Free online AFC to AU converter

Source format

AFC is a less common audio-related file extension that can appear in different software ecosystems, but in file conversion requests it is typically treated as an audio file or an audio container used by a specific application. Because AFC is not a widely standardized consumer format, it is often encountered in niche workflows, legacy software, or proprietary tools. Typical use cases include storing audio assets for a particular program, archiving sound data, or exchanging audio between older systems.

Since AFC is not broadly supported by mainstream players and editors, users usually convert it when they need better compatibility, easier playback, or editing in standard audio software.

Target format

AU is a classic Sun/NeXT audio format. It is a simple, well-known audio container that stores raw or lightly structured sound data and is recognized by many audio tools, especially on Unix-like systems and in technical workflows. AU files are valued for their simplicity and compatibility with older software, scripting environments, and some audio processing utilities.

Typical use cases for AU include legacy audio exchange, software development, embedded or Unix-based audio handling, and situations where a straightforward uncompressed audio format is preferred.

How to perform the conversion

The best conversion method depends on whether your AFC file is supported by your audio software. If it is, the most reliable approach is to open it in a desktop audio editor and export it to AU.

1. Open the AFC file in a compatible audio application. If the file is not recognized, try a different audio editor or player that supports the specific AFC variant.
2. Check the audio properties such as sample rate, channels, and bit depth before exporting.
3. Use the export function and choose AU as the output format.
4. Save the file with an .au extension.

In Audacity, for example, you can try File → Open to import the source file, then File → Export → Export Audio and select AU if the format is available in your build and import chain.

If your AFC file comes from a specialized application, the most dependable workflow is often to use that original program to export to a standard intermediate format such as WAV first, then convert WAV to AU in a second step. This can be done in tools like FFmpeg or SoX when the source is readable by the tool chain.

For command-line conversion, a typical AU export command with FFmpeg looks like ffmpeg -i input.wav output.au. If AFC is directly readable by your installed FFmpeg build, you can replace input.wav with the AFC file name. If not, convert AFC to a supported intermediate format first.

You can also convert the file on 101convert.com for free, without installing any software.

Notes on quality, compatibility, or limitations

Compatibility is the main limitation in this conversion. AFC is not a universally standardized audio format, so some files may not open in general-purpose tools at all. In those cases, conversion may require the original application or a specialized decoder.

AU itself is usually straightforward, but it may not preserve every feature from the source if the AFC file contains metadata, compression, or application-specific information. In most cases, only the audio stream is retained, while tags, project data, or proprietary structure are lost.

If the source audio is compressed, converting to AU may increase file size because AU is commonly used as an uncompressed or lightly structured format. For best results, keep the original sample rate and channel count unless you specifically need to change them.