What is the ISO channel variable for?
As firewire is a shared bus, each camera must place a unique identifier in each packet so that the software can identify which camera a frame came from. The unique identifier used here is known as the ISO channel, and is just an integer. As well as writing the ISO channel number to the camera, you must also tell the video1394 layer which channel(s) it should listen for packets on. The ISO channel allocation is automatic but you can also override it manually with dc1394_video_specify_iso_channel(). Should you choose to do it manually you should call the previous function before setting up the capture. You must first choose a unique channel number for the camera you are retrieving images from. If you are looping around an array of cameras, your loop variable “i” or “i+1” could be a suitable unique ISO channel identifier, or you could use the raw1394 (nodeid_t) node number as the channel number, which allows re-use of channel numbers on separate ports (host adaptors).
