That's pretty cool. I was thinking about something similar. Just the ability to easily blend video signals. Say two inputs on the TV.

It would be good to then plugin a 'computer' something like the Raspberry Pi, that would overlay the existing signal, or merge two video inputs (Would this be simple digitally?).

It would be nice if there was meta info available alongside a program, that you could hook into somehow, so you could do something useful with it. A cue sheet or something. Having meta info about a playing scene could be useful. Digitized credits would be nice.