it's a video file, do you want it in audio in itunes or video?
mp4 is a video file indeed, and works with itunes.. you could do that or .mov
If you want audio, you can best convert it to mp3 or aac(apples own audio format)
to convert, you can use a program, just google video converter and you'll find loads of them.. I find Super easy to use, by erightsoft, google that and you'll find it