ASF to AU Converter
Processing entirely on your device — large files may take a moment.
ASF is Microsoft's streaming container from the Windows Media era — the box that WMV video and WMA audio usually ship in. Converting AU to WAV preserves the samples in a format every modern tool reads.
iLoveConverter processes everything locally on your computer, which makes it private and fast: no upload wait, no server storage, no limits. Add as many files as you like — batch conversion is built in.
How ASF compares to AU
| ASF | AU | |
|---|---|---|
| Compression | WMV/WMA inside | µ-law or PCM |
| Quality | Of its era | Mono voice-grade (µ-law) |
| Compatibility | Windows-centric | Legacy Unix tools |
| Best for | Legacy Windows streaming files | Old system sounds and recordings |
How to convert ASF to AU
- 1
Select your files
Select your ASF video.
- 2
Convert instantly
The engine demuxes the container and encodes the audio track into your chosen format.
- 3
Download results
Download the AU audio — the video track is simply dropped.
About the ASF format
ASF (Advanced Systems Format) is Microsoft's streaming container from the Windows Media era. WMV video and WMA audio live inside it, often with DRM in its commercial life. It carries the same 188-packet-ish streaming DNA as other late-90s containers, plus Microsoft-specific metadata and marker tracks.
Outside Windows it is effectively unreadable without special tools. The exit strategy is MP4: video re-encodes to H.264, audio to AAC, and the file joins the modern world. ASF files carrying DRM-protected streams remain locked — only unprotected content converts.
+ Strengths
- ✓Native Windows Media streaming container
- ✓Holds WMV/WMA with rich metadata
! Limitations
- −Non-Windows support is poor
- −DRM-protected files are locked
About the AU format
AU is Sun Microsystems' audio format from the Unix workstation age: a small header followed by µ-law (or PCM) samples. Java's applet era shipped it everywhere, and old Unix sound tooling still emits it.
Modern players increasingly skip it. Converting AU to WAV preserves the samples bit-for-bit while moving the file into universal territory — the standard rescue path for system sounds and old recordings.
+ Strengths
- ✓Simple, lossless sample storage
- ✓Native to old Unix/Java tooling
! Limitations
- −µ-law flavor sounds dated and mono
- −Dropped by modern players
Why convert ASF to AU?
Converting makes sense where the strengths of AU meet what ASF cannot give you. Simple, lossless sample storage Meanwhile Non-Windows support is poor One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this ASF to AU converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for ASF to AU?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Why is video conversion slower than image conversion?
Every frame has to be decoded and re-encoded. This site runs that work on your own CPU via WebAssembly — nothing is uploaded, but a multi-minute video reasonably takes a few minutes. Images, by comparison, are single-frame jobs.
Will the audio track be kept?
Yes. The audio is carried over and re-encoded to the standard audio codec of AU, staying in sync with the video. If your ASF file has multiple audio tracks, the first one is used.