ZoneMinder Forums

Hi,
I finally got zoneminder working with a logitech Quickcam Web with Suse 9.0. Really a great program but my webcam looks not so good. I've read some threads about BTTV cards and I noticed that there are multiplexing cards with 4 cam inputs.

Before I start buying stuff, I wonder how ZM works with these cards and what the image frames/sec is.

Is it possible to install one 4 input BTTV multiplex card (for about $100,-) and setup a monitor for every cam connected to this card? Or do I get one monitor with 4 different images after each other?
So, does it work just like having 4 separate cards with just a lower frame rate? Does linux (suse 9) supports this by itself or do I have to think about things? How is the frame rate with such a cards?

Thanx for your reply. Hope you can help me making the right decission.
Alexander

Hi Alexander,

If you get a card with just the one BTTV chip shared between four inputs then you get one video device, say /dev/video0 and the inputs are on different channels on that device. ZM supports this setup with no problem, one monitor per channel, and you will notice no difference apart from frame rate. A card like that where only one input is used may get 25fps on that input. Two inputs and that frame rate drops to maybe 8fps each due to switching delays. Go to 3 or 4 inputs and you'll probably only be getting 3-4 fps max.

Phil,

I have such a nice card, and its driving me crazy...

I'm new to v4l and all this video stuff.
The Card i have, has one 878A Chipset and 4 Video inputs. (composite)

I'm trying to get the card working with xawtv, but wo sucsess.
I've no idea how to select the input channel, cause the device is
only /dev/video0.

i know, this is more a v4l question, but maybe somone can help me with it here too.

tnx
cornelius

Hi Cornelius,
I never used a card like you have, but I used a BT878 Chipset card today. I had problems selecting the composite input.

I think channel 0 to 3 will be for your inputs. I noticed that I had to select resolution: 320 x 240 or 356 x240 (maybe it is 352x240) and restart the system. Only after restarting the system, and then starting ZoneMinder solved my problems. See also my thread at the installation forum at: BTTV how to select composite.

Hope you can solve your problems.