camera link frame grabber

It is an interesting question, I suspect that switching video signals is a difficult thing to do. Each camera will be on its own time base and the frame grabber will have to sync up to each camera after each switch.

How fast do you need to have it? High speed, i.e. one frame from each of [n] cameras every second, or do you envision, switch and settle every few seconds at most.

If it is the former, I think you probably need different hardware designed to switch video.

If it is the latter, you could probably use relays to switch composite video signals cheaply.

You can actually switch an analog video signal with an NPN transistor like I've done below. Not fancy, but works well enough for webcams and such. Might be able to do the same with a 4066 chip.

Just to add: If the two signals are not genlocked there will be a roll until the frame is complete, and the frame grabber can reestablish vertical sync to the other signal. It's usually not objectionable, and simple video switches sold at Radio Shack and elsewhere have long operated this way. To make the transition always smooth the video will need to run from common reference sync, or use smarts in the switch to transition only at the vertical interval, or some other technique. If I were to do this I'd probably use an LM1881 sync separator to detect vertical sync, and a cheap AVR or PIC.

Great pages, BTW. Runt looks like he's (she's?) not one to be tangled with!

-- Gordon

He is very clever about sitting on the mouse, walking on the keyboard, and occupying the "captin's chair" at the computer when he wants attention (I'm having to "share" the chair as I type this).