Need Help, Troubleshooting Videos

[enycezbigd]

So I'm still relatively new to the whole mac experience and I've downloaded a couple of videos already hoping they would work. They are in avi format and at first maybe it's just because quicktime won't support these files. But then i downloaded miro hoping it would play these files and still they wont work. Actually they work but i see no picture only sound is present. Any help?

 

[kalex]

perian.org is what you need to install