File Formats

Audacity Project format (AUP)

Audacity projects are stored in an AUP file, which is a format that has been highly optimized for Audacity so that it can open and save projects extremely quickly. In order to achieve this speed, Audacity breaks larger audio files into several smaller pieces and stores these pieces in a directory with a similar name as the project. For example, if you name a project "chanson", then Audacity will create a project file called chanson.aup which stores the general information about your project, and it will store your audio in several files inside a directory called chanson_data. The Audacity Project format is not compatible with any other audio programs, so when you are finished working on a project and you want to be able to edit the audio in another program, select Export.

WAV (Windows Wave format)

This is the default uncompressed audio format on Windows, and is supported on almost all computer systems. It can also be lightly compressed (about 4:1) using the ADPCM codec, but this is less widely supported on non-windows platforms. Audacity can read and write this format, including ADPCM on all platforms.

AIFF (Audio Interchange File Format)

This is the default uncompressed audio format on the Macintosh, and it is supported by most computer systems, but it is not quite as common as the WAV format. Audacity can read and write this format.

Sun Au / NeXT

This is the default audio format on Sun and NeXT computers, and it is usually u-law compressed so not very high quality. U-law compression is a very simple, fast but low quality way to reduce the size of the audio by about 50%. It is widely used in American telephone systems.
This format was one of the first audio formats supported by Web browsers, and it is still often used for short sound effects where quality is not as important. Audacity can read this format, and write files either in 8-bit u-law compressed or 16-bit uncompressed variants.

IRCAM (Institut de Recherce et Coordination Acoustique/Musique)

This is a very general file format that is commonly used by computer music researchers. Audacity can read this format.

MP3 (MPEG I, layer 3)

This is a compressed audio format that is a very popular way to store music. It can compress audio by a factor of 10:1 with little degradation in quality. Audacity can both import and export this format. For more information on how to export MP3 files from within Audacity, see Exporting MP3 Files.

Ogg Vorbis

This is a new compressed audio format that was designed to be a free alternative to MP3 files. Ogg Vorbis files are not as common, but they are about the same size as MP3 with better quality and no patent restrictions. Audacity can import and export this format.