The problem is that in any format I export from iMovie '09 there are small black lines that appear in the footage. Apparently other people with a white MacBook and a X3100 graphics card are having the same issues - see http://discussions.apple.com/thread.jspa?messageID=8499840. Unfortunately, Apple does not seem to be interested in fixing this problem. I may need to export videos for a job - what do I do?