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 Libav.
   8  *
   9  * Libav 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  * Libav 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 Libav; 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  *  divided 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 #include "avcodec.h"
  39 #include "get_bits.h"
  40 #include "dsputil.h"
  41 #include "fft.h"
  42 #include "libavutil/audioconvert.h"
  43 #include "sinewin.h"
  44
  45 #include "imcdata.h"
  46
  47 #define IMC_BLOCK_SIZE 64
  48 #define IMC_FRAME_ID 0x21
  49 #define BANDS 32
  50 #define COEFFS 256
  51
  52 typedef struct IMCChannel {
  53     float old_floor[BANDS];
  54     float flcoeffs1[BANDS];
  55     float flcoeffs2[BANDS];
  56     float flcoeffs3[BANDS];
  57     float flcoeffs4[BANDS];
  58     float flcoeffs5[BANDS];
  59     float flcoeffs6[BANDS];
  60     float CWdecoded[COEFFS];
  61
  62     int bandWidthT[BANDS];     ///< codewords per band
  63     int bitsBandT[BANDS];      ///< how many bits per codeword in band
  64     int CWlengthT[COEFFS];     ///< how many bits in each codeword
  65     int levlCoeffBuf[BANDS];
  66     int bandFlagsBuf[BANDS];   ///< flags for each band
  67     int sumLenArr[BANDS];      ///< bits for all coeffs in band
  68     int skipFlagRaw[BANDS];    ///< skip flags are stored in raw form or not
  69     int skipFlagBits[BANDS];   ///< bits used to code skip flags
  70     int skipFlagCount[BANDS];  ///< skipped coeffients per band
  71     int skipFlags[COEFFS];     ///< skip coefficient decoding or not
  72     int codewords[COEFFS];     ///< raw codewords read from bitstream
  73
  74     float last_fft_im[COEFFS];
  75
  76     int decoder_reset;
  77 } IMCChannel;
  78
  79 typedef struct {
  80     AVFrame frame;
  81
  82     IMCChannel chctx[2];
  83
  84     /** MDCT tables */
  85     //@{
  86     float mdct_sine_window[COEFFS];
  87     float post_cos[COEFFS];
  88     float post_sin[COEFFS];
  89     float pre_coef1[COEFFS];
  90     float pre_coef2[COEFFS];
  91     //@}
  92
  93     float sqrt_tab[30];
  94     GetBitContext gb;
  95     float one_div_log2;
  96
  97     DSPContext dsp;
  98     FFTContext fft;
  99     DECLARE_ALIGNED(32, FFTComplex, samples)[COEFFS / 2];
 100     float *out_samples;
 101
 102     int8_t cyclTab[32], cyclTab2[32];
 103     float  weights1[31], weights2[31];
 104 } IMCContext;
 105
 106 static VLC huffman_vlc[4][4];
 107
 108 #define VLC_TABLES_SIZE 9512
 109
 110 static const int vlc_offsets[17] = {
 111     0,     640, 1156, 1732, 2308, 2852, 3396, 3924,
 112     4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE
 113 };
 114
 115 static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2];
 116
 117 static inline double freq2bark(double freq)
 118 {
 119     return 3.5 * atan((freq / 7500.0) * (freq / 7500.0)) + 13.0 * atan(freq * 0.00076);
 120 }
 121
 122 static av_cold void iac_generate_tabs(IMCContext *q, int sampling_rate)
 123 {
 124     double freqmin[32], freqmid[32], freqmax[32];
 125     double scale = sampling_rate / (256.0 * 2.0 * 2.0);
 126     double nyquist_freq = sampling_rate * 0.5;
 127     double freq, bark, prev_bark = 0, tf, tb;
 128     int i, j;
 129
 130     for (i = 0; i < 32; i++) {
 131         freq = (band_tab[i] + band_tab[i + 1] - 1) * scale;
 132         bark = freq2bark(freq);
 133
 134         if (i > 0) {
 135             tb = bark - prev_bark;
 136             q->weights1[i - 1] = pow(10.0, -1.0 * tb);
 137             q->weights2[i - 1] = pow(10.0, -2.7 * tb);
 138         }
 139         prev_bark = bark;
 140
 141         freqmid[i] = freq;
 142
 143         tf = freq;
 144         while (tf < nyquist_freq) {
 145             tf += 0.5;
 146             tb =  freq2bark(tf);
 147             if (tb > bark + 0.5)
 148                 break;
 149         }
 150         freqmax[i] = tf;
 151
 152         tf = freq;
 153         while (tf > 0.0) {
 154             tf -= 0.5;
 155             tb =  freq2bark(tf);
 156             if (tb <= bark - 0.5)
 157                 break;
 158         }
 159         freqmin[i] = tf;
 160     }
 161
 162     for (i = 0; i < 32; i++) {
 163         freq = freqmax[i];
 164         for (j = 31; j > 0 && freq <= freqmid[j]; j--);
 165         q->cyclTab[i] = j + 1;
 166
 167         freq = freqmin[i];
 168         for (j = 0; j < 32 && freq >= freqmid[j]; j++);
 169         q->cyclTab2[i] = j - 1;
 170     }
 171 }
 172
 173 static av_cold int imc_decode_init(AVCodecContext *avctx)
 174 {
 175     int i, j, ret;
 176     IMCContext *q = avctx->priv_data;
 177     double r1, r2;
 178
 179     if ((avctx->codec_id == CODEC_ID_IMC && avctx->channels != 1)
 180         || (avctx->codec_id == CODEC_ID_IAC && avctx->channels > 2)) {
 181         av_log_ask_for_sample(avctx, "Number of channels is not supported\n");
 182         return AVERROR_PATCHWELCOME;
 183     }
 184
 185     for (j = 0; j < avctx->channels; j++) {
 186         q->chctx[j].decoder_reset = 1;
 187
 188         for (i = 0; i < BANDS; i++)
 189             q->chctx[j].old_floor[i] = 1.0;
 190
 191         for (i = 0; i < COEFFS / 2; i++)
 192             q->chctx[j].last_fft_im[i] = 0;
 193     }
 194
 195     /* Build mdct window, a simple sine window normalized with sqrt(2) */
 196     ff_sine_window_init(q->mdct_sine_window, COEFFS);
 197     for (i = 0; i < COEFFS; i++)
 198         q->mdct_sine_window[i] *= sqrt(2.0);
 199     for (i = 0; i < COEFFS / 2; i++) {
 200         q->post_cos[i] = (1.0f / 32768) * cos(i / 256.0 * M_PI);
 201         q->post_sin[i] = (1.0f / 32768) * sin(i / 256.0 * M_PI);
 202
 203         r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
 204         r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
 205
 206         if (i & 0x1) {
 207             q->pre_coef1[i] =  (r1 + r2) * sqrt(2.0);
 208             q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
 209         } else {
 210             q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
 211             q->pre_coef2[i] =  (r1 - r2) * sqrt(2.0);
 212         }
 213     }
 214
 215     /* Generate a square root table */
 216
 217     for (i = 0; i < 30; i++)
 218         q->sqrt_tab[i] = sqrt(i);
 219
 220     /* initialize the VLC tables */
 221     for (i = 0; i < 4 ; i++) {
 222         for (j = 0; j < 4; j++) {
 223             huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
 224             huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
 225             init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
 226                      imc_huffman_lens[i][j], 1, 1,
 227                      imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);
 228         }
 229     }
 230     q->one_div_log2 = 1 / log(2);
 231
 232     if (avctx->codec_id == CODEC_ID_IAC) {
 233     }
 234
 235     if (avctx->codec_id == CODEC_ID_IAC) {
 236         iac_generate_tabs(q, avctx->sample_rate);
 237     } else {
 238         memcpy(q->cyclTab,  cyclTab,  sizeof(cyclTab));
 239         memcpy(q->cyclTab2, cyclTab2, sizeof(cyclTab2));
 240         memcpy(q->weights1, imc_weights1, sizeof(imc_weights1));
 241         memcpy(q->weights2, imc_weights2, sizeof(imc_weights2));
 242     }
 243
 244     if ((ret = ff_fft_init(&q->fft, 7, 1))) {
 245         av_log(avctx, AV_LOG_INFO, "FFT init failed\n");
 246         return ret;
 247     }
 248     ff_dsputil_init(&q->dsp, avctx);
 249     avctx->sample_fmt     = AV_SAMPLE_FMT_FLT;
 250     avctx->channel_layout = avctx->channels == 1 ? AV_CH_LAYOUT_MONO
 251                                                  : AV_CH_LAYOUT_STEREO;
 252
 253     avcodec_get_frame_defaults(&q->frame);
 254     avctx->coded_frame = &q->frame;
 255
 256     return 0;
 257 }
 258
 259 static void imc_calculate_coeffs(IMCContext *q, float *flcoeffs1,
 260                                  float *flcoeffs2, int *bandWidthT,
 261                                  float *flcoeffs3, float *flcoeffs5)
 262 {
 263     float   workT1[BANDS];
 264     float   workT2[BANDS];
 265     float   workT3[BANDS];
 266     float   snr_limit = 1.e-30;
 267     float   accum = 0.0;
 268     int i, cnt2;
 269
 270     for (i = 0; i < BANDS; i++) {
 271         flcoeffs5[i] = workT2[i] = 0.0;
 272         if (bandWidthT[i]) {
 273             workT1[i] = flcoeffs1[i] * flcoeffs1[i];
 274             flcoeffs3[i] = 2.0 * flcoeffs2[i];
 275         } else {
 276             workT1[i]    = 0.0;
 277             flcoeffs3[i] = -30000.0;
 278         }
 279         workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
 280         if (workT3[i] <= snr_limit)
 281             workT3[i] = 0.0;
 282     }
 283
 284     for (i = 0; i < BANDS; i++) {
 285         for (cnt2 = i; cnt2 < q->cyclTab[i]; cnt2++)
 286             flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
 287         workT2[cnt2 - 1] = workT2[cnt2 - 1] + workT3[i];
 288     }
 289
 290     for (i = 1; i < BANDS; i++) {
 291         accum = (workT2[i - 1] + accum) * q->weights1[i - 1];
 292         flcoeffs5[i] += accum;
 293     }
 294
 295     for (i = 0; i < BANDS; i++)
 296         workT2[i] = 0.0;
 297
 298     for (i = 0; i < BANDS; i++) {
 299         for (cnt2 = i - 1; cnt2 > q->cyclTab2[i]; cnt2--)
 300             flcoeffs5[cnt2] += workT3[i];
 301         workT2[cnt2+1] += workT3[i];
 302     }
 303
 304     accum = 0.0;
 305
 306     for (i = BANDS-2; i >= 0; i--) {
 307         accum = (workT2[i+1] + accum) * q->weights2[i];
 308         flcoeffs5[i] += accum;
 309         // there is missing code here, but it seems to never be triggered
 310     }
 311 }
 312
 313
 314 static void imc_read_level_coeffs(IMCContext *q, int stream_format_code,
 315                                   int *levlCoeffs)
 316 {
 317     int i;
 318     VLC *hufftab[4];
 319     int start = 0;
 320     const uint8_t *cb_sel;
 321     int s;
 322
 323     s = stream_format_code >> 1;
 324     hufftab[0] = &huffman_vlc[s][0];
 325     hufftab[1] = &huffman_vlc[s][1];
 326     hufftab[2] = &huffman_vlc[s][2];
 327     hufftab[3] = &huffman_vlc[s][3];
 328     cb_sel = imc_cb_select[s];
 329
 330     if (stream_format_code & 4)
 331         start = 1;
 332     if (start)
 333         levlCoeffs[0] = get_bits(&q->gb, 7);
 334     for (i = start; i < BANDS; i++) {
 335         levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table,
 336                                  hufftab[cb_sel[i]]->bits, 2);
 337         if (levlCoeffs[i] == 17)
 338             levlCoeffs[i] += get_bits(&q->gb, 4);
 339     }
 340 }
 341
 342 static void imc_decode_level_coefficients(IMCContext *q, int *levlCoeffBuf,
 343                                           float *flcoeffs1, float *flcoeffs2)
 344 {
 345     int i, level;
 346     float tmp, tmp2;
 347     // maybe some frequency division thingy
 348
 349     flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
 350     flcoeffs2[0] = log(flcoeffs1[0]) / log(2);
 351     tmp  = flcoeffs1[0];
 352     tmp2 = flcoeffs2[0];
 353
 354     for (i = 1; i < BANDS; i++) {
 355         level = levlCoeffBuf[i];
 356         if (level == 16) {
 357             flcoeffs1[i] = 1.0;
 358             flcoeffs2[i] = 0.0;
 359         } else {
 360             if (level < 17)
 361                 level -= 7;
 362             else if (level <= 24)
 363                 level -= 32;
 364             else
 365                 level -= 16;
 366
 367             tmp  *= imc_exp_tab[15 + level];
 368             tmp2 += 0.83048 * level;  // 0.83048 = log2(10) * 0.25
 369             flcoeffs1[i] = tmp;
 370             flcoeffs2[i] = tmp2;
 371         }
 372     }
 373 }
 374
 375
 376 static void imc_decode_level_coefficients2(IMCContext *q, int *levlCoeffBuf,
 377                                            float *old_floor, float *flcoeffs1,
 378                                            float *flcoeffs2)
 379 {
 380     int i;
 381     /* FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
 382      *       and flcoeffs2 old scale factors
 383      *       might be incomplete due to a missing table that is in the binary code
 384      */
 385     for (i = 0; i < BANDS; i++) {
 386         flcoeffs1[i] = 0;
 387         if (levlCoeffBuf[i] < 16) {
 388             flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
 389             flcoeffs2[i] = (levlCoeffBuf[i] - 7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
 390         } else {
 391             flcoeffs1[i] = old_floor[i];
 392         }
 393     }
 394 }
 395
 396 /**
 397  * Perform bit allocation depending on bits available
 398  */
 399 static int bit_allocation(IMCContext *q, IMCChannel *chctx,
 400                           int stream_format_code, int freebits, int flag)
 401 {
 402     int i, j;
 403     const float limit = -1.e20;
 404     float highest = 0.0;
 405     int indx;
 406     int t1 = 0;
 407     int t2 = 1;
 408     float summa = 0.0;
 409     int iacc = 0;
 410     int summer = 0;
 411     int rres, cwlen;
 412     float lowest = 1.e10;
 413     int low_indx = 0;
 414     float workT[32];
 415     int flg;
 416     int found_indx = 0;
 417
 418     for (i = 0; i < BANDS; i++)
 419         highest = FFMAX(highest, chctx->flcoeffs1[i]);
 420
 421     for (i = 0; i < BANDS - 1; i++)
 422         chctx->flcoeffs4[i] = chctx->flcoeffs3[i] - log(chctx->flcoeffs5[i]) / log(2);
 423     chctx->flcoeffs4[BANDS - 1] = limit;
 424
 425     highest = highest * 0.25;
 426
 427     for (i = 0; i < BANDS; i++) {
 428         indx = -1;
 429         if ((band_tab[i + 1] - band_tab[i]) == chctx->bandWidthT[i])
 430             indx = 0;
 431
 432         if ((band_tab[i + 1] - band_tab[i]) > chctx->bandWidthT[i])
 433             indx = 1;
 434
 435         if (((band_tab[i + 1] - band_tab[i]) / 2) >= chctx->bandWidthT[i])
 436             indx = 2;
 437
 438         if (indx == -1)
 439             return AVERROR_INVALIDDATA;
 440
 441         chctx->flcoeffs4[i] += xTab[(indx * 2 + (chctx->flcoeffs1[i] < highest)) * 2 + flag];
 442     }
 443
 444     if (stream_format_code & 0x2) {
 445         chctx->flcoeffs4[0] = limit;
 446         chctx->flcoeffs4[1] = limit;
 447         chctx->flcoeffs4[2] = limit;
 448         chctx->flcoeffs4[3] = limit;
 449     }
 450
 451     for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS - 1; i++) {
 452         iacc  += chctx->bandWidthT[i];
 453         summa += chctx->bandWidthT[i] * chctx->flcoeffs4[i];
 454     }
 455     chctx->bandWidthT[BANDS - 1] = 0;
 456     summa = (summa * 0.5 - freebits) / iacc;
 457
 458
 459     for (i = 0; i < BANDS / 2; i++) {
 460         rres = summer - freebits;
 461         if ((rres >= -8) && (rres <= 8))
 462             break;
 463
 464         summer = 0;
 465         iacc   = 0;
 466
 467         for (j = (stream_format_code & 0x2) ? 4 : 0; j < BANDS; j++) {
 468             cwlen = av_clipf(((chctx->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
 469
 470             chctx->bitsBandT[j] = cwlen;
 471             summer += chctx->bandWidthT[j] * cwlen;
 472
 473             if (cwlen > 0)
 474                 iacc += chctx->bandWidthT[j];
 475         }
 476
 477         flg = t2;
 478         t2 = 1;
 479         if (freebits < summer)
 480             t2 = -1;
 481         if (i == 0)
 482             flg = t2;
 483         if (flg != t2)
 484             t1++;
 485
 486         summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
 487     }
 488
 489     for (i = (stream_format_code & 0x2) ? 4 : 0; i < BANDS; i++) {
 490         for (j = band_tab[i]; j < band_tab[i + 1]; j++)
 491             chctx->CWlengthT[j] = chctx->bitsBandT[i];
 492     }
 493
 494     if (freebits > summer) {
 495         for (i = 0; i < BANDS; i++) {
 496             workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
 497                                               : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
 498         }
 499
 500         highest = 0.0;
 501
 502         do {
 503             if (highest <= -1.e20)
 504                 break;
 505
 506             found_indx = 0;
 507             highest = -1.e20;
 508
 509             for (i = 0; i < BANDS; i++) {
 510                 if (workT[i] > highest) {
 511                     highest = workT[i];
 512                     found_indx = i;
 513                 }
 514             }
 515
 516             if (highest > -1.e20) {
 517                 workT[found_indx] -= 2.0;
 518                 if (++chctx->bitsBandT[found_indx] == 6)
 519                     workT[found_indx] = -1.e20;
 520
 521                 for (j = band_tab[found_indx]; j < band_tab[found_indx + 1] && (freebits > summer); j++) {
 522                     chctx->CWlengthT[j]++;
 523                     summer++;
 524                 }
 525             }
 526         } while (freebits > summer);
 527     }
 528     if (freebits < summer) {
 529         for (i = 0; i < BANDS; i++) {
 530             workT[i] = chctx->bitsBandT[i] ? (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] + 1.585)
 531                                        : 1.e20;
 532         }
 533         if (stream_format_code & 0x2) {
 534             workT[0] = 1.e20;
 535             workT[1] = 1.e20;
 536             workT[2] = 1.e20;
 537             workT[3] = 1.e20;
 538         }
 539         while (freebits < summer) {
 540             lowest   = 1.e10;
 541             low_indx = 0;
 542             for (i = 0; i < BANDS; i++) {
 543                 if (workT[i] < lowest) {
 544                     lowest   = workT[i];
 545                     low_indx = i;
 546                 }
 547             }
 548             // if (lowest >= 1.e10)
 549             //     break;
 550             workT[low_indx] = lowest + 2.0;
 551
 552             if (!--chctx->bitsBandT[low_indx])
 553                 workT[low_indx] = 1.e20;
 554
 555             for (j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++) {
 556                 if (chctx->CWlengthT[j] > 0) {
 557                     chctx->CWlengthT[j]--;
 558                     summer--;
 559                 }
 560             }
 561         }
 562     }
 563     return 0;
 564 }
 565
 566 static void imc_get_skip_coeff(IMCContext *q, IMCChannel *chctx)
 567 {
 568     int i, j;
 569
 570     memset(chctx->skipFlagBits,  0, sizeof(chctx->skipFlagBits));
 571     memset(chctx->skipFlagCount, 0, sizeof(chctx->skipFlagCount));
 572     for (i = 0; i < BANDS; i++) {
 573         if (!chctx->bandFlagsBuf[i] || !chctx->bandWidthT[i])
 574             continue;
 575
 576         if (!chctx->skipFlagRaw[i]) {
 577             chctx->skipFlagBits[i] = band_tab[i + 1] - band_tab[i];
 578
 579             for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
 580                 chctx->skipFlags[j] = get_bits1(&q->gb);
 581                 if (chctx->skipFlags[j])
 582                     chctx->skipFlagCount[i]++;
 583             }
 584         } else {
 585             for (j = band_tab[i]; j < band_tab[i + 1] - 1; j += 2) {
 586                 if (!get_bits1(&q->gb)) { // 0
 587                     chctx->skipFlagBits[i]++;
 588                     chctx->skipFlags[j]      = 1;
 589                     chctx->skipFlags[j + 1]  = 1;
 590                     chctx->skipFlagCount[i] += 2;
 591                 } else {
 592                     if (get_bits1(&q->gb)) { // 11
 593                         chctx->skipFlagBits[i] += 2;
 594                         chctx->skipFlags[j]     = 0;
 595                         chctx->skipFlags[j + 1] = 1;
 596                         chctx->skipFlagCount[i]++;
 597                     } else {
 598                         chctx->skipFlagBits[i] += 3;
 599                         chctx->skipFlags[j + 1] = 0;
 600                         if (!get_bits1(&q->gb)) { // 100
 601                             chctx->skipFlags[j] = 1;
 602                             chctx->skipFlagCount[i]++;
 603                         } else { // 101
 604                             chctx->skipFlags[j] = 0;
 605                         }
 606                     }
 607                 }
 608             }
 609
 610             if (j < band_tab[i + 1]) {
 611                 chctx->skipFlagBits[i]++;
 612                 if ((chctx->skipFlags[j] = get_bits1(&q->gb)))
 613                     chctx->skipFlagCount[i]++;
 614             }
 615         }
 616     }
 617 }
 618
 619 /**
 620  * Increase highest' band coefficient sizes as some bits won't be used
 621  */
 622 static void imc_adjust_bit_allocation(IMCContext *q, IMCChannel *chctx,
 623                                       int summer)
 624 {
 625     float workT[32];
 626     int corrected = 0;
 627     int i, j;
 628     float highest  = 0;
 629     int found_indx = 0;
 630
 631     for (i = 0; i < BANDS; i++) {
 632         workT[i] = (chctx->bitsBandT[i] == 6) ? -1.e20
 633                                           : (chctx->bitsBandT[i] * -2 + chctx->flcoeffs4[i] - 0.415);
 634     }
 635
 636     while (corrected < summer) {
 637         if (highest <= -1.e20)
 638             break;
 639
 640         highest = -1.e20;
 641
 642         for (i = 0; i < BANDS; i++) {
 643             if (workT[i] > highest) {
 644                 highest = workT[i];
 645                 found_indx = i;
 646             }
 647         }
 648
 649         if (highest > -1.e20) {
 650             workT[found_indx] -= 2.0;
 651             if (++(chctx->bitsBandT[found_indx]) == 6)
 652                 workT[found_indx] = -1.e20;
 653
 654             for (j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
 655                 if (!chctx->skipFlags[j] && (chctx->CWlengthT[j] < 6)) {
 656                     chctx->CWlengthT[j]++;
 657                     corrected++;
 658                 }
 659             }
 660         }
 661     }
 662 }
 663
 664 static void imc_imdct256(IMCContext *q, IMCChannel *chctx, int channels)
 665 {
 666     int i;
 667     float re, im;
 668     float *dst1 = q->out_samples;
 669     float *dst2 = q->out_samples + (COEFFS - 1) * channels;
 670
 671     /* prerotation */
 672     for (i = 0; i < COEFFS / 2; i++) {
 673         q->samples[i].re = -(q->pre_coef1[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
 674                             (q->pre_coef2[i] * chctx->CWdecoded[i * 2]);
 675         q->samples[i].im =  (q->pre_coef2[i] * chctx->CWdecoded[COEFFS - 1 - i * 2]) -
 676                             (q->pre_coef1[i] * chctx->CWdecoded[i * 2]);
 677     }
 678
 679     /* FFT */
 680     q->fft.fft_permute(&q->fft, q->samples);
 681     q->fft.fft_calc(&q->fft, q->samples);
 682
 683     /* postrotation, window and reorder */
 684     for (i = 0; i < COEFFS / 2; i++) {
 685         re = ( q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
 686         im = (-q->samples[i].im * q->post_cos[i]) - ( q->samples[i].re * q->post_sin[i]);
 687         *dst1 =  (q->mdct_sine_window[COEFFS - 1 - i * 2] * chctx->last_fft_im[i])
 688                + (q->mdct_sine_window[i * 2] * re);
 689         *dst2 =  (q->mdct_sine_window[i * 2] * chctx->last_fft_im[i])
 690                - (q->mdct_sine_window[COEFFS - 1 - i * 2] * re);
 691         dst1 += channels * 2;
 692         dst2 -= channels * 2;
 693         chctx->last_fft_im[i] = im;
 694     }
 695 }
 696
 697 static int inverse_quant_coeff(IMCContext *q, IMCChannel *chctx,
 698                                int stream_format_code)
 699 {
 700     int i, j;
 701     int middle_value, cw_len, max_size;
 702     const float *quantizer;
 703
 704     for (i = 0; i < BANDS; i++) {
 705         for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
 706             chctx->CWdecoded[j] = 0;
 707             cw_len = chctx->CWlengthT[j];
 708
 709             if (cw_len <= 0 || chctx->skipFlags[j])
 710                 continue;
 711
 712             max_size     = 1 << cw_len;
 713             middle_value = max_size >> 1;
 714
 715             if (chctx->codewords[j] >= max_size || chctx->codewords[j] < 0)
 716                 return AVERROR_INVALIDDATA;
 717
 718             if (cw_len >= 4) {
 719                 quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
 720                 if (chctx->codewords[j] >= middle_value)
 721                     chctx->CWdecoded[j] =  quantizer[chctx->codewords[j] - 8]                * chctx->flcoeffs6[i];
 722                 else
 723                     chctx->CWdecoded[j] = -quantizer[max_size - chctx->codewords[j] - 8 - 1] * chctx->flcoeffs6[i];
 724             }else{
 725                 quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (chctx->bandFlagsBuf[i] << 1)];
 726                 if (chctx->codewords[j] >= middle_value)
 727                     chctx->CWdecoded[j] =  quantizer[chctx->codewords[j] - 1]            * chctx->flcoeffs6[i];
 728                 else
 729                     chctx->CWdecoded[j] = -quantizer[max_size - 2 - chctx->codewords[j]] * chctx->flcoeffs6[i];
 730             }
 731         }
 732     }
 733     return 0;
 734 }
 735
 736
 737 static int imc_get_coeffs(IMCContext *q, IMCChannel *chctx)
 738 {
 739     int i, j, cw_len, cw;
 740
 741     for (i = 0; i < BANDS; i++) {
 742         if (!chctx->sumLenArr[i])
 743             continue;
 744         if (chctx->bandFlagsBuf[i] || chctx->bandWidthT[i]) {
 745             for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
 746                 cw_len = chctx->CWlengthT[j];
 747                 cw = 0;
 748
 749                 if (get_bits_count(&q->gb) + cw_len > 512) {
 750                     // av_log(NULL, 0, "Band %i coeff %i cw_len %i\n", i, j, cw_len);
 751                     return AVERROR_INVALIDDATA;
 752                 }
 753
 754                 if (cw_len && (!chctx->bandFlagsBuf[i] || !chctx->skipFlags[j]))
 755                     cw = get_bits(&q->gb, cw_len);
 756
 757                 chctx->codewords[j] = cw;
 758             }
 759         }
 760     }
 761     return 0;
 762 }
 763
 764 static int imc_decode_block(AVCodecContext *avctx, IMCContext *q, int ch)
 765 {
 766     int stream_format_code;
 767     int imc_hdr, i, j, ret;
 768     int flag;
 769     int bits, summer;
 770     int counter, bitscount;
 771     IMCChannel *chctx = q->chctx + ch;
 772
 773
 774     /* Check the frame header */
 775     imc_hdr = get_bits(&q->gb, 9);
 776     if (imc_hdr & 0x18) {
 777         av_log(avctx, AV_LOG_ERROR, "frame header check failed!\n");
 778         av_log(avctx, AV_LOG_ERROR, "got %X.\n", imc_hdr);
 779         return AVERROR_INVALIDDATA;
 780     }
 781     stream_format_code = get_bits(&q->gb, 3);
 782
 783     if (stream_format_code & 1) {
 784         av_log_ask_for_sample(avctx, "Stream format %X is not supported\n",
 785                               stream_format_code);
 786         return AVERROR_PATCHWELCOME;
 787     }
 788
 789 //    av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);
 790
 791     if (stream_format_code & 0x04)
 792         chctx->decoder_reset = 1;
 793
 794     if (chctx->decoder_reset) {
 795         memset(q->out_samples, 0, sizeof(q->out_samples));
 796         for (i = 0; i < BANDS; i++)
 797             chctx->old_floor[i] = 1.0;
 798         for (i = 0; i < COEFFS; i++)
 799             chctx->CWdecoded[i] = 0;
 800         chctx->decoder_reset = 0;
 801     }
 802
 803     flag = get_bits1(&q->gb);
 804     imc_read_level_coeffs(q, stream_format_code, chctx->levlCoeffBuf);
 805
 806     if (stream_format_code & 0x4)
 807         imc_decode_level_coefficients(q, chctx->levlCoeffBuf,
 808                                       chctx->flcoeffs1, chctx->flcoeffs2);
 809     else
 810         imc_decode_level_coefficients2(q, chctx->levlCoeffBuf, chctx->old_floor,
 811                                        chctx->flcoeffs1, chctx->flcoeffs2);
 812
 813     memcpy(chctx->old_floor, chctx->flcoeffs1, 32 * sizeof(float));
 814
 815     counter = 0;
 816     for (i = 0; i < BANDS; i++) {
 817         if (chctx->levlCoeffBuf[i] == 16) {
 818             chctx->bandWidthT[i] = 0;
 819             counter++;
 820         } else
 821             chctx->bandWidthT[i] = band_tab[i + 1] - band_tab[i];
 822     }
 823     memset(chctx->bandFlagsBuf, 0, BANDS * sizeof(int));
 824     for (i = 0; i < BANDS - 1; i++) {
 825         if (chctx->bandWidthT[i])
 826             chctx->bandFlagsBuf[i] = get_bits1(&q->gb);
 827     }
 828
 829     imc_calculate_coeffs(q, chctx->flcoeffs1, chctx->flcoeffs2, chctx->bandWidthT, chctx->flcoeffs3, chctx->flcoeffs5);
 830
 831     bitscount = 0;
 832     /* first 4 bands will be assigned 5 bits per coefficient */
 833     if (stream_format_code & 0x2) {
 834         bitscount += 15;
 835
 836         chctx->bitsBandT[0] = 5;
 837         chctx->CWlengthT[0] = 5;
 838         chctx->CWlengthT[1] = 5;
 839         chctx->CWlengthT[2] = 5;
 840         for (i = 1; i < 4; i++) {
 841             bits = (chctx->levlCoeffBuf[i] == 16) ? 0 : 5;
 842             chctx->bitsBandT[i] = bits;
 843             for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
 844                 chctx->CWlengthT[j] = bits;
 845                 bitscount      += bits;
 846             }
 847         }
 848     }
 849     if (avctx->codec_id == CODEC_ID_IAC) {
 850         bitscount += !!chctx->bandWidthT[BANDS - 1];
 851         if (!(stream_format_code & 0x2))
 852             bitscount += 16;
 853     }
 854
 855     if ((ret = bit_allocation(q, chctx, stream_format_code,
 856                               512 - bitscount - get_bits_count(&q->gb),
 857                               flag)) < 0) {
 858         av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
 859         chctx->decoder_reset = 1;
 860         return ret;
 861     }
 862
 863     for (i = 0; i < BANDS; i++) {
 864         chctx->sumLenArr[i]   = 0;
 865         chctx->skipFlagRaw[i] = 0;
 866         for (j = band_tab[i]; j < band_tab[i + 1]; j++)
 867             chctx->sumLenArr[i] += chctx->CWlengthT[j];
 868         if (chctx->bandFlagsBuf[i])
 869             if ((((band_tab[i + 1] - band_tab[i]) * 1.5) > chctx->sumLenArr[i]) && (chctx->sumLenArr[i] > 0))
 870                 chctx->skipFlagRaw[i] = 1;
 871     }
 872
 873     imc_get_skip_coeff(q, chctx);
 874
 875     for (i = 0; i < BANDS; i++) {
 876         chctx->flcoeffs6[i] = chctx->flcoeffs1[i];
 877         /* band has flag set and at least one coded coefficient */
 878         if (chctx->bandFlagsBuf[i] && (band_tab[i + 1] - band_tab[i]) != chctx->skipFlagCount[i]) {
 879             chctx->flcoeffs6[i] *= q->sqrt_tab[ band_tab[i + 1] - band_tab[i]] /
 880                                    q->sqrt_tab[(band_tab[i + 1] - band_tab[i] - chctx->skipFlagCount[i])];
 881         }
 882     }
 883
 884     /* calculate bits left, bits needed and adjust bit allocation */
 885     bits = summer = 0;
 886
 887     for (i = 0; i < BANDS; i++) {
 888         if (chctx->bandFlagsBuf[i]) {
 889             for (j = band_tab[i]; j < band_tab[i + 1]; j++) {
 890                 if (chctx->skipFlags[j]) {
 891                     summer += chctx->CWlengthT[j];
 892                     chctx->CWlengthT[j] = 0;
 893                 }
 894             }
 895             bits   += chctx->skipFlagBits[i];
 896             summer -= chctx->skipFlagBits[i];
 897         }
 898     }
 899     imc_adjust_bit_allocation(q, chctx, summer);
 900
 901     for (i = 0; i < BANDS; i++) {
 902         chctx->sumLenArr[i] = 0;
 903
 904         for (j = band_tab[i]; j < band_tab[i + 1]; j++)
 905             if (!chctx->skipFlags[j])
 906                 chctx->sumLenArr[i] += chctx->CWlengthT[j];
 907     }
 908
 909     memset(chctx->codewords, 0, sizeof(chctx->codewords));
 910
 911     if (imc_get_coeffs(q, chctx) < 0) {
 912         av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
 913         chctx->decoder_reset = 1;
 914         return AVERROR_INVALIDDATA;
 915     }
 916
 917     if (inverse_quant_coeff(q, chctx, stream_format_code) < 0) {
 918         av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
 919         chctx->decoder_reset = 1;
 920         return AVERROR_INVALIDDATA;
 921     }
 922
 923     memset(chctx->skipFlags, 0, sizeof(chctx->skipFlags));
 924
 925     imc_imdct256(q, chctx, avctx->channels);
 926
 927     return 0;
 928 }
 929
 930 static int imc_decode_frame(AVCodecContext *avctx, void *data,
 931                             int *got_frame_ptr, AVPacket *avpkt)
 932 {
 933     const uint8_t *buf = avpkt->data;
 934     int buf_size = avpkt->size;
 935     int ret, i;
 936
 937     IMCContext *q = avctx->priv_data;
 938
 939     LOCAL_ALIGNED_16(uint16_t, buf16, [IMC_BLOCK_SIZE / 2]);
 940
 941     if (buf_size < IMC_BLOCK_SIZE * avctx->channels) {
 942         av_log(avctx, AV_LOG_ERROR, "frame too small!\n");
 943         return AVERROR_INVALIDDATA;
 944     }
 945
 946     /* get output buffer */
 947     q->frame.nb_samples = COEFFS;
 948     if ((ret = avctx->get_buffer(avctx, &q->frame)) < 0) {
 949         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 950         return ret;
 951     }
 952
 953     for (i = 0; i < avctx->channels; i++) {
 954         q->out_samples = (float*)q->frame.data[0] + i;
 955
 956         q->dsp.bswap16_buf(buf16, (const uint16_t*)buf, IMC_BLOCK_SIZE / 2);
 957
 958         init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
 959
 960         buf += IMC_BLOCK_SIZE;
 961
 962         if ((ret = imc_decode_block(avctx, q, i)) < 0)
 963             return ret;
 964     }
 965
 966     if (avctx->channels == 2) {
 967         float *src = (float*)q->frame.data[0], t1, t2;
 968
 969         for (i = 0; i < COEFFS; i++) {
 970             t1     = src[0];
 971             t2     = src[1];
 972             src[0] = t1 + t2;
 973             src[1] = t1 - t2;
 974             src   += 2;
 975         }
 976     }
 977
 978     *got_frame_ptr   = 1;
 979     *(AVFrame *)data = q->frame;
 980
 981     return IMC_BLOCK_SIZE * avctx->channels;
 982 }
 983
 984
 985 static av_cold int imc_decode_close(AVCodecContext * avctx)
 986 {
 987     IMCContext *q = avctx->priv_data;
 988
 989     ff_fft_end(&q->fft);
 990
 991     return 0;
 992 }
 993
 994
 995 AVCodec ff_imc_decoder = {
 996     .name           = "imc",
 997     .type           = AVMEDIA_TYPE_AUDIO,
 998     .id             = CODEC_ID_IMC,
 999     .priv_data_size = sizeof(IMCContext),
1000     .init           = imc_decode_init,
1001     .close          = imc_decode_close,
1002     .decode         = imc_decode_frame,
1003     .capabilities   = CODEC_CAP_DR1,
1004     .long_name      = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
1005 };
1006
1007 AVCodec ff_iac_decoder = {
1008     .name           = "iac",
1009     .type           = AVMEDIA_TYPE_AUDIO,
1010     .id             = CODEC_ID_IAC,
1011     .priv_data_size = sizeof(IMCContext),
1012     .init           = imc_decode_init,
1013     .close          = imc_decode_close,
1014     .decode         = imc_decode_frame,
1015     .capabilities   = CODEC_CAP_DR1,
1016     .long_name      = NULL_IF_CONFIG_SMALL("IAC (Indeo Audio Coder)"),
1017 };