How to convert AU to M4B
- 1
Add your AU files
Drag and drop AU files onto the converter, paste them, or click to browse. You can add several at once.
- 2
Choose M4B
M4B is already selected. Open Options if you want to change quality, size or metadata.
- 3
Convert
Click Convert. Your files are converted right in your browser in seconds.
- 4
Download your M4B
Download each M4B file, or everything at once as a ZIP.
AU vs M4B
From
AU · Sun Audio
AU is a simple audio format introduced by Sun Microsystems, common on early Unix systems and Java.
- Type
- Audio
- Extension
- .au
- MIME
- audio/basic
- Best for
- legacy Unix and Java applications
Legacy format
All AU conversions →To
M4B · MPEG-4 Audiobook
M4B is an MP4 audio file flagged as an audiobook, supporting chapters and resume position.
- Type
- Audio
- Extension
- .m4b
- MIME
- audio/mp4
- Best for
- audiobooks on Apple Books and other players
Lossy compression
All M4B conversions →Need it the other way around? Convert M4B to AU.
Related conversions
- M4B to AU
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- MP3 to M4B
- AU to WAV
- MP4 to M4B
- AU to M4A
- WAV to M4B
- AU to FLAC
- MOV to M4B
- AU to AAC
- M4A to M4B
- AU to OGG
Convert AU to other formats
AU to M4B: frequently asked questions
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