source: src/spectral/filterbank_mel.c @ 3b3b03e

feature/autosinkfeature/cnnfeature/cnn_orgfeature/constantqfeature/crepefeature/crepe_orgfeature/pitchshiftfeature/pydocstringsfeature/timestretchfix/ffmpeg5pitchshiftsamplertimestretchyinfft+
Last change on this file since 3b3b03e was 06cae6c, checked in by Paul Brossier <piem@piem.org>, 15 years ago

src/spectral/filterbank.c: refactorise filter bank, split mel frequency coefficients to src/spectral/filterbank_mel.c, start bumping license to GPLv3

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File size: 5.4 KB
Line 
1/*
2  Copyright (C) 2007-2009 Paul Brossier <piem@aubio.org>
3                      and Amaury Hazan <ahazan@iua.upf.edu>
4
5  This file is part of Aubio.
6
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.
11
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.
16
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/>.
19
20*/
21
22#include "aubio_priv.h"
23#include "fvec.h"
24#include "cvec.h"
25#include "spectral/filterbank.h"
26#include "mathutils.h"
27
28void aubio_filterbank_set_mel_coeffs(aubio_filterbank_t *fb, uint_t samplerate, smpl_t freq_min, smpl_t freq_max){
29
30  fvec_t *filters = aubio_filterbank_get_coeffs(fb);
31  uint_t n_filters = filters->channels, win_s = filters->length;
32 
33  //slaney params
34  smpl_t lowestFrequency = 133.3333;
35  smpl_t linearSpacing = 66.66666666;
36  smpl_t logSpacing = 1.0711703;
37
38  uint_t linearFilters = 13;
39  uint_t logFilters = 27;
40  uint_t allFilters = linearFilters + logFilters;
41 
42  //buffers for computing filter frequencies
43  fvec_t * freqs=new_fvec(allFilters+2 , 1);
44 
45  fvec_t * lower_freqs=new_fvec( allFilters, 1);
46  fvec_t * upper_freqs=new_fvec( allFilters, 1);
47  fvec_t * center_freqs=new_fvec( allFilters, 1);
48
49  fvec_t * triangle_heights=new_fvec( allFilters, 1);
50  //lookup table of each bin frequency in hz
51  fvec_t * fft_freqs=new_fvec(win_s, 1);
52
53  uint_t filter_cnt, bin_cnt;
54 
55  //first step: filling all the linear filter frequencies
56  for(filter_cnt=0; filter_cnt<linearFilters; filter_cnt++){
57    freqs->data[0][filter_cnt]=lowestFrequency+ filter_cnt*linearSpacing;
58  }
59  smpl_t lastlinearCF=freqs->data[0][filter_cnt-1];
60 
61  //second step: filling all the log filter frequencies
62  for(filter_cnt=0; filter_cnt<logFilters+2; filter_cnt++){
63    freqs->data[0][filter_cnt+linearFilters] = 
64      lastlinearCF*(pow(logSpacing,filter_cnt+1));
65  }
66
67  //Option 1. copying interesting values to lower_freqs, center_freqs and upper freqs arrays
68  //TODO: would be nicer to have a reference to freqs->data, anyway we do not care in this init step
69   
70  for(filter_cnt=0; filter_cnt<allFilters; filter_cnt++){
71    lower_freqs->data[0][filter_cnt]=freqs->data[0][filter_cnt];
72    center_freqs->data[0][filter_cnt]=freqs->data[0][filter_cnt+1];
73    upper_freqs->data[0][filter_cnt]=freqs->data[0][filter_cnt+2];
74  }
75
76  //computing triangle heights so that each triangle has unit area
77  for(filter_cnt=0; filter_cnt<allFilters; filter_cnt++){
78    triangle_heights->data[0][filter_cnt] = 2./(upper_freqs->data[0][filter_cnt] 
79      - lower_freqs->data[0][filter_cnt]);
80  }
81 
82  //AUBIO_DBG("filter tables frequencies\n");
83  //for(filter_cnt=0; filter_cnt<allFilters; filter_cnt++)
84  //  AUBIO_DBG("filter n. %d %f %f %f %f\n",
85  //    filter_cnt, lower_freqs->data[0][filter_cnt],
86  //    center_freqs->data[0][filter_cnt], upper_freqs->data[0][filter_cnt],
87  //    triangle_heights->data[0][filter_cnt]);
88
89  //filling the fft_freqs lookup table, which assigns the frequency in hz to each bin
90  for(bin_cnt=0; bin_cnt<win_s; bin_cnt++){
91    fft_freqs->data[0][bin_cnt]= aubio_bintofreq(bin_cnt, samplerate, win_s);
92  }
93
94  //building each filter table
95  for(filter_cnt=0; filter_cnt<allFilters; filter_cnt++){
96
97    //TODO:check special case : lower freq =0
98    //calculating rise increment in mag/Hz
99    smpl_t riseInc= triangle_heights->data[0][filter_cnt]/(center_freqs->data[0][filter_cnt]-lower_freqs->data[0][filter_cnt]);
100   
101    //zeroing begining of filter
102    for(bin_cnt=0; bin_cnt<win_s-1; bin_cnt++){
103      filters->data[filter_cnt][bin_cnt]=0.0;
104      if( fft_freqs->data[0][bin_cnt]  <= lower_freqs->data[0][filter_cnt] &&
105          fft_freqs->data[0][bin_cnt+1] > lower_freqs->data[0][filter_cnt]) {
106        break;
107      }
108    }
109    bin_cnt++;
110   
111    //positive slope
112    for(; bin_cnt<win_s-1; bin_cnt++){
113      filters->data[filter_cnt][bin_cnt]=(fft_freqs->data[0][bin_cnt]-lower_freqs->data[0][filter_cnt])*riseInc;
114      //if(fft_freqs->data[0][bin_cnt]<= center_freqs->data[0][filter_cnt] && fft_freqs->data[0][bin_cnt+1]> center_freqs->data[0][filter_cnt])
115      if(fft_freqs->data[0][bin_cnt+1]> center_freqs->data[0][filter_cnt])
116        break;
117    }
118    //bin_cnt++;
119   
120    //negative slope
121    for(; bin_cnt<win_s-1; bin_cnt++){
122     
123      //checking whether last value is less than 0...
124      smpl_t val=triangle_heights->data[0][filter_cnt]-(fft_freqs->data[0][bin_cnt]-center_freqs->data[0][filter_cnt])*riseInc;
125      if(val>=0)
126        filters->data[filter_cnt][bin_cnt]=val;
127      else filters->data[filter_cnt][bin_cnt]=0.0;
128     
129      //if(fft_freqs->data[0][bin_cnt]<= upper_freqs->data[0][bin_cnt] && fft_freqs->data[0][bin_cnt+1]> upper_freqs->data[0][filter_cnt])
130      //TODO: CHECK whether bugfix correct
131      if(fft_freqs->data[0][bin_cnt+1]> upper_freqs->data[0][filter_cnt])
132        break;
133    }
134    //bin_cnt++;
135   
136    //zeroing tail
137    for(; bin_cnt<win_s; bin_cnt++)
138      filters->data[filter_cnt][bin_cnt]=0.f;
139
140  }
141 
142  /* destroy temporarly allocated vectors */ 
143  del_fvec(freqs);
144  del_fvec(lower_freqs);
145  del_fvec(upper_freqs);
146  del_fvec(center_freqs);
147
148  del_fvec(triangle_heights);
149  del_fvec(fft_freqs);
150
151}
152
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