External Video Capture Device

Brand new to this, and I googled and searched using terms I could think would be related. No luck.

I am having trouble finding detailed docs on the SETTINGS > APPLICATION > VIDEO settings.

I specifically want to know if SignalRGB can capture and use a signal from an external video to usb capture device, web camera, OBS, etc.

It LOOKS to me like this could be a thing, but I can’t find info. On the above referenced settings page, the VIDEO DEVICE seems to be autoselected to be my GPU. I’d like to be able to switch to a general USB video capture device so I can process a signal from, say FireStick or XBOX.

Why:
I’d like to run SignalRGB on a Pi for my main TV, and in addition to general effects, do ambient lighting for movies without having to play them from a PC or other computer.

I’ve tried with an installed capture device (such as https://www.amazon.com/dp/B097DKNS1M) and the virtual cam output from OBS studio active. I see no way to get SignalRGB to recognize these, no less offer them for selection.

This is make or break for my SignalRGB plan, so I’m crossing fingers someone knows where to look, what to install, etc.

Thanks for anyone who can unstuck me.