PDA

View Full Version : Multiple input devices/same frame grabber



Unregistered
October 13, 2004, 22:37:02
How would I go about displaying the live stream from two input channels on the same PCI 4 input frame grabber ("device")? I have tried both a control array and individual controls, and when .LiveStart is invoked on the second input channel, the following error occurs:

"The current VideoCaptureDevice is already connected."

I downloaded and tried the multiple camera sample program you have, but it only sees the card as one device and therefore spawns only one MDI window - but it does let me switch between the separate channels.

Thanks.

Stefan Geissler
October 14, 2004, 09:24:24
Hello,

The grabber has only one chip that is able to digitize the analog video. The input channels are switched with a multiplexer to the chip. This means, you can start the grabber for the board once and switch between the input channels while the live video is running.
There is a time delay when the input channel has been changed, because the grabber must synchronize to the new video signal.
Therefore you can not see to live video parallel.
If your grabber board has more than one grabber implemented, then all devices should be listed in the list of available video capture devices. You can open each device with an own IC Imaging Control. In this case, it is possible to see parallel video streams.