1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright (c) 1992-2001 by Sun Microsystems, Inc. 24 * All rights reserved. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 /* 30 * 31 * Description: 32 * 33 * g721_encode(), g721_decode(), g721_set_law() 34 * 35 * These routines comprise an implementation of the CCITT G.721 ADPCM coding 36 * algorithm. Essentially, this implementation is identical to 37 * the bit level description except for a few deviations which 38 * take advantage of work station attributes, such as hardware 2's 39 * complement arithmetic and large memory. Specifically, certain time 40 * consuming operations such as multiplications are replaced 41 * with look up tables and software 2's complement operations are 42 * replaced with hardware 2's complement. 43 * 44 * The deviation (look up tables) from the bit level 45 * specification, preserves the bit level performance specifications. 46 * 47 * As outlined in the G.721 Recommendation, the algorithm is broken 48 * down into modules. Each section of code below is preceded by 49 * the name of the module which it is implementing. 50 * 51 */ 52 #include <stdlib.h> 53 #include <libaudio.h> 54 55 /* 56 * Maps G.721 code word to reconstructed scale factor normalized log 57 * magnitude values. 58 */ 59 static short _dqlntab[16] = {-2048, 4, 135, 213, 273, 323, 373, 425, 60 425, 373, 323, 273, 213, 135, 4, -2048}; 61 62 /* Maps G.721 code word to log of scale factor multiplier. */ 63 static long _witab[16] = {-384, 576, 1312, 2048, 3584, 6336, 11360, 35904, 64 35904, 11360, 6336, 3584, 2048, 1312, 576, -384}; 65 66 /* 67 * Maps G.721 code words to a set of values whose long and short 68 * term averages are computed and then compared to give an indication 69 * how stationary (steady state) the signal is. 70 */ 71 static short _fitab[16] = {0, 0, 0, 0x200, 0x200, 0x200, 0x600, 0xE00, 72 0xE00, 0x600, 0x200, 0x200, 0x200, 0, 0, 0}; 73 74 /* 75 * g721_init_state() 76 * 77 * Description: 78 * 79 * This routine initializes and/or resets the audio_g72x_state structure 80 * pointed to by 'state_ptr'. 81 * All the initial state values are specified in the G.721 standard specs. 82 */ 83 void 84 g721_init_state( 85 struct audio_g72x_state *state_ptr) 86 { 87 int cnta; 88 89 state_ptr->yl = 34816; 90 state_ptr->yu = 544; 91 state_ptr->dms = 0; 92 state_ptr->dml = 0; 93 state_ptr->ap = 0; 94 for (cnta = 0; cnta < 2; cnta++) { 95 state_ptr->a[cnta] = 0; 96 state_ptr->pk[cnta] = 0; 97 state_ptr->sr[cnta] = 32; 98 } 99 for (cnta = 0; cnta < 6; cnta++) { 100 state_ptr->b[cnta] = 0; 101 state_ptr->dq[cnta] = 32; 102 } 103 state_ptr->td = 0; 104 state_ptr->leftover_cnt = 0; /* no left over codes */ 105 } 106 107 /* 108 * _g721_fmult() 109 * 110 * returns the integer product of the "floating point" an and srn 111 * by the lookup table _fmultwanmant[]. 112 * 113 */ 114 static int 115 _g721_fmult( 116 int an, 117 int srn) 118 { 119 short anmag, anexp, anmant; 120 short wanexp; 121 122 if (an == 0) { 123 return ((srn >= 0) ? 124 ((srn & 077) + 1) >> (18 - (srn >> 6)) : 125 -(((srn & 077) + 1) >> (2 - (srn >> 6)))); 126 } else if (an > 0) { 127 anexp = _fmultanexp[an] - 12; 128 anmant = ((anexp >= 0) ? an >> anexp : an << -anexp) & 07700; 129 if (srn >= 0) { 130 wanexp = anexp + (srn >> 6) - 7; 131 return ((wanexp >= 0) ? 132 (_fmultwanmant[(srn & 077) + anmant] << wanexp) 133 & 0x7FFF : 134 _fmultwanmant[(srn & 077) + anmant] >> -wanexp); 135 } else { 136 wanexp = anexp + (srn >> 6) - 0xFFF7; 137 return ((wanexp >= 0) ? 138 -((_fmultwanmant[(srn & 077) + anmant] << wanexp) 139 & 0x7FFF) : 140 -(_fmultwanmant[(srn & 077) + anmant] >> -wanexp)); 141 } 142 } else { 143 anmag = (-an) & 0x1FFF; 144 anexp = _fmultanexp[anmag] - 12; 145 anmant = ((anexp >= 0) ? anmag >> anexp : anmag << -anexp) 146 & 07700; 147 if (srn >= 0) { 148 wanexp = anexp + (srn >> 6) - 7; 149 return ((wanexp >= 0) ? 150 -((_fmultwanmant[(srn & 077) + anmant] << wanexp) 151 & 0x7FFF) : 152 -(_fmultwanmant[(srn & 077) + anmant] >> -wanexp)); 153 } else { 154 wanexp = anexp + (srn >> 6) - 0xFFF7; 155 return ((wanexp >= 0) ? 156 (_fmultwanmant[(srn & 077) + anmant] << wanexp) 157 & 0x7FFF : 158 _fmultwanmant[(srn & 077) + anmant] >> -wanexp); 159 } 160 } 161 } 162 163 /* 164 * _g721_update() 165 * 166 * updates the state variables for each output code 167 * 168 */ 169 static void 170 _g721_update( 171 int y, 172 int i, 173 int dq, 174 int sr, 175 int pk0, 176 struct audio_g72x_state *state_ptr, 177 int sigpk) 178 { 179 int cnt; 180 long fi; /* FUNCTF */ 181 short mag, exp; /* FLOAT A */ 182 short a2p; /* LIMC */ 183 short a1ul; /* UPA1 */ 184 short pks1, fa1; /* UPA2 */ 185 char tr; /* tone/transition detector */ 186 short thr2; 187 188 mag = dq & 0x3FFF; 189 /* TRANS */ 190 if (state_ptr->td == 0) { 191 tr = 0; 192 } else if (state_ptr->yl > 0x40000) { 193 tr = (mag <= 0x2F80) ? 0 : 1; 194 } else { 195 thr2 = (0x20 + ((state_ptr->yl >> 10) & 0x1F)) << 196 (state_ptr->yl >> 15); 197 if (mag >= thr2) { 198 tr = 1; 199 } else { 200 tr = (mag <= (thr2 - (thr2 >> 2))) ? 0 : 1; 201 } 202 } 203 204 /* 205 * Quantizer scale factor adaptation. 206 */ 207 208 /* FUNCTW & FILTD & DELAY */ 209 state_ptr->yu = y + ((_witab[i] - y) >> 5); 210 211 /* LIMB */ 212 if (state_ptr->yu < 544) { 213 state_ptr->yu = 544; 214 } else if (state_ptr->yu > 5120) { 215 state_ptr->yu = 5120; 216 } 217 218 /* FILTE & DELAY */ 219 state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6); 220 221 /* 222 * Adaptive predictor. 223 */ 224 if (tr == 1) { 225 state_ptr->a[0] = 0; 226 state_ptr->a[1] = 0; 227 state_ptr->b[0] = 0; 228 state_ptr->b[1] = 0; 229 state_ptr->b[2] = 0; 230 state_ptr->b[3] = 0; 231 state_ptr->b[4] = 0; 232 state_ptr->b[5] = 0; 233 } else { 234 235 /* UPA2 */ 236 pks1 = pk0 ^ state_ptr->pk[0]; 237 238 a2p = state_ptr->a[1] - (state_ptr->a[1] >> 7); 239 if (sigpk == 0) { 240 fa1 = (pks1) ? state_ptr->a[0] : -state_ptr->a[0]; 241 if (fa1 < -8191) { 242 a2p -= 0x100; 243 } else if (fa1 > 8191) { 244 a2p += 0xFF; 245 } else { 246 a2p += fa1 >> 5; 247 } 248 249 if (pk0 ^ state_ptr->pk[1]) { 250 /* LIMC */ 251 if (a2p <= -12160) { 252 a2p = -12288; 253 } else if (a2p >= 12416) { 254 a2p = 12288; 255 } else { 256 a2p -= 0x80; 257 } 258 } else if (a2p <= -12416) { 259 a2p = -12288; 260 } else if (a2p >= 12160) { 261 a2p = 12288; 262 } else { 263 a2p += 0x80; 264 } 265 } 266 267 /* TRIGB & DELAY */ 268 state_ptr->a[1] = a2p; 269 270 /* UPA1 */ 271 state_ptr->a[0] -= state_ptr->a[0] >> 8; 272 if (sigpk == 0) { 273 if (pks1 == 0) { 274 state_ptr->a[0] += 192; 275 } else { 276 state_ptr->a[0] -= 192; 277 } 278 } 279 280 /* LIMD */ 281 a1ul = 15360 - a2p; 282 if (state_ptr->a[0] < -a1ul) 283 state_ptr->a[0] = -a1ul; 284 else if (state_ptr->a[0] > a1ul) 285 state_ptr->a[0] = a1ul; 286 287 /* UPB : update of b's */ 288 for (cnt = 0; cnt < 6; cnt++) { 289 state_ptr->b[cnt] -= state_ptr->b[cnt] >> 8; 290 if (dq & 0x3FFF) { 291 /* XOR */ 292 if ((dq ^ state_ptr->dq[cnt]) >= 0) 293 state_ptr->b[cnt] += 128; 294 else 295 state_ptr->b[cnt] -= 128; 296 } 297 } 298 } 299 300 for (cnt = 5; cnt > 0; cnt--) 301 state_ptr->dq[cnt] = state_ptr->dq[cnt-1]; 302 /* FLOAT A */ 303 if (mag == 0) { 304 state_ptr->dq[0] = (dq >= 0) ? 0x20 : 0xFC20; 305 } else { 306 exp = _fmultanexp[mag]; 307 state_ptr->dq[0] = (dq >= 0) ? 308 (exp << 6) + ((mag << 6) >> exp) : 309 (exp << 6) + ((mag << 6) >> exp) - 0x400; 310 } 311 312 state_ptr->sr[1] = state_ptr->sr[0]; 313 /* FLOAT B */ 314 if (sr == 0) { 315 state_ptr->sr[0] = 0x20; 316 } else if (sr > 0) { 317 exp = _fmultanexp[sr]; 318 state_ptr->sr[0] = (exp << 6) + ((sr << 6) >> exp); 319 } else { 320 mag = -sr; 321 exp = _fmultanexp[mag]; 322 state_ptr->sr[0] = (exp << 6) + ((mag << 6) >> exp) - 0x400; 323 } 324 325 /* DELAY A */ 326 state_ptr->pk[1] = state_ptr->pk[0]; 327 state_ptr->pk[0] = pk0; 328 329 /* TONE */ 330 if (tr == 1) 331 state_ptr->td = 0; 332 else if (a2p < -11776) 333 state_ptr->td = 1; 334 else 335 state_ptr->td = 0; 336 337 /* 338 * Adaptation speed control. 339 */ 340 fi = _fitab[i]; /* FUNCTF */ 341 state_ptr->dms += (fi - state_ptr->dms) >> 5; /* FILTA */ 342 state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7); /* FILTB */ 343 344 if (tr == 1) 345 state_ptr->ap = 256; 346 else if (y < 1536) /* SUBTC */ 347 state_ptr->ap += (0x200 - state_ptr->ap) >> 4; 348 else if (state_ptr->td == 1) 349 state_ptr->ap += (0x200 - state_ptr->ap) >> 4; 350 else if (abs((state_ptr->dms << 2) - state_ptr->dml) >= 351 (state_ptr->dml >> 3)) 352 state_ptr->ap += (0x200 - state_ptr->ap) >> 4; 353 else 354 state_ptr->ap += (-state_ptr->ap) >> 4; 355 } 356 357 /* 358 * _g721_quantize() 359 * 360 * Description: 361 * 362 * Given a raw sample, 'd', of the difference signal and a 363 * quantization step size scale factor, 'y', this routine returns the 364 * G.721 codeword to which that sample gets quantized. The step 365 * size scale factor division operation is done in the log base 2 domain 366 * as a subtraction. 367 */ 368 static unsigned int 369 _g721_quantize( 370 int d, /* Raw difference signal sample. */ 371 int y) /* Step size multiplier. */ 372 { 373 /* LOG */ 374 short dqm; /* Magnitude of 'd'. */ 375 short exp; /* Integer part of base 2 log of magnitude of 'd'. */ 376 short mant; /* Fractional part of base 2 log. */ 377 short dl; /* Log of magnitude of 'd'. */ 378 379 /* SUBTB */ 380 short dln; /* Step size scale factor normalized log. */ 381 382 /* QUAN */ 383 char i; /* G.721 codeword. */ 384 385 /* 386 * LOG 387 * 388 * Compute base 2 log of 'd', and store in 'dln'. 389 * 390 */ 391 dqm = abs(d); 392 exp = _fmultanexp[dqm >> 1]; 393 mant = ((dqm << 7) >> exp) & 0x7F; /* Fractional portion. */ 394 dl = (exp << 7) + mant; 395 396 /* 397 * SUBTB 398 * 399 * "Divide" by step size multiplier. 400 */ 401 dln = dl - (y >> 2); 402 403 /* 404 * QUAN 405 * 406 * Obtain codword for 'd'. 407 */ 408 i = _quani[dln & 0xFFF]; 409 if (d < 0) 410 i ^= 0xF; /* Stuff in sign of 'd'. */ 411 else if (i == 0) 412 i = 0xF; /* New in 1988 revision */ 413 414 return (i); 415 } 416 417 /* 418 * _g721_reconstr() 419 * 420 * Description: 421 * 422 * Returns reconstructed difference signal 'dq' obtained from 423 * G.721 codeword 'i' and quantization step size scale factor 'y'. 424 * Multiplication is performed in log base 2 domain as addition. 425 */ 426 static unsigned long 427 _g721_reconstr( 428 int i, /* G.721 codeword. */ 429 unsigned long y) /* Step size multiplier. */ 430 { 431 /* ADD A */ 432 short dql; /* Log of 'dq' magnitude. */ 433 434 /* ANTILOG */ 435 short dex; /* Integer part of log. */ 436 short dqt; 437 short dq; /* Reconstructed difference signal sample. */ 438 439 dql = _dqlntab[i] + (y >> 2); /* ADDA */ 440 441 if (dql < 0) 442 dq = 0; 443 else { /* ANTILOG */ 444 dex = (dql >> 7) & 15; 445 dqt = 128 + (dql & 127); 446 dq = (dqt << 7) >> (14 - dex); 447 } 448 if (i & 8) 449 dq -= 0x4000; 450 451 return (dq); 452 } 453 454 /* 455 * _tandem_adjust(sr, se, y, i) 456 * 457 * Description: 458 * 459 * At the end of ADPCM decoding, it simulates an encoder which may be receiving 460 * the output of this decoder as a tandem process. If the output of the 461 * simulated encoder differs from the input to this decoder, the decoder output 462 * is adjusted by one level of A-law or u-law codes. 463 * 464 * Input: 465 * sr decoder output linear PCM sample, 466 * se predictor estimate sample, 467 * y quantizer step size, 468 * i decoder input code 469 * 470 * Return: 471 * adjusted A-law or u-law compressed sample. 472 */ 473 static int 474 _tandem_adjust_alaw( 475 int sr, /* decoder output linear PCM sample */ 476 int se, /* predictor estimate sample */ 477 int y, /* quantizer step size */ 478 int i) /* decoder input code */ 479 { 480 unsigned char sp; /* A-law compressed 8-bit code */ 481 short dx; /* prediction error */ 482 char id; /* quantized prediction error */ 483 int sd; /* adjusted A-law decoded sample value */ 484 int im; /* biased magnitude of i */ 485 int imx; /* biased magnitude of id */ 486 487 sp = audio_s2a((sr <= -0x2000)? -0x8000 : 488 (sr >= 0x1FFF)? 0x7FFF : sr << 2); /* short to A-law compression */ 489 dx = (audio_a2s(sp) >> 2) - se; /* 16-bit prediction error */ 490 id = _g721_quantize(dx, y); 491 492 if (id == i) /* no adjustment on sp */ 493 return (sp); 494 else { /* sp adjustment needed */ 495 /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */ 496 im = i ^ 8; /* 2's complement to biased unsigned */ 497 imx = id ^ 8; 498 499 if (imx > im) { /* sp adjusted to next lower value */ 500 if (sp & 0x80) 501 sd = (sp == 0xD5)? 0x55 : 502 ((sp ^ 0x55) - 1) ^ 0x55; 503 else 504 sd = (sp == 0x2A)? 0x2A : 505 ((sp ^ 0x55) + 1) ^ 0x55; 506 } else { /* sp adjusted to next higher value */ 507 if (sp & 0x80) 508 sd = (sp == 0xAA)? 0xAA : 509 ((sp ^ 0x55) + 1) ^ 0x55; 510 else 511 sd = (sp == 0x55)? 0xD5 : 512 ((sp ^ 0x55) - 1) ^ 0x55; 513 } 514 return (sd); 515 } 516 } 517 518 static int 519 _tandem_adjust_ulaw( 520 int sr, /* decoder output linear PCM sample */ 521 int se, /* predictor estimate sample */ 522 int y, /* quantizer step size */ 523 int i) /* decoder input code */ 524 { 525 unsigned char sp; /* A-law compressed 8-bit code */ 526 short dx; /* prediction error */ 527 char id; /* quantized prediction error */ 528 int sd; /* adjusted A-law decoded sample value */ 529 int im; /* biased magnitude of i */ 530 int imx; /* biased magnitude of id */ 531 532 sp = audio_s2u((sr <= -0x2000)? -0x8000 : 533 (sr >= 0x1FFF)? 0x7FFF : sr << 2); /* short to u-law compression */ 534 dx = (audio_u2s(sp) >> 2) - se; /* 16-bit prediction error */ 535 id = _g721_quantize(dx, y); 536 if (id == i) 537 return (sp); 538 else { 539 /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */ 540 im = i ^ 8; /* 2's complement to biased unsigned */ 541 imx = id ^ 8; 542 if (imx > im) { /* sp adjusted to next lower value */ 543 if (sp & 0x80) 544 sd = (sp == 0xFF)? 0x7F : sp + 1; 545 else 546 sd = (sp == 0)? 0 : sp - 1; 547 548 } else { /* sp adjusted to next higher value */ 549 if (sp & 0x80) 550 sd = (sp == 0x80)? 0x80 : sp - 1; 551 else 552 sd = (sp == 0x7F)? 0xFF : sp + 1; 553 } 554 return (sd); 555 } 556 } 557 558 /* 559 * g721_encode() 560 * 561 * Description: 562 * 563 * Encodes a buffer of linear PCM, A-law or u-law data pointed to by 564 * 'in_buf' according * the G.721 encoding algorithm and packs the 565 * resulting code words into bytes. The bytes of codeword pairs are 566 * written to a buffer pointed to by 'out_buf'. 567 * 568 * Notes: 569 * 570 * In the event that the total number of codewords which have to be 571 * written is odd, the last unpairable codeword is saved in the 572 * state structure till the next call. It is then paired off and 573 * packed with the first codeword of the new buffer. The number of 574 * valid bytes in 'out_buf' is returned in *out_size. Note that 575 * *out_size will not always be equal to half * of 'data_size' on input. 576 * On the final call to 'g721_encode()' the calling program might want to 577 * check if a codeword was left over. This can be 578 * done by calling 'g721_encode()' with data_size = 0, which returns in 579 * *out_size a 0 if nothing was leftover and 1 if a codeword was leftover 580 * which now is in out_buf[0]. 581 * 582 * The 4 lower significant bits of an individual byte in the output byte 583 * stream is packed with a G.721 codeword first. Then the 4 higher order 584 * bits are packed with the next codeword. 585 */ 586 int 587 g721_encode( 588 void *in_buf, 589 int data_size, 590 Audio_hdr *in_header, 591 unsigned char *out_buf, 592 int *out_size, 593 struct audio_g72x_state *state_ptr) 594 { 595 short sl; /* EXPAND */ 596 short sei, sezi, se, sez; /* ACCUM */ 597 short d; /* SUBTA */ 598 float al; /* use floating point for faster multiply */ 599 short y, dif; /* MIX */ 600 short sr; /* ADDB */ 601 short pk0, sigpk, dqsez; /* ADDC */ 602 short dq, i; 603 int cnt, cnta; 604 int out_leng; 605 unsigned char *char_in; 606 unsigned char *char_out; 607 short *short_ptr; 608 609 if (data_size == 0) { 610 /* Actually, the leftover count will never be more than 4 */ 611 for (i = 0; state_ptr->leftover_cnt > 0; i++) { 612 *out_buf++ = state_ptr->leftover[i]; 613 state_ptr->leftover_cnt -= 8; 614 } 615 *out_size = i; 616 state_ptr->leftover_cnt = 0; 617 return (AUDIO_SUCCESS); 618 } 619 620 /* XXX - if linear, it had better be 16-bit! */ 621 if (in_header->encoding == AUDIO_ENCODING_LINEAR) { 622 if (data_size & 1) { 623 return (AUDIO_ERR_BADFRAME); 624 } else { 625 data_size >>= 1; /* divide to get sample cnt */ 626 short_ptr = (short *)in_buf; 627 } 628 } else { 629 char_in = (unsigned char *)in_buf; 630 } 631 char_out = (unsigned char *)out_buf; 632 if (state_ptr->leftover_cnt > 0) { 633 *char_out = state_ptr->leftover[0]; 634 state_ptr->leftover_cnt = 0; 635 data_size += 1; 636 cnta = 1; 637 } else { 638 cnta = 0; 639 } 640 out_leng = (data_size & ~0x01); /* clear low order bit */ 641 for (; cnta < data_size; cnta++) { 642 /* EXPAND */ 643 switch (in_header->encoding) { 644 case AUDIO_ENCODING_LINEAR: 645 sl = *short_ptr++ >> 2; 646 break; 647 case AUDIO_ENCODING_ALAW: 648 sl = audio_a2s(*char_in++) >> 2; 649 break; 650 case AUDIO_ENCODING_ULAW: 651 sl = audio_u2s(*char_in++) >> 2; /* u-law to short */ 652 break; 653 default: 654 return (AUDIO_ERR_ENCODING); 655 } 656 657 /* ACCUM */ 658 sezi = _g721_fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]); 659 for (cnt = 1; cnt < 6; cnt++) 660 sezi = sezi + _g721_fmult(state_ptr->b[cnt] >> 2, 661 state_ptr->dq[cnt]); 662 sei = sezi; 663 for (cnt = 1; cnt > -1; cnt--) 664 sei = sei + _g721_fmult(state_ptr->a[cnt] >> 2, 665 state_ptr->sr[cnt]); 666 sez = sezi >> 1; 667 se = sei >> 1; 668 d = sl - se; /* SUBTA */ 669 670 if (state_ptr->ap >= 256) 671 y = state_ptr->yu; 672 else { 673 y = state_ptr->yl >> 6; 674 dif = state_ptr->yu - y; 675 al = state_ptr->ap >> 2; 676 if (dif > 0) 677 y += ((int)(dif * al)) >> 6; 678 else if (dif < 0) 679 y += ((int)(dif * al) + 0x3F) >> 6; 680 } 681 682 i = _g721_quantize(d, y); 683 dq = _g721_reconstr(i, y); 684 /* ADDB */ 685 sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq; 686 687 if (cnta & 1) { 688 *char_out++ += i << 4; 689 } else if (cnta < out_leng) { 690 *char_out = i; 691 } else { 692 /* 693 * save the last codeword which can not be paired into 694 * a byte in the state stucture and set leftover_flag. 695 */ 696 state_ptr->leftover[0] = i; 697 state_ptr->leftover_cnt = 4; 698 } 699 700 dqsez = sr + sez - se; /* ADDC */ 701 if (dqsez == 0) { 702 pk0 = 0; 703 sigpk = 1; 704 } else { 705 pk0 = (dqsez < 0) ? 1 : 0; 706 sigpk = 0; 707 } 708 709 _g721_update(y, i, dq, sr, pk0, state_ptr, sigpk); 710 } 711 *out_size = cnta >> 1; 712 713 return (AUDIO_SUCCESS); 714 } 715 716 /* 717 * g721_decode() 718 * 719 * Description: 720 * 721 * Decodes a buffer of G.721 encoded data pointed to by 'in_buf' and 722 * writes the resulting linear PCM, A-law or Mu-law bytes into a buffer 723 * pointed to by 'out_buf'. 724 */ 725 int 726 g721_decode( 727 unsigned char *in_buf, /* Buffer of g721 encoded data. */ 728 int data_size, /* Size in bytes of in_buf. */ 729 Audio_hdr *out_header, 730 void *out_buf, /* Decoded data buffer. */ 731 int *out_size, 732 struct audio_g72x_state *state_ptr) /* the decoder's state structure. */ 733 { 734 short sezi, sei, sez, se; /* ACCUM */ 735 float al; /* use floating point for faster multiply */ 736 short y, dif; /* MIX */ 737 short sr; /* ADDB */ 738 char pk0, i; /* ADDC */ 739 short dq; 740 char sigpk; 741 short dqsez; 742 unsigned char *char_in; 743 unsigned char *char_out; 744 int cnt, cnta; 745 short *linear_out; 746 747 *out_size = data_size << 1; 748 char_in = (unsigned char *)in_buf; 749 char_out = (unsigned char *)out_buf; 750 linear_out = (short *)out_buf; 751 for (cnta = 0; cnta < *out_size; cnta++) { 752 if (cnta & 1) 753 i = *char_in++ >> 4; 754 else 755 i = *char_in & 0xF; 756 /* ACCUM */ 757 sezi = _g721_fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]); 758 for (cnt = 1; cnt < 6; cnt++) 759 sezi = sezi + _g721_fmult(state_ptr->b[cnt] >> 2, 760 state_ptr->dq[cnt]); 761 sei = sezi; 762 for (cnt = 1; cnt >= 0; cnt--) 763 sei = sei + _g721_fmult(state_ptr->a[cnt] >> 2, 764 state_ptr->sr[cnt]); 765 766 sez = sezi >> 1; 767 se = sei >> 1; 768 if (state_ptr->ap >= 256) 769 y = state_ptr->yu; 770 else { 771 y = state_ptr->yl >> 6; 772 dif = state_ptr->yu - y; 773 al = state_ptr->ap >> 2; 774 if (dif > 0) 775 y += ((int)(dif * al)) >> 6; 776 else if (dif < 0) 777 y += ((int)(dif * al) + 0x3F) >> 6; 778 } 779 780 dq = _g721_reconstr(i, y); 781 /* ADDB */ 782 if (dq < 0) 783 sr = se - (dq & 0x3FFF); 784 else 785 sr = se + dq; 786 787 switch (out_header->encoding) { 788 case AUDIO_ENCODING_LINEAR: 789 *linear_out++ = ((sr <= -0x2000) ? -0x8000 : 790 (sr >= 0x1FFF) ? 0x7FFF : sr << 2); 791 break; 792 case AUDIO_ENCODING_ALAW: 793 *char_out++ = _tandem_adjust_alaw(sr, se, y, i); 794 break; 795 case AUDIO_ENCODING_ULAW: 796 *char_out++ = _tandem_adjust_ulaw(sr, se, y, i); 797 break; 798 default: 799 return (AUDIO_ERR_ENCODING); 800 } 801 /* ADDC */ 802 dqsez = sr - se + sez; 803 pk0 = (dqsez < 0) ? 1 : 0; 804 sigpk = (dqsez) ? 0 : 1; 805 806 _g721_update(y, i, dq, sr, pk0, state_ptr, sigpk); 807 } 808 *out_size = cnta; 809 810 return (AUDIO_SUCCESS); 811 } 812