FFDShow is a codec for several file types.
You can play AVI files with BSplayer if ffdshow is installed..
But do you need a codec to play AVI files or a player (such as BSplayer)?
BSplayer package now is pretty huge for 56k owners (6MB+), plus you need an internet connection enabled to use it (due to WhenU Save adware now bundled into the installer), but you can still download BSplayer v1.37 [~2.5MB] (or if you want the ooooooooold v0.86.501 [~1MB] ) from here:
http://www.dvd.box.sk/index.php?pid=...=info&rid=8281 