I'm sorry if this was already answered, but I couldn't find what I was looking for in the other tickets. (Computers and their langage aren't really my force you see)
So! I bought a new MacBook? Pro a few days ago (August 5th, 2008). I didn't installed any programs (except for Microsoft MSN and LimeWire?) and I wanted to see if I could listen to some .avi files on it. So I opened one with QuickTime Player, but it didn't had anything appearing, only a black window, no sound. Another window opened to say that I needed something special to see the video, so I went ahead and downloaded XviD_1.0alpha. I put the file where they asked me to, so I had the picture, but still no sound. In the "read me" attached to it, they said that it worked only for the video settings and if there were no sounds, I had to go to this site to download the things that'll make it work. I downloaded A52Codec 1.7.6, put the things where they asked me to (A52Codec.component into /Library/Audio/Plug-Ins/Components and AC3MovieImport.component into /Library/QuickTime). I opened the same .avi file, but still no sounds.
I bet I've done something wrong or I missed something, because the whole Read Me document is chinese to me, except that "what to put where" part.
The .avi files I'm trying to watch work perfectly on my PC and on others iMac at my school. So it's really just my computer not working correctly or me being too dumb to know what to do ;P
Thank you for reading and if you ever reply to this with an answer, keep in mind that I'm not used to Mac's and its functions/programs/how it work in general...