, estimated the
bandwidth usage of that type of card (PAL, ful res, four
cameras), as 85MB/sec. With a little arbitration
overhead (the four chips taking turns bashing on the
HINT chip), that is getting close to the limits of the
PCI bus.
Now we are at the level of saying, whether your project
would work or not, might depend on where you planned on
"sinking" the data. Even on a chipset where the
Northbridge to Southbridge bandwidth was 266MB/sec,
where you moved the 85MB/sec of data after you are
done with it, is a pretty important design decision
on your part.
The Pundits have pretty ordinary desktop chipsets on
them, and high bandwidth PCI bus usage is not something
that your typical review site would test or address. In
fact, most reviews would probably not even bother to
plug a PCI card into the system. The Pundit-R has only
one PCI slot, so you are working with a pretty limiting
system configuration.
So, before you buy the Pundit, I'd want to test out the
video capture card and "X" number of cameras, on a
computer you already own. Test out your "additional
functions" first, before buying the Pundit. It could
be that a desktop system is not the right answer.
Or, that your purchase of a PCI 33MHz/32bit bus
interface quad camera card was a mistake, and a better
or different bus interface is required.
So, if you are planning on pushing this thing "to
the wall", problem #1 is there is little test
data on how modern chipsets work with 85MB/sec
loads on their PCI bus. Problem #2, is how much
interference the operation of other peripherals in
the system, might have on the real time transfer ability
of the PCI bus. PCI Express, or PCI-X, or PCI 64/66
might help with some of that, assuming you could
find video capture cards for those busses, or that
you could find a chipset with dual busses, so that
peripherals could go on one bus, and video capture
on the other. Or something like that.
Now, if it is only two cameras, maybe I'm worried
about nothing
My own experience with a BT878 and one camera,
is it is an excellent tester for PCI bus stability.
On one comp, it would not run for very long before
locking up. The other old motherboard it is currently
sitting in, is quite happy with it.
If you are using a system with MJPEG/MPEG compression
done on the capture card, bandwidth is a non-issue.
Decompression at the processor would then be the issue,
and you can apply as much horsepower as you want to do
that. Might run a bit warm though
I haven't seen
any quad input cards that do compression too, but then
again, I'm not an "upscale shopper".
In any case, I recommend tuning up what you plan on
doing, in a full sized computer. Once you have settled
on what is doable, or not doable, then buy the final
target hardware with some assurance it will work.
Good luck,
Paul
