With Visual AVI FourCC Changer you can change the FourCC code in AVI files. FourCC code in AVI format is an identifier that indicates which codec is to use for decompression and display the AVI file. Change the FourCC code is only useful if you want to use the AVI file with a slightly modified codec, which uses the same compression algorithms. Warning, a wrong AVI FourCC Code may make it unusable!
I bought a Sony BluRay that checks FourCC and refuses to play DIVX files, this was the first program I found that could convert them to XVID in multiples. I have coded a little extra to allow picking a top folder and seeking out all AVIs below that level to really streamline AVI tweaking but it's not in the project yet.