I'm working on compiling some instructional videos, and one of the ideas is to have someone composited on the video explaining what's going on. I've done keying with Motion before, but only on pre-recorded footage. Is it possible to pull in live footage and do a temporary mask which we can show to the instructor as they're recording? I've looked over the manuals and on Google but I haven't figured out how to do this or if it's even possible.
Thanks in advance.