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