How can I find out the codec of an AVI file

In the past 2 weeks I have had two people send me AVI files taken from video capture devices. In each case Windows Media Player and Quicktime could not open the files, saying that it did not have the software necessary to play the file. TMPGEnc said it was not a supported format.

How can I find out what codec was used on a file so I can play it back, and what's the best player out there for playing just about any kind of AVI file?

Thanks,
Bob

[Fragamon]

Just go to the tools section, and download the codec package. As for file info, try using virtualdub.