1 /****************************************************************************** 2 * 3 * Copyright 2021 Google, Inc. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ******************************************************************************/ 18 19 #include "sns.h" 20 #include "tables.h" 21 22 23 /* ---------------------------------------------------------------------------- 24 * DCT-16 25 * -------------------------------------------------------------------------- */ 26 27 /** 28 * Matrix of DCT-16 coefficients 29 * 30 * M[n][k] = 2f cos( Pi k (2n + 1) / 2N ) 31 * 32 * k = [0..N-1], n = [0..N-1], N = 16 33 * f = sqrt(1/4N) for k=0, sqrt(1/2N) otherwise 34 */ 35 static const float dct16_m[16][16] = { 36 37 { 2.50000000e-01, 3.51850934e-01, 3.46759961e-01, 3.38329500e-01, 38 3.26640741e-01, 3.11806253e-01, 2.93968901e-01, 2.73300467e-01, 39 2.50000000e-01, 2.24291897e-01, 1.96423740e-01, 1.66663915e-01, 40 1.35299025e-01, 1.02631132e-01, 6.89748448e-02, 3.46542923e-02 }, 41 42 { 2.50000000e-01, 3.38329500e-01, 2.93968901e-01, 2.24291897e-01, 43 1.35299025e-01, 3.46542923e-02, -6.89748448e-02, -1.66663915e-01, 44 -2.50000000e-01, -3.11806253e-01, -3.46759961e-01, -3.51850934e-01, 45 -3.26640741e-01, -2.73300467e-01, -1.96423740e-01, -1.02631132e-01 }, 46 47 { 2.50000000e-01, 3.11806253e-01, 1.96423740e-01, 3.46542923e-02, 48 -1.35299025e-01, -2.73300467e-01, -3.46759961e-01, -3.38329500e-01, 49 -2.50000000e-01, -1.02631132e-01, 6.89748448e-02, 2.24291897e-01, 50 3.26640741e-01, 3.51850934e-01, 2.93968901e-01, 1.66663915e-01 }, 51 52 { 2.50000000e-01, 2.73300467e-01, 6.89748448e-02, -1.66663915e-01, 53 -3.26640741e-01, -3.38329500e-01, -1.96423740e-01, 3.46542923e-02, 54 2.50000000e-01, 3.51850934e-01, 2.93968901e-01, 1.02631132e-01, 55 -1.35299025e-01, -3.11806253e-01, -3.46759961e-01, -2.24291897e-01 }, 56 57 { 2.50000000e-01, 2.24291897e-01, -6.89748448e-02, -3.11806253e-01, 58 -3.26640741e-01, -1.02631132e-01, 1.96423740e-01, 3.51850934e-01, 59 2.50000000e-01, -3.46542923e-02, -2.93968901e-01, -3.38329500e-01, 60 -1.35299025e-01, 1.66663915e-01, 3.46759961e-01, 2.73300467e-01 }, 61 62 { 2.50000000e-01, 1.66663915e-01, -1.96423740e-01, -3.51850934e-01, 63 -1.35299025e-01, 2.24291897e-01, 3.46759961e-01, 1.02631132e-01, 64 -2.50000000e-01, -3.38329500e-01, -6.89748448e-02, 2.73300467e-01, 65 3.26640741e-01, 3.46542923e-02, -2.93968901e-01, -3.11806253e-01 }, 66 67 { 2.50000000e-01, 1.02631132e-01, -2.93968901e-01, -2.73300467e-01, 68 1.35299025e-01, 3.51850934e-01, 6.89748448e-02, -3.11806253e-01, 69 -2.50000000e-01, 1.66663915e-01, 3.46759961e-01, 3.46542923e-02, 70 -3.26640741e-01, -2.24291897e-01, 1.96423740e-01, 3.38329500e-01 }, 71 72 { 2.50000000e-01, 3.46542923e-02, -3.46759961e-01, -1.02631132e-01, 73 3.26640741e-01, 1.66663915e-01, -2.93968901e-01, -2.24291897e-01, 74 2.50000000e-01, 2.73300467e-01, -1.96423740e-01, -3.11806253e-01, 75 1.35299025e-01, 3.38329500e-01, -6.89748448e-02, -3.51850934e-01 }, 76 77 { 2.50000000e-01, -3.46542923e-02, -3.46759961e-01, 1.02631132e-01, 78 3.26640741e-01, -1.66663915e-01, -2.93968901e-01, 2.24291897e-01, 79 2.50000000e-01, -2.73300467e-01, -1.96423740e-01, 3.11806253e-01, 80 1.35299025e-01, -3.38329500e-01, -6.89748448e-02, 3.51850934e-01 }, 81 82 { 2.50000000e-01, -1.02631132e-01, -2.93968901e-01, 2.73300467e-01, 83 1.35299025e-01, -3.51850934e-01, 6.89748448e-02, 3.11806253e-01, 84 -2.50000000e-01, -1.66663915e-01, 3.46759961e-01, -3.46542923e-02, 85 -3.26640741e-01, 2.24291897e-01, 1.96423740e-01, -3.38329500e-01 }, 86 87 { 2.50000000e-01, -1.66663915e-01, -1.96423740e-01, 3.51850934e-01, 88 -1.35299025e-01, -2.24291897e-01, 3.46759961e-01, -1.02631132e-01, 89 -2.50000000e-01, 3.38329500e-01, -6.89748448e-02, -2.73300467e-01, 90 3.26640741e-01, -3.46542923e-02, -2.93968901e-01, 3.11806253e-01 }, 91 92 { 2.50000000e-01, -2.24291897e-01, -6.89748448e-02, 3.11806253e-01, 93 -3.26640741e-01, 1.02631132e-01, 1.96423740e-01, -3.51850934e-01, 94 2.50000000e-01, 3.46542923e-02, -2.93968901e-01, 3.38329500e-01, 95 -1.35299025e-01, -1.66663915e-01, 3.46759961e-01, -2.73300467e-01 }, 96 97 { 2.50000000e-01, -2.73300467e-01, 6.89748448e-02, 1.66663915e-01, 98 -3.26640741e-01, 3.38329500e-01, -1.96423740e-01, -3.46542923e-02, 99 2.50000000e-01, -3.51850934e-01, 2.93968901e-01, -1.02631132e-01, 100 -1.35299025e-01, 3.11806253e-01, -3.46759961e-01, 2.24291897e-01 }, 101 102 { 2.50000000e-01, -3.11806253e-01, 1.96423740e-01, -3.46542923e-02, 103 -1.35299025e-01, 2.73300467e-01, -3.46759961e-01, 3.38329500e-01, 104 -2.50000000e-01, 1.02631132e-01, 6.89748448e-02, -2.24291897e-01, 105 3.26640741e-01, -3.51850934e-01, 2.93968901e-01, -1.66663915e-01 }, 106 107 { 2.50000000e-01, -3.38329500e-01, 2.93968901e-01, -2.24291897e-01, 108 1.35299025e-01, -3.46542923e-02, -6.89748448e-02, 1.66663915e-01, 109 -2.50000000e-01, 3.11806253e-01, -3.46759961e-01, 3.51850934e-01, 110 -3.26640741e-01, 2.73300467e-01, -1.96423740e-01, 1.02631132e-01 }, 111 112 { 2.50000000e-01, -3.51850934e-01, 3.46759961e-01, -3.38329500e-01, 113 3.26640741e-01, -3.11806253e-01, 2.93968901e-01, -2.73300467e-01, 114 2.50000000e-01, -2.24291897e-01, 1.96423740e-01, -1.66663915e-01, 115 1.35299025e-01, -1.02631132e-01, 6.89748448e-02, -3.46542923e-02 }, 116 117 }; 118 119 /** 120 * Forward DCT-16 transformation 121 * x, y Input and output 16 values 122 */ 123 static void dct16_forward(const float *x, float *y) 124 { 125 for (int i = 0, j; i < 16; i++) 126 for (y[i] = 0, j = 0; j < 16; j++) 127 y[i] += x[j] * dct16_m[j][i]; 128 } 129 130 /** 131 * Inverse DCT-16 transformation 132 * x, y Input and output 16 values 133 */ 134 static void dct16_inverse(const float *x, float *y) 135 { 136 for (int i = 0, j; i < 16; i++) 137 for (y[i] = 0, j = 0; j < 16; j++) 138 y[i] += x[j] * dct16_m[i][j]; 139 } 140 141 142 /* ---------------------------------------------------------------------------- 143 * Scale factors 144 * -------------------------------------------------------------------------- */ 145 146 /** 147 * Scale factors 148 * dt, sr Duration and samplerate of the frame 149 * eb Energy estimation per bands 150 * att 1: Attack detected 0: Otherwise 151 * scf Output 16 scale factors 152 */ 153 static void compute_scale_factors(enum lc3_dt dt, enum lc3_srate sr, 154 const float *eb, bool att, float *scf) 155 { 156 /* Pre-emphasis gain table : 157 * Ge[b] = 10 ^ (b * g_tilt) / 630 , b = [0..63] */ 158 159 static const float ge_table[LC3_NUM_SRATE][LC3_NUM_BANDS] = { 160 161 [LC3_SRATE_8K] = { /* g_tilt = 14 */ 162 1.00000000e+00, 1.05250029e+00, 1.10775685e+00, 1.16591440e+00, 163 1.22712524e+00, 1.29154967e+00, 1.35935639e+00, 1.43072299e+00, 164 1.50583635e+00, 1.58489319e+00, 1.66810054e+00, 1.75567629e+00, 165 1.84784980e+00, 1.94486244e+00, 2.04696827e+00, 2.15443469e+00, 166 2.26754313e+00, 2.38658979e+00, 2.51188643e+00, 2.64376119e+00, 167 2.78255940e+00, 2.92864456e+00, 3.08239924e+00, 3.24422608e+00, 168 3.41454887e+00, 3.59381366e+00, 3.78248991e+00, 3.98107171e+00, 169 4.19007911e+00, 4.41005945e+00, 4.64158883e+00, 4.88527357e+00, 170 5.14175183e+00, 5.41169527e+00, 5.69581081e+00, 5.99484250e+00, 171 6.30957344e+00, 6.64082785e+00, 6.98947321e+00, 7.35642254e+00, 172 7.74263683e+00, 8.14912747e+00, 8.57695899e+00, 9.02725178e+00, 173 9.50118507e+00, 1.00000000e+01, 1.05250029e+01, 1.10775685e+01, 174 1.16591440e+01, 1.22712524e+01, 1.29154967e+01, 1.35935639e+01, 175 1.43072299e+01, 1.50583635e+01, 1.58489319e+01, 1.66810054e+01, 176 1.75567629e+01, 1.84784980e+01, 1.94486244e+01, 2.04696827e+01, 177 2.15443469e+01, 2.26754313e+01, 2.38658979e+01, 2.51188643e+01 }, 178 179 [LC3_SRATE_16K] = { /* g_tilt = 18 */ 180 1.00000000e+00, 1.06800043e+00, 1.14062492e+00, 1.21818791e+00, 181 1.30102522e+00, 1.38949549e+00, 1.48398179e+00, 1.58489319e+00, 182 1.69266662e+00, 1.80776868e+00, 1.93069773e+00, 2.06198601e+00, 183 2.20220195e+00, 2.35195264e+00, 2.51188643e+00, 2.68269580e+00, 184 2.86512027e+00, 3.05994969e+00, 3.26802759e+00, 3.49025488e+00, 185 3.72759372e+00, 3.98107171e+00, 4.25178630e+00, 4.54090961e+00, 186 4.84969343e+00, 5.17947468e+00, 5.53168120e+00, 5.90783791e+00, 187 6.30957344e+00, 6.73862717e+00, 7.19685673e+00, 7.68624610e+00, 188 8.20891416e+00, 8.76712387e+00, 9.36329209e+00, 1.00000000e+01, 189 1.06800043e+01, 1.14062492e+01, 1.21818791e+01, 1.30102522e+01, 190 1.38949549e+01, 1.48398179e+01, 1.58489319e+01, 1.69266662e+01, 191 1.80776868e+01, 1.93069773e+01, 2.06198601e+01, 2.20220195e+01, 192 2.35195264e+01, 2.51188643e+01, 2.68269580e+01, 2.86512027e+01, 193 3.05994969e+01, 3.26802759e+01, 3.49025488e+01, 3.72759372e+01, 194 3.98107171e+01, 4.25178630e+01, 4.54090961e+01, 4.84969343e+01, 195 5.17947468e+01, 5.53168120e+01, 5.90783791e+01, 6.30957344e+01 }, 196 197 [LC3_SRATE_24K] = { /* g_tilt = 22 */ 198 1.00000000e+00, 1.08372885e+00, 1.17446822e+00, 1.27280509e+00, 199 1.37937560e+00, 1.49486913e+00, 1.62003281e+00, 1.75567629e+00, 200 1.90267705e+00, 2.06198601e+00, 2.23463373e+00, 2.42173704e+00, 201 2.62450630e+00, 2.84425319e+00, 3.08239924e+00, 3.34048498e+00, 202 3.62017995e+00, 3.92329345e+00, 4.25178630e+00, 4.60778348e+00, 203 4.99358789e+00, 5.41169527e+00, 5.86481029e+00, 6.35586411e+00, 204 6.88803330e+00, 7.46476041e+00, 8.08977621e+00, 8.76712387e+00, 205 9.50118507e+00, 1.02967084e+01, 1.11588399e+01, 1.20931568e+01, 206 1.31057029e+01, 1.42030283e+01, 1.53922315e+01, 1.66810054e+01, 207 1.80776868e+01, 1.95913107e+01, 2.12316686e+01, 2.30093718e+01, 208 2.49359200e+01, 2.70237760e+01, 2.92864456e+01, 3.17385661e+01, 209 3.43959997e+01, 3.72759372e+01, 4.03970086e+01, 4.37794036e+01, 210 4.74450028e+01, 5.14175183e+01, 5.57226480e+01, 6.03882412e+01, 211 6.54444792e+01, 7.09240702e+01, 7.68624610e+01, 8.32980665e+01, 212 9.02725178e+01, 9.78309319e+01, 1.06022203e+02, 1.14899320e+02, 213 1.24519708e+02, 1.34945600e+02, 1.46244440e+02, 1.58489319e+02 }, 214 215 [LC3_SRATE_32K] = { /* g_tilt = 26 */ 216 1.00000000e+00, 1.09968890e+00, 1.20931568e+00, 1.32987103e+00, 217 1.46244440e+00, 1.60823388e+00, 1.76855694e+00, 1.94486244e+00, 218 2.13874364e+00, 2.35195264e+00, 2.58641621e+00, 2.84425319e+00, 219 3.12779366e+00, 3.43959997e+00, 3.78248991e+00, 4.15956216e+00, 220 4.57422434e+00, 5.03022373e+00, 5.53168120e+00, 6.08312841e+00, 221 6.68954879e+00, 7.35642254e+00, 8.08977621e+00, 8.89623710e+00, 222 9.78309319e+00, 1.07583590e+01, 1.18308480e+01, 1.30102522e+01, 223 1.43072299e+01, 1.57335019e+01, 1.73019574e+01, 1.90267705e+01, 224 2.09235283e+01, 2.30093718e+01, 2.53031508e+01, 2.78255940e+01, 225 3.05994969e+01, 3.36499270e+01, 3.70044512e+01, 4.06933843e+01, 226 4.47500630e+01, 4.92111475e+01, 5.41169527e+01, 5.95118121e+01, 227 6.54444792e+01, 7.19685673e+01, 7.91430346e+01, 8.70327166e+01, 228 9.57089124e+01, 1.05250029e+02, 1.15742288e+02, 1.27280509e+02, 229 1.39968963e+02, 1.53922315e+02, 1.69266662e+02, 1.86140669e+02, 230 2.04696827e+02, 2.25102829e+02, 2.47543082e+02, 2.72220379e+02, 231 2.99357729e+02, 3.29200372e+02, 3.62017995e+02, 3.98107171e+02 }, 232 233 [LC3_SRATE_48K] = { /* g_tilt = 30 */ 234 1.00000000e+00, 1.11588399e+00, 1.24519708e+00, 1.38949549e+00, 235 1.55051578e+00, 1.73019574e+00, 1.93069773e+00, 2.15443469e+00, 236 2.40409918e+00, 2.68269580e+00, 2.99357729e+00, 3.34048498e+00, 237 3.72759372e+00, 4.15956216e+00, 4.64158883e+00, 5.17947468e+00, 238 5.77969288e+00, 6.44946677e+00, 7.19685673e+00, 8.03085722e+00, 239 8.96150502e+00, 1.00000000e+01, 1.11588399e+01, 1.24519708e+01, 240 1.38949549e+01, 1.55051578e+01, 1.73019574e+01, 1.93069773e+01, 241 2.15443469e+01, 2.40409918e+01, 2.68269580e+01, 2.99357729e+01, 242 3.34048498e+01, 3.72759372e+01, 4.15956216e+01, 4.64158883e+01, 243 5.17947468e+01, 5.77969288e+01, 6.44946677e+01, 7.19685673e+01, 244 8.03085722e+01, 8.96150502e+01, 1.00000000e+02, 1.11588399e+02, 245 1.24519708e+02, 1.38949549e+02, 1.55051578e+02, 1.73019574e+02, 246 1.93069773e+02, 2.15443469e+02, 2.40409918e+02, 2.68269580e+02, 247 2.99357729e+02, 3.34048498e+02, 3.72759372e+02, 4.15956216e+02, 248 4.64158883e+02, 5.17947468e+02, 5.77969288e+02, 6.44946677e+02, 249 7.19685673e+02, 8.03085722e+02, 8.96150502e+02, 1.00000000e+03 }, 250 }; 251 252 float e[LC3_NUM_BANDS]; 253 254 /* --- Copy and padding --- */ 255 256 int nb = LC3_MIN(lc3_band_lim[dt][sr][LC3_NUM_BANDS], LC3_NUM_BANDS); 257 int n2 = LC3_NUM_BANDS - nb; 258 259 for (int i2 = 0; i2 < n2; i2++) 260 e[2*i2 + 0] = e[2*i2 + 1] = eb[i2]; 261 262 memcpy(e + 2*n2, eb + n2, (nb - n2) * sizeof(float)); 263 264 /* --- Smoothing, pre-emphasis and logarithm --- */ 265 266 const float *ge = ge_table[sr]; 267 268 float e0 = e[0], e1 = e[0], e2; 269 float e_sum = 0; 270 271 for (int i = 0; i < LC3_NUM_BANDS-1; ) { 272 e[i] = (e0 * 0.25 + e1 * 0.5 + (e2 = e[i+1]) * 0.25) * ge[i]; 273 e_sum += e[i++]; 274 275 e[i] = (e1 * 0.25 + e2 * 0.5 + (e0 = e[i+1]) * 0.25) * ge[i]; 276 e_sum += e[i++]; 277 278 e[i] = (e2 * 0.25 + e0 * 0.5 + (e1 = e[i+1]) * 0.25) * ge[i]; 279 e_sum += e[i++]; 280 } 281 282 e[LC3_NUM_BANDS-1] = (e0 * 0.25 + e1 * 0.75) * ge[LC3_NUM_BANDS-1]; 283 e_sum += e[LC3_NUM_BANDS-1]; 284 285 float noise_floor = fmaxf(e_sum * (1e-4 / 64), 0x1p-32); 286 287 for (int i = 0; i < LC3_NUM_BANDS; i++) 288 e[i] = log2f(fmaxf(e[i], noise_floor)) * 0.5; 289 290 /* --- Grouping & scaling --- */ 291 292 float scf_sum; 293 294 scf[0] = (e[0] + e[4]) * 1./12 + 295 (e[0] + e[3]) * 2./12 + 296 (e[1] + e[2]) * 3./12 ; 297 scf_sum = scf[0]; 298 299 for (int i = 1; i < 15; i++) { 300 scf[i] = (e[4*i-1] + e[4*i+4]) * 1./12 + 301 (e[4*i ] + e[4*i+3]) * 2./12 + 302 (e[4*i+1] + e[4*i+2]) * 3./12 ; 303 scf_sum += scf[i]; 304 } 305 306 scf[15] = (e[59] + e[63]) * 1./12 + 307 (e[60] + e[63]) * 2./12 + 308 (e[61] + e[62]) * 3./12 ; 309 scf_sum += scf[15]; 310 311 for (int i = 0; i < 16; i++) 312 scf[i] = 0.85 * (scf[i] - scf_sum * 1./16); 313 314 /* --- Attack handling --- */ 315 316 if (!att) 317 return; 318 319 float s0, s1 = scf[0], s2 = scf[1], s3 = scf[2], s4 = scf[3]; 320 float sn = s1 + s2; 321 322 scf[0] = (sn += s3) * 1./3; 323 scf[1] = (sn += s4) * 1./4; 324 scf_sum = scf[0] + scf[1]; 325 326 for (int i = 2; i < 14; i++, sn -= s0) { 327 s0 = s1, s1 = s2, s2 = s3, s3 = s4, s4 = scf[i+2]; 328 scf[i] = (sn += s4) * 1./5; 329 scf_sum += scf[i]; 330 } 331 332 scf[14] = (sn ) * 1./4; 333 scf[15] = (sn -= s1) * 1./3; 334 scf_sum += scf[14] + scf[15]; 335 336 for (int i = 0; i < 16; i++) 337 scf[i] = (dt == LC3_DT_7M5 ? 0.3 : 0.5) * 338 (scf[i] - scf_sum * 1./16); 339 } 340 341 /** 342 * Codebooks 343 * scf Input 16 scale factors 344 * lf/hfcb_idx Output the low and high frequency codebooks index 345 */ 346 static void resolve_codebooks(const float *scf, int *lfcb_idx, int *hfcb_idx) 347 { 348 float dlfcb_max = 0, dhfcb_max = 0; 349 *lfcb_idx = *hfcb_idx = 0; 350 351 for (int icb = 0; icb < 32; icb++) { 352 const float *lfcb = lc3_sns_lfcb[icb]; 353 const float *hfcb = lc3_sns_hfcb[icb]; 354 float dlfcb = 0, dhfcb = 0; 355 356 for (int i = 0; i < 8; i++) { 357 dlfcb += (scf[ i] - lfcb[i]) * (scf[ i] - lfcb[i]); 358 dhfcb += (scf[8+i] - hfcb[i]) * (scf[8+i] - hfcb[i]); 359 } 360 361 if (icb == 0 || dlfcb < dlfcb_max) 362 *lfcb_idx = icb, dlfcb_max = dlfcb; 363 364 if (icb == 0 || dhfcb < dhfcb_max) 365 *hfcb_idx = icb, dhfcb_max = dhfcb; 366 } 367 } 368 369 /** 370 * Unit energy normalize pulse configuration 371 * c Pulse configuration 372 * cn Normalized pulse configuration 373 */ 374 static void normalize(const int *c, float *cn) 375 { 376 int c2_sum = 0; 377 for (int i = 0; i < 16; i++) 378 c2_sum += c[i] * c[i]; 379 380 float c_norm = 1.f / sqrtf(c2_sum); 381 382 for (int i = 0; i < 16; i++) 383 cn[i] = c[i] * c_norm; 384 } 385 386 /** 387 * Sub-procedure of `quantize()`, add unit pulse 388 * x, y, n Transformed residual, and vector of pulses with length 389 * start, end Current number of pulses, limit to reach 390 * corr, energy Correlation (x,y) and y energy, updated at output 391 */ 392 static void add_pulse(const float *x, int *y, int n, 393 int start, int end, float *corr, float *energy) 394 { 395 for (int k = start; k < end; k++) { 396 float best_c2 = (*corr + x[0]) * (*corr + x[0]); 397 float best_e = *energy + 2*y[0] + 1; 398 int nbest = 0; 399 400 for (int i = 1; i < n; i++) { 401 float c2 = (*corr + x[i]) * (*corr + x[i]); 402 float e = *energy + 2*y[i] + 1; 403 404 if (c2 * best_e > e * best_c2) 405 best_c2 = c2, best_e = e, nbest = i; 406 } 407 408 *corr += x[nbest]; 409 *energy += 2*y[nbest] + 1; 410 y[nbest]++; 411 } 412 } 413 414 /** 415 * Quantization of codebooks residual 416 * scf Input 16 scale factors, output quantized version 417 * lf/hfcb_idx Codebooks index 418 * c, cn Output 4 pulse configurations candidates, normalized 419 * shape/gain_idx Output selected shape/gain indexes 420 */ 421 static void quantize(const float *scf, int lfcb_idx, int hfcb_idx, 422 int (*c)[16], float (*cn)[16], int *shape_idx, int *gain_idx) 423 { 424 /* --- Residual --- */ 425 426 const float *lfcb = lc3_sns_lfcb[lfcb_idx]; 427 const float *hfcb = lc3_sns_hfcb[hfcb_idx]; 428 float r[16], x[16]; 429 430 for (int i = 0; i < 8; i++) { 431 r[ i] = scf[ i] - lfcb[i]; 432 r[8+i] = scf[8+i] - hfcb[i]; 433 } 434 435 dct16_forward(r, x); 436 437 /* --- Shape 3 candidate --- 438 * Project to or below pyramid N = 16, K = 6, 439 * then add unit pulses until you reach K = 6, over N = 16 */ 440 441 float xm[16]; 442 float xm_sum = 0; 443 444 for (int i = 0; i < 16; i++) { 445 xm[i] = fabsf(x[i]); 446 xm_sum += xm[i]; 447 } 448 449 float proj_factor = (6 - 1) / fmaxf(xm_sum, 1e-31); 450 float corr = 0, energy = 0; 451 int npulses = 0; 452 453 for (int i = 0; i < 16; i++) { 454 c[3][i] = floorf(xm[i] * proj_factor); 455 npulses += c[3][i]; 456 corr += c[3][i] * xm[i]; 457 energy += c[3][i] * c[3][i]; 458 } 459 460 add_pulse(xm, c[3], 16, npulses, 6, &corr, &energy); 461 npulses = 6; 462 463 /* --- Shape 2 candidate --- 464 * Add unit pulses until you reach K = 8 on shape 3 */ 465 466 memcpy(c[2], c[3], sizeof(c[2])); 467 468 add_pulse(xm, c[2], 16, npulses, 8, &corr, &energy); 469 npulses = 8; 470 471 /* --- Shape 1 candidate --- 472 * Remove any unit pulses from shape 2 that are not part of 0 to 9 473 * Update energy and correlation terms accordingly 474 * Add unit pulses until you reach K = 10, over N = 10 */ 475 476 memcpy(c[1], c[2], sizeof(c[1])); 477 478 for (int i = 10; i < 16; i++) { 479 c[1][i] = 0; 480 npulses -= c[2][i]; 481 corr -= c[2][i] * xm[i]; 482 energy -= c[2][i] * c[2][i]; 483 } 484 485 add_pulse(xm, c[1], 10, npulses, 10, &corr, &energy); 486 npulses = 10; 487 488 /* --- Shape 0 candidate --- 489 * Add unit pulses until you reach K = 1, on shape 1 */ 490 491 memcpy(c[0], c[1], sizeof(c[0])); 492 493 add_pulse(xm + 10, c[0] + 10, 6, 0, 1, &corr, &energy); 494 495 /* --- Add sign and unit energy normalize --- */ 496 497 for (int j = 0; j < 16; j++) 498 for (int i = 0; i < 4; i++) 499 c[i][j] = x[j] < 0 ? -c[i][j] : c[i][j]; 500 501 for (int i = 0; i < 4; i++) 502 normalize(c[i], cn[i]); 503 504 /* --- Determe shape & gain index --- 505 * Search the Mean Square Error, within (shape, gain) combinations */ 506 507 float mse_min = INFINITY; 508 *shape_idx = *gain_idx = 0; 509 510 for (int ic = 0; ic < 4; ic++) { 511 const struct lc3_sns_vq_gains *cgains = lc3_sns_vq_gains + ic; 512 float cmse_min = INFINITY; 513 int cgain_idx = 0; 514 515 for (int ig = 0; ig < cgains->count; ig++) { 516 float g = cgains->v[ig]; 517 518 float mse = 0; 519 for (int i = 0; i < 16; i++) 520 mse += (x[i] - g * cn[ic][i]) * (x[i] - g * cn[ic][i]); 521 522 if (mse < cmse_min) { 523 cgain_idx = ig, 524 cmse_min = mse; 525 } 526 } 527 528 if (cmse_min < mse_min) { 529 *shape_idx = ic, *gain_idx = cgain_idx; 530 mse_min = cmse_min; 531 } 532 } 533 } 534 535 /** 536 * Unquantization of codebooks residual 537 * lf/hfcb_idx Low and high frequency codebooks index 538 * c Table of normalized pulse configuration 539 * shape/gain Selected shape/gain indexes 540 * scf Return unquantized scale factors 541 */ 542 static void unquantize(int lfcb_idx, int hfcb_idx, 543 const float *c, int shape, int gain, float *scf) 544 { 545 const float *lfcb = lc3_sns_lfcb[lfcb_idx]; 546 const float *hfcb = lc3_sns_hfcb[hfcb_idx]; 547 float g = lc3_sns_vq_gains[shape].v[gain]; 548 549 dct16_inverse(c, scf); 550 551 for (int i = 0; i < 8; i++) 552 scf[i] = lfcb[i] + g * scf[i]; 553 554 for (int i = 8; i < 16; i++) 555 scf[i] = hfcb[i-8] + g * scf[i]; 556 } 557 558 /** 559 * Sub-procedure of `sns_enumerate()`, enumeration of a vector 560 * c, n Table of pulse configuration, and length 561 * idx, ls Return enumeration set 562 */ 563 static void enum_mvpq(const int *c, int n, int *idx, bool *ls) 564 { 565 int ci, i, j; 566 567 /* --- Scan for 1st significant coeff --- */ 568 569 for (i = 0, c += n; (ci = *(--c)) == 0 ; i++); 570 571 *idx = 0; 572 *ls = ci < 0; 573 574 /* --- Scan remaining coefficients --- */ 575 576 for (i++, j = LC3_ABS(ci); i < n; i++, j += LC3_ABS(ci)) { 577 578 if ((ci = *(--c)) != 0) { 579 *idx = (*idx << 1) | *ls; 580 *ls = ci < 0; 581 } 582 583 *idx += lc3_sns_mpvq_offsets[i][j]; 584 } 585 } 586 587 /** 588 * Sub-procedure of `sns_deenumerate()`, deenumeration of a vector 589 * idx, ls Enumeration set 590 * npulses Number of pulses in the set 591 * c, n Table of pulses configuration, and length 592 */ 593 static void deenum_mvpq(int idx, bool ls, int npulses, int *c, int n) 594 { 595 int i; 596 597 /* --- Scan for coefficients --- */ 598 599 for (i = n-1; i >= 0 && idx; i--) { 600 601 int ci = 0; 602 603 for (ci = 0; idx < lc3_sns_mpvq_offsets[i][npulses - ci]; ci++); 604 idx -= lc3_sns_mpvq_offsets[i][npulses - ci]; 605 606 *(c++) = ls ? -ci : ci; 607 npulses -= ci; 608 if (ci > 0) { 609 ls = idx & 1; 610 idx >>= 1; 611 } 612 } 613 614 /* --- Set last significant --- */ 615 616 int ci = npulses; 617 618 if (i-- >= 0) 619 *(c++) = ls ? -ci : ci; 620 621 while (i-- >= 0) 622 *(c++) = 0; 623 } 624 625 /** 626 * SNS Enumeration of PVQ configuration 627 * shape Selected shape index 628 * c Selected pulse configuration 629 * idx_a, ls_a Return enumeration set A 630 * idx_b, ls_b Return enumeration set B (shape = 0) 631 */ 632 static void enumerate(int shape, const int *c, 633 int *idx_a, bool *ls_a, int *idx_b, bool *ls_b) 634 { 635 enum_mvpq(c, shape < 2 ? 10 : 16, idx_a, ls_a); 636 637 if (shape == 0) 638 enum_mvpq(c + 10, 6, idx_b, ls_b); 639 } 640 641 /** 642 * SNS Deenumeration of PVQ configuration 643 * shape Selected shape index 644 * idx_a, ls_a enumeration set A 645 * idx_b, ls_b enumeration set B (shape = 0) 646 * c Return pulse configuration 647 */ 648 static void deenumerate(int shape, 649 int idx_a, bool ls_a, int idx_b, bool ls_b, int *c) 650 { 651 int npulses_a = (const int []){ 10, 10, 8, 6 }[shape]; 652 653 deenum_mvpq(idx_a, ls_a, npulses_a, c, shape < 2 ? 10 : 16); 654 655 if (shape == 0) 656 deenum_mvpq(idx_b, ls_b, 1, c + 10, 6); 657 else if (shape == 1) 658 memset(c + 10, 0, 6 * sizeof(*c)); 659 } 660 661 662 /* ---------------------------------------------------------------------------- 663 * Filtering 664 * -------------------------------------------------------------------------- */ 665 666 /** 667 * Spectral shaping 668 * dt, sr Duration and samplerate of the frame 669 * scf_q Quantized scale factors 670 * inv True on inverse shaping, False otherwise 671 * x Spectral coefficients 672 * y Return shapped coefficients 673 * 674 * `x` and `y` can be the same buffer 675 */ 676 static void spectral_shaping(enum lc3_dt dt, enum lc3_srate sr, 677 const float *scf_q, bool inv, const float *x, float *y) 678 { 679 /* --- Interpolate scale factors --- */ 680 681 float scf[LC3_NUM_BANDS]; 682 float s0, s1 = inv ? -scf_q[0] : scf_q[0]; 683 684 scf[0] = scf[1] = s1; 685 for (int i = 0; i < 15; i++) { 686 s0 = s1, s1 = inv ? -scf_q[i+1] : scf_q[i+1]; 687 scf[4*i+2] = s0 + 0.125 * (s1 - s0); 688 scf[4*i+3] = s0 + 0.375 * (s1 - s0); 689 scf[4*i+4] = s0 + 0.625 * (s1 - s0); 690 scf[4*i+5] = s0 + 0.875 * (s1 - s0); 691 } 692 scf[62] = s1 + 0.125 * (s1 - s0); 693 scf[63] = s1 + 0.375 * (s1 - s0); 694 695 int nb = LC3_MIN(lc3_band_lim[dt][sr][LC3_NUM_BANDS], LC3_NUM_BANDS); 696 int n2 = LC3_NUM_BANDS - nb; 697 698 for (int i2 = 0; i2 < n2; i2++) 699 scf[i2] = 0.5 * (scf[2*i2] + scf[2*i2+1]); 700 701 if (n2 > 0) 702 memmove(scf + n2, scf + 2*n2, (nb - n2) * sizeof(float)); 703 704 /* --- Spectral shaping --- */ 705 706 const int *lim = lc3_band_lim[dt][sr]; 707 708 for (int i = 0, ib = 0; ib < nb; ib++) { 709 float g_sns = powf(2, -scf[ib]); 710 711 for ( ; i < lim[ib+1]; i++) 712 y[i] = x[i] * g_sns; 713 } 714 } 715 716 717 /* ---------------------------------------------------------------------------- 718 * Interface 719 * -------------------------------------------------------------------------- */ 720 721 /** 722 * SNS analysis 723 */ 724 void lc3_sns_analyze(enum lc3_dt dt, enum lc3_srate sr, 725 const float *eb, bool att, struct lc3_sns_data *data, 726 const float *x, float *y) 727 { 728 /* Processing steps : 729 * - Determine 16 scale factors from bands energy estimation 730 * - Get codebooks indexes that match thoses scale factors 731 * - Quantize the residual with the selected codebook 732 * - The pulse configuration `c[]` is enumerated 733 * - Finally shape the spectrum coefficients accordingly */ 734 735 float scf[16], cn[4][16]; 736 int c[4][16]; 737 738 compute_scale_factors(dt, sr, eb, att, scf); 739 740 resolve_codebooks(scf, &data->lfcb, &data->hfcb); 741 742 quantize(scf, data->lfcb, data->hfcb, 743 c, cn, &data->shape, &data->gain); 744 745 unquantize(data->lfcb, data->hfcb, 746 cn[data->shape], data->shape, data->gain, scf); 747 748 enumerate(data->shape, c[data->shape], 749 &data->idx_a, &data->ls_a, &data->idx_b, &data->ls_b); 750 751 spectral_shaping(dt, sr, scf, false, x, y); 752 } 753 754 /** 755 * SNS synthesis 756 */ 757 void lc3_sns_synthesize(enum lc3_dt dt, enum lc3_srate sr, 758 const lc3_sns_data_t *data, const float *x, float *y) 759 { 760 float scf[16], cn[16]; 761 int c[16]; 762 763 deenumerate(data->shape, 764 data->idx_a, data->ls_a, data->idx_b, data->ls_b, c); 765 766 normalize(c, cn); 767 768 unquantize(data->lfcb, data->hfcb, cn, data->shape, data->gain, scf); 769 770 spectral_shaping(dt, sr, scf, true, x, y); 771 } 772 773 /** 774 * Return number of bits coding the bitstream data 775 */ 776 int lc3_sns_get_nbits(void) 777 { 778 return 38; 779 } 780 781 /** 782 * Put bitstream data 783 */ 784 void lc3_sns_put_data(lc3_bits_t *bits, const struct lc3_sns_data *data) 785 { 786 /* --- Codebooks --- */ 787 788 lc3_put_bits(bits, data->lfcb, 5); 789 lc3_put_bits(bits, data->hfcb, 5); 790 791 /* --- Shape, gain and vectors --- * 792 * Write MSB bit of shape index, next LSB bits of shape and gain, 793 * and MVPQ vectors indexes are muxed */ 794 795 int shape_msb = data->shape >> 1; 796 lc3_put_bit(bits, shape_msb); 797 798 if (shape_msb == 0) { 799 const int size_a = 2390004; 800 int submode = data->shape & 1; 801 802 int mux_high = submode == 0 ? 803 2 * (data->idx_b + 1) + data->ls_b : data->gain & 1; 804 int mux_code = mux_high * size_a + data->idx_a; 805 806 lc3_put_bits(bits, data->gain >> submode, 1); 807 lc3_put_bits(bits, data->ls_a, 1); 808 lc3_put_bits(bits, mux_code, 25); 809 810 } else { 811 const int size_a = 15158272; 812 int submode = data->shape & 1; 813 814 int mux_code = submode == 0 ? 815 data->idx_a : size_a + 2 * data->idx_a + (data->gain & 1); 816 817 lc3_put_bits(bits, data->gain >> submode, 2); 818 lc3_put_bits(bits, data->ls_a, 1); 819 lc3_put_bits(bits, mux_code, 24); 820 } 821 } 822 823 /** 824 * Get bitstream data 825 */ 826 int lc3_sns_get_data(lc3_bits_t *bits, struct lc3_sns_data *data) 827 { 828 /* --- Codebooks --- */ 829 830 *data = (struct lc3_sns_data){ 831 .lfcb = lc3_get_bits(bits, 5), 832 .hfcb = lc3_get_bits(bits, 5) 833 }; 834 835 /* --- Shape, gain and vectors --- */ 836 837 int shape_msb = lc3_get_bit(bits); 838 data->gain = lc3_get_bits(bits, 1 + shape_msb); 839 data->ls_a = lc3_get_bit(bits); 840 841 int mux_code = lc3_get_bits(bits, 25 - shape_msb); 842 843 if (shape_msb == 0) { 844 const int size_a = 2390004; 845 846 if (mux_code >= size_a * 14) 847 return -1; 848 849 data->idx_a = mux_code % size_a; 850 mux_code = mux_code / size_a; 851 852 data->shape = (mux_code < 2); 853 854 if (data->shape == 0) { 855 data->idx_b = (mux_code - 2) / 2; 856 data->ls_b = (mux_code - 2) % 2; 857 } else { 858 data->gain = (data->gain << 1) + (mux_code % 2); 859 } 860 861 } else { 862 const int size_a = 15158272; 863 864 if (mux_code >= size_a + 1549824) 865 return -1; 866 867 data->shape = 2 + (mux_code >= size_a); 868 if (data->shape == 2) { 869 data->idx_a = mux_code; 870 } else { 871 mux_code -= size_a; 872 data->idx_a = mux_code / 2; 873 data->gain = (data->gain << 1) + (mux_code % 2); 874 } 875 } 876 877 return 0; 878 } 879