Live, real time video, compositing onto a virtual studio Is there a way to use Blender and (say) a 3d virtual "tv studio", together with input streaming from a camera into the application in real time?

So, from a physical camera > USB input > here I am available in Blender as a stream of data by 

My interest comes from a desire to create a live stream "tv studio" where the studio is a CG model and the actor is in a green screen studio.
You can do this after the fact, but unless you're running a supercomputer, Blender probably won't be able to keep up with the live feed.