AU to W64 Converter
Processing entirely on your device — large files may take a moment.
Sun Microsystems Audio and Sony Wave64 exist for different jobs: AU is the µ-law audio format of old Unix systems and Java applets — tiny mono files from another era. Convert W64 recordings to WAV or FLAC for standard editors.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How AU compares to W64
| AU | W64 | |
|---|---|---|
| Compatibility | Legacy Unix tools | Sony Vegas, ffmpeg, Sound Forge |
| Best for | Old system sounds and recordings | Long-duration uncompressed sessions |
How to convert AU to W64
- 1
Select your files
Drag & drop your AU files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to W64". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted W64 file individually, or grab everything at once as a ZIP archive.
About the AU format
AU is Sun Microsystems' audio format from the Unix workstation age: a small header followed by µ-law (or PCM) samples. Java's applet era shipped it everywhere, and old Unix sound tooling still emits it.
Modern players increasingly skip it. Converting AU to WAV preserves the samples bit-for-bit while moving the file into universal territory — the standard rescue path for system sounds and old recordings.
+ Strengths
- ✓Simple, lossless sample storage
- ✓Native to old Unix/Java tooling
! Limitations
- −µ-law flavor sounds dated and mono
- −Dropped by modern players
About the W64 format
W64 is Sony's Wave64 — what happens when WAV's 32-bit size fields run out of road. A RIFF variant with 64-bit offsets, it shrugs off the 4 GB ceiling that makes plain WAV choke, which is why long field-recording sessions and Sony Vegas projects land in W64.
Inside, it is the same uncompressed PCM as WAV — ffmpeg hands W64 to WAV, FLAC or MP3 without touching a single sample, so conversion is purely about container compatibility.
+ Strengths
- ✓No 4 GB size ceiling — hours-long recordings
- ✓Bit-exact PCM, same as WAV inside
- ✓Standard in Sony Vegas workflows
! Limitations
- −Almost nothing outside Sony tools opens it
- −Uncompressed — very large files
- −Legacy niche — new tools prefer RF64
Why convert AU to W64?
Think of it as moving your file to the container that fits the job. µ-law flavor sounds dated and mono W64 works differently: No 4 GB size ceiling — hours-long recordings If any of that sounds like your task, run the conversion — it takes seconds and nothing leaves your device.
Frequently asked questions
Is this AU to W64 converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for AU to W64?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Will converting AU to W64 reduce audio quality?
If W64 is lossless, the output contains everything the AU file contains — no further loss is added. If W64 is lossy, one recompression pass is unavoidable; the quality slider controls how much. Loss that already happened in the source file can never be undone by converting.
Are tags like title and artist preserved?
Tag handling varies between target formats and this conversion focuses on the audio itself. For archival copies where tags matter, keep the original file; the converted copy is for playback and sharing.