I’ve posted a couple of times now about my experiences creating audio and video on OS X. A couple of weeks ago, I had a brief conversation with my friend Ian Hughes, aka epredator, who was trying to get himself setup:
Good one. All I knew was that DIVX AVI files were playing on my machine fine, through QuickTime.
The answer, which I’d evidently missed before, is Perian. This is a really simple, installable package which enables support for a whole range of “other” file formats in QuickTime. You’ll also want to install Flip4Mac, which gives support for Windows formats like WMV. It’s also worth adding the Xiph component for formats like FLAC and OGG. Once you’ve got those in place, you should be fine to import, play and edit in iMovie and other QuickTime-based applications.