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MP3 to AU - Online Audio Converter
Convert MP3 to AU online. Private, client-side - no uploadrequired. Batch conversion, quality presets, codec control.
Convert MP3 to AU
Drop MP3 audio here or click to select
MP3
AU (PCM 16-bit)
About MP3 to AU
Convert MP3 to AU. MP3 is the MPEG-1 Layer III codec, playable on virtually every device. AU is Sun's simple container, usually holding 8 kHz telephony audio. Headers are minimal; verify sample rate after conversion..
Why convert MP3 to AU?
- Larger files than lossy shares with AU uncompressed quality.
- Keep quality where supported.
- Private, no upload - runs in your browser.
MP3 vs AU
| Codec | libmp3lame | PCM 16-bit |
|---|---|---|
| Compression | lossy | uncompressed |
| Sample behavior | Quality set by bitrate | Full quality kept |
| Typical use | MP3 is the MPEG-1 Layer III codec, playable on virtually every device. | AU is Sun's simple container, usually holding 8 kHz telephony audio. |
When not to convert MP3 to AU
- Skip AU for the smallest share: lossless output stays large, so prefer a lossy target when sending MP3 files.
- Keep a master copy: repeated exports stack small losses, so archive MP3 before batch AU shares.
Limits
Starting point: MP3 - Lossy compressed music near 128-256 kbps. Repeated re-encoding stacks artifacts; convert from the master. Headers are minimal; verify sample rate after conversion. Encode AU (PCM 16-bit) from MP3 at 256k for music or 128k for speech, starting from the master.
How conversion works
Conversion runs entirely in your browser with FFmpeg WASM. Files never leave your device.
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FAQ
How do I convert MP3 to AU?
Drop your MP3 file onto this page, choose quality and codec settings, then click Convert. The result downloads as AU instantly. All processing runs in your browser.
What codec is used for AU?
The default codec for AU is PCM 16-bit. You can change audio parameters in Advanced mode.
How do you store my files?
We do not store any processed audio. All conversion happens entirely in your browser using FFmpeg WASM.