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AU to ALAC (M4A) - Online Audio Converter
Convert AU to ALAC (M4A) online. Private, client-side - no uploadrequired. Batch conversion, quality presets, codec control.
Convert AU to ALAC (M4A)
Drop AU audio here or click to select
AU
ALAC (M4A) (ALAC)
About AU to ALAC (M4A)
Convert AU to ALAC (M4A). AU is Sun's simple container, usually holding 8 kHz telephony audio. ALAC is Apple's lossless codec stored inside M4A files. Stays bit-identical to WAV while tagging like AAC..
Why convert AU to ALAC (M4A)?
- Larger files than lossy shares with ALAC (M4A) lossless quality.
- Keep quality where supported.
- Private, no upload - runs in your browser.
AU vs ALAC (M4A)
| Codec | PCM 16-bit | ALAC |
|---|---|---|
| Compression | uncompressed | lossless |
| Sample behavior | Full quality kept | Full quality kept |
| Typical use | AU is Sun's simple container, usually holding 8 kHz telephony audio. | ALAC is Apple's lossless codec stored inside M4A files. |
When not to convert AU to ALAC (M4A)
- Skip ALAC (M4A) for the smallest share: lossless output stays large, so prefer a lossy target when sending AU files.
- Keep a master copy: repeated exports stack small losses, so archive AU before batch ALAC (M4A) shares.
Limits
Starting point: AU - AU is Sun's simple container, usually holding 8 kHz telephony audio. Headers are minimal; verify sample rate after conversion. Stays bit-identical to WAV while tagging like AAC. Encode ALAC (M4A) (ALAC) from AU 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 AU to ALAC (M4A)?
Drop your AU file onto this page, choose quality and codec settings, then click Convert. The result downloads as ALAC (M4A) instantly. All processing runs in your browser.
What codec is used for ALAC (M4A)?
The default codec for ALAC (M4A) is ALAC. 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.