ASF to AU Converter

Browser-based ASF to AU audio converter

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ASF to AU Made Easy

Switching from ASF to AU takes seconds. Upload, convert, and enjoy broader audio compatibility instantly.

Data Safety First

Files are processed securely and deleted after conversion. Nothing lingers on servers — your privacy is fully protected.

Cloud-Powered Engine

The entire conversion runs on remote servers — your device stays fast and unburdened during the ASF to AU process.

How to convert ASF to AU

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose au or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your au file right afterwards

About formats

ASF (Advanced Systems Format) is a proprietary digital media container developed by Microsoft to support streaming over networks. Introduced in 1996, it was originally called Active Streaming Format and later renamed to Advanced Streaming Format before receiving its current name. ASF serves as the underlying container for Windows Media Audio (WMA) and Windows Media Video (WMV) content, though it can accommodate data from any codec. The format was architected with network delivery in mind, incorporating features such as forward error correction, scalable bit rate support, and the ability to seek within streams without downloading the entire file. ASF files include a header object containing metadata, a data object holding the actual media content, and optional index objects that enable efficient random access. One key advantage is built-in support for digital rights management, which made ASF a popular choice for commercial content distribution during the early days of online media. The container handles multiple synchronized streams, including video, audio, script commands, and metadata markers. While ASF has been largely superseded by more modern containers in many use cases, it remains relevant in legacy Windows media ecosystems and enterprise environments that rely on Windows Media Services infrastructure.
Developer: Microsoft
Initial release: March 12, 1996
AU is an audio file format introduced by Sun Microsystems for its Unix workstations and the NeXT platform. It features a minimal 24-byte header specifying data offset, size, encoding type, sample rate, and channel count, followed by the audio payload. AU supports numerous encodings, including uncompressed linear PCM at various bit depths, mu-law and A-law companding (logarithmic compression used in telephone systems), and several ADPCM variants. This versatility made AU a workhorse across early Unix environments, web audio (Java applets defaulted to AU), and telephony applications. One advantage is simplicity: the compact header and straightforward structure make it trivial to parse, generate, and stream programmatically. The built-in mu-law option provides another benefit, delivering reasonable voice quality at just 8 KB per second — half the rate of 16-bit uncompressed audio — invaluable when storage and bandwidth were scarce. Although modern formats have largely supplanted AU in consumer applications, it retains a foothold in scientific computing and audio processing pipelines where minimal overhead and reliable cross-platform behavior are valued.
Developer: Sun Microsystems
Initial release: 1992

Frequently Asked Questions

Why convert ASF to AU?

ASF, Microsoft's Advanced Systems Format, can be hard to play across platforms. Switching to AU gives you cross-platform Unix audio support.

How do I open an AU file?

You can play AU using Audacity, SoX, or most Unix-based audio utilities. No special configuration is usually required.

Can I adjust the output bitrate?

Yes — set the desired bitrate before converting. Lower bitrates produce smaller files, while higher bitrates preserve more audio detail.

How long does the conversion take?

Conversion speed depends on the ASF file size and chosen quality settings. Most files process within seconds to a couple of minutes.

What devices can play AU?

AU playback requires compatible software on your desktop or laptop. Check the recommended apps above to find the right player for your system.

ASF to AU Quality Rating

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