Free online CAFF to AU converter

Source format

CAFF is the Core Audio File Format, an audio container used on Apple platforms. It can store uncompressed or compressed audio and is commonly associated with macOS and iOS audio workflows. CAFF is useful for high-quality audio storage, sound effects, and application assets where Apple-native compatibility matters.

Target format

AU is the Sun/NeXT Audio format, a classic audio container that is widely recognized by older Unix systems and many audio tools. It is simple, lightweight, and often used for basic PCM audio or legacy compatibility. AU is a good choice when you need a straightforward, broadly readable audio file with minimal container overhead.

How to perform the conversion

The most reliable way to convert CAFF to AU is with FFmpeg, which supports both formats and preserves audio data accurately when the codecs are compatible.

1. Install FFmpeg on your computer.
2. Open a terminal or command prompt.
3. Run a conversion command such as ffmpeg -i input.caf output.au.
4. If you need a specific audio encoding for AU compatibility, you can force PCM output, for example ffmpeg -i input.caf -c:a pcm_s16be output.au.
5. Check the resulting file in an audio player or editor that supports AU.

If you prefer a simpler workflow, you can also convert the file on 101convert.com for free without installing any software.

Notes on quality and compatibility

CAFF may contain audio encoded with codecs that are not ideal for AU. Since AU is most commonly used with PCM audio, some CAFF files may need re-encoding during conversion, which can affect quality if the source is compressed. If the CAFF file already contains uncompressed PCM audio, conversion is usually straightforward and lossless at the container level.

Compatibility can also depend on the exact AU variant expected by the target software. For best results, use 16-bit PCM unless you know the destination application supports other AU encodings. Metadata support is limited in AU compared with more modern audio formats, so tags and extra information may not carry over.