Use External Camera on Mac - Swift/objc

Hello, i want to feed the Video Signal of a DSLR Camera with a HDMI Capture Card and Output it with Filters on a external Monitor. How do i implement it into the code, so the Camera Controller wont use the internal Webcam but the HDMI Capture Card?

You should be able to switch to this camera using the switch camera functionality on the basic quick-start sample, have you tried it?