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 "fmat.h" |
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24 | #include "fvec.h" |
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25 | #include "cvec.h" |
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26 | #include "spectral/filterbank.h" |
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27 | #include "spectral/filterbank_mel.h" |
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28 | #include "mathutils.h" |
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29 | |
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30 | uint_t |
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31 | aubio_filterbank_set_triangle_bands (aubio_filterbank_t * fb, |
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32 | const fvec_t * freqs, smpl_t samplerate) |
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33 | { |
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34 | |
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35 | fmat_t *filters = aubio_filterbank_get_coeffs (fb); |
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36 | uint_t n_filters = filters->height, win_s = filters->length; |
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37 | fvec_t *lower_freqs, *upper_freqs, *center_freqs; |
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38 | fvec_t *triangle_heights, *fft_freqs; |
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39 | |
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40 | uint_t fn; /* filter counter */ |
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41 | uint_t bin; /* bin counter */ |
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42 | |
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43 | smpl_t riseInc, downInc; |
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44 | |
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45 | /* freqs define the bands of triangular overlapping windows. |
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46 | throw a warning if filterbank object fb is too short. */ |
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47 | if (freqs->length - 2 > n_filters) { |
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48 | AUBIO_WRN ("not enough filters, %d allocated but %d requested\n", |
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49 | n_filters, freqs->length - 2); |
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50 | } |
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51 | |
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52 | if (freqs->length - 2 < n_filters) { |
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53 | AUBIO_WRN ("too many filters, %d allocated but %d requested\n", |
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54 | n_filters, freqs->length - 2); |
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55 | } |
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56 | |
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57 | for (fn = 0; fn < freqs->length; fn++) { |
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58 | if (freqs->data[fn] < 0) { |
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59 | AUBIO_ERR("filterbank_mel: freqs must contain only positive values.\n"); |
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60 | return AUBIO_FAIL; |
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61 | } else if (freqs->data[fn] > samplerate / 2) { |
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62 | AUBIO_WRN("filterbank_mel: freqs should contain only " |
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63 | "values < samplerate / 2.\n"); |
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64 | } else if (fn > 0 && freqs->data[fn] < freqs->data[fn-1]) { |
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65 | AUBIO_ERR("filterbank_mel: freqs should be a list of frequencies " |
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66 | "sorted from low to high, but freq[%d] < freq[%d-1]\n", fn, fn); |
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67 | return AUBIO_FAIL; |
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68 | } else if (fn > 0 && freqs->data[fn] == freqs->data[fn-1]) { |
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69 | AUBIO_WRN("filterbank_mel: set_triangle_bands received a list " |
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70 | "with twice the frequency %f\n", freqs->data[fn]); |
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71 | } |
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72 | } |
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73 | |
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74 | /* convenience reference to lower/center/upper frequency for each triangle */ |
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75 | lower_freqs = new_fvec (n_filters); |
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76 | upper_freqs = new_fvec (n_filters); |
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77 | center_freqs = new_fvec (n_filters); |
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78 | |
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79 | /* height of each triangle */ |
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80 | triangle_heights = new_fvec (n_filters); |
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81 | |
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82 | /* lookup table of each bin frequency in hz */ |
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83 | fft_freqs = new_fvec (win_s); |
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84 | |
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85 | /* fill up the lower/center/upper */ |
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86 | for (fn = 0; fn < n_filters; fn++) { |
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87 | lower_freqs->data[fn] = freqs->data[fn]; |
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88 | center_freqs->data[fn] = freqs->data[fn + 1]; |
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89 | upper_freqs->data[fn] = freqs->data[fn + 2]; |
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90 | } |
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91 | |
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92 | /* compute triangle heights so that each triangle has unit area */ |
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93 | for (fn = 0; fn < n_filters; fn++) { |
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94 | triangle_heights->data[fn] = |
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95 | 2. / (upper_freqs->data[fn] - lower_freqs->data[fn]); |
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96 | } |
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97 | |
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98 | /* fill fft_freqs lookup table, which assigns the frequency in hz to each bin */ |
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99 | for (bin = 0; bin < win_s; bin++) { |
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100 | fft_freqs->data[bin] = |
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101 | aubio_bintofreq (bin, samplerate, (win_s - 1) * 2); |
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102 | } |
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103 | |
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104 | /* zeroing of all filters */ |
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105 | fmat_zeros (filters); |
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106 | |
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107 | /* building each filter table */ |
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108 | for (fn = 0; fn < n_filters; fn++) { |
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109 | |
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110 | /* skip first elements */ |
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111 | for (bin = 0; bin < win_s - 1; bin++) { |
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112 | if (fft_freqs->data[bin] <= lower_freqs->data[fn] && |
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113 | fft_freqs->data[bin + 1] > lower_freqs->data[fn]) { |
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114 | bin++; |
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115 | break; |
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116 | } |
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117 | } |
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118 | |
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119 | /* compute positive slope step size */ |
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120 | riseInc = |
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121 | triangle_heights->data[fn] / |
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122 | (center_freqs->data[fn] - lower_freqs->data[fn]); |
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123 | |
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124 | /* compute coefficients in positive slope */ |
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125 | for (; bin < win_s - 1; bin++) { |
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126 | filters->data[fn][bin] = |
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127 | (fft_freqs->data[bin] - lower_freqs->data[fn]) * riseInc; |
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128 | |
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129 | if (fft_freqs->data[bin + 1] >= center_freqs->data[fn]) { |
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130 | bin++; |
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131 | break; |
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132 | } |
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133 | } |
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134 | |
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135 | /* compute negative slope step size */ |
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136 | downInc = |
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137 | triangle_heights->data[fn] / |
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138 | (upper_freqs->data[fn] - center_freqs->data[fn]); |
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139 | |
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140 | /* compute coefficents in negative slope */ |
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141 | for (; bin < win_s - 1; bin++) { |
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142 | filters->data[fn][bin] += |
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143 | (upper_freqs->data[fn] - fft_freqs->data[bin]) * downInc; |
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144 | |
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145 | if (filters->data[fn][bin] < 0.) { |
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146 | filters->data[fn][bin] = 0.; |
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147 | } |
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148 | |
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149 | if (fft_freqs->data[bin + 1] >= upper_freqs->data[fn]) |
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150 | break; |
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151 | } |
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152 | /* nothing else to do */ |
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153 | |
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154 | } |
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155 | |
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156 | /* destroy temporarly allocated vectors */ |
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157 | del_fvec (lower_freqs); |
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158 | del_fvec (upper_freqs); |
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159 | del_fvec (center_freqs); |
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160 | |
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161 | del_fvec (triangle_heights); |
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162 | del_fvec (fft_freqs); |
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163 | |
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164 | return AUBIO_OK; |
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165 | } |
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166 | |
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167 | uint_t |
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168 | aubio_filterbank_set_mel_coeffs_slaney (aubio_filterbank_t * fb, |
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169 | smpl_t samplerate) |
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170 | { |
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171 | uint_t retval; |
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172 | |
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173 | /* Malcolm Slaney parameters */ |
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174 | smpl_t lowestFrequency = 133.3333; |
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175 | smpl_t linearSpacing = 66.66666666; |
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176 | smpl_t logSpacing = 1.0711703; |
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177 | |
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178 | uint_t linearFilters = 13; |
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179 | uint_t logFilters = 27; |
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180 | uint_t n_filters = linearFilters + logFilters; |
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181 | |
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182 | uint_t fn; /* filter counter */ |
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183 | |
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184 | smpl_t lastlinearCF; |
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185 | |
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186 | /* buffers to compute filter frequencies */ |
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187 | fvec_t *freqs = new_fvec (n_filters + 2); |
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188 | |
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189 | /* first step: fill all the linear filter frequencies */ |
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190 | for (fn = 0; fn < linearFilters; fn++) { |
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191 | freqs->data[fn] = lowestFrequency + fn * linearSpacing; |
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192 | } |
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193 | lastlinearCF = freqs->data[fn - 1]; |
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194 | |
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195 | /* second step: fill all the log filter frequencies */ |
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196 | for (fn = 0; fn < logFilters + 2; fn++) { |
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197 | freqs->data[fn + linearFilters] = |
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198 | lastlinearCF * (POW (logSpacing, fn + 1)); |
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199 | } |
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200 | |
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201 | /* now compute the actual coefficients */ |
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202 | retval = aubio_filterbank_set_triangle_bands (fb, freqs, samplerate); |
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203 | |
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204 | /* destroy vector used to store frequency limits */ |
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205 | del_fvec (freqs); |
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206 | |
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207 | return retval; |
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208 | } |
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