Free online AU to CAFF converter
AU audio can be converted to CAFF for Apple-compatible playback and editing.
Convert AU to CAFF online - free
Your file is processed instantly and deleted as soon as you download it.
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Paste a direct link to the file. We download it to our server and it is converted exactly like an upload.
How it works
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Upload your .au file
Click to browse to select your file you want to convert or simply drag & drop your file into selected area.
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Perform .au to .caff conversion
After successful file upload, click to convert when you are ready.
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Download converted .caff file
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How to convert au to caff file
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Source format: AU
AU is a simple audio file format originally associated with Sun Microsystems and early Unix systems. It is often used for basic sound clips, legacy audio archives, and older software or hardware that expects straightforward uncompressed or lightly compressed audio. AU files may contain different encodings, but they are generally considered a legacy format today.
Target format: CAFF
CAFF stands for Core Audio Format, an Apple audio container designed for modern macOS and iOS workflows. It supports high-quality audio, metadata, and a wide range of encodings, including uncompressed PCM and compressed audio. CAFF is useful when you need a flexible, Apple-friendly format for editing, archiving, or application development.
How to perform the conversion
The most reliable way to convert AU to CAFF is with FFmpeg, which supports both formats and preserves audio quality when the source encoding allows it. If you want a no-install option, you can also convert the file on 101convert.com for free.
- Install FFmpeg if it is not already available on your system.
- Open a terminal or command prompt.
- Run a command such as
ffmpeg -i input.au output.caf. - Check the output file in an audio player or editor that supports CAFF.
If you prefer a graphical workflow, some audio editors that can open AU files may export to CAFF or to a compatible intermediate format. In that case, use File → Open to load the AU file, then File → Export or File → Save As and choose CAFF or .caf if available.
Notes on quality and compatibility
AU to CAFF conversion is usually straightforward because CAFF can store the audio data without unnecessary re-encoding. However, the exact result depends on the AU encoding: if the source is already uncompressed PCM, the conversion should be effectively lossless; if the AU file uses a compressed or unusual encoding, FFmpeg may decode and re-encode it into a CAFF-compatible stream.
Compatibility is the main limitation. CAFF is well supported in Apple ecosystems and some professional tools, but it is not as universally recognized as WAV or MP3. If you need broad playback support, consider creating a second copy in a more common format after conversion.
Note: This au to caff conversion record is incomplete, must be verified, and may contain inaccuracies. Please vote below whether you found this information helpful or not.
AU vs CAFF: format comparison
How the AU and CAFF formats compare on the properties that matter most for this conversion.
| Property | .AU Sun/NeXT audio file | .CAFF Core Audio File Format |
|---|---|---|
| Compression | Uncompressed | Both |
| Audio quality | — | High |
| Audio channels | — | Multichannel |
| Metadata support | Basic | Basic |
| Streaming | Yes | — |
| DRM protection | No DRM | — |
| Opens in a web browser | Partial | No |
| Typical file size | Large | Small |
| Open standard | Yes | No |
| Best used for | Speech and voice | Music |
| Introduced | 1988 | 2007 |
| Developer | Sun Microsystems / NeXT | Apple Inc. |
| MIME type | audio/basic | — |
Frequently asked questions
Is the AU to CAFF converter free?
Yes, converting AU to CAFF on 101convert.com is completely free. No registration, email address or installation is required. If you need a higher file size limit or want to convert more files at once, see our plans.
How large can my AU file be?
You can upload AU files up to 1000 MB and convert up to 100 files at once in a single batch.
What happens to my uploaded files?
Files are processed automatically and deleted from our servers within a few minutes after conversion. We never view or share your files.
Do I need to install any software to convert AU to CAFF?
No. The AU to CAFF conversion runs entirely online in your browser and works on Windows, Mac, Linux, Android and iPhone.
Did the conversion fail?
In most cases, the cause is an incorrect file format. Please upload a valid AU file for this AU to CAFF conversion. Occasionally, the issue may be on our side. We analyze recurring conversion failures and disable or fix the converter if we detect a defect.