I explained this somewhat in a previous post… iTunes, as some of the worlds population may use, is a software based system for your iPod and nothing more! When sending music to DJs, please do not send un-formatted mp4 files! The demand is still and will always be for mp3 files only because it is a universal file used by everyone and not just Apple. If you are using iTunes to catalog your music then refer to my “How to properly label & Tag An mp3 & Why it Is Important” post, it will explain the proper format when labeling and sending music that iTunes does not follow, Why?!, because (again), its a software based system designed for the use of cataloging music for the iPod or iPhone systems only! This is not a universal software. Please stop sending mp4 formatted songs, they are almost always ignore by professionals and are not used by the real world. iTunes does allow you to convert back to mp3 within the software so I would suggest that you do that before you make that mistake.