AU Converter
Convert files to and from AU online for free. Fast, secure, and high-quality file conversion with no sign-up or software required.
Maximum file size is 1GB
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What is an AU file?
The AU file format is a simple container format introduced by Sun Microsystems and NeXT for UNIX-based systems. It typically contains μ-law (mu-law) logarithmic encoded audio data (G.711 standard) stored in a big-endian byte order, identified by the hexadecimal magic number 0x2e736e64 ('.snd'). The file structure consists of a minimal 24-byte header specifying data offset, sample rate, and encoding type, followed by an optional annotation block and the contiguous audio data, making it a standard for early Web audio (Java applets) and SPARCstation workstations.
How to open an AU file
Modern operating systems often lack direct associations for AU files due to their obsolescence. While some Linux distributions and macOS (via Core Audio) may support basic playback, Windows requires third-party software. The VLC media player is the primary recommendation for opening AU files across all platforms; alternatively, Audacity can be used to import the raw data and convert it to modern PCM formats like WAV.
AU Technical Info
- Full Name
- Sun Microsystems Audio
- Developed By
- Sun Microsystems / NeXT
- Initial Release
- 1988
- MIME Type
- audio/basic
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