audio format

What is a .AU file?

AU is Sun Microsystems' classic Unix audio format, one of the earliest sound formats, still seen in old Unix and Java applications.

Full name
Sun Audio
Developed by
Sun Microsystems
Released
1992
Extension
.au
MIME type
audio/au
Transparency
No

How to open a AU file

AU plays in VLC and Audacity; convert to MP3/WAV for everyday use.

What AU files are used for

Music & podcasts

Listening on any device or app.

Editing & mastering

Production-quality source audio.

Voice notes & clips

Lightweight recordings to share.

Strengths & limitations

✔ Strengths✖ Limitations
Excellent compatibilityNo transparency support
Limited support — may need converting

Need more than a conversion?

Remove the background from AU images, upscale to 4K, or generate new visuals with SharkFoto AI.

Frequently asked questions

AU is Sun Microsystems' classic Unix audio format, one of the earliest sound formats, still seen in old Unix and Java applications.

AU plays in VLC and Audacity; convert to MP3/WAV for everyday use.

AU is optimised for its specific use rather than strictly lossless storage.

Use SharkFoto's free tools — upload your AU file and convert it to a more convenient format in seconds. It's free, processed securely and never stored.

No — AU doesn't store transparency; convert to PNG or WEBP if you need it.