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 libavcodec/imc.c IMC - Intel Music Coder 26 * A mdct based codec using a 256 points large transform 27 * divied into 32 bands with some mix of scale factors. 28 * Only mono is supported. 29 * 30 */ 31 32 33#include <math.h> 34#include <stddef.h> 35#include <stdio.h> 36 37#define ALT_BITSTREAM_READER 38#include "avcodec.h" 39#include "bitstream.h" 40#include "dsputil.h" 41 42#include "imcdata.h" 43 44#define IMC_BLOCK_SIZE 64 45#define IMC_FRAME_ID 0x21 46#define BANDS 32 47#define COEFFS 256 48 49typedef struct { 50 float old_floor[BANDS]; 51 float flcoeffs1[BANDS]; 52 float flcoeffs2[BANDS]; 53 float flcoeffs3[BANDS]; 54 float flcoeffs4[BANDS]; 55 float flcoeffs5[BANDS]; 56 float flcoeffs6[BANDS]; 57 float CWdecoded[COEFFS]; 58 59 /** MDCT tables */ 60 //@{ 61 float mdct_sine_window[COEFFS]; 62 float post_cos[COEFFS]; 63 float post_sin[COEFFS]; 64 float pre_coef1[COEFFS]; 65 float pre_coef2[COEFFS]; 66 float last_fft_im[COEFFS]; 67 //@} 68 69 int bandWidthT[BANDS]; ///< codewords per band 70 int bitsBandT[BANDS]; ///< how many bits per codeword in band 71 int CWlengthT[COEFFS]; ///< how many bits in each codeword 72 int levlCoeffBuf[BANDS]; 73 int bandFlagsBuf[BANDS]; ///< flags for each band 74 int sumLenArr[BANDS]; ///< bits for all coeffs in band 75 int skipFlagRaw[BANDS]; ///< skip flags are stored in raw form or not 76 int skipFlagBits[BANDS]; ///< bits used to code skip flags 77 int skipFlagCount[BANDS]; ///< skipped coeffients per band 78 int skipFlags[COEFFS]; ///< skip coefficient decoding or not 79 int codewords[COEFFS]; ///< raw codewords read from bitstream 80 float sqrt_tab[30]; 81 GetBitContext gb; 82 int decoder_reset; 83 float one_div_log2; 84 85 DSPContext dsp; 86 FFTContext fft; 87 DECLARE_ALIGNED_16(FFTComplex, samples[COEFFS/2]); 88 DECLARE_ALIGNED_16(float, out_samples[COEFFS]); 89} IMCContext; 90 91static VLC huffman_vlc[4][4]; 92 93#define VLC_TABLES_SIZE 9512 94 95static const int vlc_offsets[17] = { 96 0, 640, 1156, 1732, 2308, 2852, 3396, 3924, 97 4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE}; 98 99static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2]; 100 101static av_cold int imc_decode_init(AVCodecContext * avctx) 102{ 103 int i, j; 104 IMCContext *q = avctx->priv_data; 105 double r1, r2; 106 107 q->decoder_reset = 1; 108 109 for(i = 0; i < BANDS; i++) 110 q->old_floor[i] = 1.0; 111 112 /* Build mdct window, a simple sine window normalized with sqrt(2) */ 113 ff_sine_window_init(q->mdct_sine_window, COEFFS); 114 for(i = 0; i < COEFFS; i++) 115 q->mdct_sine_window[i] *= sqrt(2.0); 116 for(i = 0; i < COEFFS/2; i++){ 117 q->post_cos[i] = cos(i / 256.0 * M_PI); 118 q->post_sin[i] = sin(i / 256.0 * M_PI); 119 120 r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI); 121 r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI); 122 123 if (i & 0x1) 124 { 125 q->pre_coef1[i] = (r1 + r2) * sqrt(2.0); 126 q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0); 127 } 128 else 129 { 130 q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0); 131 q->pre_coef2[i] = (r1 - r2) * sqrt(2.0); 132 } 133 134 q->last_fft_im[i] = 0; 135 } 136 137 /* Generate a square root table */ 138 139 for(i = 0; i < 30; i++) { 140 q->sqrt_tab[i] = sqrt(i); 141 } 142 143 /* initialize the VLC tables */ 144 for(i = 0; i < 4 ; i++) { 145 for(j = 0; j < 4; j++) { 146 huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]]; 147 huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j]; 148 init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i], 149 imc_huffman_lens[i][j], 1, 1, 150 imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC); 151 } 152 } 153 q->one_div_log2 = 1/log(2); 154 155 ff_fft_init(&q->fft, 7, 1); 156 dsputil_init(&q->dsp, avctx); 157 avctx->sample_fmt = SAMPLE_FMT_S16; 158 avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO; 159 return 0; 160} 161 162static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT, 163 float* flcoeffs3, float* flcoeffs5) 164{ 165 float workT1[BANDS]; 166 float workT2[BANDS]; 167 float workT3[BANDS]; 168 float snr_limit = 1.e-30; 169 float accum = 0.0; 170 int i, cnt2; 171 172 for(i = 0; i < BANDS; i++) { 173 flcoeffs5[i] = workT2[i] = 0.0; 174 if (bandWidthT[i]){ 175 workT1[i] = flcoeffs1[i] * flcoeffs1[i]; 176 flcoeffs3[i] = 2.0 * flcoeffs2[i]; 177 } else { 178 workT1[i] = 0.0; 179 flcoeffs3[i] = -30000.0; 180 } 181 workT3[i] = bandWidthT[i] * workT1[i] * 0.01; 182 if (workT3[i] <= snr_limit) 183 workT3[i] = 0.0; 184 } 185 186 for(i = 0; i < BANDS; i++) { 187 for(cnt2 = i; cnt2 < cyclTab[i]; cnt2++) 188 flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i]; 189 workT2[cnt2-1] = workT2[cnt2-1] + workT3[i]; 190 } 191 192 for(i = 1; i < BANDS; i++) { 193 accum = (workT2[i-1] + accum) * imc_weights1[i-1]; 194 flcoeffs5[i] += accum; 195 } 196 197 for(i = 0; i < BANDS; i++) 198 workT2[i] = 0.0; 199 200 for(i = 0; i < BANDS; i++) { 201 for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--) 202 flcoeffs5[cnt2] += workT3[i]; 203 workT2[cnt2+1] += workT3[i]; 204 } 205 206 accum = 0.0; 207 208 for(i = BANDS-2; i >= 0; i--) { 209 accum = (workT2[i+1] + accum) * imc_weights2[i]; 210 flcoeffs5[i] += accum; 211 //there is missing code here, but it seems to never be triggered 212 } 213} 214 215 216static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs) 217{ 218 int i; 219 VLC *hufftab[4]; 220 int start = 0; 221 const uint8_t *cb_sel; 222 int s; 223 224 s = stream_format_code >> 1; 225 hufftab[0] = &huffman_vlc[s][0]; 226 hufftab[1] = &huffman_vlc[s][1]; 227 hufftab[2] = &huffman_vlc[s][2]; 228 hufftab[3] = &huffman_vlc[s][3]; 229 cb_sel = imc_cb_select[s]; 230 231 if(stream_format_code & 4) 232 start = 1; 233 if(start) 234 levlCoeffs[0] = get_bits(&q->gb, 7); 235 for(i = start; i < BANDS; i++){ 236 levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2); 237 if(levlCoeffs[i] == 17) 238 levlCoeffs[i] += get_bits(&q->gb, 4); 239 } 240} 241 242static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1, 243 float* flcoeffs2) 244{ 245 int i, level; 246 float tmp, tmp2; 247 //maybe some frequency division thingy 248 249 flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125 250 flcoeffs2[0] = log(flcoeffs1[0])/log(2); 251 tmp = flcoeffs1[0]; 252 tmp2 = flcoeffs2[0]; 253 254 for(i = 1; i < BANDS; i++) { 255 level = levlCoeffBuf[i]; 256 if (level == 16) { 257 flcoeffs1[i] = 1.0; 258 flcoeffs2[i] = 0.0; 259 } else { 260 if (level < 17) 261 level -=7; 262 else if (level <= 24) 263 level -=32; 264 else 265 level -=16; 266 267 tmp *= imc_exp_tab[15 + level]; 268 tmp2 += 0.83048 * level; // 0.83048 = log2(10) * 0.25 269 flcoeffs1[i] = tmp; 270 flcoeffs2[i] = tmp2; 271 } 272 } 273} 274 275 276static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1, 277 float* flcoeffs2) { 278 int i; 279 //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors 280 // and flcoeffs2 old scale factors 281 // might be incomplete due to a missing table that is in the binary code 282 for(i = 0; i < BANDS; i++) { 283 flcoeffs1[i] = 0; 284 if(levlCoeffBuf[i] < 16) { 285 flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i]; 286 flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25 287 } else { 288 flcoeffs1[i] = old_floor[i]; 289 } 290 } 291} 292 293/** 294 * Perform bit allocation depending on bits available 295 */ 296static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) { 297 int i, j; 298 const float limit = -1.e20; 299 float highest = 0.0; 300 int indx; 301 int t1 = 0; 302 int t2 = 1; 303 float summa = 0.0; 304 int iacc = 0; 305 int summer = 0; 306 int rres, cwlen; 307 float lowest = 1.e10; 308 int low_indx = 0; 309 float workT[32]; 310 int flg; 311 int found_indx = 0; 312 313 for(i = 0; i < BANDS; i++) 314 highest = FFMAX(highest, q->flcoeffs1[i]); 315 316 for(i = 0; i < BANDS-1; i++) { 317 q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2); 318 } 319 q->flcoeffs4[BANDS - 1] = limit; 320 321 highest = highest * 0.25; 322 323 for(i = 0; i < BANDS; i++) { 324 indx = -1; 325 if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i]) 326 indx = 0; 327 328 if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i]) 329 indx = 1; 330 331 if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i]) 332 indx = 2; 333 334 if (indx == -1) 335 return -1; 336 337 q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag]; 338 } 339 340 if (stream_format_code & 0x2) { 341 q->flcoeffs4[0] = limit; 342 q->flcoeffs4[1] = limit; 343 q->flcoeffs4[2] = limit; 344 q->flcoeffs4[3] = limit; 345 } 346 347 for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) { 348 iacc += q->bandWidthT[i]; 349 summa += q->bandWidthT[i] * q->flcoeffs4[i]; 350 } 351 q->bandWidthT[BANDS-1] = 0; 352 summa = (summa * 0.5 - freebits) / iacc; 353 354 355 for(i = 0; i < BANDS/2; i++) { 356 rres = summer - freebits; 357 if((rres >= -8) && (rres <= 8)) break; 358 359 summer = 0; 360 iacc = 0; 361 362 for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) { 363 cwlen = av_clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6); 364 365 q->bitsBandT[j] = cwlen; 366 summer += q->bandWidthT[j] * cwlen; 367 368 if (cwlen > 0) 369 iacc += q->bandWidthT[j]; 370 } 371 372 flg = t2; 373 t2 = 1; 374 if (freebits < summer) 375 t2 = -1; 376 if (i == 0) 377 flg = t2; 378 if(flg != t2) 379 t1++; 380 381 summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa; 382 } 383 384 for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) { 385 for(j = band_tab[i]; j < band_tab[i+1]; j++) 386 q->CWlengthT[j] = q->bitsBandT[i]; 387 } 388 389 if (freebits > summer) { 390 for(i = 0; i < BANDS; i++) { 391 workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415); 392 } 393 394 highest = 0.0; 395 396 do{ 397 if (highest <= -1.e20) 398 break; 399 400 found_indx = 0; 401 highest = -1.e20; 402 403 for(i = 0; i < BANDS; i++) { 404 if (workT[i] > highest) { 405 highest = workT[i]; 406 found_indx = i; 407 } 408 } 409 410 if (highest > -1.e20) { 411 workT[found_indx] -= 2.0; 412 if (++(q->bitsBandT[found_indx]) == 6) 413 workT[found_indx] = -1.e20; 414 415 for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){ 416 q->CWlengthT[j]++; 417 summer++; 418 } 419 } 420 }while (freebits > summer); 421 } 422 if (freebits < summer) { 423 for(i = 0; i < BANDS; i++) { 424 workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20; 425 } 426 if (stream_format_code & 0x2) { 427 workT[0] = 1.e20; 428 workT[1] = 1.e20; 429 workT[2] = 1.e20; 430 workT[3] = 1.e20; 431 } 432 while (freebits < summer){ 433 lowest = 1.e10; 434 low_indx = 0; 435 for(i = 0; i < BANDS; i++) { 436 if (workT[i] < lowest) { 437 lowest = workT[i]; 438 low_indx = i; 439 } 440 } 441 //if(lowest >= 1.e10) break; 442 workT[low_indx] = lowest + 2.0; 443 444 if (!(--q->bitsBandT[low_indx])) 445 workT[low_indx] = 1.e20; 446 447 for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){ 448 if(q->CWlengthT[j] > 0){ 449 q->CWlengthT[j]--; 450 summer--; 451 } 452 } 453 } 454 } 455 return 0; 456} 457 458static void imc_get_skip_coeff(IMCContext* q) { 459 int i, j; 460 461 memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits)); 462 memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount)); 463 for(i = 0; i < BANDS; i++) { 464 if (!q->bandFlagsBuf[i] || !q->bandWidthT[i]) 465 continue; 466 467 if (!q->skipFlagRaw[i]) { 468 q->skipFlagBits[i] = band_tab[i+1] - band_tab[i]; 469 470 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 471 if ((q->skipFlags[j] = get_bits1(&q->gb))) 472 q->skipFlagCount[i]++; 473 } 474 } else { 475 for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) { 476 if(!get_bits1(&q->gb)){//0 477 q->skipFlagBits[i]++; 478 q->skipFlags[j]=1; 479 q->skipFlags[j+1]=1; 480 q->skipFlagCount[i] += 2; 481 }else{ 482 if(get_bits1(&q->gb)){//11 483 q->skipFlagBits[i] +=2; 484 q->skipFlags[j]=0; 485 q->skipFlags[j+1]=1; 486 q->skipFlagCount[i]++; 487 }else{ 488 q->skipFlagBits[i] +=3; 489 q->skipFlags[j+1]=0; 490 if(!get_bits1(&q->gb)){//100 491 q->skipFlags[j]=1; 492 q->skipFlagCount[i]++; 493 }else{//101 494 q->skipFlags[j]=0; 495 } 496 } 497 } 498 } 499 500 if (j < band_tab[i+1]) { 501 q->skipFlagBits[i]++; 502 if ((q->skipFlags[j] = get_bits1(&q->gb))) 503 q->skipFlagCount[i]++; 504 } 505 } 506 } 507} 508 509/** 510 * Increase highest' band coefficient sizes as some bits won't be used 511 */ 512static void imc_adjust_bit_allocation (IMCContext* q, int summer) { 513 float workT[32]; 514 int corrected = 0; 515 int i, j; 516 float highest = 0; 517 int found_indx=0; 518 519 for(i = 0; i < BANDS; i++) { 520 workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415); 521 } 522 523 while (corrected < summer) { 524 if(highest <= -1.e20) 525 break; 526 527 highest = -1.e20; 528 529 for(i = 0; i < BANDS; i++) { 530 if (workT[i] > highest) { 531 highest = workT[i]; 532 found_indx = i; 533 } 534 } 535 536 if (highest > -1.e20) { 537 workT[found_indx] -= 2.0; 538 if (++(q->bitsBandT[found_indx]) == 6) 539 workT[found_indx] = -1.e20; 540 541 for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) { 542 if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) { 543 q->CWlengthT[j]++; 544 corrected++; 545 } 546 } 547 } 548 } 549} 550 551static void imc_imdct256(IMCContext *q) { 552 int i; 553 float re, im; 554 555 /* prerotation */ 556 for(i=0; i < COEFFS/2; i++){ 557 q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) - 558 (q->pre_coef2[i] * q->CWdecoded[i*2]); 559 q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) - 560 (q->pre_coef1[i] * q->CWdecoded[i*2]); 561 } 562 563 /* FFT */ 564 ff_fft_permute(&q->fft, q->samples); 565 ff_fft_calc (&q->fft, q->samples); 566 567 /* postrotation, window and reorder */ 568 for(i = 0; i < COEFFS/2; i++){ 569 re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]); 570 im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]); 571 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); 572 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); 573 q->last_fft_im[i] = im; 574 } 575} 576 577static int inverse_quant_coeff (IMCContext* q, int stream_format_code) { 578 int i, j; 579 int middle_value, cw_len, max_size; 580 const float* quantizer; 581 582 for(i = 0; i < BANDS; i++) { 583 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 584 q->CWdecoded[j] = 0; 585 cw_len = q->CWlengthT[j]; 586 587 if (cw_len <= 0 || q->skipFlags[j]) 588 continue; 589 590 max_size = 1 << cw_len; 591 middle_value = max_size >> 1; 592 593 if (q->codewords[j] >= max_size || q->codewords[j] < 0) 594 return -1; 595 596 if (cw_len >= 4){ 597 quantizer = imc_quantizer2[(stream_format_code & 2) >> 1]; 598 if (q->codewords[j] >= middle_value) 599 q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i]; 600 else 601 q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i]; 602 }else{ 603 quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)]; 604 if (q->codewords[j] >= middle_value) 605 q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i]; 606 else 607 q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i]; 608 } 609 } 610 } 611 return 0; 612} 613 614 615static int imc_get_coeffs (IMCContext* q) { 616 int i, j, cw_len, cw; 617 618 for(i = 0; i < BANDS; i++) { 619 if(!q->sumLenArr[i]) continue; 620 if (q->bandFlagsBuf[i] || q->bandWidthT[i]) { 621 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 622 cw_len = q->CWlengthT[j]; 623 cw = 0; 624 625 if (get_bits_count(&q->gb) + cw_len > 512){ 626//av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len); 627 return -1; 628 } 629 630 if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j])) 631 cw = get_bits(&q->gb, cw_len); 632 633 q->codewords[j] = cw; 634 } 635 } 636 } 637 return 0; 638} 639 640static int imc_decode_frame(AVCodecContext * avctx, 641 void *data, int *data_size, 642 const uint8_t * buf, int buf_size) 643{ 644 645 IMCContext *q = avctx->priv_data; 646 647 int stream_format_code; 648 int imc_hdr, i, j; 649 int flag; 650 int bits, summer; 651 int counter, bitscount; 652 uint16_t buf16[IMC_BLOCK_SIZE / 2]; 653 654 if (buf_size < IMC_BLOCK_SIZE) { 655 av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n"); 656 return -1; 657 } 658 for(i = 0; i < IMC_BLOCK_SIZE / 2; i++) 659 buf16[i] = bswap_16(((const uint16_t*)buf)[i]); 660 661 init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8); 662 663 /* Check the frame header */ 664 imc_hdr = get_bits(&q->gb, 9); 665 if (imc_hdr != IMC_FRAME_ID) { 666 av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n"); 667 av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr); 668 return -1; 669 } 670 stream_format_code = get_bits(&q->gb, 3); 671 672 if(stream_format_code & 1){ 673 av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code); 674 return -1; 675 } 676 677// av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code); 678 679 if (stream_format_code & 0x04) 680 q->decoder_reset = 1; 681 682 if(q->decoder_reset) { 683 memset(q->out_samples, 0, sizeof(q->out_samples)); 684 for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0; 685 for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0; 686 q->decoder_reset = 0; 687 } 688 689 flag = get_bits1(&q->gb); 690 imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf); 691 692 if (stream_format_code & 0x4) 693 imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2); 694 else 695 imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2); 696 697 memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float)); 698 699 counter = 0; 700 for (i=0 ; i<BANDS ; i++) { 701 if (q->levlCoeffBuf[i] == 16) { 702 q->bandWidthT[i] = 0; 703 counter++; 704 } else 705 q->bandWidthT[i] = band_tab[i+1] - band_tab[i]; 706 } 707 memset(q->bandFlagsBuf, 0, BANDS * sizeof(int)); 708 for(i = 0; i < BANDS-1; i++) { 709 if (q->bandWidthT[i]) 710 q->bandFlagsBuf[i] = get_bits1(&q->gb); 711 } 712 713 imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5); 714 715 bitscount = 0; 716 /* first 4 bands will be assigned 5 bits per coefficient */ 717 if (stream_format_code & 0x2) { 718 bitscount += 15; 719 720 q->bitsBandT[0] = 5; 721 q->CWlengthT[0] = 5; 722 q->CWlengthT[1] = 5; 723 q->CWlengthT[2] = 5; 724 for(i = 1; i < 4; i++){ 725 bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5; 726 q->bitsBandT[i] = bits; 727 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 728 q->CWlengthT[j] = bits; 729 bitscount += bits; 730 } 731 } 732 } 733 734 if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) { 735 av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n"); 736 q->decoder_reset = 1; 737 return -1; 738 } 739 740 for(i = 0; i < BANDS; i++) { 741 q->sumLenArr[i] = 0; 742 q->skipFlagRaw[i] = 0; 743 for(j = band_tab[i]; j < band_tab[i+1]; j++) 744 q->sumLenArr[i] += q->CWlengthT[j]; 745 if (q->bandFlagsBuf[i]) 746 if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0)) 747 q->skipFlagRaw[i] = 1; 748 } 749 750 imc_get_skip_coeff(q); 751 752 for(i = 0; i < BANDS; i++) { 753 q->flcoeffs6[i] = q->flcoeffs1[i]; 754 /* band has flag set and at least one coded coefficient */ 755 if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){ 756 q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] / 757 q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])]; 758 } 759 } 760 761 /* calculate bits left, bits needed and adjust bit allocation */ 762 bits = summer = 0; 763 764 for(i = 0; i < BANDS; i++) { 765 if (q->bandFlagsBuf[i]) { 766 for(j = band_tab[i]; j < band_tab[i+1]; j++) { 767 if(q->skipFlags[j]) { 768 summer += q->CWlengthT[j]; 769 q->CWlengthT[j] = 0; 770 } 771 } 772 bits += q->skipFlagBits[i]; 773 summer -= q->skipFlagBits[i]; 774 } 775 } 776 imc_adjust_bit_allocation(q, summer); 777 778 for(i = 0; i < BANDS; i++) { 779 q->sumLenArr[i] = 0; 780 781 for(j = band_tab[i]; j < band_tab[i+1]; j++) 782 if (!q->skipFlags[j]) 783 q->sumLenArr[i] += q->CWlengthT[j]; 784 } 785 786 memset(q->codewords, 0, sizeof(q->codewords)); 787 788 if(imc_get_coeffs(q) < 0) { 789 av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n"); 790 q->decoder_reset = 1; 791 return 0; 792 } 793 794 if(inverse_quant_coeff(q, stream_format_code) < 0) { 795 av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n"); 796 q->decoder_reset = 1; 797 return 0; 798 } 799 800 memset(q->skipFlags, 0, sizeof(q->skipFlags)); 801 802 imc_imdct256(q); 803 804 q->dsp.float_to_int16(data, q->out_samples, COEFFS); 805 806 *data_size = COEFFS * sizeof(int16_t); 807 808 return IMC_BLOCK_SIZE; 809} 810 811 812static av_cold int imc_decode_close(AVCodecContext * avctx) 813{ 814 IMCContext *q = avctx->priv_data; 815 816 ff_fft_end(&q->fft); 817 return 0; 818} 819 820 821AVCodec imc_decoder = { 822 .name = "imc", 823 .type = CODEC_TYPE_AUDIO, 824 .id = CODEC_ID_IMC, 825 .priv_data_size = sizeof(IMCContext), 826 .init = imc_decode_init, 827 .close = imc_decode_close, 828 .decode = imc_decode_frame, 829 .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"), 830}; 831