Free online AU to AMR converter
Convert AU audio to AMR speech format with FFmpeg or 101convert.com.
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How to convert au to amr file
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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 archived audio samples. AU files may contain uncompressed PCM audio or compressed data, and they are still recognized by many audio tools because of their straightforward structure.
Target format: AMR
AMR stands for Adaptive Multi-Rate, a speech-focused audio format designed for efficient voice compression. It is widely used in mobile phones, voice recordings, VoIP systems, and other applications where small file size matters more than high-fidelity music playback. AMR is especially good for speech, but it is not ideal for music or full-range audio.
How to perform the conversion
The most reliable way to convert AU to AMR is with FFmpeg, a powerful desktop command-line tool that supports both formats. If you prefer a graphical workflow, audio editors such as Audacity can open AU files, but AMR export support may depend on installed codecs or plugins. For a simple local conversion, FFmpeg is usually the best choice.
- Install FFmpeg on your computer.
- Open a terminal or command prompt in the folder containing your AU file.
- Run a command such as
ffmpeg -i input.au output.amr. - If needed, adjust the audio for speech-friendly AMR settings, for example by converting to mono and a supported sample rate before encoding.
- Check the resulting AMR file in a compatible player or on a device that supports AMR playback.
If you want a simpler no-install option, you can convert the file on 101convert.com for free without installing any software.
Notes on quality and compatibility
AMR is optimized for voice, so converting AU audio that contains music, effects, or wide-frequency content will usually reduce quality noticeably. For best results, use mono speech audio with a supported sample rate. Some AMR players support only specific variants such as AMR-NB (narrowband), so compatibility can vary depending on the target device or software. If your AU file is stereo or high-fidelity, expect the conversion to discard detail because AMR is designed for compression efficiency rather than audio fidelity.
Note: This au to amr conversion record is incomplete, must be verified, and may contain inaccuracies. Please vote below whether you found this information helpful or not.
AU vs AMR: format comparison
How the AU and AMR formats compare on the properties that matter most for this conversion.
| Property | .AU Sun/NeXT audio file | .AMR Adaptive Multi-Rate Audio Codec |
|---|---|---|
| Compression | Uncompressed | Lossy |
| Audio quality | — | Low |
| Audio channels | — | Mono |
| Metadata support | Basic | Basic |
| Streaming | Yes | Yes |
| DRM protection | No DRM | — |
| Opens in a web browser | Partial | No |
| Typical file size | Large | Very small |
| Open standard | Yes | Partly open |
| Best used for | Speech and voice | Speech and voice |
| Introduced | 1988 | 1999 |
| Developer | Sun Microsystems / NeXT | 3GPP |
| MIME type | audio/basic | audio/amr |
Frequently asked questions
Is the AU to AMR converter free?
Yes, converting AU to AMR on 101convert.com is completely free. No registration, email address or installation is required.
How large can my AU file be?
You can upload AU files up to 1000 MB and convert up to 100 files at once in a single batch.
What happens to my uploaded files?
Files are processed automatically and deleted from our servers within a few minutes after conversion. We never view or share your files.
Do I need to install any software to convert AU to AMR?
No. The AU to AMR conversion runs entirely online in your browser and works on Windows, Mac, Linux, Android and iPhone.
Did the conversion fail?
In most cases, the cause is an incorrect file format. Please upload a valid AU file for this AU to AMR conversion. Occasionally, the issue may be on our side. We analyze recurring conversion failures and disable or fix the converter if we detect a defect.