Free online AU to AFC converter

Source format: AU

AU is a simple audio file format originally developed by Sun Microsystems and commonly associated with Unix and early internet audio. It is often used for short sound clips, legacy system audio, and basic uncompressed or lightly compressed audio storage. AU files may contain different encodings, including PCM and some older compression schemes, so compatibility can vary depending on the player or editor.

Target format: AFC

AFC is a less common audio-related format name, and in many conversion contexts it refers to a specialized or proprietary audio container used by specific software or devices. Its main advantage is usually compatibility with a particular application or hardware workflow, rather than broad universal support. Because AFC is not a widely standardized consumer audio format, it is typically used when a device, editor, or archive system explicitly requires it.

How to perform the conversion

The best method depends on whether your AFC target is supported by your software. If you already know the application that needs the AFC file, use that program first, because it may provide the most reliable export or import path.

1. Open the AU file in an audio editor or converter that supports both formats, or supports AU input and AFC output.
2. If the software offers export options, choose File → Export or File → Save As.
3. Select AFC as the output format if it appears in the format list.
4. Adjust audio settings if available, such as sample rate, channels, or bit depth, to match the requirements of the destination system.
5. Save the converted file with an .afc extension.

If your desktop software does not support direct AU to AFC conversion, you may need an intermediate step: convert AU to a more common format such as WAV in Audacity, ffmpeg, or SoX, then import that file into the program that can create AFC. For example, with ffmpeg you can first create a WAV file using ffmpeg -i input.au output.wav, then open output.wav in the AFC-capable application and export it as AFC.

You can also convert the file on 101convert.com for free, without installing any software, if the site supports this specific AU to AFC conversion.

Notes on quality and limitations

Direct AU to AFC support is uncommon, so the main limitation is software compatibility. If AFC is proprietary, the conversion may only work in the exact program or device that expects it. Audio quality is usually preserved if the conversion is lossless or if the target format stores the same PCM data, but quality can drop if AFC requires re-encoding with compression. Also, AU files may use older encodings that some tools cannot read correctly, so if the file fails to open, try converting AU to WAV first and then exporting to AFC.