AU → AAC
Convert AU audio to AAC entirely in your browser — no upload, no watermark, no sign-up.
Drop files here
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images · audio · video · documents · archives · Free: 200 MB per file · Pro: 5 GB
Your first conversion lands here automatically — saved on this device only, never uploaded.
100% Private
Runs in your browser. No upload.
Instant
No queue, no server roundtrip.
Offline-ready
Works after first load.
Moving AU audio to AAC is about compatibility and size — which players accept the file and how much disk or bandwidth it costs once it gets there. AAC (Advanced Audio Coding) earns its place here: efficient modern compression that sounds better than MP3 at equal bitrates. AU is the original Unix and Java system-sound format. Simple, ancient and occasionally still produced by scientific and telephony software.
AU is the original Unix and Java system-sound format. Simple, ancient and occasionally still produced by scientific and telephony software.
The audio is decoded and re-encoded, so the running time, channels and sample content stay intact while bitrate and file size follow AAC. Going from a compressed AU file to any other lossy format is a second generation of compression — start from the highest-quality source you have when it matters, and expect a lossless target to grow the file rather than improve the sound.
What you gain with AAC: Efficient modern compression that sounds better than MP3 at equal bitrates.
Drop your AU file above and Morphio decodes it locally, then re-encodes it as AAC using WebAssembly + the browser's native codecs. Nothing is ever uploaded — your files stay on your device. Free supports batches of 5 files; Pro supports batches of 250, subject to your device's memory. See exactly how in-browser conversion works.
Open the AU to AAC page, drop your audio file on the drop zone and press convert. Morphio runs an FFmpeg build compiled to WebAssembly that runs inside the page, so the AU data never leaves your device and no server ever receives a copy.
Sample rate and channel layout carry across, and you keep the original file untouched on disk. Converting AU to AAC only rewrites the container and encoding you asked for — the source file on your disk is never modified.
Yes. The free plan covers 10 conversions a day with files up to 200 MB and adds no watermark or sign-up. Morphio Pro ($5/month, or $29 once for lifetime access) removes the daily cap and raises the per-file limit to 5 GB.
Morphio decodes the AU file at full fidelity and re-encodes it at a high-quality AAC setting, so the difference is normally invisible or inaudible. What conversion cannot do is recover detail the original AU file already threw away.
Yes — Free supports batches of 5 files and 10 conversions per day; Pro supports batches of 250 with no daily conversion cap. Your device's memory can impose a lower practical limit. Only usage counts reach the server, never files.
No. The conversion runs entirely inside your browser, so the file never leaves your device. The page and the required decoder must load first; free usage-limit checks may require a connection.