All formats
AU
Audio format
The AU format
AU is a simple audio format from Sun and NeXT workstations. AU comes from Sun and NeXT workstations around 1992, and was the early web’s sound format.
When to use AU
Convert AU files to WAV or MP3 to use them in anything current.
It is best for old Unix and Java software, and it opens on VLC, Audacity and Unix tools.
How to open it: VLC and Audacity open AU files.
| Full name | Sun Audio |
|---|---|
| Extensions | .au, .snd |
| MIME type | audio/basic |
| Introduced | 1992 |
| Compression | Uncompressed |
| Typical quality | often 8 kHz μ-law |
| Support | Specialist format |
| Typical size | About 480 KB a minute at 8 kHz μ-law |
Good at
- A tiny header over plain samples
Not so good at
- Mostly 8-bit μ-law phone-quality sound
- Few modern apps open it
The common mistake
Most AU files are 8 kHz μ-law, so they sound thin however you convert them.
Questions
What is an AU file?
AU (Sun Audio) is a simple audio format from Sun and NeXT workstations. AU comes from Sun and NeXT workstations around 1992, and was the early web’s sound format.
How do I open an AU file?
VLC and Audacity open AU files.