I use adobe premiere, however if you have issues with your graphics card on moviemaker I don't think this would run either.

James, on imovie if you encode the video in m4v format you can just change the filetype to mp4 as the container is the same. Saves reencoding it, failing that as far as I know YouTube should support mov files anyway which would save it been converted twice (once to mp4 and another time when YouTube encodes it again)

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