ref: 88199cee9bb703d33e28636e043109db53681ccb
dir: /src/mfcc.h/
/*
Copyright (C) 2006 Amaury Hazan
Ported to aubio from LibXtract
http://libxtract.sourceforge.net/
This program 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 2 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef MFCC_H
#define MFCC_H
#define NYQUIST 22050.f
//libXtract enums
// TODO: remove them
/** \brief Enumeration of feature initialisation functions */
enum xtract_feature_init_ {
XTRACT_INIT_MFCC = 100,
XTRACT_INIT_BARK
};
/** \brief Enumeration of feature types */
enum xtract_feature_types_ {
XTRACT_SCALAR,
XTRACT_VECTOR,
XTRACT_DELTA
};
/** \brief Enumeration of mfcc types */
enum xtract_mfcc_types_ {
XTRACT_EQUAL_GAIN,
XTRACT_EQUAL_AREA
};
/** \brief Enumeration of return codes */
enum xtract_return_codes_ {
XTRACT_SUCCESS,
XTRACT_MALLOC_FAILED,
XTRACT_BAD_ARGV,
XTRACT_BAD_VECTOR_SIZE,
XTRACT_NO_RESULT,
XTRACT_FEATURE_NOT_IMPLEMENTED
};
/** \brief Enumeration of spectrum types */
enum xtract_spectrum_ {
XTRACT_MAGNITUDE_SPECTRUM,
XTRACT_LOG_MAGNITUDE_SPECTRUM,
XTRACT_POWER_SPECTRUM,
XTRACT_LOG_POWER_SPECTRUM
};
/** \brief Enumeration of data types*/
typedef enum type_ {
XTRACT_FLOAT,
XTRACT_FLOATARRAY,
XTRACT_INT,
XTRACT_MEL_FILTER
} xtract_type_t;
/** \brief Enumeration of units*/
typedef enum unit_ {
/* NONE, ANY */
XTRACT_HERTZ = 2,
XTRACT_ANY_AMPLITUDE_HERTZ,
XTRACT_DBFS,
XTRACT_DBFS_HERTZ,
XTRACT_PERCENT,
XTRACT_SONE
} xtract_unit_t;
/** \brief Boolean */
typedef enum {
XTRACT_FALSE,
XTRACT_TRUE
} xtract_bool_t;
/** \brief Enumeration of vector format types*/
typedef enum xtract_vector_ {
/* N/2 magnitude/log-magnitude/power/log-power coeffs and N/2 frequencies */
XTRACT_SPECTRAL,
/* N spectral amplitudes */
XTRACT_SPECTRAL_MAGNITUDES,
/* N/2 magnitude/log-magnitude/power/log-power peak coeffs and N/2
* frequencies */
XTRACT_SPECTRAL_PEAKS,
/* N spectral peak amplitudes */
XTRACT_SPECTRAL_PEAKS_MAGNITUDES,
/* N spectral peak frequencies */
XTRACT_SPECTRAL_PEAKS_FREQUENCIES,
/* N/2 magnitude/log-magnitude/power/log-power harmonic peak coeffs and N/2
* frequencies */
XTRACT_SPECTRAL_HARMONICS,
/* N spectral harmonic amplitudes */
XTRACT_SPECTRAL_HARMONICS_MAGNITUDES,
/* N spectral harmonic frequencies */
XTRACT_SPECTRAL_HARMONICS_FREQUENCIES,
XTRACT_ARBITRARY_SERIES,
XTRACT_AUDIO_SAMPLES,
XTRACT_MEL_COEFFS,
XTRACT_BARK_COEFFS,
XTRACT_NO_DATA
} xtract_vector_t;
// Computation
/** \brief Extract Mel Frequency Cepstral Coefficients based on a method described by Rabiner
*
* \param *data: a pointer to the first element in an array of spectral magnitudes, e.g. the first half of the array pointed to by *resul from xtract_spectrum()
* \param N: the number of array elements to be considered
* \param *argv: a pointer to a data structure of type xtract_mel_filter, containing n_filters coefficient tables to make up a mel-spaced filterbank
* \param *result: a pointer to an array containing the resultant MFCC
*
* The data structure pointed to by *argv must be obtained by first calling xtract_init_mfcc
*/
int aubio_mfcc_do(const float *data, const int N, const void *argv, float *result);
/** \brief Extract the Discrete Cosine transform of a time domain signal
* \param *data: a pointer to the first element in an array of floats representing an audio vector
* \param N: the number of array elements to be considered
* \param *argv: a pointer to NULL
* \param *result: a pointer to an array containing resultant dct coefficients
*/
int aubio_dct_do(const float *data, const int N, const void *argv, float *result);
#endif