aubio is a library for audio labeling. Its features include segmenting a sound file before each of its attacks, performing pitch detection, tapping the beat and producing midi streams from live audio. The name aubio comes from audio with a typo: several transcription errors are likely to be found in the results too. The aim of this project is to provide these automatic labeling features to other audio software. Functions can be used offline in sound editors and software samplers, or online in audio effects and virtual instruments.