There is a program called Switch Audio Converter (google it) and it has a free trial that will copy mp3s. You just drag and drop your mp4s from the itunes folder (usually in My Music and assuming you are using a PC) into the Switch program and select an output folder and format (mp3) then click convert and copy and paste these new mp3s to your mp3 player. This process will take a while depending on the size of your library, maybe even an hour or two for a library of about 1000 songs. Hope this helps.