About the AU file format
Sun/NeXT Audio (AU) is an audio format supported by mp3.now for conversion, extraction, or playback workflows.
The guide and converter lists are generated from the live MP3.now catalog, so every conversion shown here is available.
Why AU files are used
Sun/NeXT Audio files store digital audio using the .au extension.
Audio formats differ in compression, quality, metadata, channel support and compatibility with players and editing software.
What to know about AU
Audio encoding
AU uses format-specific rules to store or compress sound.
Quality and size
Bit rate, sample rate, bit depth and compression influence both fidelity and file size.
Metadata
Track titles, artists, artwork and other tags may be supported depending on the format.
Compatibility
Support for AU varies across browsers, devices, editors and media players.
How AU conversion works
Converting AU decodes the source audio and encodes it with the destination format's codec and selected quality settings.
Lossy conversion cannot restore detail already removed from the source, so keep the original when quality matters.
mp3.now accepts AU as input and can also create AU output.
AU compatibility and software support
Check that the target player or editing application supports AU before choosing it for delivery.
MP3 remains a practical fallback when broad playback compatibility is the priority.
AU and related formats
When should you use AU?
- Everyday listening: Prepare audio for phones, computers and portable players.
- Editing: Move sound into a format supported by an audio editor.
- Publishing: Create audio for websites, podcasts or distribution platforms.
- Archiving: Keep a high-quality source and create smaller access copies.
Convert from AU
Use AU as the source.
Convert to AU
Create AU output.
AU file format FAQ
What is a AU file?
Sun/NeXT Audio (AU) is an audio format supported by mp3.now for conversion, extraction, or playback workflows.
Can MP3.now convert AU files?
mp3.now accepts AU as input and can also create AU output.
What changes when AU is converted?
Converting AU decodes the source audio and encodes it with the destination format's codec and selected quality settings.
Should I keep the original AU file?
Lossy conversion cannot restore detail already removed from the source, so keep the original when quality matters.