1 files changed, 194 insertions, 0 deletions
diff --git a/src/spectral/specdesc.h b/src/spectral/specdesc.h
new file mode 100644
index 0000000..2cdb87a
--- /dev/null
+++ b/src/spectral/specdesc.h
@@ -0,0 +1,194 @@
+/*
+  Copyright (C) 2003-2013 Paul Brossier <piem@aubio.org>
+
+  This file is part of aubio.
+
+  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.
+
+  aubio is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with aubio.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+/** \file
+
+  Spectral description functions
+
+  All of the following spectral description functions take as arguments the FFT
+  of a windowed signal (as created with aubio_pvoc). They output one smpl_t per
+  buffer (stored in a vector of size [1]).
+
+  \section specdesc Spectral description functions
+
+  A list of the spectral description methods currently available follows.
+
+  \subsection onsetdesc Onset detection functions
+
+  These functions are designed to raise at notes attacks in music signals.
+
+  \b \p energy : Energy based onset detection function
+
+  This function calculates the local energy of the input spectral frame.
+
+  \b \p hfc : High Frequency Content onset detection function
+
+  This method computes the High Frequency Content (HFC) of the input spectral
+  frame. The resulting function is efficient at detecting percussive onsets.
+
+  Paul Masri. Computer modeling of Sound for Transformation and Synthesis of
+  Musical Signal. PhD dissertation, University of Bristol, UK, 1996.
+
+  \b \p complex : Complex Domain Method onset detection function
+
+  Christopher Duxbury, Mike E. Davies, and Mark B. Sandler. Complex domain
+  onset detection for musical signals. In Proceedings of the Digital Audio
+  Effects Conference, DAFx-03, pages 90-93, London, UK, 2003.
+
+  \b \p phase : Phase Based Method onset detection function
+
+  Juan-Pablo Bello, Mike P. Davies, and Mark B. Sandler. Phase-based note onset
+  detection for music signals. In Proceedings of the IEEE International
+  Conference on Acoustics Speech and Signal Processing, pages 441444,
+  Hong-Kong, 2003.
+
+  \b \p specdiff : Spectral difference method onset detection function
+
+  Jonhatan Foote and Shingo Uchihashi. The beat spectrum: a new approach to
+  rhythm analysis. In IEEE International Conference on Multimedia and Expo
+  (ICME 2001), pages 881884, Tokyo, Japan, August 2001.
+
+  \b \p kl : Kullback-Liebler onset detection function
+
+  Stephen Hainsworth and Malcom Macleod. Onset detection in music audio
+  signals. In Proceedings of the International Computer Music Conference
+  (ICMC), Singapore, 2003.
+
+  \b \p mkl : Modified Kullback-Liebler onset detection function
+
+  Paul Brossier, ``Automatic annotation of musical audio for interactive
+  systems'', Chapter 2, Temporal segmentation, PhD thesis, Centre for Digital
+  music, Queen Mary University of London, London, UK, 2006.
+
+  \b \p specflux : Spectral Flux
+
+  Simon Dixon, Onset Detection Revisited, in ``Proceedings of the 9th
+  International Conference on Digital Audio Effects'' (DAFx-06), Montreal,
+  Canada, 2006.
+
+  \subsection shapedesc Spectral shape descriptors
+
+  The following descriptors are described in:
+
+  Geoffroy Peeters, <i>A large set of audio features for sound description
+  (similarity and classification) in the CUIDADO project</i>, CUIDADO I.S.T.
+  Project Report 2004 (<a
+  href="http://www.ircam.fr/anasyn/peeters/ARTICLES/Peeters_2003_cuidadoaudiofeatures.pdf">pdf</a>)
+
+  \b \p centroid : Spectral centroid
+
+  The spectral centroid represents the barycenter of the spectrum.
+
+  \e Note: This function returns the result in bin. To get the spectral
+  centroid in Hz, aubio_bintofreq() should be used.
+
+  \b \p spread : Spectral spread
+
+  The spectral spread is the variance of the spectral distribution around its
+  centroid.
+
+  See also <a href="http://en.wikipedia.org/wiki/Standard_deviation">Standard
+  deviation</a> on Wikipedia.
+
+  \b \p skewness : Spectral skewness
+
+  Similarly, the skewness is computed from the third order moment of the
+  spectrum. A negative skewness indicates more energy on the lower part of the
+  spectrum. A positive skewness indicates more energy on the high frequency of
+  the spectrum.
+
+  See also <a href="http://en.wikipedia.org/wiki/Skewness">Skewness</a> on
+  Wikipedia.
+
+  \b \p kurtosis : Spectral kurtosis
+
+  The kurtosis is a measure of the flatness of the spectrum, computed from the
+  fourth order moment.
+
+  See also <a href="http://en.wikipedia.org/wiki/Kurtosis">Kurtosis</a> on
+  Wikipedia.
+
+  \b \p slope : Spectral slope
+
+  The spectral slope represents decreasing rate of the spectral amplitude,
+  computed using a linear regression.
+
+  \b \p decrease : Spectral decrease
+
+  The spectral decrease is another representation of the decreasing rate,
+  based on perceptual criteria.
+
+  \b \p rolloff : Spectral roll-off
+
+  This function returns the bin number below which 95% of the spectrum energy
+  is found.
+
+  \example spectral/test-specdesc.c
+
+*/
+
+
+#ifndef AUBIO_SPECDESC_H
+#define AUBIO_SPECDESC_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** spectral description structure */
+typedef struct _aubio_specdesc_t aubio_specdesc_t;
+
+/** execute spectral description function on a spectral frame
+
+  Generic function to compute spectral description.
+
+  \param o spectral description object as returned by new_aubio_specdesc()
+  \param fftgrain input signal spectrum as computed by aubio_pvoc_do
+  \param desc output vector (one sample long, to send to the peak picking)
+
+*/
+void aubio_specdesc_do (aubio_specdesc_t * o, const cvec_t * fftgrain,
+    fvec_t * desc);
+
+/** creation of a spectral description object
+
+  \param method spectral description method
+  \param buf_size length of the input spectrum frame
+
+  The parameter \p method is a string that can be any of:
+
+    - `energy`, `hfc`, `complex`, `phase`, `specdiff`, `kl`, `mkl`, `specflux`
+    - `centroid`, `spread`, `skewness`, `kurtosis`, `slope`, `decrease`, `rolloff`
+
+*/
+aubio_specdesc_t *new_aubio_specdesc (const char_t * method, uint_t buf_size);
+
+/** deletion of a spectral descriptor
+
+  \param o spectral descriptor object as returned by new_aubio_specdesc()
+
+*/
+void del_aubio_specdesc (aubio_specdesc_t * o);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* AUBIO_SPECDESC_H */