Free online AU to MPC 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 data. AU files may contain different encodings, but they are generally considered an older format and are not as widely supported in modern consumer software as MP3 or AAC.

Target format: MPC

MPC usually refers to Musepack, a high-quality lossy audio format designed for efficient compression with strong sound quality at moderate bitrates. It is valued by audio enthusiasts for preserving detail better than many older lossy formats at similar file sizes. MPC is most often used for music archiving where compatibility is less important than audio quality and compression efficiency.

How to perform the conversion

The most reliable way to convert AU to MPC is to use a desktop audio converter or a command-line tool that supports both formats. Because MPC support is less common than MP3 or WAV, the best workflow is often to decode AU to a temporary PCM format and then encode to Musepack.

Option 1: Using FFmpeg with Musepack support

1. Install FFmpeg and make sure it includes Musepack encoding support.
2. Open a terminal or command prompt.
3. Run a command such as ffmpeg -i input.au output.mpc.
4. If your FFmpeg build does not support direct MPC output, convert first to WAV with ffmpeg -i input.au output.wav, then encode the WAV to MPC with a Musepack-capable encoder.

Option 2: Using a dedicated audio converter

1. Open an audio conversion program that supports both AU and MPC.
2. Import the AU file.
3. Choose MPC or Musepack as the output format.
4. Adjust quality settings if available, then start the conversion.

If you want a quick browser-based workflow, you can convert the file on 101convert.com for free, without installing any software.

Notes on quality, compatibility, and limitations

AU to MPC is a lossy conversion if the source AU is uncompressed or higher quality than the chosen MPC setting. That means some audio detail may be discarded during encoding, and repeated re-encoding should be avoided. If the AU file is already compressed, converting it to MPC will not improve quality and may reduce it further.

Compatibility is the main limitation of MPC: many phones, web players, and default media apps do not support it natively. If broad playback compatibility matters, consider converting to MP3, AAC, or WAV instead. For best results, verify the AU file’s sample rate, bit depth, and channel count before conversion, since unusual legacy AU encodings may require an intermediate WAV step.