libavcodec/imc.c

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