Audio project file created by Audacity, a free sound editor and recorder; saved in an XML format and contains references to audio files as well as any applied sound edits; used for saving audio editing work.

AUP files are saved with a corresponding folder named myproject_data, where myproject.aup is the project filename. This folder saves small chunks of audio data in an optimized, proprietary format that can only be opened by Audacity (the files use the ".au" extension). When finished with sound editing, you can export an audio project to many different formats, including .WAV, .AIFF, .MP3, .M4A, and .WMA.