1 | /* |
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2 | Copyright (C) 2007-2009 Paul Brossier <piem@aubio.org> |
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3 | and Amaury Hazan <ahazan@iua.upf.edu> |
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4 | |
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5 | This file is part of aubio. |
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6 | |
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7 | aubio is free software: you can redistribute it and/or modify |
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8 | it under the terms of the GNU General Public License as published by |
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9 | the Free Software Foundation, either version 3 of the License, or |
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10 | (at your option) any later version. |
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11 | |
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12 | aubio is distributed in the hope that it will be useful, |
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13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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15 | GNU General Public License for more details. |
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16 | |
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17 | You should have received a copy of the GNU General Public License |
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18 | along with aubio. If not, see <http://www.gnu.org/licenses/>. |
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19 | |
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20 | */ |
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21 | |
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22 | #include "aubio_priv.h" |
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23 | #include "fvec.h" |
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24 | #include "cvec.h" |
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25 | #include "spectral/filterbank.h" |
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26 | #include "mathutils.h" |
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27 | |
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28 | void |
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29 | aubio_filterbank_set_mel_coeffs (aubio_filterbank_t * fb, fvec_t * freqs, |
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30 | smpl_t samplerate) |
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31 | { |
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32 | |
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33 | fvec_t *filters = aubio_filterbank_get_coeffs (fb); |
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34 | uint_t n_filters = filters->channels, win_s = filters->length; |
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35 | |
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36 | uint_t fn; /* filter counter */ |
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37 | uint_t bin; /* bin counter */ |
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38 | |
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39 | /* freqs define the bands of triangular overlapping windows. |
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40 | throw a warning if filterbank object fb is too short. */ |
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41 | if (freqs->length - 2 > n_filters) { |
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42 | AUBIO_WRN ("not enough filters, %d allocated but %d requested\n", |
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43 | n_filters, freqs->length - 2); |
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44 | } |
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45 | |
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46 | /* convenience reference to lower/center/upper frequency for each triangle */ |
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47 | fvec_t *lower_freqs = new_fvec (n_filters, 1); |
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48 | fvec_t *upper_freqs = new_fvec (n_filters, 1); |
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49 | fvec_t *center_freqs = new_fvec (n_filters, 1); |
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50 | |
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51 | /* height of each triangle */ |
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52 | fvec_t *triangle_heights = new_fvec (n_filters, 1); |
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53 | |
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54 | /* lookup table of each bin frequency in hz */ |
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55 | fvec_t *fft_freqs = new_fvec (win_s, 1); |
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56 | |
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57 | /* fill up the lower/center/upper */ |
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58 | for (fn = 0; fn < n_filters; fn++) { |
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59 | lower_freqs->data[0][fn] = freqs->data[0][fn]; |
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60 | center_freqs->data[0][fn] = freqs->data[0][fn + 1]; |
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61 | upper_freqs->data[0][fn] = freqs->data[0][fn + 2]; |
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62 | } |
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63 | |
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64 | /* compute triangle heights so that each triangle has unit area */ |
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65 | for (fn = 0; fn < n_filters; fn++) { |
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66 | triangle_heights->data[0][fn] = |
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67 | 2. / (upper_freqs->data[0][fn] - lower_freqs->data[0][fn]); |
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68 | } |
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69 | |
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70 | /* fill fft_freqs lookup table, which assigns the frequency in hz to each bin */ |
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71 | for (bin = 0; bin < win_s; bin++) { |
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72 | fft_freqs->data[0][bin] = aubio_bintofreq (bin, samplerate, (win_s - 1) * 2); |
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73 | } |
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74 | |
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75 | /* zeroing of all filters */ |
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76 | fvec_zeros (filters); |
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77 | |
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78 | /* building each filter table */ |
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79 | for (fn = 0; fn < n_filters; fn++) { |
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80 | |
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81 | /* skip first elements */ |
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82 | for (bin = 0; bin < win_s - 1; bin++) { |
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83 | if (fft_freqs->data[0][bin] <= lower_freqs->data[0][fn] && |
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84 | fft_freqs->data[0][bin + 1] > lower_freqs->data[0][fn]) { |
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85 | break; |
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86 | } |
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87 | } |
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88 | bin++; |
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89 | |
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90 | /* compute positive slope step size */ |
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91 | smpl_t riseInc = |
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92 | triangle_heights->data[0][fn] / |
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93 | (center_freqs->data[0][fn] - lower_freqs->data[0][fn]); |
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94 | |
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95 | /* compute coefficients in positive slope */ |
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96 | for (; bin < win_s - 1; bin++) { |
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97 | filters->data[fn][bin] = |
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98 | (fft_freqs->data[0][bin] - lower_freqs->data[0][fn]) * riseInc; |
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99 | |
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100 | if (fft_freqs->data[0][bin + 1] > center_freqs->data[0][fn]) |
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101 | break; |
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102 | } |
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103 | bin++; |
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104 | |
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105 | /* compute negative slope step size */ |
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106 | smpl_t downInc = |
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107 | triangle_heights->data[0][fn] / |
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108 | (upper_freqs->data[0][fn] - center_freqs->data[0][fn]); |
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109 | |
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110 | /* compute coefficents in negative slope */ |
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111 | for (; bin < win_s - 1; bin++) { |
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112 | filters->data[fn][bin] += |
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113 | (upper_freqs->data[0][fn] - fft_freqs->data[0][bin]) * downInc; |
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114 | |
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115 | if (fft_freqs->data[0][bin + 1] > upper_freqs->data[0][fn]) |
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116 | break; |
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117 | } |
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118 | /* nothing else to do */ |
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119 | |
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120 | } |
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121 | |
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122 | /* destroy temporarly allocated vectors */ |
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123 | del_fvec (lower_freqs); |
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124 | del_fvec (upper_freqs); |
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125 | del_fvec (center_freqs); |
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126 | |
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127 | del_fvec (triangle_heights); |
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128 | del_fvec (fft_freqs); |
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129 | |
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130 | } |
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131 | |
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132 | void |
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133 | aubio_filterbank_set_mel_coeffs_slaney (aubio_filterbank_t * fb, |
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134 | smpl_t samplerate) |
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135 | { |
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136 | /* Malcolm Slaney parameters */ |
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137 | smpl_t lowestFrequency = 133.3333; |
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138 | smpl_t linearSpacing = 66.66666666; |
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139 | smpl_t logSpacing = 1.0711703; |
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140 | |
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141 | uint_t linearFilters = 13; |
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142 | uint_t logFilters = 27; |
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143 | uint_t n_filters = linearFilters + logFilters; |
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144 | |
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145 | uint_t fn; /* filter counter */ |
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146 | |
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147 | /* buffers to compute filter frequencies */ |
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148 | fvec_t *freqs = new_fvec (n_filters + 2, 1); |
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149 | |
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150 | /* first step: fill all the linear filter frequencies */ |
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151 | for (fn = 0; fn < linearFilters; fn++) { |
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152 | freqs->data[0][fn] = lowestFrequency + fn * linearSpacing; |
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153 | } |
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154 | smpl_t lastlinearCF = freqs->data[0][fn - 1]; |
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155 | |
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156 | /* second step: fill all the log filter frequencies */ |
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157 | for (fn = 0; fn < logFilters + 2; fn++) { |
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158 | freqs->data[0][fn + linearFilters] = |
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159 | lastlinearCF * (POW (logSpacing, fn + 1)); |
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160 | } |
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161 | |
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162 | /* now compute the actual coefficients */ |
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163 | aubio_filterbank_set_mel_coeffs (fb, freqs, samplerate); |
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164 | |
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165 | /* destroy vector used to store frequency limits */ |
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166 | del_fvec (freqs); |
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167 | |
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168 | } |
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