1/* 2 * IMC compatible decoder 3 * Copyright (c) 2002-2004 Maxim Poliakovski 4 * Copyright (c) 2006 Benjamin Larsson 5 * Copyright (c) 2006 Konstantin Shishkov 6 * 7 * This file is part of FFmpeg. 8 * 9 * FFmpeg is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU Lesser General Public 11 * License as published by the Free Software Foundation; either 12 * version 2.1 of the License, or (at your option) any later version. 13 * 14 * FFmpeg is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * Lesser General Public License for more details. 18 * 19 * You should have received a copy of the GNU Lesser General Public 20 * License along with FFmpeg; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 22 */ 23 24/** 25 * @file 26 * IMC - Intel Music Coder 27 * A mdct based codec using a 256 points large transform 28 * divied into 32 bands with some mix of scale factors. 29 * Only mono is supported. 30 * 31 */ 32 33 34#include <math.h> 35#include <stddef.h> 36#include <stdio.h> 37 38#define ALT_BITSTREAM_READER 39#include "avcodec.h" 40#include "get_bits.h" 41#include "dsputil.h" 42#include "fft.h" 43 44#include "imcdata.h" 45 46#define IMC_BLOCK_SIZE 64 47#define IMC_FRAME_ID 0x21 48#define BANDS 32 49#define COEFFS 256 50 51typedef struct { 52 float old_floor[BANDS]; 53 float flcoeffs1[BANDS]; 54 float flcoeffs2[BANDS]; 55 float flcoeffs3[BANDS]; 56 float flcoeffs4[BANDS]; 57 float flcoeffs5[BANDS]; 58 float flcoeffs6[BANDS]; 59 float CWdecoded[COEFFS]; 60 61 /** MDCT tables */ 62 //@{ 63 float mdct_sine_window[COEFFS]; 64 float post_cos[COEFFS]; 65 float post_sin[COEFFS]; 66 float pre_coef1[COEFFS]; 67 float pre_coef2[COEFFS]; 68 float last_fft_im[COEFFS]; 69 //@} 70 71 int bandWidthT[BANDS]; ///< codewords per band 72 int bitsBandT[BANDS]; ///< how many bits per codeword in band 73 int CWlengthT[COEFFS]; ///< how many bits in each codeword 74 int levlCoeffBuf[BANDS]; 75 int bandFlagsBuf[BANDS]; ///< flags for each band 76 int sumLenArr[BANDS]; ///< bits for all coeffs in band 77 int skipFlagRaw[BANDS]; ///< skip flags are stored in raw form or not 78 int skipFlagBits[BANDS]; ///< bits used to code skip flags 79 int skipFlagCount[BANDS]; ///< skipped coeffients per band 80 int skipFlags[COEFFS]; ///< skip coefficient decoding or not 81 int codewords[COEFFS]; ///< raw codewords read from bitstream 82 float sqrt_tab[30]; 83 GetBitContext gb; 84 int decoder_reset; 85 float one_div_log2; 86 87 DSPContext dsp; 88 FFTContext fft; 89 DECLARE_ALIGNED(16, FFTComplex, samples)[COEFFS/2]; 90 DECLARE_ALIGNED(16, float, out_samples)[COEFFS]; 91} IMCContext; 92 93static VLC huffman_vlc[4][4]; 94 95#define VLC_TABLES_SIZE 9512 96 97static const int vlc_offsets[17] = { 98 0, 640, 1156, 1732, 2308, 2852, 3396, 3924, 99 4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE}; 100 101static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2]; 102 103static av_cold int imc_decode_init(AVCodecContext * avctx) 104{ 105 int i, j; 106 IMCContext *q = avctx->priv_data; 107 double r1, r2; 108 109 q->decoder_reset = 1; 110 111 for(i = 0; i < BANDS; i++) 112 q->old_floor[i] = 1.0; 113 114 /* Build mdct window, a simple sine window normalized with sqrt(2) */ 115 ff_sine_window_init(q->mdct_sine_window, COEFFS); 116 for(i = 0; i < COEFFS; i++) 117 q->mdct_sine_window[i] *= sqrt(2.0); 118 for(i = 0; i < COEFFS/2; i++){ 119 q->post_cos[i] = cos(i / 256.0 * M_PI); 120 q->post_sin[i] = sin(i / 256.0 * M_PI); 121 122 r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI); 123 r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI); 124 125 if (i & 0x1) 126 { 127 q->pre_coef1[i] = (r1 + r2) * sqrt(2.0); 128 q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0); 129 } 130 else 131 { 132 q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0); 133 q->pre_coef2[i] = (r1 - r2) * sqrt(2.0); 134 } 135 136 q->last_fft_im[i] = 0; 137 } 138 139 /* Generate a square root table */ 140 141 for(i = 0; i < 30; i++) { 142 q->sqrt_tab[i] = sqrt(i); 143 } 144 145 /* initialize the VLC tables */ 146 for(i = 0; i < 4 ; i++) { 147 for(j = 0; j < 4; j++) { 148 huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]]; 149 huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j]; 150 init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i], 151 imc_huffman_lens[i][j], 1, 1, 152 imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC); 153 } 154 } 155 q->one_div_log2 = 1/log(2); 156 157 ff_fft_init(&q->fft, 7, 1); 158 dsputil_init(&q->dsp, avctx); 159 avctx->sample_fmt = SAMPLE_FMT_S16; 160 avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO; 161 return 0; 162} 163 164static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT, 165 float* flcoeffs3, float* flcoeffs5) 166{ 167 float workT1[BANDS]; 168 float workT2[BANDS]; 169 float workT3[BANDS]; 170 float snr_limit = 1.e-30; 171 float accum = 0.0; 172 int i, cnt2; 173 174 for(i = 0; i < BANDS; i++) { 175 flcoeffs5[i] = workT2[i] = 0.0; 176 if (bandWidthT[i]){ 177 workT1[i] = flcoeffs1[i] * flcoeffs1[i]; 178 flcoeffs3[i] = 2.0 * flcoeffs2[i]; 179 } else { 180 workT1[i] = 0.0; 181 flcoeffs3[i] = -30000.0; 182 } 183 workT3[i] = bandWidthT[i] * workT1[i] * 0.01; 184 if (workT3[i] <= snr_limit) 185 workT3[i] = 0.0; 186 } 187 188 for(i = 0; i < BANDS; i++) { 189 for(cnt2 = i; cnt2 < cyclTab[i]; cnt2++) 190 flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i]; 191 workT2[cnt2-1] = workT2[cnt2-1] + workT3[i]; 192 } 193 194 for(i = 1; i < BANDS; i++) { 195 accum = (workT2[i-1] + accum) * imc_weights1[i-1]; 196 flcoeffs5[i] += accum; 197 } 198 199 for(i = 0; i < BANDS; i++) 200 workT2[i] = 0.0; 201 202 for(i = 0; i < BANDS; i++) { 203 for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--) 204 flcoeffs5[cnt2] += workT3[i]; 205 workT2[cnt2+1] += workT3[i]; 206 } 207 208 accum = 0.0; 209 210 for(i = BANDS-2; i >= 0; i--) { 211 accum = (workT2[i+1] + accum) * imc_weights2[i]; 212 flcoeffs5[i] += accum; 213 //there is missing code here, but it seems to never be triggered 214 } 215} 216 217 218static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs) 219{ 220 int i; 221 VLC *hufftab[4]; 222 int start = 0; 223 const uint8_t *cb_sel; 224 int s; 225 226 s = stream_format_code >> 1; 227 hufftab[0] = &huffman_vlc[s][0]; 228 hufftab[1] = &huffman_vlc[s][1]; 229 hufftab[2] = &huffman_vlc[s][2]; 230 hufftab[3] = &huffman_vlc[s][3]; 231 cb_sel = imc_cb_select[s]; 232 233 if(stream_format_code & 4) 234 start = 1; 235 if(start) 236 levlCoeffs[0] = get_bits(&q->gb, 7); 237 for(i = start; i < BANDS; i++){ 238 levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2); 239 if(levlCoeffs[i] == 17) 240 levlCoeffs[i] += get_bits(&q->gb, 4); 241 } 242} 243 244static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1, 245 float* flcoeffs2) 246{ 247 int i, level; 248 float tmp, tmp2; 249 //maybe some frequency division thingy 250 251 flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125 252 flcoeffs2[0] = log(flcoeffs1[0])/log(2); 253 tmp = flcoeffs1[0]; 254 tmp2 = flcoeffs2[0]; 255 256 for(i = 1; i < BANDS; i++) { 257 level = levlCoeffBuf[i]; 258 if (level == 16) { 259 flcoeffs1[i] = 1.0; 260 flcoeffs2[i] = 0.0; 261 } else { 262 if (level < 17) 263 level -=7; 264 else if (level <= 24) 265 level -=32; 266 else 267 level -=16; 268 269 tmp *= imc_exp_tab[15 + level]; 270 tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25 271 flcoeffs1[i] = tmp; 272 flcoeffs2[i] = tmp2; 273 } 274 } 275} 276 277 278static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1, 279 float* flcoeffs2) { 280 int i; 281 //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors 282 // and flcoeffs2 old scale factors 283 // might be incomplete due to a missing table that is in the binary code 284 for(i = 0; i < BANDS; i++) { 285 flcoeffs1[i] = 0; 286 if(levlCoeffBuf[i] < 16) { 287 flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i]; 288 flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25 289 } else { 290 flcoeffs1[i] = old_floor[i]; 291 } 292 } 293} 294 295/** 296 * Perform bit allocation depending on bits available 297 */ 298static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) { 299 int i, j; 300 const float limit = -1.e20; 301 float highest = 0.0; 302 int indx; 303 int t1 = 0; 304 int t2 = 1; 305 float summa = 0.0; 306 int iacc = 0; 307 int summer = 0; 308 int rres, cwlen; 309 float lowest = 1.e10; 310 int low_indx = 0; 311 float workT[32]; 312 int flg; 313 int found_indx = 0; 314 315 for(i = 0; i < BANDS; i++) 316 highest = FFMAX(highest, q->flcoeffs1[i]); 317 318 for(i = 0; i < BANDS-1; i++) { 319 q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2); 320 } 321 q->flcoeffs4[BANDS - 1] = limit; 322 323 highest = highest * 0.25; 324 325 for(i = 0; i < BANDS; i++) { 326 indx = -1; 327 if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i]) 328 indx = 0; 329 330 if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i]) 331 indx = 1; 332 333 if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i]) 334 indx = 2; 335 336 if (indx == -1) 337 return -1; 338 339 q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag]; 340 } 341 342 if (stream_format_code & 0x2) { 343 q->flcoeffs4[0] = limit; 344 q->flcoeffs4[1] = limit; 345 q->flcoeffs4[2] = limit; 346 q->flcoeffs4[3] = limit; 347 } 348 349 for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) { 350 iacc += q->bandWidthT[i]; 351 summa += q->bandWidthT[i] * q->flcoeffs4[i]; 352 } 353 q->bandWidthT[BANDS-1] = 0; 354 summa = (summa * 0.5 - freebits) / iacc; 355 356 357 for(i = 0; i < BANDS/2; i++) { 358 rres = summer - freebits; 359 if((rres >= -8) && (rres <= 8)) break; 360 361 summer = 0; 362 iacc = 0; 363 364 for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) { 365 cwlen = av_clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6); 366 367 q->bitsBandT[j] = cwlen; 368 summer += q->bandWidthT[j] * cwlen; 369 370 if (cwlen > 0) 371 iacc += q->bandWidthT[j]; 372 } 373 374 flg = t2; 375 t2 = 1; 376 if (freebits < summer) 377 t2 = -1; 378 if (i == 0) 379 flg = t2; 380 if(flg != t2) 381 t1++; 382 383 summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa; 384 } 385 386 for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) { 387 for(j = band_tab[i]; j < band_tab[i+1]; j++) 388 q->CWlengthT[j] = q->bitsBandT[i]; 389 } 390 391 if (freebits > summer) { 392 for(i = 0; i < BANDS; i++) { 393 workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415); 394 } 395 396 highest = 0.0; 397 398 do{ 399 if (highest <= -1.e20) 400 break; 401 402 found_indx = 0; 403 highest = -1.e20; 404 405 for(i = 0; i < BANDS; i++) { 406 if (workT[i] > highest) { 407 highest = workT[i]; 408 found_indx = i; 409 } 410 } 411 412 if (highest > -1.e20) { 413 workT[found_indx] -= 2.0; 414 if (++(q->bitsBandT[found_indx]) == 6) 415 workT[found_indx] = -1.e20; 416 417 for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){ 418 q->CWlengthT[j]++; 419 summer++; 420 } 421 } 422 }while (freebits > summer); 423 } 424 if (freebits < summer) { 425 for(i = 0; i < BANDS; i++) { 426 workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20; 427 } 428 if (stream_format_code & 0x2) { 429 workT[0] = 1.e20; 430 workT[1] = 1.e20; 431 workT[2] = 1.e20; 432 workT[3] = 1.e20; 433 } 434 while (freebits < summer){ 435 lowest = 1.e10; 436 low_indx = 0; 437 for(i = 0; i < BANDS; i++) { 438 if (workT[i] < lowest) { 439 lowest = workT[i]; 440 low_indx = i; 441 } 442 } 443 //if(lowest >= 1.e10) break; 444 workT[low_indx] = lowest + 2.0; 445 446 if (!(--q->bitsBandT[low_indx])) 447 workT[low_indx] = 1.e20; 448 449 for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){ 450 if(q->CWlengthT[j] > 0){ 451 q->CWlengthT[j]--; 452 summer--; 453 } 454 } 455 } 456 } 457 return 0; 458} 459 460static void imc_get_skip_coeff(IMCContext* q) { 461 int i, j; 462 463 memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits)); 464 memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount)); 465 for(i = 0; i < BANDS; i++) { 466 if (!q->bandFlagsBuf[i] || !q->bandWidthT[i]) 467 continue; 468 469 if (!q->skipFlagRaw[i]) { 470 q->skipFlagBits[i] = band_tab[i+1] - band_tab[i]; 471 472 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 473 if ((q->skipFlags[j] = get_bits1(&q->gb))) 474 q->skipFlagCount[i]++; 475 } 476 } else { 477 for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) { 478 if(!get_bits1(&q->gb)){//0 479 q->skipFlagBits[i]++; 480 q->skipFlags[j]=1; 481 q->skipFlags[j+1]=1; 482 q->skipFlagCount[i] += 2; 483 }else{ 484 if(get_bits1(&q->gb)){//11 485 q->skipFlagBits[i] +=2; 486 q->skipFlags[j]=0; 487 q->skipFlags[j+1]=1; 488 q->skipFlagCount[i]++; 489 }else{ 490 q->skipFlagBits[i] +=3; 491 q->skipFlags[j+1]=0; 492 if(!get_bits1(&q->gb)){//100 493 q->skipFlags[j]=1; 494 q->skipFlagCount[i]++; 495 }else{//101 496 q->skipFlags[j]=0; 497 } 498 } 499 } 500 } 501 502 if (j < band_tab[i+1]) { 503 q->skipFlagBits[i]++; 504 if ((q->skipFlags[j] = get_bits1(&q->gb))) 505 q->skipFlagCount[i]++; 506 } 507 } 508 } 509} 510 511/** 512 * Increase highest' band coefficient sizes as some bits won't be used 513 */ 514static void imc_adjust_bit_allocation (IMCContext* q, int summer) { 515 float workT[32]; 516 int corrected = 0; 517 int i, j; 518 float highest = 0; 519 int found_indx=0; 520 521 for(i = 0; i < BANDS; i++) { 522 workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415); 523 } 524 525 while (corrected < summer) { 526 if(highest <= -1.e20) 527 break; 528 529 highest = -1.e20; 530 531 for(i = 0; i < BANDS; i++) { 532 if (workT[i] > highest) { 533 highest = workT[i]; 534 found_indx = i; 535 } 536 } 537 538 if (highest > -1.e20) { 539 workT[found_indx] -= 2.0; 540 if (++(q->bitsBandT[found_indx]) == 6) 541 workT[found_indx] = -1.e20; 542 543 for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) { 544 if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) { 545 q->CWlengthT[j]++; 546 corrected++; 547 } 548 } 549 } 550 } 551} 552 553static void imc_imdct256(IMCContext *q) { 554 int i; 555 float re, im; 556 557 /* prerotation */ 558 for(i=0; i < COEFFS/2; i++){ 559 q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) - 560 (q->pre_coef2[i] * q->CWdecoded[i*2]); 561 q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) - 562 (q->pre_coef1[i] * q->CWdecoded[i*2]); 563 } 564 565 /* FFT */ 566 ff_fft_permute(&q->fft, q->samples); 567 ff_fft_calc (&q->fft, q->samples); 568 569 /* postrotation, window and reorder */ 570 for(i = 0; i < COEFFS/2; i++){ 571 re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]); 572 im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]); 573 q->out_samples[i*2] = (q->mdct_sine_window[COEFFS-1-i*2] * q->last_fft_im[i]) + (q->mdct_sine_window[i*2] * re); 574 q->out_samples[COEFFS-1-i*2] = (q->mdct_sine_window[i*2] * q->last_fft_im[i]) - (q->mdct_sine_window[COEFFS-1-i*2] * re); 575 q->last_fft_im[i] = im; 576 } 577} 578 579static int inverse_quant_coeff (IMCContext* q, int stream_format_code) { 580 int i, j; 581 int middle_value, cw_len, max_size; 582 const float* quantizer; 583 584 for(i = 0; i < BANDS; i++) { 585 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 586 q->CWdecoded[j] = 0; 587 cw_len = q->CWlengthT[j]; 588 589 if (cw_len <= 0 || q->skipFlags[j]) 590 continue; 591 592 max_size = 1 << cw_len; 593 middle_value = max_size >> 1; 594 595 if (q->codewords[j] >= max_size || q->codewords[j] < 0) 596 return -1; 597 598 if (cw_len >= 4){ 599 quantizer = imc_quantizer2[(stream_format_code & 2) >> 1]; 600 if (q->codewords[j] >= middle_value) 601 q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i]; 602 else 603 q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i]; 604 }else{ 605 quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)]; 606 if (q->codewords[j] >= middle_value) 607 q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i]; 608 else 609 q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i]; 610 } 611 } 612 } 613 return 0; 614} 615 616 617static int imc_get_coeffs (IMCContext* q) { 618 int i, j, cw_len, cw; 619 620 for(i = 0; i < BANDS; i++) { 621 if(!q->sumLenArr[i]) continue; 622 if (q->bandFlagsBuf[i] || q->bandWidthT[i]) { 623 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 624 cw_len = q->CWlengthT[j]; 625 cw = 0; 626 627 if (get_bits_count(&q->gb) + cw_len > 512){ 628//av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len); 629 return -1; 630 } 631 632 if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j])) 633 cw = get_bits(&q->gb, cw_len); 634 635 q->codewords[j] = cw; 636 } 637 } 638 } 639 return 0; 640} 641 642static int imc_decode_frame(AVCodecContext * avctx, 643 void *data, int *data_size, 644 AVPacket *avpkt) 645{ 646 const uint8_t *buf = avpkt->data; 647 int buf_size = avpkt->size; 648 649 IMCContext *q = avctx->priv_data; 650 651 int stream_format_code; 652 int imc_hdr, i, j; 653 int flag; 654 int bits, summer; 655 int counter, bitscount; 656 uint16_t buf16[IMC_BLOCK_SIZE / 2]; 657 658 if (buf_size < IMC_BLOCK_SIZE) { 659 av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n"); 660 return -1; 661 } 662 for(i = 0; i < IMC_BLOCK_SIZE / 2; i++) 663 buf16[i] = bswap_16(((const uint16_t*)buf)[i]); 664 665 init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8); 666 667 /* Check the frame header */ 668 imc_hdr = get_bits(&q->gb, 9); 669 if (imc_hdr != IMC_FRAME_ID) { 670 av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n"); 671 av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr); 672 return -1; 673 } 674 stream_format_code = get_bits(&q->gb, 3); 675 676 if(stream_format_code & 1){ 677 av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code); 678 return -1; 679 } 680 681// av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code); 682 683 if (stream_format_code & 0x04) 684 q->decoder_reset = 1; 685 686 if(q->decoder_reset) { 687 memset(q->out_samples, 0, sizeof(q->out_samples)); 688 for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0; 689 for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0; 690 q->decoder_reset = 0; 691 } 692 693 flag = get_bits1(&q->gb); 694 imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf); 695 696 if (stream_format_code & 0x4) 697 imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2); 698 else 699 imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2); 700 701 memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float)); 702 703 counter = 0; 704 for (i=0 ; i<BANDS ; i++) { 705 if (q->levlCoeffBuf[i] == 16) { 706 q->bandWidthT[i] = 0; 707 counter++; 708 } else 709 q->bandWidthT[i] = band_tab[i+1] - band_tab[i]; 710 } 711 memset(q->bandFlagsBuf, 0, BANDS * sizeof(int)); 712 for(i = 0; i < BANDS-1; i++) { 713 if (q->bandWidthT[i]) 714 q->bandFlagsBuf[i] = get_bits1(&q->gb); 715 } 716 717 imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5); 718 719 bitscount = 0; 720 /* first 4 bands will be assigned 5 bits per coefficient */ 721 if (stream_format_code & 0x2) { 722 bitscount += 15; 723 724 q->bitsBandT[0] = 5; 725 q->CWlengthT[0] = 5; 726 q->CWlengthT[1] = 5; 727 q->CWlengthT[2] = 5; 728 for(i = 1; i < 4; i++){ 729 bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5; 730 q->bitsBandT[i] = bits; 731 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 732 q->CWlengthT[j] = bits; 733 bitscount += bits; 734 } 735 } 736 } 737 738 if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) { 739 av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n"); 740 q->decoder_reset = 1; 741 return -1; 742 } 743 744 for(i = 0; i < BANDS; i++) { 745 q->sumLenArr[i] = 0; 746 q->skipFlagRaw[i] = 0; 747 for(j = band_tab[i]; j < band_tab[i+1]; j++) 748 q->sumLenArr[i] += q->CWlengthT[j]; 749 if (q->bandFlagsBuf[i]) 750 if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0)) 751 q->skipFlagRaw[i] = 1; 752 } 753 754 imc_get_skip_coeff(q); 755 756 for(i = 0; i < BANDS; i++) { 757 q->flcoeffs6[i] = q->flcoeffs1[i]; 758 /* band has flag set and at least one coded coefficient */ 759 if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){ 760 q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] / 761 q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])]; 762 } 763 } 764 765 /* calculate bits left, bits needed and adjust bit allocation */ 766 bits = summer = 0; 767 768 for(i = 0; i < BANDS; i++) { 769 if (q->bandFlagsBuf[i]) { 770 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 771 if(q->skipFlags[j]) { 772 summer += q->CWlengthT[j]; 773 q->CWlengthT[j] = 0; 774 } 775 } 776 bits += q->skipFlagBits[i]; 777 summer -= q->skipFlagBits[i]; 778 } 779 } 780 imc_adjust_bit_allocation(q, summer); 781 782 for(i = 0; i < BANDS; i++) { 783 q->sumLenArr[i] = 0; 784 785 for(j = band_tab[i]; j < band_tab[i+1]; j++) 786 if (!q->skipFlags[j]) 787 q->sumLenArr[i] += q->CWlengthT[j]; 788 } 789 790 memset(q->codewords, 0, sizeof(q->codewords)); 791 792 if(imc_get_coeffs(q) < 0) { 793 av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n"); 794 q->decoder_reset = 1; 795 return 0; 796 } 797 798 if(inverse_quant_coeff(q, stream_format_code) < 0) { 799 av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n"); 800 q->decoder_reset = 1; 801 return 0; 802 } 803 804 memset(q->skipFlags, 0, sizeof(q->skipFlags)); 805 806 imc_imdct256(q); 807 808 q->dsp.float_to_int16(data, q->out_samples, COEFFS); 809 810 *data_size = COEFFS * sizeof(int16_t); 811 812 return IMC_BLOCK_SIZE; 813} 814 815 816static av_cold int imc_decode_close(AVCodecContext * avctx) 817{ 818 IMCContext *q = avctx->priv_data; 819 820 ff_fft_end(&q->fft); 821 return 0; 822} 823 824 825AVCodec imc_decoder = { 826 .name = "imc", 827 .type = AVMEDIA_TYPE_AUDIO, 828 .id = CODEC_ID_IMC, 829 .priv_data_size = sizeof(IMCContext), 830 .init = imc_decode_init, 831 .close = imc_decode_close, 832 .decode = imc_decode_frame, 833 .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"), 834}; 835