Selecting a different video source

I'm asking this basic question here as I couldn't seem to find it elsewhere.

How do I select say a USB camera as a video source, rather than using the default webcam?

What do I have to change here?

Thanks.

The issue provides only an HTML video element and does not name a tracking.js file or test. Start by locating how the project obtains its video input and reviewing the browser API for choosing a camera source. Done means documenting whether and how a USB camera can replace the default webcam.

Written by the indexing model from the issue text.