source: src/spectral/mfcc.c @ 6c7d49b

feature/autosinkfeature/constantqfeature/pitchshiftfeature/pydocstringsfeature/timestretchpitchshiftsamplertimestretchyinfft+
Last change on this file since 6c7d49b was 6c7d49b, checked in by Paul Brossier <piem@piem.org>, 12 years ago

remove src/sample.h

  • Property mode set to 100644
File size: 3.8 KB
Line 
1/*
2   Copyright (C) 2006 Amaury Hazan
3   Ported to aubio from LibXtract
4   http://libxtract.sourceforge.net/
5   
6
7   This program 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 2 of the License, or
10   (at your option) any later version.
11
12   This program 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.
16
17   You should have received a copy of the GNU General Public License
18   along with this program; if not, write to the Free Software
19   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20
21*/
22
23#include "aubio_priv.h"
24#include "fvec.h"
25#include "cvec.h"
26#include "spectral/fft.h"
27#include "spectral/filterbank.h"
28#include "spectral/mfcc.h"
29
30/** Internal structure for mfcc object **/
31
32struct aubio_mfcc_t_{
33  uint_t win_s;             /** grain length */
34  uint_t samplerate;        /** sample rate (needed?) */
35  uint_t channels;          /** number of channels */
36  uint_t n_filters;         /** number of  *filters */
37  uint_t n_coefs;           /** number of coefficients (<= n_filters/2 +1) */
38  smpl_t lowfreq;           /** lowest frequency for filters */ 
39  smpl_t highfreq;          /** highest frequency for filters */
40  aubio_filterbank_t * fb;  /** filter bank */
41  fvec_t * in_dct;          /** input buffer for dct * [fb->n_filters] */
42  aubio_fft_t * fft_dct;   /** fft object for dct */
43  cvec_t * fftgrain_dct;    /** output buffer for dct */
44};
45
46
47aubio_mfcc_t * new_aubio_mfcc (uint_t win_s, uint_t samplerate, uint_t n_filters, uint_t n_coefs, smpl_t lowfreq, smpl_t highfreq, uint_t channels){
48  /** allocating space for mfcc object */
49  aubio_mfcc_t * mfcc = AUBIO_NEW(aubio_mfcc_t);
50
51  //we need (n_coefs-1)*2 filters to obtain n_coefs coefficients after dct
52  //uint_t n_filters = (n_coefs-1)*2;
53 
54  mfcc->win_s=win_s;
55  mfcc->samplerate=samplerate;
56  mfcc->channels=channels;
57  mfcc->n_filters=n_filters;
58  mfcc->n_coefs=n_coefs;
59  mfcc->lowfreq=lowfreq;
60  mfcc->highfreq=highfreq;
61
62 
63  /** filterbank allocation */
64  mfcc->fb = new_aubio_filterbank_mfcc(n_filters, mfcc->win_s, samplerate, lowfreq, highfreq);
65
66  /** allocating space for fft object (used for dct) */
67  mfcc->fft_dct=new_aubio_fft(n_filters, 1);
68
69  /** allocating buffers */
70  mfcc->in_dct=new_fvec(mfcc->win_s, 1);
71 
72  mfcc->fftgrain_dct=new_cvec(n_filters, 1);
73
74  return mfcc;
75};
76
77void del_aubio_mfcc(aubio_mfcc_t *mf){
78  /** deleting filterbank */
79  del_aubio_filterbank(mf->fb);
80  /** deleting fft object */
81  del_aubio_fft(mf->fft_dct);
82  /** deleting buffers */
83  del_fvec(mf->in_dct);
84  del_cvec(mf->fftgrain_dct);
85 
86  /** deleting mfcc object */
87  AUBIO_FREE(mf);
88}
89
90
91/** intermediate dct involved in aubio_mfcc_do
92
93  \param mf mfcc object as returned by new_aubio_mfcc
94  \param in input spectrum (n_filters long)
95  \param out output mel coefficients buffer (n_filters/2 +1 long)
96
97*/
98void aubio_dct_do(aubio_mfcc_t * mf, fvec_t *in, fvec_t *out);
99
100void aubio_mfcc_do(aubio_mfcc_t * mf, cvec_t *in, fvec_t *out){
101    // compute filterbank
102    aubio_filterbank_do(mf->fb, in, mf->in_dct);
103    //TODO: check that zero padding
104    // the following line seems useless since the in_dct buffer has the correct size
105    //for(n = filter + 1; n < N; n++) result[n] = 0;
106   
107    aubio_dct_do(mf, mf->in_dct, out);
108
109    return;
110}
111
112void aubio_dct_do(aubio_mfcc_t * mf, fvec_t *in, fvec_t *out){
113    uint_t i;
114    //compute mag spectrum
115    aubio_fft_do (mf->fft_dct, in, mf->fftgrain_dct);
116    //extract real part of fft grain
117    for(i=0; i<mf->n_coefs ;i++){
118    //for(i=0; i<out->length;i++){
119      out->data[0][i]= mf->fftgrain_dct->norm[0][i]
120        *COS(mf->fftgrain_dct->phas[0][i]);
121    }
122    return;
123}
124
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