Add your AU file
Drop one or more .au files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
AU to AIFF
Re-encoding .au audio as .aiff changes how the sound is compressed and which players will accept it. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop AU files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting Sun audio to Audio Interchange File
Re-encoding .au audio as .aiff changes how the sound is compressed and which players will accept it. An .au file is the Sun audio format, one of the earliest structured audio files, created for Unix workstations. A minimal header followed by sample data, classically 8 kHz mu-law telephony audio, makes .au about as simple as an audio format can get.
An .aiff file is Apple's Audio Interchange File Format, storing uncompressed PCM audio much as WAV does on Windows. Mac-based studios have exchanged .aiff masters for decades, and Logic Pro sessions and sample libraries remain full of them. For this route the practical draw is bit-perfect audio identical in fidelity to WAV and loop and marker metadata that samplers actually read — balanced against as bulky as any uncompressed format, which is worth knowing before you commit a large batch.
Why convert AU to AIFF?
The practical trigger for this conversion is usually a mismatch: with .au, essentially obsolete outside legacy systems. Switching to .aiff buys you bit-perfect audio identical in fidelity to WAV, which is why it is the better fit for delivering masters from macOS-based studios. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
AU vs AIFF at a glance
| Aspect | Sun audio (.au) | Audio Interchange File (.aiff) |
|---|---|---|
| Format type | Lossless — every pixel or sample is preserved exactly | Lossless — every pixel or sample is preserved exactly |
| How it stores data | a 24-byte header carries a '.snd' magic number, data offset, encoding type, sample rate, and channel count | classic AIFF stores big-endian PCM, the opposite byte order from WAV, in COMM and SSND chunks |
| Strongest at | maintaining sound assets in vintage Unix and Java software | delivering masters from macOS-based studios |
| Weak spot | essentially obsolete outside legacy systems | as bulky as any uncompressed format |
| Metadata | an optional annotation field in the header can hold a short text string; no formal tag structure exists | nAME, AUTH, and ANNO chunks provide basic text, marker and instrument chunks store loop data, and an ID3 chunk is a common unofficial extension used by iTunes |
Pick AIFF as the output
Select .aiff in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if AIFF is selectable, the route is real and validated.
Convert on your device
Press Convert. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid AIFF file. Outputs keep the original filename with the .aiff extension.
AU to AIFF questions, answered
Will converting AU to AIFF lose quality?
Both sides are re-encoded, so expect a small generation loss controlled by the quality setting: au is lossless-oriented and aiff is lossless-oriented. For visually or audibly transparent results keep quality high; for smaller files lower it and compare.
Is it private to convert AU files here?
Yes — the .au file is processed inside your browser tab and never uploaded. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device. Close the tab and the file is gone from memory.
Where will the AIFF file work?
macOS and all serious audio software open .aiff without hesitation, and Windows editors generally support it even though WAV is their default. Browsers offer partial support at best, and the format's size makes it a poor web choice regardless.
Will the AIFF file be bigger or smaller than my AU?
It depends on the content: classic AIFF stores big-endian PCM, the opposite byte order from WAV, in COMM and SSND chunks. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my AU file?
This converter strips container metadata deliberately (the FFmpeg command runs with metadata mapping disabled) so exported files do not leak recording details. In the source, an optional annotation field in the header can hold a short text string; no formal tag structure exists; none of it is transmitted anywhere because the file never leaves your browser.
Can I convert AIFF back to AU?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .au → .aiff → .au is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.