Yes, but remember that an mpeg is like a jpeg, a compressed file. Each time you open it, manipulate it (like editing), and resave it, information is thrown away. I've had clients who take my files, fool around with them again and again, and then complain that they look really bad. I'm not an expert on video, but for the first save to the hard drive I'd go for some type of uncompressed (or minimally compressed) file.