Free online AU to W64 converter
Convert legacy AU audio to large-file W64 for professional editing.
Convert AU to W64 online - free
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How to convert au to w64 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, system sounds, legacy software, and archived audio samples. AU files may contain uncompressed PCM audio or older compressed variants, and they are still recognized by many audio tools because of their straightforward structure.
Target format: W64
W64 is the Wave64 audio container format, designed by Sony as an extension of WAV for files larger than the 4 GB limit of standard RIFF/WAV. It is used in professional audio workflows, long recordings, and high-resolution projects where large file sizes are common. Its main advantage is support for very large audio files while preserving PCM-style compatibility in many editors and DAWs.
How to perform the conversion
The most reliable way to convert AU to W64 is with a desktop audio tool that supports both formats, such as FFmpeg or Audacity.
Using FFmpeg
- Install FFmpeg on your computer.
- Open a terminal or command prompt in the folder containing the AU file.
- Run a command such as
ffmpeg -i input.au output.w64. - Check the output file in an audio editor or player that supports W64.
Using Audacity
- Open the AU file in Audacity.
- If needed, verify the sample rate and channels before exporting.
- Choose File → Export → Export Audio.
- Select W64 as the output format if it is available in your version, then save the file.
If you want a quick browser-based option, you can convert the file on 101convert.com for free without installing any software.
Quality, compatibility, and limitations
Because AU is often an older format, the main limitation is not audio quality but codec compatibility. Some AU files use uncommon encodings that may not convert cleanly in every program. If the source audio is uncompressed PCM, conversion to W64 is usually straightforward and lossless; however, if the AU file is already compressed, the conversion may require decoding and re-encoding, which can affect quality depending on the chosen output settings.
W64 is well suited for large, high-quality audio, but it is less universally supported than standard WAV. For maximum compatibility with players and devices, WAV is often preferred; for very large files or professional editing, W64 is a strong choice.
Note: This au to w64 conversion record is incomplete, must be verified, and may contain inaccuracies. Please vote below whether you found this information helpful or not.
AU vs W64: format comparison
How the AU and W64 formats compare on the properties that matter most for this conversion.
| Property | .AU Sun/NeXT audio file | .W64 Sony Wave64 |
|---|---|---|
| Compression | Uncompressed | Uncompressed |
| Audio quality | — | Lossless |
| Audio channels | — | Multichannel |
| Metadata support | Basic | Basic |
| Streaming | Yes | No |
| DRM protection | No DRM | No DRM |
| Opens in a web browser | Partial | No |
| Typical file size | Large | Very large |
| Open standard | Yes | Partly open |
| Best used for | Speech and voice | Professional production |
| Introduced | 1988 | — |
| Developer | Sun Microsystems / NeXT | Sony |
| MIME type | audio/basic | audio/wave64 |
Frequently asked questions
Is the AU to W64 converter free?
Yes, converting AU to W64 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 W64?
No. The AU to W64 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 W64 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.