A Gentle Perian Warning
2008.07.17 in thoughts
Any Mac users here probably know of Perian — in fact, I'd venture a guess you've probably got it installed!
In any case, I'm just writing this to note that if you try to export (transcode) a video file in Quicktime Pro, there's a chance that, if you have Perian installed, the audio won't come through — in fact, you'll find yourself completely unable to extract the audio from the file!
The only solution I've found is to use the proper codec for the video (and I've not found a solution for situations where said proper codec doesn't exist, except try to wade through the mencoder {warning: 1.1 MB wall of text} mess...). Perian's great, but this would be a good bug for them to fix.
I've only had this problem with DivX files, which, luckily, have an alternate, 'official' codec.