m4a and m4r difference
Hi, I haven't examined file headers or code but in my opinion there is no difference between these file formats only for the three letter extension. When making a ringtone for an iPhone, a sound file must be saved using the AAC format which gives it a .m4a extension. Change the 'a' on the extension to 'r' and it will be a ringtone. However please note - ringtones should be less than 40 seconds in length. This has worked for me.
Another point worth mentioning is that iPhone SMS tones are in fact .aif files with file extensions changed to .caf. I'm not sure about the time limit on these sounds but they should be very short, around five seconds.
