Was ist AU? Sun Audio Format erklärt
Ein einfaches Big-Endian-Audioformat von Sun Microsystems, lange ein de facto Unix-Soundstandard.
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What is it?
AU is a simple audio file format introduced by Sun Microsystems and historically associated with Unix and NeXT systems, where files typically carry the .au extension (Sun) or .snd extension (NeXT). It became a de facto standard for system sounds on Unix-like platforms and was widely used for short audio clips on early web pages.
An AU file begins with the four-byte magic number 0x2E736E64 (the ASCII string '.snd'), followed by a header of six big-endian 32-bit fields specifying the data offset, data size, encoding, sample rate, and channel count, then optional annotation text and the audio data itself. The original default encoding was 8-bit G.711 mu-law sampled at 8000 Hz, but the encoding field also allows linear PCM, A-law, ADPCM, and floating-point data.
Technical Specifications
Pros & Cons
Advantages
A short, fixed header followed by raw audio makes AU files easy to parse, generate, and stream without complex containers.
As a Unix standard, AU is readable by many cross-platform tools and was natively supported by the Java Sound API and early browsers.
The data size can be left unspecified, allowing audio to be written or transmitted as a continuous stream of unknown length.
The encoding field supports many sample formats, from 8-bit mu-law telephony audio to 16/24/32-bit linear PCM and floating point.
Disadvantages
Beyond an optional free-text annotation field, AU has no structured support for tags, cover art, or rich metadata.
AU has been superseded by WAV, AIFF, and modern codecs, and is rarely used in new audio workflows today.
Its classic 8-bit mu-law, 8000 Hz default offers only telephone-grade quality unless higher-resolution PCM encodings are used.
When to Use It
AU appears mainly in legacy Unix audio, programming environments, and historical web content.
Unix-Systemklänge
AU served as the native sound format on Sun, NeXT, and other Unix workstations for alerts and recorded clips.
Java-Audio
Early Java applets and the Java Sound API used AU as a built-in format for short sound effects and clips.
Frühes Web-Audio
Small AU files were common for embedded sounds on 1990s web pages before MP3 and streaming formats took over.
How to open a AU file
The software landscape for working with AU files includes professional audio editing suites, free and open-source tools, browser-based applications, and built-in system utilities. Professional tools are ideal for audio engineers and musicians needing advanced features, while free and open-source options cater to hobbyists and those on a budget. Browser-based applications offer convenience for quick tasks, and built-in utilities provide basic functionality for casual users.
When choosing software for AU files, key decision factors include feature fidelity, the distinction between editing and viewing capabilities, cost, platform compatibility, and export needs. Users should consider whether they require advanced editing features or simple playback, as well as whether they need to convert AU files to other formats for broader compatibility. In some cases, converting AU files to more widely supported formats may be the better option.
Audacity 3.2.1
Audacity is a free, open-source audio editing software that supports AU files for both viewing and editing. It provides a robust set of tools for manipulating audio tracks with high fidelity, making it suitable for both casual users and professionals.
- Multi-track editing and mixing
- Support for various audio formats
- Real-time audio effects processing
- Spectrogram view for frequency analysis
- Batch processing for multiple files
- Completely free with no limitations
- Extensive community support and plugins
- Cross-platform compatibility
- Interface can be overwhelming for beginners
- Limited support for advanced MIDI features
Exportiert nach: WAV, MP3, OGG, FLAC
Am besten für: Audacity is ideal for users seeking a powerful, free tool for editing AU files with extensive community support.
Besuchen Audacity →Adobe Audition 2023
Adobe Audition is a professional audio editing software that offers comprehensive support for AU files, allowing users to edit, mix, and restore audio with high precision. Its advanced features cater to sound designers and audio engineers looking for top-tier fidelity.
- Multi-track editing with unlimited tracks
- Advanced noise reduction tools
- Support for VST and AU plugins
- Integrated video editing capabilities
- Dynamic mixing and mastering tools
- Industry-standard software with extensive features
- Seamless integration with Adobe Creative Cloud
- High-quality audio processing and effects
- Subscription model can be costly
- Steeper learning curve for beginners
Exportiert nach: WAV, MP3, AAC, AIFF
Am besten für: Adobe Audition is perfect for professionals needing a comprehensive audio editing solution with robust AU support.
Besuchen Adobe Audition →VLC Media Player 3.0.16
VLC Media Player is a versatile media player that can play AU files without the need for additional codecs. While primarily designed for playback, it offers basic editing features and is suitable for users who need to quickly access AU audio.
- Playback of various audio and video formats
- Basic audio effects and equalizer
- Streaming capabilities for audio files
- Playlist management and organization
- Lightweight and fast performance
- Completely free and open-source
- Cross-platform support with no ads
- Easy to use for quick playback
- Limited editing capabilities compared to dedicated software
- Not suitable for professional audio work
Exportiert nach: MP3, OGG, WAV
Am besten für: VLC Media Player is ideal for users who need a free, simple solution for playing AU files without advanced editing needs.
Besuchen VLC Media Player →Sound Forge Pro 15.0
Sound Forge Pro is a professional audio editing software that provides extensive support for AU files, allowing for high-quality audio manipulation and mastering. It is designed for audio professionals who require detailed editing capabilities and high fidelity.
- High-resolution audio recording
- Comprehensive audio restoration tools
- Support for multi-channel audio editing
- Advanced spectral analysis features
- Batch processing for efficiency
- Professional-grade audio editing features
- Excellent audio quality and fidelity
- User-friendly interface for experienced users
- High one-time purchase cost
- Windows-only platform limits accessibility
Exportiert nach: WAV, MP3, FLAC, OGG
Am besten für: Sound Forge Pro is best for audio professionals seeking a powerful, one-time purchase solution for editing AU files.
Besuchen Sound Forge Pro →Convert AU Files Free
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