1 | /* |
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2 | Copyright (C) 2003-2009 Paul Brossier <piem@aubio.org> |
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3 | |
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4 | This file is part of aubio. |
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5 | |
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6 | aubio is free software: you can redistribute it and/or modify |
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7 | it under the terms of the GNU General Public License as published by |
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8 | the Free Software Foundation, either version 3 of the License, or |
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9 | (at your option) any later version. |
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10 | |
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11 | aubio is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | GNU General Public License for more details. |
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15 | |
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16 | You should have received a copy of the GNU General Public License |
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17 | along with aubio. If not, see <http://www.gnu.org/licenses/>. |
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18 | |
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19 | */ |
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20 | |
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21 | |
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22 | /* Requires lsmp_t to be long or double. float will NOT give reliable |
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23 | * results */ |
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24 | |
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25 | #include "aubio_priv.h" |
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26 | #include "fvec.h" |
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27 | #include "lvec.h" |
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28 | #include "mathutils.h" |
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29 | #include "temporal/filter.h" |
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30 | |
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31 | struct _aubio_filter_t |
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32 | { |
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33 | uint_t order; |
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34 | uint_t samplerate; |
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35 | lvec_t *a; |
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36 | lvec_t *b; |
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37 | lvec_t *y; |
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38 | lvec_t *x; |
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39 | }; |
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40 | |
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41 | void |
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42 | aubio_filter_do_outplace (aubio_filter_t * f, fvec_t * in, fvec_t * out) |
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43 | { |
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44 | fvec_copy (in, out); |
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45 | aubio_filter_do (f, out); |
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46 | } |
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47 | |
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48 | void |
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49 | aubio_filter_do (aubio_filter_t * f, fvec_t * in) |
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50 | { |
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51 | uint_t j, l, order = f->order; |
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52 | lsmp_t *x = f->x->data; |
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53 | lsmp_t *y = f->y->data; |
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54 | lsmp_t *a = f->a->data; |
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55 | lsmp_t *b = f->b->data; |
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56 | |
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57 | for (j = 0; j < in->length; j++) { |
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58 | /* new input */ |
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59 | x[0] = KILL_DENORMAL (in->data[j]); |
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60 | y[0] = b[0] * x[0]; |
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61 | for (l = 1; l < order; l++) { |
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62 | y[0] += b[l] * x[l]; |
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63 | y[0] -= a[l] * y[l]; |
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64 | } |
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65 | /* new output */ |
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66 | in->data[j] = y[0]; |
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67 | /* store for next sample */ |
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68 | for (l = order - 1; l > 0; l--) { |
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69 | x[l] = x[l - 1]; |
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70 | y[l] = y[l - 1]; |
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71 | } |
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72 | } |
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73 | } |
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74 | |
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75 | /* The rough way: reset memory of filter between each run to avoid end effects. */ |
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76 | void |
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77 | aubio_filter_do_filtfilt (aubio_filter_t * f, fvec_t * in, fvec_t * tmp) |
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78 | { |
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79 | uint_t j; |
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80 | uint_t length = in->length; |
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81 | /* apply filtering */ |
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82 | aubio_filter_do (f, in); |
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83 | aubio_filter_do_reset (f); |
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84 | /* mirror */ |
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85 | for (j = 0; j < length; j++) |
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86 | tmp->data[length - j - 1] = in->data[j]; |
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87 | /* apply filtering on mirrored */ |
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88 | aubio_filter_do (f, tmp); |
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89 | aubio_filter_do_reset (f); |
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90 | /* invert back */ |
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91 | for (j = 0; j < length; j++) |
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92 | in->data[j] = tmp->data[length - j - 1]; |
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93 | } |
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94 | |
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95 | lvec_t * |
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96 | aubio_filter_get_feedback (aubio_filter_t * f) |
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97 | { |
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98 | return f->a; |
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99 | } |
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100 | |
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101 | lvec_t * |
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102 | aubio_filter_get_feedforward (aubio_filter_t * f) |
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103 | { |
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104 | return f->b; |
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105 | } |
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106 | |
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107 | uint_t |
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108 | aubio_filter_get_order (aubio_filter_t * f) |
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109 | { |
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110 | return f->order; |
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111 | } |
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112 | |
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113 | uint_t |
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114 | aubio_filter_get_samplerate (aubio_filter_t * f) |
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115 | { |
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116 | return f->samplerate; |
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117 | } |
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118 | |
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119 | uint_t |
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120 | aubio_filter_set_samplerate (aubio_filter_t * f, uint_t samplerate) |
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121 | { |
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122 | f->samplerate = samplerate; |
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123 | return AUBIO_OK; |
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124 | } |
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125 | |
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126 | void |
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127 | aubio_filter_do_reset (aubio_filter_t * f) |
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128 | { |
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129 | lvec_zeros (f->x); |
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130 | lvec_zeros (f->y); |
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131 | } |
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132 | |
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133 | aubio_filter_t * |
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134 | new_aubio_filter (uint_t order) |
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135 | { |
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136 | aubio_filter_t *f = AUBIO_NEW (aubio_filter_t); |
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137 | if ((sint_t)order < 1) { |
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138 | AUBIO_FREE(f); |
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139 | return NULL; |
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140 | } |
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141 | f->x = new_lvec (order); |
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142 | f->y = new_lvec (order); |
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143 | f->a = new_lvec (order); |
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144 | f->b = new_lvec (order); |
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145 | /* by default, samplerate is not set */ |
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146 | f->samplerate = 0; |
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147 | f->order = order; |
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148 | /* set default to identity */ |
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149 | f->a->data[0] = 1.; |
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150 | f->b->data[0] = 1.; |
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151 | return f; |
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152 | } |
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153 | |
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154 | void |
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155 | del_aubio_filter (aubio_filter_t * f) |
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156 | { |
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157 | del_lvec (f->a); |
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158 | del_lvec (f->b); |
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159 | del_lvec (f->x); |
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160 | del_lvec (f->y); |
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161 | AUBIO_FREE (f); |
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162 | return; |
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163 | } |
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