Convert AU to M4R
Convert your AU files to M4R online
AU format for reliable data storage
This audio format was developed by Sun Microsystems. It is intended for storing audio files; the file itself consists of three components: the header, the annotation unit, and the audio file itself. What distinguishes this format is the small file size, due to which its sound quality is low. It can be converted into other formats, such as mp3 or MPEG. Although this format is mostly used on personal computers that are powered by operating systems Sun or Unix, AU files can also be opened using other audio players.
M4R: the ringtone file used in Apple iOS
The M4R format is used in Apples mobile devices, mostly for storing ringtones. You can create an M4R file by converting other formats or downloading it from the official iTunes store. The sound conversion employs a special type of compression, which significantly reduces the file size. The advantages of this format make it ideal for iPhone owners. M4R is one of the constituents of the standardized MPEG-4 format. One of its strong points is that the high sound quality is fully preserved after compression.