What do the video1394 device files stand for?
Contrary to many beginners’ idea, the video1394 device filenames (like /dev/video1394/0, /dev/video1394/1, etc…) do not correspond to a video channel to the camera. In other words, they are not related to ISO channels or to a specific camera on the bus. They are referring to IEEE1394 interface cards. Yes, that means the physical card (PCI or other) that you have inserted in your computer. For instance, if you have a laptop with an integrated 1394 port it will be assigned to /dev/video1394/0. This device filename will be used for all cameras attached to that port. Imagine that you want another port on your laptop. You insert a PCMCIA card and you now have two 1394 interfaces, hence two busses, hence /dev/video1394/0 and /dev/video1394/1 will refer to your integrated and PCMCIA cards. Not respectively: the device number depends on the order of the devices on the PCI bus (or other buses like PCIe, PCIx,…). If the PCMCIA port is probed before the integrated firewire of your laptop the
