In the end, TNet just sends bytes like everything else, so yes it's supported.
But video is heavy, so you're going to have to perform a lot of compression to achieve any kind of suitable result.
I don't have any experience in this area. My brief (5 minutes of googling) research shows H.264 seems to be the standard.
I'd look at how something like OBS works and go from there. I think OBS is open source? I mean, it has open in the name, so I'd hope so.
Then you just have to get the bytes from the webcam, feed them to your encoder, and send the output across the network. Then decode and display on the other end.
A lot harder than it sounds, I'm sure

maybe Unity already has an encoder you can use? I'd look into their new video player stuff.