imc.c 24.5 KB
Newer Older
Kostya Shishkov's avatar
Kostya Shishkov committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
/*
 * IMC compatible decoder
 * Copyright (c) 2002-2004 Maxim Poliakovski
 * Copyright (c) 2006 Benjamin Larsson
 * Copyright (c) 2006 Konstantin Shishkov
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 *  @file imc.c IMC - Intel Music Coder
 *  A mdct based codec using a 256 points large transform
 *  divied into 32 bands with some mix of scale factors.
 *  Only mono is supported.
 *
 */


#include <math.h>
#include <stddef.h>
#include <stdio.h>

#define ALT_BITSTREAM_READER
#include "avcodec.h"
#include "bitstream.h"
#include "dsputil.h"

#include "imcdata.h"

44
#define IMC_BLOCK_SIZE 64
Kostya Shishkov's avatar
Kostya Shishkov committed
45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90
#define IMC_FRAME_ID 0x21
#define BANDS 32
#define COEFFS 256

typedef struct {
    float old_floor[BANDS];
    float flcoeffs1[BANDS];
    float flcoeffs2[BANDS];
    float flcoeffs3[BANDS];
    float flcoeffs4[BANDS];
    float flcoeffs5[BANDS];
    float flcoeffs6[BANDS];
    float CWdecoded[COEFFS];

    /** MDCT tables */
    //@{
    float mdct_sine_window[COEFFS];
    float post_cos[COEFFS];
    float post_sin[COEFFS];
    float pre_coef1[COEFFS];
    float pre_coef2[COEFFS];
    float last_fft_im[COEFFS];
    //@}

    int bandWidthT[BANDS];     ///< codewords per band
    int bitsBandT[BANDS];      ///< how many bits per codeword in band
    int CWlengthT[COEFFS];     ///< how many bits in each codeword
    int levlCoeffBuf[BANDS];
    int bandFlagsBuf[BANDS];   ///< flags for each band
    int sumLenArr[BANDS];      ///< bits for all coeffs in band
    int skipFlagRaw[BANDS];    ///< skip flags are stored in raw form or not
    int skipFlagBits[BANDS];   ///< bits used to code skip flags
    int skipFlagCount[BANDS];  ///< skipped coeffients per band
    int skipFlags[COEFFS];     ///< skip coefficient decoding or not
    int codewords[COEFFS];     ///< raw codewords read from bitstream
    float sqrt_tab[30];
    GetBitContext gb;
    int decoder_reset;
    float one_div_log2;

    DSPContext dsp;
    FFTContext fft;
    DECLARE_ALIGNED_16(FFTComplex, samples[COEFFS/2]);
    DECLARE_ALIGNED_16(float, out_samples[COEFFS]);
} IMCContext;

91 92 93 94 95 96 97 98 99
static VLC huffman_vlc[4][4];

#define VLC_TABLES_SIZE 9512

static const int vlc_offsets[17] = {
    0,     640, 1156, 1732, 2308, 2852, 3396, 3924,
    4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE};

static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2];
Kostya Shishkov's avatar
Kostya Shishkov committed
100

101
static av_cold int imc_decode_init(AVCodecContext * avctx)
Kostya Shishkov's avatar
Kostya Shishkov committed
102 103 104 105 106 107 108 109 110 111 112
{
    int i, j;
    IMCContext *q = avctx->priv_data;
    double r1, r2;

    q->decoder_reset = 1;

    for(i = 0; i < BANDS; i++)
        q->old_floor[i] = 1.0;

    /* Build mdct window, a simple sine window normalized with sqrt(2) */
113
    ff_sine_window_init(q->mdct_sine_window, COEFFS);
Kostya Shishkov's avatar
Kostya Shishkov committed
114
    for(i = 0; i < COEFFS; i++)
115
        q->mdct_sine_window[i] *= sqrt(2.0);
Kostya Shishkov's avatar
Kostya Shishkov committed
116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145
    for(i = 0; i < COEFFS/2; i++){
        q->post_cos[i] = cos(i / 256.0 * M_PI);
        q->post_sin[i] = sin(i / 256.0 * M_PI);

        r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
        r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);

        if (i & 0x1)
        {
            q->pre_coef1[i] =  (r1 + r2) * sqrt(2.0);
            q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
        }
        else
        {
            q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
            q->pre_coef2[i] =  (r1 - r2) * sqrt(2.0);
        }

        q->last_fft_im[i] = 0;
    }

    /* Generate a square root table */

    for(i = 0; i < 30; i++) {
        q->sqrt_tab[i] = sqrt(i);
    }

    /* initialize the VLC tables */
    for(i = 0; i < 4 ; i++) {
        for(j = 0; j < 4; j++) {
146 147 148
            huffman_vlc[i][j].table = vlc_tables[vlc_offsets[i * 4 + j]];
            huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
            init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
Kostya Shishkov's avatar
Kostya Shishkov committed
149
                     imc_huffman_lens[i][j], 1, 1,
150
                     imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);
Kostya Shishkov's avatar
Kostya Shishkov committed
151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222
        }
    }
    q->one_div_log2 = 1/log(2);

    ff_fft_init(&q->fft, 7, 1);
    dsputil_init(&q->dsp, avctx);
    return 0;
}

static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT,
                                float* flcoeffs3, float* flcoeffs5)
{
    float   workT1[BANDS];
    float   workT2[BANDS];
    float   workT3[BANDS];
    float   snr_limit = 1.e-30;
    float   accum = 0.0;
    int i, cnt2;

    for(i = 0; i < BANDS; i++) {
        flcoeffs5[i] = workT2[i] = 0.0;
        if (bandWidthT[i]){
            workT1[i] = flcoeffs1[i] * flcoeffs1[i];
            flcoeffs3[i] = 2.0 * flcoeffs2[i];
        } else {
            workT1[i] = 0.0;
            flcoeffs3[i] = -30000.0;
        }
        workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
        if (workT3[i] <= snr_limit)
            workT3[i] = 0.0;
    }

    for(i = 0; i < BANDS; i++) {
        for(cnt2 = i; cnt2 < cyclTab[i]; cnt2++)
            flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
        workT2[cnt2-1] = workT2[cnt2-1] + workT3[i];
    }

    for(i = 1; i < BANDS; i++) {
        accum = (workT2[i-1] + accum) * imc_weights1[i-1];
        flcoeffs5[i] += accum;
    }

    for(i = 0; i < BANDS; i++)
        workT2[i] = 0.0;

    for(i = 0; i < BANDS; i++) {
        for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--)
            flcoeffs5[cnt2] += workT3[i];
        workT2[cnt2+1] += workT3[i];
    }

    accum = 0.0;

    for(i = BANDS-2; i >= 0; i--) {
        accum = (workT2[i+1] + accum) * imc_weights2[i];
        flcoeffs5[i] += accum;
        //there is missing code here, but it seems to never be triggered
    }
}


static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs)
{
    int i;
    VLC *hufftab[4];
    int start = 0;
    const uint8_t *cb_sel;
    int s;

    s = stream_format_code >> 1;
223 224 225 226
    hufftab[0] = &huffman_vlc[s][0];
    hufftab[1] = &huffman_vlc[s][1];
    hufftab[2] = &huffman_vlc[s][2];
    hufftab[3] = &huffman_vlc[s][3];
Kostya Shishkov's avatar
Kostya Shishkov committed
227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246
    cb_sel = imc_cb_select[s];

    if(stream_format_code & 4)
        start = 1;
    if(start)
        levlCoeffs[0] = get_bits(&q->gb, 7);
    for(i = start; i < BANDS; i++){
        levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2);
        if(levlCoeffs[i] == 17)
            levlCoeffs[i] += get_bits(&q->gb, 4);
    }
}

static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1,
                                         float* flcoeffs2)
{
    int i, level;
    float tmp, tmp2;
    //maybe some frequency division thingy

Benjamin Larsson's avatar
Benjamin Larsson committed
247 248
    flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
    flcoeffs2[0] = log(flcoeffs1[0])/log(2);
Kostya Shishkov's avatar
Kostya Shishkov committed
249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265
    tmp = flcoeffs1[0];
    tmp2 = flcoeffs2[0];

    for(i = 1; i < BANDS; i++) {
        level = levlCoeffBuf[i];
        if (level == 16) {
            flcoeffs1[i] = 1.0;
            flcoeffs2[i] = 0.0;
        } else {
            if (level < 17)
                level -=7;
            else if (level <= 24)
                level -=32;
            else
                level -=16;

            tmp  *= imc_exp_tab[15 + level];
Benjamin Larsson's avatar
Benjamin Larsson committed
266
            tmp2 += 0.83048 * level;  // 0.83048 = log2(10) * 0.25
Kostya Shishkov's avatar
Kostya Shishkov committed
267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283
            flcoeffs1[i] = tmp;
            flcoeffs2[i] = tmp2;
        }
    }
}


static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1,
                                          float* flcoeffs2) {
    int i;
        //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
        //      and flcoeffs2 old scale factors
        //      might be incomplete due to a missing table that is in the binary code
    for(i = 0; i < BANDS; i++) {
        flcoeffs1[i] = 0;
        if(levlCoeffBuf[i] < 16) {
            flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
Benjamin Larsson's avatar
Benjamin Larsson committed
284
            flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
Kostya Shishkov's avatar
Kostya Shishkov committed
285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314
        } else {
            flcoeffs1[i] = old_floor[i];
        }
    }
}

/**
 * Perform bit allocation depending on bits available
 */
static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) {
    int i, j;
    const float limit = -1.e20;
    float highest = 0.0;
    int indx;
    int t1 = 0;
    int t2 = 1;
    float summa = 0.0;
    int iacc = 0;
    int summer = 0;
    int rres, cwlen;
    float lowest = 1.e10;
    int low_indx = 0;
    float workT[32];
    int flg;
    int found_indx = 0;

    for(i = 0; i < BANDS; i++)
        highest = FFMAX(highest, q->flcoeffs1[i]);

    for(i = 0; i < BANDS-1; i++) {
Benjamin Larsson's avatar
Benjamin Larsson committed
315
        q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2);
Kostya Shishkov's avatar
Kostya Shishkov committed
316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360
    }
    q->flcoeffs4[BANDS - 1] = limit;

    highest = highest * 0.25;

    for(i = 0; i < BANDS; i++) {
        indx = -1;
        if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i])
            indx = 0;

        if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i])
            indx = 1;

        if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i])
            indx = 2;

        if (indx == -1)
            return -1;

        q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag];
    }

    if (stream_format_code & 0x2) {
        q->flcoeffs4[0] = limit;
        q->flcoeffs4[1] = limit;
        q->flcoeffs4[2] = limit;
        q->flcoeffs4[3] = limit;
    }

    for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) {
        iacc += q->bandWidthT[i];
        summa += q->bandWidthT[i] * q->flcoeffs4[i];
    }
    q->bandWidthT[BANDS-1] = 0;
    summa = (summa * 0.5 - freebits) / iacc;


    for(i = 0; i < BANDS/2; i++) {
        rres = summer - freebits;
        if((rres >= -8) && (rres <= 8)) break;

        summer = 0;
        iacc = 0;

        for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) {
361
            cwlen = av_clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
Kostya Shishkov's avatar
Kostya Shishkov committed
362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468

            q->bitsBandT[j] = cwlen;
            summer += q->bandWidthT[j] * cwlen;

            if (cwlen > 0)
                iacc += q->bandWidthT[j];
        }

        flg = t2;
        t2 = 1;
        if (freebits < summer)
            t2 = -1;
        if (i == 0)
            flg = t2;
        if(flg != t2)
            t1++;

        summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
    }

    for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) {
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
            q->CWlengthT[j] = q->bitsBandT[i];
    }

    if (freebits > summer) {
        for(i = 0; i < BANDS; i++) {
            workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
        }

        highest = 0.0;

        do{
            if (highest <= -1.e20)
                break;

            found_indx = 0;
            highest = -1.e20;

            for(i = 0; i < BANDS; i++) {
                if (workT[i] > highest) {
                    highest = workT[i];
                    found_indx = i;
                }
            }

            if (highest > -1.e20) {
                workT[found_indx] -= 2.0;
                if (++(q->bitsBandT[found_indx]) == 6)
                    workT[found_indx] = -1.e20;

                for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){
                    q->CWlengthT[j]++;
                    summer++;
                }
            }
        }while (freebits > summer);
    }
    if (freebits < summer) {
        for(i = 0; i < BANDS; i++) {
            workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20;
        }
        if (stream_format_code & 0x2) {
            workT[0] = 1.e20;
            workT[1] = 1.e20;
            workT[2] = 1.e20;
            workT[3] = 1.e20;
        }
        while (freebits < summer){
            lowest = 1.e10;
            low_indx = 0;
            for(i = 0; i < BANDS; i++) {
                if (workT[i] < lowest) {
                    lowest = workT[i];
                    low_indx = i;
                }
            }
            //if(lowest >= 1.e10) break;
            workT[low_indx] = lowest + 2.0;

            if (!(--q->bitsBandT[low_indx]))
                workT[low_indx] = 1.e20;

            for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){
                if(q->CWlengthT[j] > 0){
                    q->CWlengthT[j]--;
                    summer--;
                }
            }
        }
    }
    return 0;
}

static void imc_get_skip_coeff(IMCContext* q) {
    int i, j;

    memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits));
    memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount));
    for(i = 0; i < BANDS; i++) {
        if (!q->bandFlagsBuf[i] || !q->bandWidthT[i])
            continue;

        if (!q->skipFlagRaw[i]) {
            q->skipFlagBits[i] = band_tab[i+1] - band_tab[i];

            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
469
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
Kostya Shishkov's avatar
Kostya Shishkov committed
470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499
                    q->skipFlagCount[i]++;
            }
        } else {
            for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) {
                if(!get_bits1(&q->gb)){//0
                    q->skipFlagBits[i]++;
                    q->skipFlags[j]=1;
                    q->skipFlags[j+1]=1;
                    q->skipFlagCount[i] += 2;
                }else{
                    if(get_bits1(&q->gb)){//11
                        q->skipFlagBits[i] +=2;
                        q->skipFlags[j]=0;
                        q->skipFlags[j+1]=1;
                        q->skipFlagCount[i]++;
                    }else{
                        q->skipFlagBits[i] +=3;
                        q->skipFlags[j+1]=0;
                        if(!get_bits1(&q->gb)){//100
                            q->skipFlags[j]=1;
                            q->skipFlagCount[i]++;
                        }else{//101
                            q->skipFlags[j]=0;
                        }
                    }
                }
            }

            if (j < band_tab[i+1]) {
                q->skipFlagBits[i]++;
500
                if ((q->skipFlags[j] = get_bits1(&q->gb)))
Kostya Shishkov's avatar
Kostya Shishkov committed
501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548
                    q->skipFlagCount[i]++;
            }
        }
    }
}

/**
 * Increase highest' band coefficient sizes as some bits won't be used
 */
static void imc_adjust_bit_allocation (IMCContext* q, int summer) {
    float workT[32];
    int corrected = 0;
    int i, j;
    float highest = 0;
    int found_indx=0;

    for(i = 0; i < BANDS; i++) {
        workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
    }

    while (corrected < summer) {
        if(highest <= -1.e20)
            break;

        highest = -1.e20;

        for(i = 0; i < BANDS; i++) {
            if (workT[i] > highest) {
                highest = workT[i];
                found_indx = i;
            }
        }

        if (highest > -1.e20) {
            workT[found_indx] -= 2.0;
            if (++(q->bitsBandT[found_indx]) == 6)
                workT[found_indx] = -1.e20;

            for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
                if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) {
                    q->CWlengthT[j]++;
                    corrected++;
                }
            }
        }
    }
}

549
static void imc_imdct256(IMCContext *q) {
Kostya Shishkov's avatar
Kostya Shishkov committed
550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639
    int i;
    float re, im;

    /* prerotation */
    for(i=0; i < COEFFS/2; i++){
        q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) -
                           (q->pre_coef2[i] * q->CWdecoded[i*2]);
        q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) -
                           (q->pre_coef1[i] * q->CWdecoded[i*2]);
    }

    /* FFT */
    ff_fft_permute(&q->fft, q->samples);
    ff_fft_calc (&q->fft, q->samples);

    /* postrotation, window and reorder */
    for(i = 0; i < COEFFS/2; i++){
        re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
        im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]);
        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);
        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);
        q->last_fft_im[i] = im;
    }
}

static int inverse_quant_coeff (IMCContext* q, int stream_format_code) {
    int i, j;
    int middle_value, cw_len, max_size;
    const float* quantizer;

    for(i = 0; i < BANDS; i++) {
        for(j = band_tab[i]; j < band_tab[i+1]; j++) {
            q->CWdecoded[j] = 0;
            cw_len = q->CWlengthT[j];

            if (cw_len <= 0 || q->skipFlags[j])
                continue;

            max_size = 1 << cw_len;
            middle_value = max_size >> 1;

            if (q->codewords[j] >= max_size || q->codewords[j] < 0)
                return -1;

            if (cw_len >= 4){
                quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
                if (q->codewords[j] >= middle_value)
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i];
                else
                    q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i];
            }else{
                quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)];
                if (q->codewords[j] >= middle_value)
                    q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i];
                else
                    q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i];
            }
        }
    }
    return 0;
}


static int imc_get_coeffs (IMCContext* q) {
    int i, j, cw_len, cw;

    for(i = 0; i < BANDS; i++) {
        if(!q->sumLenArr[i]) continue;
        if (q->bandFlagsBuf[i] || q->bandWidthT[i]) {
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
                cw_len = q->CWlengthT[j];
                cw = 0;

                if (get_bits_count(&q->gb) + cw_len > 512){
//av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len);
                    return -1;
                }

                if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j]))
                    cw = get_bits(&q->gb, cw_len);

                q->codewords[j] = cw;
            }
        }
    }
    return 0;
}

static int imc_decode_frame(AVCodecContext * avctx,
                            void *data, int *data_size,
Michael Niedermayer's avatar
Michael Niedermayer committed
640
                            const uint8_t * buf, int buf_size)
Kostya Shishkov's avatar
Kostya Shishkov committed
641 642 643 644 645 646 647 648 649
{

    IMCContext *q = avctx->priv_data;

    int stream_format_code;
    int imc_hdr, i, j;
    int flag;
    int bits, summer;
    int counter, bitscount;
650
    uint16_t buf16[IMC_BLOCK_SIZE / 2];
Kostya Shishkov's avatar
Kostya Shishkov committed
651

652 653 654 655
    if (buf_size < IMC_BLOCK_SIZE) {
        av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n");
        return -1;
    }
656
    for(i = 0; i < IMC_BLOCK_SIZE / 2; i++)
657
        buf16[i] = bswap_16(((const uint16_t*)buf)[i]);
Kostya Shishkov's avatar
Kostya Shishkov committed
658

659
    init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
Kostya Shishkov's avatar
Kostya Shishkov committed
660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805

    /* Check the frame header */
    imc_hdr = get_bits(&q->gb, 9);
    if (imc_hdr != IMC_FRAME_ID) {
        av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n");
        av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr);
        return -1;
    }
    stream_format_code = get_bits(&q->gb, 3);

    if(stream_format_code & 1){
        av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code);
        return -1;
    }

//    av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);

    if (stream_format_code & 0x04)
        q->decoder_reset = 1;

    if(q->decoder_reset) {
        memset(q->out_samples, 0, sizeof(q->out_samples));
        for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0;
        for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0;
        q->decoder_reset = 0;
    }

    flag = get_bits1(&q->gb);
    imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf);

    if (stream_format_code & 0x4)
        imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2);
    else
        imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2);

    memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float));

    counter = 0;
    for (i=0 ; i<BANDS ; i++) {
        if (q->levlCoeffBuf[i] == 16) {
            q->bandWidthT[i] = 0;
            counter++;
        } else
            q->bandWidthT[i] = band_tab[i+1] - band_tab[i];
    }
    memset(q->bandFlagsBuf, 0, BANDS * sizeof(int));
    for(i = 0; i < BANDS-1; i++) {
        if (q->bandWidthT[i])
            q->bandFlagsBuf[i] = get_bits1(&q->gb);
    }

    imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5);

    bitscount = 0;
    /* first 4 bands will be assigned 5 bits per coefficient */
    if (stream_format_code & 0x2) {
        bitscount += 15;

        q->bitsBandT[0] = 5;
        q->CWlengthT[0] = 5;
        q->CWlengthT[1] = 5;
        q->CWlengthT[2] = 5;
        for(i = 1; i < 4; i++){
            bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5;
            q->bitsBandT[i] = bits;
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
                q->CWlengthT[j] = bits;
                bitscount += bits;
            }
        }
    }

    if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) {
        av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
        q->decoder_reset = 1;
        return -1;
    }

    for(i = 0; i < BANDS; i++) {
        q->sumLenArr[i] = 0;
        q->skipFlagRaw[i] = 0;
        for(j = band_tab[i]; j < band_tab[i+1]; j++)
            q->sumLenArr[i] += q->CWlengthT[j];
        if (q->bandFlagsBuf[i])
            if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0))
                q->skipFlagRaw[i] = 1;
    }

    imc_get_skip_coeff(q);

    for(i = 0; i < BANDS; i++) {
        q->flcoeffs6[i] = q->flcoeffs1[i];
        /* band has flag set and at least one coded coefficient */
        if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){
                q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] /
                                   q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])];
        }
    }

    /* calculate bits left, bits needed and adjust bit allocation */
    bits = summer = 0;

    for(i = 0; i < BANDS; i++) {
        if (q->bandFlagsBuf[i]) {
            for(j = band_tab[i]; j < band_tab[i+1]; j++) {
                if(q->skipFlags[j]) {
                    summer += q->CWlengthT[j];
                    q->CWlengthT[j] = 0;
                }
            }
            bits += q->skipFlagBits[i];
            summer -= q->skipFlagBits[i];
        }
    }
    imc_adjust_bit_allocation(q, summer);

    for(i = 0; i < BANDS; i++) {
        q->sumLenArr[i] = 0;

        for(j = band_tab[i]; j < band_tab[i+1]; j++)
            if (!q->skipFlags[j])
                q->sumLenArr[i] += q->CWlengthT[j];
    }

    memset(q->codewords, 0, sizeof(q->codewords));

    if(imc_get_coeffs(q) < 0) {
        av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
        q->decoder_reset = 1;
        return 0;
    }

    if(inverse_quant_coeff(q, stream_format_code) < 0) {
        av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
        q->decoder_reset = 1;
        return 0;
    }

    memset(q->skipFlags, 0, sizeof(q->skipFlags));

    imc_imdct256(q);

    q->dsp.float_to_int16(data, q->out_samples, COEFFS);

    *data_size = COEFFS * sizeof(int16_t);

806
    return IMC_BLOCK_SIZE;
Kostya Shishkov's avatar
Kostya Shishkov committed
807 808 809
}


810
static av_cold int imc_decode_close(AVCodecContext * avctx)
Kostya Shishkov's avatar
Kostya Shishkov committed
811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826
{
    IMCContext *q = avctx->priv_data;

    ff_fft_end(&q->fft);
    return 0;
}


AVCodec imc_decoder = {
    .name = "imc",
    .type = CODEC_TYPE_AUDIO,
    .id = CODEC_ID_IMC,
    .priv_data_size = sizeof(IMCContext),
    .init = imc_decode_init,
    .close = imc_decode_close,
    .decode = imc_decode_frame,
827
    .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
Kostya Shishkov's avatar
Kostya Shishkov committed
828
};