2 Copyright (C) 2007-2013 Paul Brossier <piem@aubio.org>
3 and Amaury Hazan <ahazan@iua.upf.edu>
5 This file is part of aubio.
7 aubio is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
12 aubio is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with aubio. If not, see <http://www.gnu.org/licenses/>.
24 Mel-Frequency Cepstrum Coefficients object
26 This object computes MFCC coefficients on an input cvec_t.
28 The implementation follows the specifications established by Malcolm Slaney
29 in its Auditory Toolbox, available online at the following address (see
32 https://engineering.purdue.edu/~malcolm/interval/1998-010/
34 \example spectral/test-mfcc.c
47 typedef struct _aubio_mfcc_t aubio_mfcc_t;
49 /** create mfcc object
51 \param buf_size size of analysis buffer (and length the FFT transform)
52 \param samplerate audio sampling rate
53 \param n_coeffs number of desired coefficients
54 \param n_filters number of desired filters
57 aubio_mfcc_t *new_aubio_mfcc (uint_t buf_size,
58 uint_t n_filters, uint_t n_coeffs, uint_t samplerate);
60 /** delete mfcc object
62 \param mf mfcc object as returned by new_aubio_mfcc
65 void del_aubio_mfcc (aubio_mfcc_t * mf);
67 /** mfcc object processing
69 \param mf mfcc object as returned by new_aubio_mfcc
70 \param in input spectrum (buf_size long)
71 \param out output mel coefficients buffer (n_coeffs long)
74 void aubio_mfcc_do (aubio_mfcc_t * mf, const cvec_t * in, fvec_t * out);
76 /** set power parameter
78 \param mf mfcc object, as returned by new_aubio_mfcc()
79 \param power Raise norm of the input spectrum norm to this power before
80 computing filterbank. Defaults to `1`.
82 See aubio_filterbank_set_power().
85 uint_t aubio_mfcc_set_power (aubio_mfcc_t *mf, smpl_t power);
87 /** get power parameter
89 \param mf mfcc object, as returned by new_aubio_mfcc()
90 \return current power parameter. Defaults to `1`.
92 See aubio_filterbank_get_power().
95 smpl_t aubio_mfcc_get_power (aubio_mfcc_t *mf);
97 /** set scaling parameter
99 \param mf mfcc object, as returned by new_aubio_mfcc()
100 \param scale Scaling value to apply.
102 Scales the output of the filterbank after taking its logarithm and before
103 computing the DCT. Defaults to `1`.
106 uint_t aubio_mfcc_set_scale (aubio_mfcc_t *mf, smpl_t scale);
108 /** get scaling parameter
110 \param mf mfcc object, as returned by new_aubio_mfcc()
111 \return current scaling parameter. Defaults to `1`.
114 smpl_t aubio_mfcc_get_scale (aubio_mfcc_t *mf);
116 /** Mel filterbank initialization
118 \param mf mfcc object
119 \param fmin start frequency, in Hz
120 \param fmax end frequency, in Hz
122 The filterbank will be initialized with bands linearly spaced in the mel
123 scale, from `fmin` to `fmax`.
128 aubio_filterbank_set_mel_coeffs()
131 uint_t aubio_mfcc_set_mel_coeffs (aubio_mfcc_t *mf,
132 smpl_t fmin, smpl_t fmax);
134 /** Mel filterbank initialization
136 \param mf mfcc object
137 \param fmin start frequency, in Hz
138 \param fmax end frequency, in Hz
140 The bank of filters will be initalized to to cover linearly spaced bands in
141 the Htk mel scale, from `fmin` to `fmax`.
146 aubio_filterbank_set_mel_coeffs_htk()
149 uint_t aubio_mfcc_set_mel_coeffs_htk (aubio_mfcc_t *mf,
150 smpl_t fmin, smpl_t fmax);
152 /** Mel filterbank initialization (Auditory Toolbox's parameters)
154 \param mf mfcc object
156 The filter coefficients are built to match exactly Malcolm Slaney's Auditory
157 Toolbox implementation. The number of filters should be 40.
159 This is the default filterbank when `mf` was created with `n_filters = 40`.
164 aubio_filterbank_set_mel_coeffs_slaney()
167 uint_t aubio_mfcc_set_mel_coeffs_slaney (aubio_mfcc_t *mf);
173 #endif /* AUBIO_MFCC_H */