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a library for audio labeling: pitch, onset, tempo tracking, and more

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aubio library

aubio is a library to label music and sounds. It listens to audio signals and attempts to detect events. For instance, when a drum is hit, at which frequency is a note, or at what tempo is a rhythmic melody.

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.

aubio provide several algorithms and routines, including:

  • several onset detection methods
  • different pitch detection methods
  • tempo tracking and beat detection
  • MFCC (mel-frequency cepstrum coefficients)
  • FFT and phase vocoder
  • up/down-sampling
  • digital filters (low pass, high pass, and more)
  • spectral filtering
  • transient/steady-state separation
  • sound file and audio devices read and write access
  • various mathematics utilities for music applications

The name aubio comes from audio with a typo: some errors are likely to be found in the results.

Python module

A python module to access the library functions is also provided. Please see the file python/README for more information on how to use it.

Examples tools

A few simple command line tools are included along with the library:

  • aubioonset outputs the time stamp of detected note onsets
  • aubiopitch attempts to identify a fundamental frequency, or pitch, for each frame of the input sound
  • aubiomfcc computes Mel-frequency Cepstrum Coefficients
  • aubiotrack outputs the time stamp of detected beats
  • aubionotes emits midi-like notes, with an onset, a pitch, and a duration
  • aubioquiet extracts quiet and loud regions

Additionaly, the python module comes with the following script:

  • aubiocut slices sound files at onset or beat timestamps

Implementation and Design Basics

The library is written in C and is optimised for speed and portability.

The C API is designed in the following way:

aubio_something_t * new_aubio_something (void * args);
audio_something_do (aubio_something_t * t, void * args);
smpl_t aubio_something_get_a_parameter (aubio_something_t *t);
uint_t aubio_something_set_a_parameter (aubio_something_t *t, smpl_t a_parameter);
void del_aubio_something (aubio_something_t * t);

For performance and real-time operation, no memory allocation or freeing take place in the _do methods. Instead, memory allocation should always take place in the new_ methods, whereas free operations are done in the del_ methods.

The latest version of the documentation can be found at:

Installation and Build Instructions

A number of distributions already include aubio. Check your favorite package management system, or have a look at the download page.

aubio uses waf to configure, compile, and test the source:

./waf configure
./waf build
sudo ./waf install

aubio compiles on Linux, Mac OS X, Cygwin, and iPhone.

Credits and Publications

This library gathers music signal processing algorithms designed at the Centre for Digital Music and elsewhere. This software project was developed along the research I did at the Centre for Digital Music, Queen Mary, University of London. Most of this C code was written by myself, starting from published papers and existing code. The header files of each algorithm contains brief descriptions and references to the corresponding papers.

Special thanks go Juan Pablo Bello, Chris Duxbury, Samer Abdallah, Alain de Cheveigne for their help and publications. Also many thanks to Miguel Ramirez and Nicolas Wack for their bug fixing.

Substantial informations about the algorithms and their evaluation are gathered in:

Additional results obtained with this software were discussed in the following papers:

Contact Info and Mailing List

The home page of this project can be found at:

Questions, comments, suggestions, and contributions are welcome. Use the mailing list:

To subscribe to the list, use the mailman form:

Alternatively, feel free to contact directly the author.

Copyright and License Information

Copyright (C) 2003-2013 Paul Brossier

aubio is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

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