Quicktime/OS X: No Audio For AVI Files? Solution: Perian

.avi files are all over the place in the BitTorrent world.

If your Mac doesn’t seem to be able to play back .avi files with sound, you’re not alone. 

But the solution is simple.  After a year of this, I finally found it. No longer do I need the VLC player, which was my old work-around for this problem.  

Download Perian, “The swiss army knife of Quicktime components.” 

Problem solved.  I can finally play avi movies and hear the audio in quicktime, itunes etc.

Interestingly enough, some people are saying that AVI is actually supposed to be an obsolete format. From a mac support forum: 

“AVI is merely an (outdated) container which can include a number of different codecs, not all of which can be made Mac-compatible.”

…And from some random MIT-related site, I found:

“AVI (Audio-Video Interleave) is a rather old file format that Microsoft has been trying to abandon for years in an attempt to get people to switch to their Windows Media format instead. However, the simplicity of AVI and its ubiquity and made it quite popular, so AVIs are still widely used. There are many third-party developers using AVIs, so there is a wide array of AVI codecs available.”