Free online AMR to AU converter

AMR is a compressed audio format commonly used for speech recordings on mobile devices, while AU is an older Sun/NeXT audio container that can store uncompressed or simple encoded audio data. Converting AMR to AU is useful when you need broader compatibility with legacy systems, audio tools, or software that supports AU more readily than AMR.

Why convert amr to au

AMR is optimized for voice and low bitrates, but it is not widely supported outside telephony and mobile workflows. AU can be easier to open in classic Unix-based tools and some audio editors. If you need to archive a voice clip, process it in older software, or move it into a format accepted by a specific system, converting to AU can help.

Best software for conversion

The most reliable choice is FFmpeg, because it supports both AMR input and AU output in many builds. It is fast, free, and works on Windows, macOS, and Linux. For a graphical option, Audacity can import AMR through supported libraries or plugins and export to AU if the required codec support is available. If you want a simple online converter, choose one that explicitly supports AMR and AU, but be careful with privacy when uploading voice recordings.

How to convert with ffmpeg

Use a command like this:

ffmpeg -i input.amr output.au

If the default audio encoding is not accepted by your target AU player, you may need to specify a compatible codec and sample rate. For example, some workflows work better with PCM audio inside AU containers.

How to convert with audacity

Open the AMR file in Audacity, then export it using File → Export → Export Audio and choose AU as the output format if available. This is a good option when you want to inspect or trim the recording before saving it.

Things to check before converting

• Audio quality: AMR is speech-focused, so the result may sound narrowband after conversion.
• Codec support: Not every AU player supports every encoding inside the container.
• Sample rate: Match the target system requirements if the file will be used in legacy software.
• File size: AU files can be much larger than AMR because they often store less-compressed audio.

Recommended workflow

For most users, the best workflow is to use FFmpeg for direct conversion. If you need editing first, use Audacity and then export to AU. For batch jobs, FFmpeg is the strongest option because it can automate many conversions quickly.

Summary

AMR to AU conversion is mainly about improving compatibility with older audio environments. FFmpeg is the best overall converter, while Audacity is a good choice when you also want to edit the recording.