Just FYI, MPEG isn’t good for editing. Don’t save your stuff as MPEG, especially if your source is encoded with intraframe compression or you will toss out a lot of data converting to a GOP codec.
Anyway, If you’re talking about your saving 30 minute countdown project, I agree, just save it as a .mov with DV/NTSC, but if in the future you ever make something that is more complicated, ProRes422 is good for archiving. ProRes422 is good for editing actually…
