Whether you've some AVI videos stored on your hard drive for a while, or you've been downloading movies from torrent, you probably have a few AVI movies somewhere on your Mac. If you try to import these AVI to iTunes for iPod, you'll notice that iTunes don't understand what to do with it.
AVI is a vast supported format by lots of hard devices and software, but it can't be imported to all mobile phones, so if your phone is the exactly one lacking of the function of playing AVI files, you could convert AVI to 3GP for 3GP is normally the compatible format of mobile phones.downloading movies from torrent, you probably have a few AVI movies somewhere on your Mac. If you try to import these AVI to iTunes for iPod, you'll notice that iTunes don't understand what to do with it.