What is an AU file?
The .AU file extension primarily represents an Audacity Audio File. Audacity, a popular open-source audio editor, uses .AU files as small data blocks to store raw audio segments of a larger project. Sometimes, .AU files are also standard Sun/NeXT audio files historically developed by Sun Microsystems. In rare cases, they can even be renamed .MP4 video files generated by the VidMate Android application.
Because .AU has multiple possible meanings, viewer.online/au analyzes .AU files to identify their exact format and creator software, shows which programs can open the file, and usually previews it.
How to open AU files?
To open an Audacity Audio File, you typically do not open the .AU file directly. Instead, you open the main .AUP or .AUP3 project file in Audacity, which automatically loads the associated .AU data blocks. If you have a legacy Sun/NeXT audio file, you can play it using modern media players like VLC media player or process it using command-line tools like SoX. If your file is a renamed video, tools like GPAC can handle it.
Best practices and troubleshooting
If you find a folder full of .AU files, do not move or rename them. They belong to an Audacity project, and changing them will corrupt your audio session. For standalone audio tracks, you can easily convert playable .AU files to standard formats using convert.guru. We recommend converting them to .MP3 or .WAV for universal playback compatibility.
Summary
viewer.online/au directly opens and previews .AU files in the browser, eliminating the need to install software or troubleshoot compatibility issues.