QuickTime only plays AVI files that both the audio and the video were compressed using a codec that QuickTime can use. If the audio or video or both were created using codecs that QuickTime cannot use, it won’t play AVI file normally, either with video missing or sound missing. In fact, many Mac users upgrade their Mac to Snow Leopard found that QuickTime X cannot recognize their AVI files. That’s really annoying!
Below are some solutions for playing AVI files on Mac (Snow Leopard included) that have been tested to be workable. Hope it helps!
Solution 1: Switch to other media player.
VLC player and Plex are two highly recommended players and in most cases they work like a charm under Mac. If you are using Snow Leopard, VLC player would be a better choice considering some Snow Leopard users reported that they ran into some problems with Plex on Snow Leopard. If you have Front Row install, you can also consider give it a try and it works for some AVI files.
Solution 2: Download and install Perian
Perian is a free QuickTime component that adds native support for many popular video formats. The current version (1.1.4) of Perian is compatible with Snow Leopard and it works perfectly for most of the AVI files.
Solution 3:
Convert the AVI file to QuickTime MOV
This is not the best solution but if you want to play your AVI videos and the above two solution just not work for you and you’ve no better choice.