WHAT IS AU?
What is AU? AU is short for “audio”, which means that this file type was created to store sound. It is not a very common format; it is primarily used on Unix systems, which are not widely themselves. Still, playback of AU files on Windows or Mac is also possible; several programs are able to open these audio files. Below, you’ll find information on how to play AUs.
The AU format specification has three main parts: a header, an annotation, and the main block that contains audio data. This data can be encoded by μ-law, PCM, or A-law algorithms. Aside from the programs listed below, you can also use Java apps to play AU files.
Windows Media Player, QuickTime, VLC, others