Need to download something for quicktime

I have an avi file that I want to play using quicktime on my mac, but whenever i try to play it, it says that I am missing a needed component that I can download on their site. it doesn't say what it is, and when I click on the link to the site, there are several things to download. anyone know which it is?

Happens to me all the time when it associates itself with files automatically, I just ignore it and use VLC.

You're missing a codec, it's probably DivX/XviD or something that you VLC plays it becdon't have installed. ause VLC contains its own internal codecs and doesn't depend on external ones like most players do.

thanks guys... downloaded the divx codec and it works. is there any software that i can download that will play avi files full screen, though?

Any video viewing application should be able to do that. VLC, Windows Media for Mac. I think QT will only allow you to view full screen if you pay for it.