AU to FLAC converter
A free AU to FLAC converter for Sun Audio files. Browser-based pairs here usually run in this tab, with no file upload.
Drop your AU files here
or browse your device · paste with Ctrl+V
Accepts .au, .snd files. You can queue several files; each is processed one after another on your own device.
Your files never leave this device — there is no upload and no server to delete them from.
- 01
Add your AU files
Drop them onto the box above or click to browse. They are read straight from disk — nothing is sent anywhere.
- 02
Check the settings
FLAC is already selected. Open the gear icon on any row if you want to change quality, dimensions or codec before converting.
- 03
Download your FLAC
Press convert and wait for the row to finish. Convert several files and you can take them all as a single ZIP.
AU
Sun AudioThe Unix system-sound format from Sun Microsystems, usually holding 8-bit mu-law audio. Historically important, practically obsolete.
- Developed by
- Sun Microsystems
- Released
- 1992
- Extension
- .au, .snd
- MIME type
- audio/basic
- Compression
- Lossy or lossless
FLAC
Free Lossless Audio CodecLossless compression that halves the size of a WAV while reproducing it bit for bit. Open, patent-free and the default choice for archiving a music collection or selling hi-res downloads.
- Developed by
- Xiph.Org
- Released
- 2001
- Extension
- .flac
- MIME type
- audio/flac
- Compression
- Lossless
- Specification
- Open
- FLAC stores the incoming samples as provided, so this step does not add generic quality loss. If the source AU was already lossy, those earlier losses remain.
Questions about converting AU to FLAC
Is this AU to FLAC converter free?
Yes. Converting AU to FLAC here is free, with no account, no watermark and no daily quota. The work runs on your own device, so there is no server cost to pass on to you.
Is my AU file uploaded anywhere?
For browser-based pairs, your file is read locally and converted by ffmpeg in this tab. No file payload is uploaded; you may still see analytics and engine downloads in network logs.
Is there a file-size limit for AU to FLAC?
There is no imposed upload cap when it runs in-browser, but each conversion still depends on your device and browser memory. Large videos are the first practical limit, then memory-heavy documents or images.
Does converting AU to FLAC lose quality?
No. FLAC stores its data losslessly, so everything in your AU file is preserved exactly.
Can I convert several AU files to FLAC at once?
Yes. Drop in several files and each gets its own row; they are processed one after another on your device. You can download them one by one or as one ZIP.
Does AU to FLAC work on a phone, Mac or Chromebook?
Most modern browsers on Windows, macOS, Linux, ChromeOS, Android and iOS work. Very large videos are often more reliable on desktop or a browser with more memory.
Why do some conversions take longer on first run?
The conversion engine has to download first. Small codec bundles are fast, while ffmpeg is commonly 12–30 MB; later conversions of similar type use the cached engine.
I converted a file and the output is blank or unusable. What should I check?
Start over with default settings, then change one option at a time (quality, bitrate, page size, or codec) to isolate what changed behavior. If it keeps failing, retry with a smaller file and confirm the source format matches the pair.
Convert other formats to FLAC
41 formats can become FLAC here.
Convert AU to other formats
A AU file can become any of these.
FLAC to AU
The reverse conversion
MP4 to FLAC
MP3 to FLAC
WAV to FLAC
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