1 /****************************************************************************** 2 * 3 * Copyright 2022 Google LLC 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 "ltpf.h" 20 #include "tables.h" 21 22 #include "ltpf_neon.h" 23 #include "ltpf_arm.h" 24 25 26 /* ---------------------------------------------------------------------------- 27 * Resampling 28 * -------------------------------------------------------------------------- */ 29 30 /** 31 * Resampling coefficients 32 * The coefficients, in fixed Q15, are reordered by phase for each source 33 * samplerate (coefficient matrix transposed) 34 */ 35 36 #ifndef resample_8k_12k8 37 static const int16_t h_8k_12k8_q15[8*10] = { 38 214, 417, -1052, -4529, 26233, -4529, -1052, 417, 214, 0, 39 180, 0, -1522, -2427, 24506, -5289, 0, 763, 156, -28, 40 92, -323, -1361, 0, 19741, -3885, 1317, 861, 0, -61, 41 0, -457, -752, 1873, 13068, 0, 2389, 598, -213, -79, 42 -61, -398, 0, 2686, 5997, 5997, 2686, 0, -398, -61, 43 -79, -213, 598, 2389, 0, 13068, 1873, -752, -457, 0, 44 -61, 0, 861, 1317, -3885, 19741, 0, -1361, -323, 92, 45 -28, 156, 763, 0, -5289, 24506, -2427, -1522, 0, 180, 46 }; 47 #endif /* resample_8k_12k8 */ 48 49 #ifndef resample_16k_12k8 50 static const int16_t h_16k_12k8_q15[4*20] = { 51 -61, 214, -398, 417, 0, -1052, 2686, -4529, 5997, 26233, 52 5997, -4529, 2686, -1052, 0, 417, -398, 214, -61, 0, 53 54 -79, 180, -213, 0, 598, -1522, 2389, -2427, 0, 24506, 55 13068, -5289, 1873, 0, -752, 763, -457, 156, 0, -28, 56 57 -61, 92, 0, -323, 861, -1361, 1317, 0, -3885, 19741, 58 19741, -3885, 0, 1317, -1361, 861, -323, 0, 92, -61, 59 60 -28, 0, 156, -457, 763, -752, 0, 1873, -5289, 13068, 61 24506, 0, -2427, 2389, -1522, 598, 0, -213, 180, -79, 62 }; 63 #endif /* resample_16k_12k8 */ 64 65 #ifndef resample_32k_12k8 66 static const int16_t h_32k_12k8_q15[2*40] = { 67 -30, -31, 46, 107, 0, -199, -162, 209, 430, 0, 68 -681, -526, 658, 1343, 0, -2264, -1943, 2999, 9871, 13116, 69 9871, 2999, -1943, -2264, 0, 1343, 658, -526, -681, 0, 70 430, 209, -162, -199, 0, 107, 46, -31, -30, 0, 71 72 -14, -39, 0, 90, 78, -106, -229, 0, 382, 299, 73 -376, -761, 0, 1194, 937, -1214, -2644, 0, 6534, 12253, 74 12253, 6534, 0, -2644, -1214, 937, 1194, 0, -761, -376, 75 299, 382, 0, -229, -106, 78, 90, 0, -39, -14, 76 }; 77 #endif /* resample_32k_12k8 */ 78 79 #ifndef resample_24k_12k8 80 static const int16_t h_24k_12k8_q15[8*30] = { 81 -50, 19, 143, -93, -290, 278, 485, -658, -701, 1396, 82 901, -3019, -1042, 10276, 17488, 10276, -1042, -3019, 901, 1396, 83 -701, -658, 485, 278, -290, -93, 143, 19, -50, 0, 84 85 -46, 0, 141, -45, -305, 185, 543, -501, -854, 1153, 86 1249, -2619, -1908, 8712, 17358, 11772, 0, -3319, 480, 1593, 87 -504, -796, 399, 367, -261, -142, 138, 40, -52, -5, 88 89 -41, -17, 133, 0, -304, 91, 574, -334, -959, 878, 90 1516, -2143, -2590, 7118, 16971, 13161, 1202, -3495, 0, 1731, 91 -267, -908, 287, 445, -215, -188, 125, 62, -52, -12, 92 93 -34, -30, 120, 41, -291, 0, 577, -164, -1015, 585, 94 1697, -1618, -3084, 5534, 16337, 14406, 2544, -3526, -523, 1800, 95 0, -985, 152, 509, -156, -230, 104, 83, -48, -19, 96 97 -26, -41, 103, 76, -265, -83, 554, 0, -1023, 288, 98 1791, -1070, -3393, 3998, 15474, 15474, 3998, -3393, -1070, 1791, 99 288, -1023, 0, 554, -83, -265, 76, 103, -41, -26, 100 101 -19, -48, 83, 104, -230, -156, 509, 152, -985, 0, 102 1800, -523, -3526, 2544, 14406, 16337, 5534, -3084, -1618, 1697, 103 585, -1015, -164, 577, 0, -291, 41, 120, -30, -34, 104 105 -12, -52, 62, 125, -188, -215, 445, 287, -908, -267, 106 1731, 0, -3495, 1202, 13161, 16971, 7118, -2590, -2143, 1516, 107 878, -959, -334, 574, 91, -304, 0, 133, -17, -41, 108 109 -5, -52, 40, 138, -142, -261, 367, 399, -796, -504, 110 1593, 480, -3319, 0, 11772, 17358, 8712, -1908, -2619, 1249, 111 1153, -854, -501, 543, 185, -305, -45, 141, 0, -46, 112 }; 113 #endif /* resample_24k_12k8 */ 114 115 #ifndef resample_48k_12k8 116 static const int16_t h_48k_12k8_q15[4*60] = { 117 -13, -25, -20, 10, 51, 71, 38, -47, -133, -145, 118 -42, 139, 277, 242, 0, -329, -511, -351, 144, 698, 119 895, 450, -535, -1510, -1697, -521, 1999, 5138, 7737, 8744, 120 7737, 5138, 1999, -521, -1697, -1510, -535, 450, 895, 698, 121 144, -351, -511, -329, 0, 242, 277, 139, -42, -145, 122 -133, -47, 38, 71, 51, 10, -20, -25, -13, 0, 123 124 -9, -23, -24, 0, 41, 71, 52, -23, -115, -152, 125 -78, 92, 254, 272, 76, -251, -493, -427, 0, 576, 126 900, 624, -262, -1309, -1763, -954, 1272, 4356, 7203, 8679, 127 8169, 5886, 2767, 0, -1542, -1660, -809, 240, 848, 796, 128 292, -252, -507, -398, -82, 199, 288, 183, 0, -130, 129 -145, -71, 20, 69, 60, 20, -15, -26, -17, -3, 130 131 -6, -20, -26, -8, 31, 67, 62, 0, -94, -152, 132 -108, 45, 223, 287, 143, -167, -454, -480, -134, 439, 133 866, 758, 0, -1071, -1748, -1295, 601, 3559, 6580, 8485, 134 8485, 6580, 3559, 601, -1295, -1748, -1071, 0, 758, 866, 135 439, -134, -480, -454, -167, 143, 287, 223, 45, -108, 136 -152, -94, 0, 62, 67, 31, -8, -26, -20, -6, 137 138 -3, -17, -26, -15, 20, 60, 69, 20, -71, -145, 139 -130, 0, 183, 288, 199, -82, -398, -507, -252, 292, 140 796, 848, 240, -809, -1660, -1542, 0, 2767, 5886, 8169, 141 8679, 7203, 4356, 1272, -954, -1763, -1309, -262, 624, 900, 142 576, 0, -427, -493, -251, 76, 272, 254, 92, -78, 143 -152, -115, -23, 52, 71, 41, 0, -24, -23, -9, 144 }; 145 #endif /* resample_48k_12k8 */ 146 147 #ifndef resample_96k_12k8 148 static const int16_t h_96k_12k8_q15[2*120] = { 149 -3, -7, -10, -13, -13, -10, -4, 5, 15, 26, 150 33, 36, 31, 19, 0, -23, -47, -66, -76, -73, 151 -54, -21, 23, 70, 111, 139, 143, 121, 72, 0, 152 -84, -165, -227, -256, -240, -175, -67, 72, 219, 349, 153 433, 448, 379, 225, 0, -268, -536, -755, -874, -848, 154 -648, -260, 301, 1000, 1780, 2569, 3290, 3869, 4243, 4372, 155 4243, 3869, 3290, 2569, 1780, 1000, 301, -260, -648, -848, 156 -874, -755, -536, -268, 0, 225, 379, 448, 433, 349, 157 219, 72, -67, -175, -240, -256, -227, -165, -84, 0, 158 72, 121, 143, 139, 111, 70, 23, -21, -54, -73, 159 -76, -66, -47, -23, 0, 19, 31, 36, 33, 26, 160 15, 5, -4, -10, -13, -13, -10, -7, -3, 0, 161 162 -1, -5, -8, -12, -13, -12, -8, 0, 10, 21, 163 30, 35, 34, 26, 10, -11, -35, -58, -73, -76, 164 -65, -39, 0, 46, 92, 127, 144, 136, 100, 38, 165 -41, -125, -199, -246, -254, -214, -126, 0, 146, 288, 166 398, 450, 424, 312, 120, -131, -405, -655, -830, -881, 167 -771, -477, 0, 636, 1384, 2178, 2943, 3601, 4084, 4340, 168 4340, 4084, 3601, 2943, 2178, 1384, 636, 0, -477, -771, 169 -881, -830, -655, -405, -131, 120, 312, 424, 450, 398, 170 288, 146, 0, -126, -214, -254, -246, -199, -125, -41, 171 38, 100, 136, 144, 127, 92, 46, 0, -39, -65, 172 -76, -73, -58, -35, -11, 10, 26, 34, 35, 30, 173 21, 10, 0, -8, -12, -13, -12, -8, -5, -1, 174 }; 175 #endif /* resample_96k_12k8 */ 176 177 178 /** 179 * High-pass 50Hz filtering, at 12.8 KHz samplerate 180 * hp50 Biquad filter state 181 * xn Input sample, in fixed Q30 182 * return Filtered sample, in fixed Q30 183 */ 184 LC3_HOT static inline int32_t filter_hp50( 185 struct lc3_ltpf_hp50_state *hp50, int32_t xn) 186 { 187 int32_t yn; 188 189 const int32_t a1 = -2110217691, a2 = 1037111617; 190 const int32_t b1 = -2110535566, b2 = 1055267782; 191 192 yn = (hp50->s1 + (int64_t)xn * b2) >> 30; 193 hp50->s1 = (hp50->s2 + (int64_t)xn * b1 - (int64_t)yn * a1); 194 hp50->s2 = ( (int64_t)xn * b2 - (int64_t)yn * a2); 195 196 return yn; 197 } 198 199 /** 200 * Resample from 8 / 16 / 32 KHz to 12.8 KHz Template 201 * p Resampling factor with compared to 192 KHz (8, 4 or 2) 202 * h Arrange by phase coefficients table 203 * hp50 High-Pass biquad filter state 204 * x [-d..-1] Previous, [0..ns-1] Current samples, Q15 205 * y, n [0..n-1] Output `n` processed samples, Q14 206 * 207 * The `x` vector is aligned on 32 bits 208 * The number of previous samples `d` accessed on `x` is : 209 * d: { 10, 20, 40 } - 1 for resampling factors 8, 4 and 2. 210 */ 211 #if !defined(resample_8k_12k8) || !defined(resample_16k_12k8) \ 212 || !defined(resample_32k_12k8) 213 LC3_HOT static inline void resample_x64k_12k8(const int p, const int16_t *h, 214 struct lc3_ltpf_hp50_state *hp50, const int16_t *x, int16_t *y, int n) 215 { 216 const int w = 2*(40 / p); 217 218 x -= w - 1; 219 220 for (int i = 0; i < 5*n; i += 5) { 221 const int16_t *hn = h + (i % p) * w; 222 const int16_t *xn = x + (i / p); 223 int32_t un = 0; 224 225 for (int k = 0; k < w; k += 10) { 226 un += *(xn++) * *(hn++); 227 un += *(xn++) * *(hn++); 228 un += *(xn++) * *(hn++); 229 un += *(xn++) * *(hn++); 230 un += *(xn++) * *(hn++); 231 un += *(xn++) * *(hn++); 232 un += *(xn++) * *(hn++); 233 un += *(xn++) * *(hn++); 234 un += *(xn++) * *(hn++); 235 un += *(xn++) * *(hn++); 236 } 237 238 int32_t yn = filter_hp50(hp50, un); 239 *(y++) = (yn + (1 << 15)) >> 16; 240 } 241 } 242 #endif 243 244 /** 245 * Resample from 24 / 48 KHz to 12.8 KHz Template 246 * p Resampling factor with compared to 192 KHz (8 or 4) 247 * h Arrange by phase coefficients table 248 * hp50 High-Pass biquad filter state 249 * x [-d..-1] Previous, [0..ns-1] Current samples, Q15 250 * y, n [0..n-1] Output `n` processed samples, Q14 251 * 252 * The `x` vector is aligned on 32 bits 253 * The number of previous samples `d` accessed on `x` is : 254 * d: { 30, 60 } - 1 for resampling factors 8 and 4. 255 */ 256 #if !defined(resample_24k_12k8) || !defined(resample_48k_12k8) \ 257 || !defined(resample_96k_12k8) 258 LC3_HOT static inline void resample_x192k_12k8(const int p, const int16_t *h, 259 struct lc3_ltpf_hp50_state *hp50, const int16_t *x, int16_t *y, int n) 260 { 261 const int w = 2*(120 / p); 262 263 x -= w - 1; 264 265 for (int i = 0; i < 15*n; i += 15) { 266 const int16_t *hn = h + (i % p) * w; 267 const int16_t *xn = x + (i / p); 268 int32_t un = 0; 269 270 for (int k = 0; k < w; k += 15) { 271 un += *(xn++) * *(hn++); 272 un += *(xn++) * *(hn++); 273 un += *(xn++) * *(hn++); 274 un += *(xn++) * *(hn++); 275 un += *(xn++) * *(hn++); 276 un += *(xn++) * *(hn++); 277 un += *(xn++) * *(hn++); 278 un += *(xn++) * *(hn++); 279 un += *(xn++) * *(hn++); 280 un += *(xn++) * *(hn++); 281 un += *(xn++) * *(hn++); 282 un += *(xn++) * *(hn++); 283 un += *(xn++) * *(hn++); 284 un += *(xn++) * *(hn++); 285 un += *(xn++) * *(hn++); 286 } 287 288 int32_t yn = filter_hp50(hp50, un); 289 *(y++) = (yn + (1 << 15)) >> 16; 290 } 291 } 292 #endif 293 294 /** 295 * Resample from 8 Khz to 12.8 KHz 296 * hp50 High-Pass biquad filter state 297 * x [-10..-1] Previous, [0..ns-1] Current samples, Q15 298 * y, n [0..n-1] Output `n` processed samples, Q14 299 * 300 * The `x` vector is aligned on 32 bits 301 */ 302 #ifndef resample_8k_12k8 303 LC3_HOT static void resample_8k_12k8( 304 struct lc3_ltpf_hp50_state *hp50, const int16_t *x, int16_t *y, int n) 305 { 306 resample_x64k_12k8(8, h_8k_12k8_q15, hp50, x, y, n); 307 } 308 #endif /* resample_8k_12k8 */ 309 310 /** 311 * Resample from 16 Khz to 12.8 KHz 312 * hp50 High-Pass biquad filter state 313 * x [-20..-1] Previous, [0..ns-1] Current samples, in fixed Q15 314 * y, n [0..n-1] Output `n` processed samples, in fixed Q14 315 * 316 * The `x` vector is aligned on 32 bits 317 */ 318 #ifndef resample_16k_12k8 319 LC3_HOT static void resample_16k_12k8( 320 struct lc3_ltpf_hp50_state *hp50, const int16_t *x, int16_t *y, int n) 321 { 322 resample_x64k_12k8(4, h_16k_12k8_q15, hp50, x, y, n); 323 } 324 #endif /* resample_16k_12k8 */ 325 326 /** 327 * Resample from 32 Khz to 12.8 KHz 328 * hp50 High-Pass biquad filter state 329 * x [-30..-1] Previous, [0..ns-1] Current samples, in fixed Q15 330 * y, n [0..n-1] Output `n` processed samples, in fixed Q14 331 * 332 * The `x` vector is aligned on 32 bits 333 */ 334 #ifndef resample_32k_12k8 335 LC3_HOT static void resample_32k_12k8( 336 struct lc3_ltpf_hp50_state *hp50, const int16_t *x, int16_t *y, int n) 337 { 338 resample_x64k_12k8(2, h_32k_12k8_q15, hp50, x, y, n); 339 } 340 #endif /* resample_32k_12k8 */ 341 342 /** 343 * Resample from 24 Khz to 12.8 KHz 344 * hp50 High-Pass biquad filter state 345 * x [-30..-1] Previous, [0..ns-1] Current samples, in fixed Q15 346 * y, n [0..n-1] Output `n` processed samples, in fixed Q14 347 * 348 * The `x` vector is aligned on 32 bits 349 */ 350 #ifndef resample_24k_12k8 351 LC3_HOT static void resample_24k_12k8( 352 struct lc3_ltpf_hp50_state *hp50, const int16_t *x, int16_t *y, int n) 353 { 354 resample_x192k_12k8(8, h_24k_12k8_q15, hp50, x, y, n); 355 } 356 #endif /* resample_24k_12k8 */ 357 358 /** 359 * Resample from 48 Khz to 12.8 KHz 360 * hp50 High-Pass biquad filter state 361 * x [-60..-1] Previous, [0..ns-1] Current samples, in fixed Q15 362 * y, n [0..n-1] Output `n` processed samples, in fixed Q14 363 * 364 * The `x` vector is aligned on 32 bits 365 */ 366 #ifndef resample_48k_12k8 367 LC3_HOT static void resample_48k_12k8( 368 struct lc3_ltpf_hp50_state *hp50, const int16_t *x, int16_t *y, int n) 369 { 370 resample_x192k_12k8(4, h_48k_12k8_q15, hp50, x, y, n); 371 } 372 #endif /* resample_48k_12k8 */ 373 374 /** 375 * Resample from 96 Khz to 12.8 KHz 376 * hp50 High-Pass biquad filter state 377 * x [-120..-1] Previous, [0..ns-1] Current samples, in fixed Q15 378 * y, n [0..n-1] Output `n` processed samples, in fixed Q14 379 * 380 * The `x` vector is aligned on 32 bits 381 */ 382 #ifndef resample_96k_12k8 383 LC3_HOT static void resample_96k_12k8( 384 struct lc3_ltpf_hp50_state *hp50, const int16_t *x, int16_t *y, int n) 385 { 386 resample_x192k_12k8(2, h_96k_12k8_q15, hp50, x, y, n); 387 } 388 #endif /* resample_96k_12k8 */ 389 390 /** 391 * Resample to 6.4 KHz 392 * x [-3..-1] Previous, [0..n-1] Current samples 393 * y, n [0..n-1] Output `n` processed samples 394 * 395 * The `x` vector is aligned on 32 bits 396 */ 397 #ifndef resample_6k4 398 LC3_HOT static void resample_6k4(const int16_t *x, int16_t *y, int n) 399 { 400 static const int16_t h[] = { 18477, 15424, 8105 }; 401 const int16_t *ye = y + n; 402 403 for (x--; y < ye; x += 2) 404 *(y++) = (x[0] * h[0] + (x[-1] + x[1]) * h[1] 405 + (x[-2] + x[2]) * h[2]) >> 16; 406 } 407 #endif /* resample_6k4 */ 408 409 /** 410 * LTPF Resample to 12.8 KHz implementations for each samplerates 411 */ 412 413 static void (* const resample_12k8[]) 414 (struct lc3_ltpf_hp50_state *, const int16_t *, int16_t *, int ) = 415 { 416 [LC3_SRATE_8K ] = resample_8k_12k8, 417 [LC3_SRATE_16K ] = resample_16k_12k8, 418 [LC3_SRATE_24K ] = resample_24k_12k8, 419 [LC3_SRATE_32K ] = resample_32k_12k8, 420 [LC3_SRATE_48K ] = resample_48k_12k8, 421 [LC3_SRATE_48K_HR] = resample_48k_12k8, 422 [LC3_SRATE_96K_HR] = resample_96k_12k8, 423 }; 424 425 426 /* ---------------------------------------------------------------------------- 427 * Analysis 428 * -------------------------------------------------------------------------- */ 429 430 /** 431 * Return dot product of 2 vectors 432 * a, b, n The 2 vectors of size `n` (> 0 and <= 128) 433 * return sum( a[i] * b[i] ), i = [0..n-1] 434 * 435 * The size `n` of vectors must be multiple of 16, and less or equal to 128 436 */ 437 #ifndef dot 438 LC3_HOT static inline float dot(const int16_t *a, const int16_t *b, int n) 439 { 440 int64_t v = 0; 441 442 for (int i = 0; i < (n >> 4); i++) 443 for (int j = 0; j < 16; j++) 444 v += *(a++) * *(b++); 445 446 int32_t v32 = (v + (1 << 5)) >> 6; 447 return (float)v32; 448 } 449 #endif /* dot */ 450 451 /** 452 * Return vector of correlations 453 * a, b, n The 2 vector of size `n` (> 0 and <= 128) 454 * y, nc Output the correlation vector of size `nc` 455 * 456 * The first vector `a` is aligned of 32 bits 457 * The size `n` of vectors is multiple of 16, and less or equal to 128 458 */ 459 #ifndef correlate 460 LC3_HOT static void correlate( 461 const int16_t *a, const int16_t *b, int n, float *y, int nc) 462 { 463 for (const float *ye = y + nc; y < ye; ) 464 *(y++) = dot(a, b--, n); 465 } 466 #endif /* correlate */ 467 468 /** 469 * Search the maximum value and returns its argument 470 * x, n The input vector of size `n` 471 * x_max Return the maximum value 472 * return Return the argument of the maximum 473 */ 474 LC3_HOT static int argmax(const float *x, int n, float *x_max) 475 { 476 int arg = 0; 477 478 *x_max = x[arg = 0]; 479 for (int i = 1; i < n; i++) 480 if (*x_max < x[i]) 481 *x_max = x[arg = i]; 482 483 return arg; 484 } 485 486 /** 487 * Search the maximum weithed value and returns its argument 488 * x, n The input vector of size `n` 489 * w_incr Increment of the weight 490 * x_max, xw_max Return the maximum not weighted value 491 * return Return the argument of the weigthed maximum 492 */ 493 LC3_HOT static int argmax_weighted( 494 const float *x, int n, float w_incr, float *x_max) 495 { 496 int arg; 497 498 float xw_max = (*x_max = x[arg = 0]); 499 float w = 1 + w_incr; 500 501 for (int i = 1; i < n; i++, w += w_incr) 502 if (xw_max < x[i] * w) 503 xw_max = (*x_max = x[arg = i]) * w; 504 505 return arg; 506 } 507 508 /** 509 * Interpolate from pitch detected value 510 * x, n [-2..-1] Previous, [0..n] Current input 511 * d The phase of interpolation (0 to 3) 512 * return The interpolated vector 513 * 514 * The size `n` of vectors must be multiple of 4 515 */ 516 LC3_HOT static void interpolate(const int16_t *x, int n, int d, int16_t *y) 517 { 518 static const int16_t h4_q15[][4] = { 519 { 6877, 19121, 6877, 0 }, { 3506, 18025, 11000, 220 }, 520 { 1300, 15048, 15048, 1300 }, { 220, 11000, 18025, 3506 } }; 521 522 const int16_t *h = h4_q15[d]; 523 int16_t x3 = x[-2], x2 = x[-1], x1, x0; 524 525 x1 = (*x++); 526 for (const int16_t *ye = y + n; y < ye; ) { 527 int32_t yn; 528 529 yn = (x0 = *(x++)) * h[0] + x1 * h[1] + x2 * h[2] + x3 * h[3]; 530 *(y++) = yn >> 15; 531 532 yn = (x3 = *(x++)) * h[0] + x0 * h[1] + x1 * h[2] + x2 * h[3]; 533 *(y++) = yn >> 15; 534 535 yn = (x2 = *(x++)) * h[0] + x3 * h[1] + x0 * h[2] + x1 * h[3]; 536 *(y++) = yn >> 15; 537 538 yn = (x1 = *(x++)) * h[0] + x2 * h[1] + x3 * h[2] + x0 * h[3]; 539 *(y++) = yn >> 15; 540 } 541 } 542 543 /** 544 * Interpolate autocorrelation 545 * x [-4..-1] Previous, [0..4] Current input 546 * d The phase of interpolation (-3 to 3) 547 * return The interpolated value 548 */ 549 LC3_HOT static float interpolate_corr(const float *x, int d) 550 { 551 static const float h4[][8] = { 552 { 1.53572770e-02, -4.72963246e-02, 8.35788573e-02, 8.98638285e-01, 553 8.35788573e-02, -4.72963246e-02, 1.53572770e-02, }, 554 { 2.74547165e-03, 4.59833449e-03, -7.54404636e-02, 8.17488686e-01, 555 3.30182571e-01, -1.05835916e-01, 2.86823405e-02, -2.87456116e-03 }, 556 { -3.00125103e-03, 2.95038503e-02, -1.30305021e-01, 6.03297008e-01, 557 6.03297008e-01, -1.30305021e-01, 2.95038503e-02, -3.00125103e-03 }, 558 { -2.87456116e-03, 2.86823405e-02, -1.05835916e-01, 3.30182571e-01, 559 8.17488686e-01, -7.54404636e-02, 4.59833449e-03, 2.74547165e-03 }, 560 }; 561 562 const float *h = h4[(4+d) % 4]; 563 564 float y = d < 0 ? x[-4] * *(h++) : 565 d > 0 ? x[ 4] * *(h+7) : 0; 566 567 y += x[-3] * h[0] + x[-2] * h[1] + x[-1] * h[2] + x[0] * h[3] + 568 x[ 1] * h[4] + x[ 2] * h[5] + x[ 3] * h[6]; 569 570 return y; 571 } 572 573 /** 574 * Pitch detection algorithm 575 * ltpf Context of analysis 576 * x, n [-114..-17] Previous, [0..n-1] Current 6.4KHz samples 577 * tc Return the pitch-lag estimation 578 * return True when pitch present 579 * 580 * The `x` vector is aligned on 32 bits 581 */ 582 static bool detect_pitch(struct lc3_ltpf_analysis *ltpf, 583 const int16_t *x, int n, int *tc) 584 { 585 float rm1, rm2; 586 float r[98]; 587 588 const int r0 = 17, nr = 98; 589 int k0 = LC3_MAX( 0, ltpf->tc-4); 590 int nk = LC3_MIN(nr-1, ltpf->tc+4) - k0 + 1; 591 592 correlate(x, x - r0, n, r, nr); 593 594 int t1 = argmax_weighted(r, nr, -.5f/(nr-1), &rm1); 595 int t2 = k0 + argmax(r + k0, nk, &rm2); 596 597 const int16_t *x1 = x - (r0 + t1); 598 const int16_t *x2 = x - (r0 + t2); 599 600 float nc1 = rm1 <= 0 ? 0 : 601 rm1 / sqrtf(dot(x, x, n) * dot(x1, x1, n)); 602 603 float nc2 = rm2 <= 0 ? 0 : 604 rm2 / sqrtf(dot(x, x, n) * dot(x2, x2, n)); 605 606 int t1sel = nc2 <= 0.85f * nc1; 607 ltpf->tc = (t1sel ? t1 : t2); 608 609 *tc = r0 + ltpf->tc; 610 return (t1sel ? nc1 : nc2) > 0.6f; 611 } 612 613 /** 614 * Pitch-lag parameter 615 * x, n [-232..-28] Previous, [0..n-1] Current 12.8KHz samples, Q14 616 * tc Pitch-lag estimation 617 * pitch The pitch value, in fixed .4 618 * return The bitstream pitch index value 619 * 620 * The `x` vector is aligned on 32 bits 621 */ 622 static int refine_pitch(const int16_t *x, int n, int tc, int *pitch) 623 { 624 float r[17], rm; 625 int e, f; 626 627 int r0 = LC3_MAX( 32, 2*tc - 4); 628 int nr = LC3_MIN(228, 2*tc + 4) - r0 + 1; 629 630 correlate(x, x - (r0 - 4), n, r, nr + 8); 631 632 e = r0 + argmax(r + 4, nr, &rm); 633 const float *re = r + (e - (r0 - 4)); 634 635 float dm = interpolate_corr(re, f = 0); 636 for (int i = 1; i <= 3; i++) { 637 float d; 638 639 if (e >= 127 && ((i & 1) | (e >= 157))) 640 continue; 641 642 if ((d = interpolate_corr(re, i)) > dm) 643 dm = d, f = i; 644 645 if (e > 32 && (d = interpolate_corr(re, -i)) > dm) 646 dm = d, f = -i; 647 } 648 649 e -= (f < 0); 650 f += 4*(f < 0); 651 652 *pitch = 4*e + f; 653 return e < 127 ? 4*e + f - 128 : 654 e < 157 ? 2*e + (f >> 1) + 126 : e + 283; 655 } 656 657 /** 658 * LTPF Analysis 659 */ 660 bool lc3_ltpf_analyse( 661 enum lc3_dt dt, enum lc3_srate sr, struct lc3_ltpf_analysis *ltpf, 662 const int16_t *x, struct lc3_ltpf_data *data) 663 { 664 /* --- Resampling to 12.8 KHz --- */ 665 666 int z_12k8 = sizeof(ltpf->x_12k8) / sizeof(*ltpf->x_12k8); 667 int n_12k8 = (1 + dt) * 32; 668 669 memmove(ltpf->x_12k8, ltpf->x_12k8 + n_12k8, 670 (z_12k8 - n_12k8) * sizeof(*ltpf->x_12k8)); 671 672 int16_t *x_12k8 = ltpf->x_12k8 + (z_12k8 - n_12k8); 673 674 resample_12k8[sr](<pf->hp50, x, x_12k8, n_12k8); 675 676 x_12k8 -= (dt == LC3_DT_7M5 ? 44 : 24); 677 678 /* --- Resampling to 6.4 KHz --- */ 679 680 int z_6k4 = sizeof(ltpf->x_6k4) / sizeof(*ltpf->x_6k4); 681 int n_6k4 = n_12k8 >> 1; 682 683 memmove(ltpf->x_6k4, ltpf->x_6k4 + n_6k4, 684 (z_6k4 - n_6k4) * sizeof(*ltpf->x_6k4)); 685 686 int16_t *x_6k4 = ltpf->x_6k4 + (z_6k4 - n_6k4); 687 688 resample_6k4(x_12k8, x_6k4, n_6k4); 689 690 /* --- Enlarge for small frame size --- */ 691 692 if (dt == LC3_DT_2M5) { 693 x_12k8 -= n_12k8, x_6k4 -= n_6k4; 694 n_12k8 += n_12k8; n_6k4 += n_6k4; 695 } 696 697 /* --- Pitch detection --- */ 698 699 int tc, pitch = 0; 700 float nc = 0; 701 702 bool pitch_present = detect_pitch(ltpf, x_6k4, n_6k4, &tc); 703 704 if (pitch_present) { 705 int16_t u[128], v[128]; 706 707 data->pitch_index = refine_pitch(x_12k8, n_12k8, tc, &pitch); 708 709 interpolate(x_12k8, n_12k8, 0, u); 710 interpolate(x_12k8 - (pitch >> 2), n_12k8, pitch & 3, v); 711 712 nc = dot(u, v, n_12k8) / sqrtf(dot(u, u, n_12k8) * dot(v, v, n_12k8)); 713 } 714 715 /* --- Activation --- */ 716 717 if (ltpf->active) { 718 int pitch_diff = 719 LC3_MAX(pitch, ltpf->pitch) - LC3_MIN(pitch, ltpf->pitch); 720 float nc_diff = nc - ltpf->nc[0]; 721 722 data->active = !lc3_hr(sr) && pitch_present && 723 ((nc > 0.9f) || (nc > 0.84f && pitch_diff < 8 && nc_diff > -0.1f)); 724 725 } else { 726 data->active = !lc3_hr(sr) && pitch_present && 727 ( (dt == LC3_DT_10M || ltpf->nc[1] > 0.94f) && 728 (ltpf->nc[0] > 0.94f && nc > 0.94f) ); 729 } 730 731 ltpf->active = data->active; 732 ltpf->pitch = pitch; 733 ltpf->nc[1] = ltpf->nc[0]; 734 ltpf->nc[0] = nc; 735 736 return pitch_present; 737 } 738 739 740 /* ---------------------------------------------------------------------------- 741 * Synthesis 742 * -------------------------------------------------------------------------- */ 743 744 /** 745 * Width of synthesis filter 746 */ 747 748 #define MAX_FILTER_WIDTH \ 749 (LC3_MAX_SRATE_HZ / 4000) 750 751 752 /** 753 * Synthesis filter template 754 * xh, nh History ring buffer of filtered samples 755 * lag Lag parameter in the ring buffer 756 * x0 w-1 previous input samples 757 * x, n Current samples as input, filtered as output 758 * c, w Coefficients `den` then `num`, and width of filter 759 * fade Fading mode of filter -1: Out 1: In 0: None 760 */ 761 LC3_HOT static inline void synthesize_template( 762 const float *xh, int nh, int lag, 763 const float *x0, float *x, int n, 764 const float *c, const int w, int fade) 765 { 766 float g = (float)(fade <= 0); 767 float g_incr = (float)((fade > 0) - (fade < 0)) / n; 768 float u[MAX_FILTER_WIDTH]; 769 770 /* --- Load previous samples --- */ 771 772 lag += (w >> 1); 773 774 const float *y = x - xh < lag ? x + (nh - lag) : x - lag; 775 const float *y_end = xh + nh - 1; 776 777 for (int j = 0; j < w-1; j++) { 778 779 u[j] = 0; 780 781 float yi = *y, xi = *(x0++); 782 y = y < y_end ? y + 1 : xh; 783 784 for (int k = 0; k <= j; k++) 785 u[j-k] -= yi * c[k]; 786 787 for (int k = 0; k <= j; k++) 788 u[j-k] += xi * c[w+k]; 789 } 790 791 u[w-1] = 0; 792 793 /* --- Process by filter length --- */ 794 795 for (int i = 0; i < n; i += w) 796 for (int j = 0; j < w; j++, g += g_incr) { 797 798 float yi = *y, xi = *x; 799 y = y < y_end ? y + 1 : xh; 800 801 for (int k = 0; k < w; k++) 802 u[(j+(w-1)-k)%w] -= yi * c[k]; 803 804 for (int k = 0; k < w; k++) 805 u[(j+(w-1)-k)%w] += xi * c[w+k]; 806 807 *(x++) = xi - g * u[j]; 808 u[j] = 0; 809 } 810 } 811 812 /** 813 * Synthesis filter for each samplerates (width of filter) 814 */ 815 816 817 LC3_HOT static void synthesize_4(const float *xh, int nh, int lag, 818 const float *x0, float *x, int n, const float *c, int fade) 819 { 820 synthesize_template(xh, nh, lag, x0, x, n, c, 4, fade); 821 } 822 823 LC3_HOT static void synthesize_6(const float *xh, int nh, int lag, 824 const float *x0, float *x, int n, const float *c, int fade) 825 { 826 synthesize_template(xh, nh, lag, x0, x, n, c, 6, fade); 827 } 828 829 LC3_HOT static void synthesize_8(const float *xh, int nh, int lag, 830 const float *x0, float *x, int n, const float *c, int fade) 831 { 832 synthesize_template(xh, nh, lag, x0, x, n, c, 8, fade); 833 } 834 835 LC3_HOT static void synthesize_12(const float *xh, int nh, int lag, 836 const float *x0, float *x, int n, const float *c, int fade) 837 { 838 synthesize_template(xh, nh, lag, x0, x, n, c, 12, fade); 839 } 840 841 static void (* const synthesize[])(const float *, int, int, 842 const float *, float *, int, const float *, int) = 843 { 844 [LC3_SRATE_8K ] = synthesize_4, 845 [LC3_SRATE_16K] = synthesize_4, 846 [LC3_SRATE_24K] = synthesize_6, 847 [LC3_SRATE_32K] = synthesize_8, 848 [LC3_SRATE_48K] = synthesize_12, 849 }; 850 851 852 /** 853 * LTPF Synthesis 854 */ 855 void lc3_ltpf_synthesize(enum lc3_dt dt, enum lc3_srate sr, int nbytes, 856 lc3_ltpf_synthesis_t *ltpf, const lc3_ltpf_data_t *data, 857 const float *xh, float *x) 858 { 859 int nh = lc3_ns(dt, sr) + lc3_nh(dt, sr); 860 861 /* --- Filter parameters --- */ 862 863 int p_idx = data ? data->pitch_index : 0; 864 int pitch = 865 p_idx >= 440 ? (((p_idx ) - 283) << 2) : 866 p_idx >= 380 ? (((p_idx >> 1) - 63) << 2) + (((p_idx & 1)) << 1) : 867 (((p_idx >> 2) + 32) << 2) + (((p_idx & 3)) << 0) ; 868 869 pitch = (pitch * lc3_ns(LC3_DT_10M, sr) + 64) / 128; 870 871 int nbits = (nbytes*8 * (1 + LC3_DT_10M)) / (1 + dt); 872 if (dt == LC3_DT_2M5) 873 nbits = (6 * nbits + 5) / 10; 874 if (dt == LC3_DT_5M) 875 nbits -= 160; 876 877 int g_idx = LC3_MAX(nbits / 80, (int)(3 + sr)) - (3 + sr); 878 bool active = data && data->active && g_idx < 4; 879 880 int w = LC3_MAX(4, lc3_ns_4m[sr] >> 4); 881 float c[2 * MAX_FILTER_WIDTH]; 882 883 for (int i = 0; i < w; i++) { 884 float g = active ? 0.4f - 0.05f * g_idx : 0; 885 c[ i] = g * lc3_ltpf_cden[sr][pitch & 3][(w-1)-i]; 886 c[w+i] = 0.85f * g * lc3_ltpf_cnum[sr][LC3_MIN(g_idx, 3)][(w-1)-i]; 887 } 888 889 /* --- Transition handling --- */ 890 891 int ns = lc3_ns(dt, sr); 892 int nt = ns / (1 + dt); 893 float x0[2][MAX_FILTER_WIDTH]; 894 895 memcpy(x0[0], ltpf->x, (w-1) * sizeof(float)); 896 memcpy(ltpf->x, x + ns - (w-1), (w-1) * sizeof(float)); 897 898 if (active) 899 memcpy(x0[1], x + nt-(w-1), (w-1) * sizeof(float)); 900 901 if (!ltpf->active && active) 902 synthesize[sr](xh, nh, pitch/4, x0[0], x, nt, c, 1); 903 else if (ltpf->active && !active) 904 synthesize[sr](xh, nh, ltpf->pitch/4, x0[0], x, nt, ltpf->c, -1); 905 else if (ltpf->active && active && ltpf->pitch == pitch) 906 synthesize[sr](xh, nh, pitch/4, x0[0], x, nt, c, 0); 907 else if (ltpf->active && active) { 908 synthesize[sr](xh, nh, ltpf->pitch/4, x0[0], x, nt, ltpf->c, -1); 909 synthesize[sr](xh, nh, pitch/4, 910 (x <= xh ? x + nh : x) - (w-1), x, nt, c, 1); 911 } 912 913 /* --- Remainder --- */ 914 915 if (active && ns > nt) 916 synthesize[sr](xh, nh, pitch/4, x0[1], x + nt, ns-nt, c, 0); 917 918 /* --- Update state --- */ 919 920 ltpf->active = active; 921 ltpf->pitch = pitch; 922 memcpy(ltpf->c, c, 2*w * sizeof(*ltpf->c)); 923 } 924 925 926 /* ---------------------------------------------------------------------------- 927 * Bitstream data 928 * -------------------------------------------------------------------------- */ 929 930 /** 931 * LTPF disable 932 */ 933 void lc3_ltpf_disable(struct lc3_ltpf_data *data) 934 { 935 data->active = false; 936 } 937 938 /** 939 * Return number of bits coding the bitstream data 940 */ 941 int lc3_ltpf_get_nbits(bool pitch) 942 { 943 return 1 + 10 * pitch; 944 } 945 946 /** 947 * Put bitstream data 948 */ 949 void lc3_ltpf_put_data(lc3_bits_t *bits, 950 const struct lc3_ltpf_data *data) 951 { 952 lc3_put_bit(bits, data->active); 953 lc3_put_bits(bits, data->pitch_index, 9); 954 } 955 956 /** 957 * Get bitstream data 958 */ 959 void lc3_ltpf_get_data(lc3_bits_t *bits, 960 struct lc3_ltpf_data *data) 961 { 962 data->active = lc3_get_bit(bits); 963 data->pitch_index = lc3_get_bits(bits, 9); 964 } 965