Add your OGG file
Drop one or more .ogg 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.
Re-encoding .ogg audio as .au changes how the sound is compressed and which players will accept it. Free, private, and validated — the file never leaves your browser.
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.Re-encoding .ogg audio as .au changes how the sound is compressed and which players will accept it. An .ogg file almost always means Vorbis-compressed audio in the Ogg container, the free-software world's answer to MP3. The .ogg extension originally covered any Xiph media; audio kept the name when video moved to .ogv, and game developers and Wikipedia still lean on it heavily.
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. For this route the practical draw is so simple that nearly any audio tool can parse it and pCM variants preserve the recording exactly — balanced against essentially obsolete outside legacy systems, which is worth knowing before you commit a large batch.
The practical trigger for this conversion is usually a mismatch: with .ogg, apple's Music app and iOS offer no native playback. Switching to .au buys you so simple that nearly any audio tool can parse it, which is why it is the better fit for maintaining sound assets in vintage Unix and Java software. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
| Aspect | Ogg audio (.ogg) | Sun audio (.au) |
|---|---|---|
| Format type | Lossy — discards detail it judges invisible to shrink files | Lossless — every pixel or sample is preserved exactly |
| How it stores data | vorbis is an MDCT-based lossy codec tuned through a quality scale (-q) rather than fixed bitrates | a 24-byte header carries a '.snd' magic number, data offset, encoding type, sample rate, and channel count |
| Strongest at | shipping game audio assets without codec royalties | maintaining sound assets in vintage Unix and Java software |
| Weak spot | apple's Music app and iOS offer no native playback | essentially obsolete outside legacy systems |
| Metadata | vorbis comments, the flexible key=value system shared with FLAC and Opus, plus METADATA_BLOCK_PICTURE for embedded cover art | an optional annotation field in the header can hold a short text string; no formal tag structure exists |
Drop one or more .ogg 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.
Select .au in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if AU is selectable, the route is real and validated.
Press Convert. The transcode runs on an FFmpeg engine compiled to WebAssembly, so the audio never leaves your device.
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid AU file. Outputs keep the original filename with the .au extension.
No new loss is introduced — since ogg is lossy-oriented and au is lossless-oriented, everything the .ogg file still contains is carried over exactly. What was already discarded by the original lossy encode cannot be recovered, though; converting to .au does not "restore" quality.
Yes — the .ogg 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.
Audio tools such as Audacity, sox, and ffmpeg open .au readily, and Java's sound APIs still accept it. Consumer players, phones, and browsers dropped meaningful support long ago, so conversion to WAV or MP3 is the practical route.
Larger, sometimes much larger. A lossless .au must store every pixel or sample the decoder produced, without the perceptual shortcuts .ogg used. Use this route for editing headroom, not for saving space.
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, vorbis comments, the flexible key=value system shared with FLAC and Opus, plus METADATA_BLOCK_PICTURE for embedded cover art; none of it is transmitted anywhere because the file never leaves your browser.
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .ogg → .au → .ogg is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.