1 /* 2 * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische 3 * Universitaet Berlin. See the accompanying file "COPYRIGHT" for 4 * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE. 5 */ 6 7 /* $Header: /tmp_amd/presto/export/kbs/jutta/src/gsm/RCS/long_term.c,v 1.6 1996/07/02 12:33:19 jutta Exp $ */ 8 9 #include <stdio.h> 10 #include <assert.h> 11 12 #include "private.h" 13 14 #include "gsm.h" 15 #include "proto.h" 16 17 /* 18 * 4.2.11 .. 4.2.12 LONG TERM PREDICTOR (LTP) SECTION 19 */ 20 21 22 /* 23 * This module computes the LTP gain (bc) and the LTP lag (Nc) 24 * for the long term analysis filter. This is done by calculating a 25 * maximum of the cross-correlation function between the current 26 * sub-segment short term residual signal d[0..39] (output of 27 * the short term analysis filter; for simplification the index 28 * of this array begins at 0 and ends at 39 for each sub-segment of the 29 * RPE-LTP analysis) and the previous reconstructed short term 30 * residual signal dp[ -120 .. -1 ]. A dynamic scaling must be 31 * performed to avoid overflow. 32 */ 33 34 /* The next procedure exists in six versions. First two integer 35 * version (if USE_FLOAT_MUL is not defined); then four floating 36 * point versions, twice with proper scaling (USE_FLOAT_MUL defined), 37 * once without (USE_FLOAT_MUL and FAST defined, and fast run-time 38 * option used). Every pair has first a Cut version (see the -C 39 * option to toast or the LTP_CUT option to gsm_option()), then the 40 * uncut one. (For a detailed explanation of why this is altogether 41 * a bad idea, see Henry Spencer and Geoff Collyer, ``#ifdef Considered 42 * Harmful''.) 43 */ 44 45 #ifndef USE_FLOAT_MUL 46 47 #ifdef LTP_CUT 48 49 static void Cut_Calculation_of_the_LTP_parameters P5((st, d,dp,bc_out,Nc_out), 50 51 struct gsm_state * st, 52 53 register word * d, /* [0..39] IN */ 54 register word * dp, /* [-120..-1] IN */ 55 word * bc_out, /* OUT */ 56 word * Nc_out /* OUT */ 57 ) 58 { 59 register int k, lambda; 60 word Nc, bc; 61 word wt[40]; 62 63 longword L_result; 64 longword L_max, L_power; 65 word R, S, dmax, scal, best_k; 66 word ltp_cut; 67 68 register word temp, wt_k; 69 70 /* Search of the optimum scaling of d[0..39]. 71 */ 72 dmax = 0; 73 for (k = 0; k <= 39; k++) { 74 temp = d[k]; 75 temp = GSM_ABS( temp ); 76 if (temp > dmax) { 77 dmax = temp; 78 best_k = k; 79 } 80 } 81 temp = 0; 82 if (dmax == 0) scal = 0; 83 else { 84 assert(dmax > 0); 85 temp = gsm_norm( (longword)dmax << 16 ); 86 } 87 if (temp > 6) scal = 0; 88 else scal = 6 - temp; 89 assert(scal >= 0); 90 91 /* Search for the maximum cross-correlation and coding of the LTP lag 92 */ 93 L_max = 0; 94 Nc = 40; /* index for the maximum cross-correlation */ 95 wt_k = SASR(d[best_k], scal); 96 97 for (lambda = 40; lambda <= 120; lambda++) { 98 L_result = (longword)wt_k * dp[best_k - lambda]; 99 if (L_result > L_max) { 100 Nc = lambda; 101 L_max = L_result; 102 } 103 } 104 *Nc_out = Nc; 105 L_max <<= 1; 106 107 /* Rescaling of L_max 108 */ 109 assert(scal <= 100 && scal >= -100); 110 L_max = L_max >> (6 - scal); /* sub(6, scal) */ 111 112 assert( Nc <= 120 && Nc >= 40); 113 114 /* Compute the power of the reconstructed short term residual 115 * signal dp[..] 116 */ 117 L_power = 0; 118 for (k = 0; k <= 39; k++) { 119 120 register longword L_temp; 121 122 L_temp = SASR( dp[k - Nc], 3 ); 123 L_power += L_temp * L_temp; 124 } 125 L_power <<= 1; /* from L_MULT */ 126 127 /* Normalization of L_max and L_power 128 */ 129 130 if (L_max <= 0) { 131 *bc_out = 0; 132 return; 133 } 134 if (L_max >= L_power) { 135 *bc_out = 3; 136 return; 137 } 138 139 temp = gsm_norm( L_power ); 140 141 R = SASR( L_max << temp, 16 ); 142 S = SASR( L_power << temp, 16 ); 143 144 /* Coding of the LTP gain 145 */ 146 147 /* Table 4.3a must be used to obtain the level DLB[i] for the 148 * quantization of the LTP gain b to get the coded version bc. 149 */ 150 for (bc = 0; bc <= 2; bc++) if (R <= gsm_mult(S, gsm_DLB[bc])) break; 151 *bc_out = bc; 152 } 153 154 #endif /* LTP_CUT */ 155 156 static void Calculation_of_the_LTP_parameters P4((d,dp,bc_out,Nc_out), 157 register word * d, /* [0..39] IN */ 158 register word * dp, /* [-120..-1] IN */ 159 word * bc_out, /* OUT */ 160 word * Nc_out /* OUT */ 161 ) 162 { 163 register int k, lambda; 164 word Nc, bc; 165 word wt[40]; 166 167 longword L_max, L_power; 168 word R, S, dmax, scal; 169 register word temp; 170 171 /* Search of the optimum scaling of d[0..39]. 172 */ 173 dmax = 0; 174 175 for (k = 0; k <= 39; k++) { 176 temp = d[k]; 177 temp = GSM_ABS( temp ); 178 if (temp > dmax) dmax = temp; 179 } 180 181 temp = 0; 182 if (dmax == 0) scal = 0; 183 else { 184 assert(dmax > 0); 185 temp = gsm_norm( (longword)dmax << 16 ); 186 } 187 188 if (temp > 6) scal = 0; 189 else scal = 6 - temp; 190 191 assert(scal >= 0); 192 193 /* Initialization of a working array wt 194 */ 195 196 for (k = 0; k <= 39; k++) wt[k] = SASR( d[k], scal ); 197 198 /* Search for the maximum cross-correlation and coding of the LTP lag 199 */ 200 L_max = 0; 201 Nc = 40; /* index for the maximum cross-correlation */ 202 203 for (lambda = 40; lambda <= 120; lambda++) { 204 205 # undef STEP 206 # define STEP(k) (longword)wt[k] * dp[k - lambda] 207 208 register longword L_result; 209 210 L_result = STEP(0) ; L_result += STEP(1) ; 211 L_result += STEP(2) ; L_result += STEP(3) ; 212 L_result += STEP(4) ; L_result += STEP(5) ; 213 L_result += STEP(6) ; L_result += STEP(7) ; 214 L_result += STEP(8) ; L_result += STEP(9) ; 215 L_result += STEP(10) ; L_result += STEP(11) ; 216 L_result += STEP(12) ; L_result += STEP(13) ; 217 L_result += STEP(14) ; L_result += STEP(15) ; 218 L_result += STEP(16) ; L_result += STEP(17) ; 219 L_result += STEP(18) ; L_result += STEP(19) ; 220 L_result += STEP(20) ; L_result += STEP(21) ; 221 L_result += STEP(22) ; L_result += STEP(23) ; 222 L_result += STEP(24) ; L_result += STEP(25) ; 223 L_result += STEP(26) ; L_result += STEP(27) ; 224 L_result += STEP(28) ; L_result += STEP(29) ; 225 L_result += STEP(30) ; L_result += STEP(31) ; 226 L_result += STEP(32) ; L_result += STEP(33) ; 227 L_result += STEP(34) ; L_result += STEP(35) ; 228 L_result += STEP(36) ; L_result += STEP(37) ; 229 L_result += STEP(38) ; L_result += STEP(39) ; 230 231 if (L_result > L_max) { 232 233 Nc = lambda; 234 L_max = L_result; 235 } 236 } 237 238 *Nc_out = Nc; 239 240 L_max <<= 1; 241 242 /* Rescaling of L_max 243 */ 244 assert(scal <= 100 && scal >= -100); 245 L_max = L_max >> (6 - scal); /* sub(6, scal) */ 246 247 assert( Nc <= 120 && Nc >= 40); 248 249 /* Compute the power of the reconstructed short term residual 250 * signal dp[..] 251 */ 252 L_power = 0; 253 for (k = 0; k <= 39; k++) { 254 255 register longword L_temp; 256 257 L_temp = SASR( dp[k - Nc], 3 ); 258 L_power += L_temp * L_temp; 259 } 260 L_power <<= 1; /* from L_MULT */ 261 262 /* Normalization of L_max and L_power 263 */ 264 265 if (L_max <= 0) { 266 *bc_out = 0; 267 return; 268 } 269 if (L_max >= L_power) { 270 *bc_out = 3; 271 return; 272 } 273 274 temp = gsm_norm( L_power ); 275 276 R = SASR( L_max << temp, 16 ); 277 S = SASR( L_power << temp, 16 ); 278 279 /* Coding of the LTP gain 280 */ 281 282 /* Table 4.3a must be used to obtain the level DLB[i] for the 283 * quantization of the LTP gain b to get the coded version bc. 284 */ 285 for (bc = 0; bc <= 2; bc++) if (R <= gsm_mult(S, gsm_DLB[bc])) break; 286 *bc_out = bc; 287 } 288 289 #else /* USE_FLOAT_MUL */ 290 291 #ifdef LTP_CUT 292 293 static void Cut_Calculation_of_the_LTP_parameters P5((st, d,dp,bc_out,Nc_out), 294 struct gsm_state * st, /* IN */ 295 register word * d, /* [0..39] IN */ 296 register word * dp, /* [-120..-1] IN */ 297 word * bc_out, /* OUT */ 298 word * Nc_out /* OUT */ 299 ) 300 { 301 register int k, lambda; 302 word Nc, bc; 303 word ltp_cut; 304 305 float wt_float[40]; 306 float dp_float_base[120], * dp_float = dp_float_base + 120; 307 308 longword L_max, L_power; 309 word R, S, dmax, scal; 310 register word temp; 311 312 /* Search of the optimum scaling of d[0..39]. 313 */ 314 dmax = 0; 315 316 for (k = 0; k <= 39; k++) { 317 temp = d[k]; 318 temp = GSM_ABS( temp ); 319 if (temp > dmax) dmax = temp; 320 } 321 322 temp = 0; 323 if (dmax == 0) scal = 0; 324 else { 325 assert(dmax > 0); 326 temp = gsm_norm( (longword)dmax << 16 ); 327 } 328 329 if (temp > 6) scal = 0; 330 else scal = 6 - temp; 331 332 assert(scal >= 0); 333 ltp_cut = (longword)SASR(dmax, scal) * st->ltp_cut / 100; 334 335 336 /* Initialization of a working array wt 337 */ 338 339 for (k = 0; k < 40; k++) { 340 register word w = SASR( d[k], scal ); 341 if (w < 0 ? w > -ltp_cut : w < ltp_cut) { 342 wt_float[k] = 0.0; 343 } 344 else { 345 wt_float[k] = w; 346 } 347 } 348 for (k = -120; k < 0; k++) dp_float[k] = dp[k]; 349 350 /* Search for the maximum cross-correlation and coding of the LTP lag 351 */ 352 L_max = 0; 353 Nc = 40; /* index for the maximum cross-correlation */ 354 355 for (lambda = 40; lambda <= 120; lambda += 9) { 356 357 /* Calculate L_result for l = lambda .. lambda + 9. 358 */ 359 register float *lp = dp_float - lambda; 360 361 register float W; 362 register float a = lp[-8], b = lp[-7], c = lp[-6], 363 d = lp[-5], e = lp[-4], f = lp[-3], 364 g = lp[-2], h = lp[-1]; 365 register float E; 366 register float S0 = 0, S1 = 0, S2 = 0, S3 = 0, S4 = 0, 367 S5 = 0, S6 = 0, S7 = 0, S8 = 0; 368 369 # undef STEP 370 # define STEP(K, a, b, c, d, e, f, g, h) \ 371 if ((W = wt_float[K]) != 0.0) { \ 372 E = W * a; S8 += E; \ 373 E = W * b; S7 += E; \ 374 E = W * c; S6 += E; \ 375 E = W * d; S5 += E; \ 376 E = W * e; S4 += E; \ 377 E = W * f; S3 += E; \ 378 E = W * g; S2 += E; \ 379 E = W * h; S1 += E; \ 380 a = lp[K]; \ 381 E = W * a; S0 += E; } else (a = lp[K]) 382 383 # define STEP_A(K) STEP(K, a, b, c, d, e, f, g, h) 384 # define STEP_B(K) STEP(K, b, c, d, e, f, g, h, a) 385 # define STEP_C(K) STEP(K, c, d, e, f, g, h, a, b) 386 # define STEP_D(K) STEP(K, d, e, f, g, h, a, b, c) 387 # define STEP_E(K) STEP(K, e, f, g, h, a, b, c, d) 388 # define STEP_F(K) STEP(K, f, g, h, a, b, c, d, e) 389 # define STEP_G(K) STEP(K, g, h, a, b, c, d, e, f) 390 # define STEP_H(K) STEP(K, h, a, b, c, d, e, f, g) 391 392 STEP_A( 0); STEP_B( 1); STEP_C( 2); STEP_D( 3); 393 STEP_E( 4); STEP_F( 5); STEP_G( 6); STEP_H( 7); 394 395 STEP_A( 8); STEP_B( 9); STEP_C(10); STEP_D(11); 396 STEP_E(12); STEP_F(13); STEP_G(14); STEP_H(15); 397 398 STEP_A(16); STEP_B(17); STEP_C(18); STEP_D(19); 399 STEP_E(20); STEP_F(21); STEP_G(22); STEP_H(23); 400 401 STEP_A(24); STEP_B(25); STEP_C(26); STEP_D(27); 402 STEP_E(28); STEP_F(29); STEP_G(30); STEP_H(31); 403 404 STEP_A(32); STEP_B(33); STEP_C(34); STEP_D(35); 405 STEP_E(36); STEP_F(37); STEP_G(38); STEP_H(39); 406 407 if (S0 > L_max) { L_max = S0; Nc = lambda; } 408 if (S1 > L_max) { L_max = S1; Nc = lambda + 1; } 409 if (S2 > L_max) { L_max = S2; Nc = lambda + 2; } 410 if (S3 > L_max) { L_max = S3; Nc = lambda + 3; } 411 if (S4 > L_max) { L_max = S4; Nc = lambda + 4; } 412 if (S5 > L_max) { L_max = S5; Nc = lambda + 5; } 413 if (S6 > L_max) { L_max = S6; Nc = lambda + 6; } 414 if (S7 > L_max) { L_max = S7; Nc = lambda + 7; } 415 if (S8 > L_max) { L_max = S8; Nc = lambda + 8; } 416 417 } 418 *Nc_out = Nc; 419 420 L_max <<= 1; 421 422 /* Rescaling of L_max 423 */ 424 assert(scal <= 100 && scal >= -100); 425 L_max = L_max >> (6 - scal); /* sub(6, scal) */ 426 427 assert( Nc <= 120 && Nc >= 40); 428 429 /* Compute the power of the reconstructed short term residual 430 * signal dp[..] 431 */ 432 L_power = 0; 433 for (k = 0; k <= 39; k++) { 434 435 register longword L_temp; 436 437 L_temp = SASR( dp[k - Nc], 3 ); 438 L_power += L_temp * L_temp; 439 } 440 L_power <<= 1; /* from L_MULT */ 441 442 /* Normalization of L_max and L_power 443 */ 444 445 if (L_max <= 0) { 446 *bc_out = 0; 447 return; 448 } 449 if (L_max >= L_power) { 450 *bc_out = 3; 451 return; 452 } 453 454 temp = gsm_norm( L_power ); 455 456 R = SASR( L_max << temp, 16 ); 457 S = SASR( L_power << temp, 16 ); 458 459 /* Coding of the LTP gain 460 */ 461 462 /* Table 4.3a must be used to obtain the level DLB[i] for the 463 * quantization of the LTP gain b to get the coded version bc. 464 */ 465 for (bc = 0; bc <= 2; bc++) if (R <= gsm_mult(S, gsm_DLB[bc])) break; 466 *bc_out = bc; 467 } 468 469 #endif /* LTP_CUT */ 470 471 static void Calculation_of_the_LTP_parameters P4((d,dp,bc_out,Nc_out), 472 register word * d, /* [0..39] IN */ 473 register word * dp, /* [-120..-1] IN */ 474 word * bc_out, /* OUT */ 475 word * Nc_out /* OUT */ 476 ) 477 { 478 register int k, lambda; 479 word Nc, bc; 480 481 float wt_float[40]; 482 float dp_float_base[120], * dp_float = dp_float_base + 120; 483 484 longword L_max, L_power; 485 word R, S, dmax, scal; 486 register word temp; 487 488 /* Search of the optimum scaling of d[0..39]. 489 */ 490 dmax = 0; 491 492 for (k = 0; k <= 39; k++) { 493 temp = d[k]; 494 temp = GSM_ABS( temp ); 495 if (temp > dmax) dmax = temp; 496 } 497 498 temp = 0; 499 if (dmax == 0) scal = 0; 500 else { 501 assert(dmax > 0); 502 temp = gsm_norm( (longword)dmax << 16 ); 503 } 504 505 if (temp > 6) scal = 0; 506 else scal = 6 - temp; 507 508 assert(scal >= 0); 509 510 /* Initialization of a working array wt 511 */ 512 513 for (k = 0; k < 40; k++) wt_float[k] = SASR( d[k], scal ); 514 for (k = -120; k < 0; k++) dp_float[k] = dp[k]; 515 516 /* Search for the maximum cross-correlation and coding of the LTP lag 517 */ 518 L_max = 0; 519 Nc = 40; /* index for the maximum cross-correlation */ 520 521 for (lambda = 40; lambda <= 120; lambda += 9) { 522 523 /* Calculate L_result for l = lambda .. lambda + 9. 524 */ 525 register float *lp = dp_float - lambda; 526 527 register float W; 528 register float a = lp[-8], b = lp[-7], c = lp[-6], 529 d = lp[-5], e = lp[-4], f = lp[-3], 530 g = lp[-2], h = lp[-1]; 531 register float E; 532 register float S0 = 0, S1 = 0, S2 = 0, S3 = 0, S4 = 0, 533 S5 = 0, S6 = 0, S7 = 0, S8 = 0; 534 535 # undef STEP 536 # define STEP(K, a, b, c, d, e, f, g, h) \ 537 W = wt_float[K]; \ 538 E = W * a; S8 += E; \ 539 E = W * b; S7 += E; \ 540 E = W * c; S6 += E; \ 541 E = W * d; S5 += E; \ 542 E = W * e; S4 += E; \ 543 E = W * f; S3 += E; \ 544 E = W * g; S2 += E; \ 545 E = W * h; S1 += E; \ 546 a = lp[K]; \ 547 E = W * a; S0 += E 548 549 # define STEP_A(K) STEP(K, a, b, c, d, e, f, g, h) 550 # define STEP_B(K) STEP(K, b, c, d, e, f, g, h, a) 551 # define STEP_C(K) STEP(K, c, d, e, f, g, h, a, b) 552 # define STEP_D(K) STEP(K, d, e, f, g, h, a, b, c) 553 # define STEP_E(K) STEP(K, e, f, g, h, a, b, c, d) 554 # define STEP_F(K) STEP(K, f, g, h, a, b, c, d, e) 555 # define STEP_G(K) STEP(K, g, h, a, b, c, d, e, f) 556 # define STEP_H(K) STEP(K, h, a, b, c, d, e, f, g) 557 558 STEP_A( 0); STEP_B( 1); STEP_C( 2); STEP_D( 3); 559 STEP_E( 4); STEP_F( 5); STEP_G( 6); STEP_H( 7); 560 561 STEP_A( 8); STEP_B( 9); STEP_C(10); STEP_D(11); 562 STEP_E(12); STEP_F(13); STEP_G(14); STEP_H(15); 563 564 STEP_A(16); STEP_B(17); STEP_C(18); STEP_D(19); 565 STEP_E(20); STEP_F(21); STEP_G(22); STEP_H(23); 566 567 STEP_A(24); STEP_B(25); STEP_C(26); STEP_D(27); 568 STEP_E(28); STEP_F(29); STEP_G(30); STEP_H(31); 569 570 STEP_A(32); STEP_B(33); STEP_C(34); STEP_D(35); 571 STEP_E(36); STEP_F(37); STEP_G(38); STEP_H(39); 572 573 if (S0 > L_max) { L_max = S0; Nc = lambda; } 574 if (S1 > L_max) { L_max = S1; Nc = lambda + 1; } 575 if (S2 > L_max) { L_max = S2; Nc = lambda + 2; } 576 if (S3 > L_max) { L_max = S3; Nc = lambda + 3; } 577 if (S4 > L_max) { L_max = S4; Nc = lambda + 4; } 578 if (S5 > L_max) { L_max = S5; Nc = lambda + 5; } 579 if (S6 > L_max) { L_max = S6; Nc = lambda + 6; } 580 if (S7 > L_max) { L_max = S7; Nc = lambda + 7; } 581 if (S8 > L_max) { L_max = S8; Nc = lambda + 8; } 582 } 583 *Nc_out = Nc; 584 585 L_max <<= 1; 586 587 /* Rescaling of L_max 588 */ 589 assert(scal <= 100 && scal >= -100); 590 L_max = L_max >> (6 - scal); /* sub(6, scal) */ 591 592 assert( Nc <= 120 && Nc >= 40); 593 594 /* Compute the power of the reconstructed short term residual 595 * signal dp[..] 596 */ 597 L_power = 0; 598 for (k = 0; k <= 39; k++) { 599 600 register longword L_temp; 601 602 L_temp = SASR( dp[k - Nc], 3 ); 603 L_power += L_temp * L_temp; 604 } 605 L_power <<= 1; /* from L_MULT */ 606 607 /* Normalization of L_max and L_power 608 */ 609 610 if (L_max <= 0) { 611 *bc_out = 0; 612 return; 613 } 614 if (L_max >= L_power) { 615 *bc_out = 3; 616 return; 617 } 618 619 temp = gsm_norm( L_power ); 620 621 R = SASR( L_max << temp, 16 ); 622 S = SASR( L_power << temp, 16 ); 623 624 /* Coding of the LTP gain 625 */ 626 627 /* Table 4.3a must be used to obtain the level DLB[i] for the 628 * quantization of the LTP gain b to get the coded version bc. 629 */ 630 for (bc = 0; bc <= 2; bc++) if (R <= gsm_mult(S, gsm_DLB[bc])) break; 631 *bc_out = bc; 632 } 633 634 #ifdef FAST 635 #ifdef LTP_CUT 636 637 static void Cut_Fast_Calculation_of_the_LTP_parameters P5((st, 638 d,dp,bc_out,Nc_out), 639 struct gsm_state * st, /* IN */ 640 register word * d, /* [0..39] IN */ 641 register word * dp, /* [-120..-1] IN */ 642 word * bc_out, /* OUT */ 643 word * Nc_out /* OUT */ 644 ) 645 { 646 register int k, lambda; 647 register float wt_float; 648 word Nc, bc; 649 word wt_max, best_k, ltp_cut; 650 651 float dp_float_base[120], * dp_float = dp_float_base + 120; 652 653 register float L_result, L_max, L_power; 654 655 wt_max = 0; 656 657 for (k = 0; k < 40; ++k) { 658 if ( d[k] > wt_max) wt_max = d[best_k = k]; 659 else if (-d[k] > wt_max) wt_max = -d[best_k = k]; 660 } 661 662 assert(wt_max >= 0); 663 wt_float = (float)wt_max; 664 665 for (k = -120; k < 0; ++k) dp_float[k] = (float)dp[k]; 666 667 /* Search for the maximum cross-correlation and coding of the LTP lag 668 */ 669 L_max = 0; 670 Nc = 40; /* index for the maximum cross-correlation */ 671 672 for (lambda = 40; lambda <= 120; lambda++) { 673 L_result = wt_float * dp_float[best_k - lambda]; 674 if (L_result > L_max) { 675 Nc = lambda; 676 L_max = L_result; 677 } 678 } 679 680 *Nc_out = Nc; 681 if (L_max <= 0.) { 682 *bc_out = 0; 683 return; 684 } 685 686 /* Compute the power of the reconstructed short term residual 687 * signal dp[..] 688 */ 689 dp_float -= Nc; 690 L_power = 0; 691 for (k = 0; k < 40; ++k) { 692 register float f = dp_float[k]; 693 L_power += f * f; 694 } 695 696 if (L_max >= L_power) { 697 *bc_out = 3; 698 return; 699 } 700 701 /* Coding of the LTP gain 702 * Table 4.3a must be used to obtain the level DLB[i] for the 703 * quantization of the LTP gain b to get the coded version bc. 704 */ 705 lambda = L_max / L_power * 32768.; 706 for (bc = 0; bc <= 2; ++bc) if (lambda <= gsm_DLB[bc]) break; 707 *bc_out = bc; 708 } 709 710 #endif /* LTP_CUT */ 711 712 static void Fast_Calculation_of_the_LTP_parameters P4((d,dp,bc_out,Nc_out), 713 register word * d, /* [0..39] IN */ 714 register word * dp, /* [-120..-1] IN */ 715 word * bc_out, /* OUT */ 716 word * Nc_out /* OUT */ 717 ) 718 { 719 register int k, lambda; 720 word Nc, bc; 721 722 float wt_float[40]; 723 float dp_float_base[120], * dp_float = dp_float_base + 120; 724 725 register float L_max, L_power; 726 727 for (k = 0; k < 40; ++k) wt_float[k] = (float)d[k]; 728 for (k = -120; k < 0; ++k) dp_float[k] = (float)dp[k]; 729 730 /* Search for the maximum cross-correlation and coding of the LTP lag 731 */ 732 L_max = 0; 733 Nc = 40; /* index for the maximum cross-correlation */ 734 735 for (lambda = 40; lambda <= 120; lambda += 9) { 736 737 /* Calculate L_result for l = lambda .. lambda + 9. 738 */ 739 register float *lp = dp_float - lambda; 740 741 register float W; 742 register float a = lp[-8], b = lp[-7], c = lp[-6], 743 d = lp[-5], e = lp[-4], f = lp[-3], 744 g = lp[-2], h = lp[-1]; 745 register float E; 746 register float S0 = 0, S1 = 0, S2 = 0, S3 = 0, S4 = 0, 747 S5 = 0, S6 = 0, S7 = 0, S8 = 0; 748 749 # undef STEP 750 # define STEP(K, a, b, c, d, e, f, g, h) \ 751 W = wt_float[K]; \ 752 E = W * a; S8 += E; \ 753 E = W * b; S7 += E; \ 754 E = W * c; S6 += E; \ 755 E = W * d; S5 += E; \ 756 E = W * e; S4 += E; \ 757 E = W * f; S3 += E; \ 758 E = W * g; S2 += E; \ 759 E = W * h; S1 += E; \ 760 a = lp[K]; \ 761 E = W * a; S0 += E 762 763 # define STEP_A(K) STEP(K, a, b, c, d, e, f, g, h) 764 # define STEP_B(K) STEP(K, b, c, d, e, f, g, h, a) 765 # define STEP_C(K) STEP(K, c, d, e, f, g, h, a, b) 766 # define STEP_D(K) STEP(K, d, e, f, g, h, a, b, c) 767 # define STEP_E(K) STEP(K, e, f, g, h, a, b, c, d) 768 # define STEP_F(K) STEP(K, f, g, h, a, b, c, d, e) 769 # define STEP_G(K) STEP(K, g, h, a, b, c, d, e, f) 770 # define STEP_H(K) STEP(K, h, a, b, c, d, e, f, g) 771 772 STEP_A( 0); STEP_B( 1); STEP_C( 2); STEP_D( 3); 773 STEP_E( 4); STEP_F( 5); STEP_G( 6); STEP_H( 7); 774 775 STEP_A( 8); STEP_B( 9); STEP_C(10); STEP_D(11); 776 STEP_E(12); STEP_F(13); STEP_G(14); STEP_H(15); 777 778 STEP_A(16); STEP_B(17); STEP_C(18); STEP_D(19); 779 STEP_E(20); STEP_F(21); STEP_G(22); STEP_H(23); 780 781 STEP_A(24); STEP_B(25); STEP_C(26); STEP_D(27); 782 STEP_E(28); STEP_F(29); STEP_G(30); STEP_H(31); 783 784 STEP_A(32); STEP_B(33); STEP_C(34); STEP_D(35); 785 STEP_E(36); STEP_F(37); STEP_G(38); STEP_H(39); 786 787 if (S0 > L_max) { L_max = S0; Nc = lambda; } 788 if (S1 > L_max) { L_max = S1; Nc = lambda + 1; } 789 if (S2 > L_max) { L_max = S2; Nc = lambda + 2; } 790 if (S3 > L_max) { L_max = S3; Nc = lambda + 3; } 791 if (S4 > L_max) { L_max = S4; Nc = lambda + 4; } 792 if (S5 > L_max) { L_max = S5; Nc = lambda + 5; } 793 if (S6 > L_max) { L_max = S6; Nc = lambda + 6; } 794 if (S7 > L_max) { L_max = S7; Nc = lambda + 7; } 795 if (S8 > L_max) { L_max = S8; Nc = lambda + 8; } 796 } 797 *Nc_out = Nc; 798 799 if (L_max <= 0.) { 800 *bc_out = 0; 801 return; 802 } 803 804 /* Compute the power of the reconstructed short term residual 805 * signal dp[..] 806 */ 807 dp_float -= Nc; 808 L_power = 0; 809 for (k = 0; k < 40; ++k) { 810 register float f = dp_float[k]; 811 L_power += f * f; 812 } 813 814 if (L_max >= L_power) { 815 *bc_out = 3; 816 return; 817 } 818 819 /* Coding of the LTP gain 820 * Table 4.3a must be used to obtain the level DLB[i] for the 821 * quantization of the LTP gain b to get the coded version bc. 822 */ 823 lambda = L_max / L_power * 32768.; 824 for (bc = 0; bc <= 2; ++bc) if (lambda <= gsm_DLB[bc]) break; 825 *bc_out = bc; 826 } 827 828 #endif /* FAST */ 829 #endif /* USE_FLOAT_MUL */ 830 831 832 /* 4.2.12 */ 833 834 static void Long_term_analysis_filtering P6((bc,Nc,dp,d,dpp,e), 835 word bc, /* IN */ 836 word Nc, /* IN */ 837 register word * dp, /* previous d [-120..-1] IN */ 838 register word * d, /* d [0..39] IN */ 839 register word * dpp, /* estimate [0..39] OUT */ 840 register word * e /* long term res. signal [0..39] OUT */ 841 ) 842 /* 843 * In this part, we have to decode the bc parameter to compute 844 * the samples of the estimate dpp[0..39]. The decoding of bc needs the 845 * use of table 4.3b. The long term residual signal e[0..39] 846 * is then calculated to be fed to the RPE encoding section. 847 */ 848 { 849 register int k; 850 register longword ltmp; 851 852 # undef STEP 853 # define STEP(BP) \ 854 for (k = 0; k <= 39; k++) { \ 855 dpp[k] = GSM_MULT_R( BP, dp[k - Nc]); \ 856 e[k] = GSM_SUB( d[k], dpp[k] ); \ 857 } 858 859 switch (bc) { 860 case 0: STEP( 3277 ); break; 861 case 1: STEP( 11469 ); break; 862 case 2: STEP( 21299 ); break; 863 case 3: STEP( 32767 ); break; 864 } 865 } 866 867 void Gsm_Long_Term_Predictor P7((S,d,dp,e,dpp,Nc,bc), /* 4x for 160 samples */ 868 869 struct gsm_state * S, 870 871 word * d, /* [0..39] residual signal IN */ 872 word * dp, /* [-120..-1] d' IN */ 873 874 word * e, /* [0..39] OUT */ 875 word * dpp, /* [0..39] OUT */ 876 word * Nc, /* correlation lag OUT */ 877 word * bc /* gain factor OUT */ 878 ) 879 { 880 assert( d ); assert( dp ); assert( e ); 881 assert( dpp); assert( Nc ); assert( bc ); 882 883 #if defined(FAST) && defined(USE_FLOAT_MUL) 884 if (S->fast) 885 #if defined (LTP_CUT) 886 if (S->ltp_cut) 887 Cut_Fast_Calculation_of_the_LTP_parameters(S, 888 d, dp, bc, Nc); 889 else 890 #endif /* LTP_CUT */ 891 Fast_Calculation_of_the_LTP_parameters(d, dp, bc, Nc ); 892 else 893 #endif /* FAST & USE_FLOAT_MUL */ 894 #ifdef LTP_CUT 895 if (S->ltp_cut) 896 Cut_Calculation_of_the_LTP_parameters(S, d, dp, bc, Nc); 897 else 898 #endif 899 Calculation_of_the_LTP_parameters(d, dp, bc, Nc); 900 901 Long_term_analysis_filtering( *bc, *Nc, dp, d, dpp, e ); 902 } 903 904 /* 4.3.2 */ 905 void Gsm_Long_Term_Synthesis_Filtering P5((S,Ncr,bcr,erp,drp), 906 struct gsm_state * S, 907 908 word Ncr, 909 word bcr, 910 register word * erp, /* [0..39] IN */ 911 register word * drp /* [-120..-1] IN, [-120..40] OUT */ 912 ) 913 /* 914 * This procedure uses the bcr and Ncr parameter to realize the 915 * long term synthesis filtering. The decoding of bcr needs 916 * table 4.3b. 917 */ 918 { 919 register longword ltmp; /* for ADD */ 920 register int k; 921 word brp, drpp, Nr; 922 923 /* Check the limits of Nr. 924 */ 925 Nr = Ncr < 40 || Ncr > 120 ? S->nrp : Ncr; 926 S->nrp = Nr; 927 assert(Nr >= 40 && Nr <= 120); 928 929 /* Decoding of the LTP gain bcr 930 */ 931 brp = gsm_QLB[ bcr ]; 932 933 /* Computation of the reconstructed short term residual 934 * signal drp[0..39] 935 */ 936 assert(brp != MIN_WORD); 937 938 for (k = 0; k <= 39; k++) { 939 drpp = GSM_MULT_R( brp, drp[ k - Nr ] ); 940 drp[k] = GSM_ADD( erp[k], drpp ); 941 } 942 943 /* 944 * Update of the reconstructed short term residual signal 945 * drp[ -1..-120 ] 946 */ 947 948 for (k = 0; k <= 119; k++) drp[ -120 + k ] = drp[ -80 + k ]; 949 } 950