Quoting aaAzhyd <aaazhyd@xxxxxxxxx>: > programmer to modify either the kernel module or > camserv itself to support 4 video devices @ once on a > card using a single bt878 chipset (the GrandTec > e-Guard). They know that you can't actually have all > streams @ once, but instead they want it to rotate > grabbing frames from each source quickly enough to > were it will be @ least 5 frames a second for each > device. The receiver has to synchronize to the signal, and that may take some time. I don't know how fast the bt878 can do that, and how. TV sets use PLLs to match the frequency *and* the phase of the source, and PLLs are quite slow. Change the channel on your home TV and watch how long it takes to reestablish the lock onto the new signal. You'd probably want to synchronize all your sources, if possible. Another obvious issue is the switching. Unless bt878 is programmed to *automatically* switch between channels (during the vertical sync pulse or around), you will be losing frames right there - because when your app realizes that the frame 1 is done, the frame 2 is already half-way through, and you can't switch onto it in time; so you miss it. I'd say, use several bt878-based PCI cards, if you can. It all depends on your needs, of course. A mass production device would benefit from several bt878 chips, they can't be *that* expensive. A piece of a lab equipment (or a custom-made hardware) would do well with a bunch of video cards stuffed into a decent PC. None of this requires programming (less risk). Another option, if you don't insist on speed, is to use cheap USB video chipsets, they have various inputs. For example, you can buy a USB camera with the composite input and connect several such cameras to your computer (use several HCs for speed if necessary). A FireWire camera will work even better (I have no experience with those.) So before you start soldering and hacking you need to determine the most efficient way of solving your problem. Dmitri -- Microsoft: "You didn't want to save that, didja?"
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