I want to do an overlay of a couple of unmoved camera clips to blend what's moving on screen together. It's a guy walking around the room. What I want to do is have him walking around the room, then start to fade out as he fades in in another part of the room from a different clip. I do and don't know how to do this. The more layers I make the picture gets darker and darker, I need to know how to keep it normal?