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parse.c

/*
 * parse.c
 * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
 *
 * This file is part of a52dec, a free ATSC A-52 stream decoder.
 * See http://liba52.sourceforge.net/ for updates.
 *
 * a52dec is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * a52dec 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include "a52.h"
#include "a52_internal.h"
#include "bitstream.h"
#include "tables.h"

#if defined(HAVE_MEMALIGN) && !defined(__cplusplus)
/* some systems have memalign() but no declaration for it */
void * memalign (size_t align, size_t size);
#else
/* assume malloc alignment is sufficient */
#define memalign(align,size) malloc (size)
#endif

typedef struct {
    quantizer_t q1[2];
    quantizer_t q2[2];
    quantizer_t q4;
    int q1_ptr;
    int q2_ptr;
    int q4_ptr;
} quantizer_set_t;

static uint8_t halfrate[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3};

a52_state_t * a52_init (uint32_t mm_accel)
{
    a52_state_t * state;
    int i;

    state = (a52_state_t *) malloc (sizeof (a52_state_t));
    if (state == NULL)
      return NULL;

    state->samples = (sample_t *) memalign (16, 256 * 12 * sizeof (sample_t));
    if (state->samples == NULL) {
      free (state);
      return NULL;
    }

    for (i = 0; i < 256 * 12; i++)
      state->samples[i] = 0;

    state->downmixed = 1;

    state->lfsr_state = 1;

    a52_imdct_init (mm_accel);

    return state;
}

sample_t * a52_samples (a52_state_t * state)
{
    return state->samples;
}

int a52_syncinfo (uint8_t * buf, int * flags,
              int * sample_rate, int * bit_rate)
{
    static int rate[] = { 32,  40,  48,  56,  64,  80,  96, 112,
                   128, 160, 192, 224, 256, 320, 384, 448,
                   512, 576, 640};
    static uint8_t lfeon[8] = {0x10, 0x10, 0x04, 0x04, 0x04, 0x01, 0x04, 0x01};
    int frmsizecod;
    int bitrate;
    int half;
    int acmod;

    if ((buf[0] != 0x0b) || (buf[1] != 0x77))   /* syncword */
      return 0;

    if (buf[5] >= 0x60)       /* bsid >= 12 */
      return 0;
    half = halfrate[buf[5] >> 3];

    /* acmod, dsurmod and lfeon */
    acmod = buf[6] >> 5;
    *flags = ((((buf[6] & 0xf8) == 0x50) ? A52_DOLBY : acmod) |
            ((buf[6] & lfeon[acmod]) ? A52_LFE : 0));

    frmsizecod = buf[4] & 63;
    if (frmsizecod >= 38)
      return 0;
    bitrate = rate [frmsizecod >> 1];
    *bit_rate = (bitrate * 1000) >> half;

    switch (buf[4] & 0xc0) {
    case 0:
      *sample_rate = 48000 >> half;
      return 4 * bitrate;
    case 0x40:
      *sample_rate = 44100 >> half;
      return 2 * (320 * bitrate / 147 + (frmsizecod & 1));
    case 0x80:
      *sample_rate = 32000 >> half;
      return 6 * bitrate;
    default:
      return 0;
    }
}

int a52_frame (a52_state_t * state, uint8_t * buf, int * flags,
             level_t * level, sample_t bias)
{
    static level_t clev[4] = { LEVEL (LEVEL_3DB), LEVEL (LEVEL_45DB),
                         LEVEL (LEVEL_6DB), LEVEL (LEVEL_45DB) };
    static level_t slev[4] = { LEVEL (LEVEL_3DB), LEVEL (LEVEL_6DB),
                         0,                 LEVEL (LEVEL_6DB) };
    int chaninfo;
    int acmod;

    state->fscod = buf[4] >> 6;
    state->halfrate = halfrate[buf[5] >> 3];
    state->acmod = acmod = buf[6] >> 5;

    a52_bitstream_set_ptr (state, buf + 6);
    bitstream_get (state, 3); /* skip acmod we already parsed */

    if ((acmod == 2) && (bitstream_get (state, 2) == 2))    /* dsurmod */
      acmod = A52_DOLBY;

    state->clev = state->slev = 0;

    if ((acmod & 1) && (acmod != 1))
      state->clev = clev[bitstream_get (state, 2)];   /* cmixlev */

    if (acmod & 4)
      state->slev = slev[bitstream_get (state, 2)];   /* surmixlev */

    state->lfeon = bitstream_get (state, 1);

    state->output = a52_downmix_init (acmod, *flags, level,
                              state->clev, state->slev);
    if (state->output < 0)
      return 1;
    if (state->lfeon && (*flags & A52_LFE))
      state->output |= A52_LFE;
    *flags = state->output;
    /* the 2* compensates for differences in imdct */
    state->dynrng = state->level = MUL_C (*level, 2);
    state->bias = bias;
    state->dynrnge = 1;
    state->dynrngcall = NULL;
    state->cplba.deltbae = DELTA_BIT_NONE;
    state->ba[0].deltbae = state->ba[1].deltbae = state->ba[2].deltbae =
      state->ba[3].deltbae = state->ba[4].deltbae = DELTA_BIT_NONE;

    chaninfo = !acmod;
    do {
      bitstream_get (state, 5);     /* dialnorm */
      if (bitstream_get (state, 1)) /* compre */
          bitstream_get (state, 8); /* compr */
      if (bitstream_get (state, 1)) /* langcode */
          bitstream_get (state, 8); /* langcod */
      if (bitstream_get (state, 1)) /* audprodie */
          bitstream_get (state, 7); /* mixlevel + roomtyp */
    } while (chaninfo--);

    bitstream_get (state, 2);       /* copyrightb + origbs */

    if (bitstream_get (state, 1))   /* timecod1e */
      bitstream_get (state, 14);    /* timecod1 */
    if (bitstream_get (state, 1))   /* timecod2e */
      bitstream_get (state, 14);    /* timecod2 */

    if (bitstream_get (state, 1)) { /* addbsie */
      int addbsil;

      addbsil = bitstream_get (state, 6);
      do {
          bitstream_get (state, 8); /* addbsi */
      } while (addbsil--);
    }

    return 0;
}

void a52_dynrng (a52_state_t * state,
             level_t (* call) (level_t, void *), void * data)
{
    state->dynrnge = 0;
    if (call) {
      state->dynrnge = 1;
      state->dynrngcall = call;
      state->dynrngdata = data;
    }
}

static int parse_exponents (a52_state_t * state, int expstr, int ngrps,
                      uint8_t exponent, uint8_t * dest)
{
    int exps;

    while (ngrps--) {
      exps = bitstream_get (state, 7);

      exponent += exp_1[exps];
      if (exponent > 24)
          return 1;

      switch (expstr) {
      case EXP_D45:
          *(dest++) = exponent;
          *(dest++) = exponent;
      case EXP_D25:
          *(dest++) = exponent;
      case EXP_D15:
          *(dest++) = exponent;
      }

      exponent += exp_2[exps];
      if (exponent > 24)
          return 1;

      switch (expstr) {
      case EXP_D45:
          *(dest++) = exponent;
          *(dest++) = exponent;
      case EXP_D25:
          *(dest++) = exponent;
      case EXP_D15:
          *(dest++) = exponent;
      }

      exponent += exp_3[exps];
      if (exponent > 24)
          return 1;

      switch (expstr) {
      case EXP_D45:
          *(dest++) = exponent;
          *(dest++) = exponent;
      case EXP_D25:
          *(dest++) = exponent;
      case EXP_D15:
          *(dest++) = exponent;
      }
    }

    return 0;
}

static int parse_deltba (a52_state_t * state, int8_t * deltba)
{
    int deltnseg, deltlen, delta, j;

    memset (deltba, 0, 50);

    deltnseg = bitstream_get (state, 3);
    j = 0;
    do {
      j += bitstream_get (state, 5);
      deltlen = bitstream_get (state, 4);
      delta = bitstream_get (state, 3);
      delta -= (delta >= 4) ? 3 : 4;
      if (!deltlen)
          continue;
      if (j + deltlen >= 50)
          return 1;
      while (deltlen--)
          deltba[j++] = delta;
    } while (deltnseg--);

    return 0;
}

static inline int zero_snr_offsets (int nfchans, a52_state_t * state)
{
    int i;

    if ((state->csnroffst) ||
      (state->chincpl && state->cplba.bai >> 3) ||    /* cplinu, fsnroffst */
      (state->lfeon && state->lfeba.bai >> 3))  /* fsnroffst */
      return 0;
    for (i = 0; i < nfchans; i++)
      if (state->ba[i].bai >> 3)                /* fsnroffst */
          return 0;
    return 1;
}

static inline int16_t dither_gen (a52_state_t * state)
{
    int16_t nstate;

    nstate = dither_lut[state->lfsr_state >> 8] ^ (state->lfsr_state << 8);

    state->lfsr_state = (uint16_t) nstate;

    return (3 * nstate) >> 2;
}

#ifndef LIBA52_FIXED
#define COEFF(c,t,l,s,e) (c) = (t) * (s)[e]
#else
#define COEFF(c,_t,_l,s,e) do {                             \
    quantizer_t t = (_t);                             \
    level_t l = (_l);                                 \
    int shift = e - 5;                                \
    sample_t tmp = t * (l >> 16) + ((t * (l & 0xffff)) >> 16);    \
    if (shift >= 0)                                   \
      (c) = tmp >> shift;                             \
    else                                        \
      (c) = tmp << -shift;                            \
} while (0)
#endif

static void coeff_get (a52_state_t * state, sample_t * coeff,
                   expbap_t * expbap, quantizer_set_t * quant,
                   level_t level, int dither, int end)
{
    int i;
    uint8_t * exp;
    int8_t * bap;

#ifndef LIBA52_FIXED
    sample_t factor[25];

    for (i = 0; i <= 24; i++)
      factor[i] = scale_factor[i] * level;
#endif

    exp = expbap->exp;
    bap = expbap->bap;

    for (i = 0; i < end; i++) {
      int bapi;

      bapi = bap[i];
      switch (bapi) {
      case 0:
          if (dither) {
            COEFF (coeff[i], dither_gen (state), level, factor, exp[i]);
            continue;
          } else {
            coeff[i] = 0;
            continue;
          }

      case -1:
          if (quant->q1_ptr >= 0) {
            COEFF (coeff[i], quant->q1[quant->q1_ptr--], level,
                   factor, exp[i]);
            continue;
          } else {
            int code;

            code = bitstream_get (state, 5);

            quant->q1_ptr = 1;
            quant->q1[0] = q_1_2[code];
            quant->q1[1] = q_1_1[code];
            COEFF (coeff[i], q_1_0[code], level, factor, exp[i]);
            continue;
          }

      case -2:
          if (quant->q2_ptr >= 0) {
            COEFF (coeff[i], quant->q2[quant->q2_ptr--], level,
                   factor, exp[i]);
            continue;
          } else {
            int code;

            code = bitstream_get (state, 7);

            quant->q2_ptr = 1;
            quant->q2[0] = q_2_2[code];
            quant->q2[1] = q_2_1[code];
            COEFF (coeff[i], q_2_0[code], level, factor, exp[i]);
            continue;
          }

      case 3:
          COEFF (coeff[i], q_3[bitstream_get (state, 3)], level,
               factor, exp[i]);
          continue;

      case -3:
          if (quant->q4_ptr == 0) {
            quant->q4_ptr = -1;
            COEFF (coeff[i], quant->q4, level, factor, exp[i]);
            continue;
          } else {
            int code;

            code = bitstream_get (state, 7);

            quant->q4_ptr = 0;
            quant->q4 = q_4_1[code];
            COEFF (coeff[i], q_4_0[code], level, factor, exp[i]);
            continue;
          }

      case 4:
          COEFF (coeff[i], q_5[bitstream_get (state, 4)], level,
               factor, exp[i]);
          continue;

      default:
          COEFF (coeff[i], bitstream_get_2 (state, bapi) << (16 - bapi),
               level, factor, exp[i]);
      }
    }
}

static void coeff_get_coupling (a52_state_t * state, int nfchans,
                        level_t * coeff, sample_t (* samples)[256],
                        quantizer_set_t * quant, uint8_t dithflag[5])
{
    int cplbndstrc, bnd, i, i_end, ch;
    uint8_t * exp;
    int8_t * bap;
    level_t cplco[5];

    exp = state->cpl_expbap.exp;
    bap = state->cpl_expbap.bap;
    bnd = 0;
    cplbndstrc = state->cplbndstrc;
    i = state->cplstrtmant;
    while (i < state->cplendmant) {
      i_end = i + 12;
      while (cplbndstrc & 1) {
          cplbndstrc >>= 1;
          i_end += 12;
      }
      cplbndstrc >>= 1;
      for (ch = 0; ch < nfchans; ch++)
          cplco[ch] = MUL_L (state->cplco[ch][bnd], coeff[ch]);
      bnd++;

      while (i < i_end) {
          quantizer_t cplcoeff;
          int bapi;

          bapi = bap[i];
          switch (bapi) {
          case 0:
            for (ch = 0; ch < nfchans; ch++)
                if ((state->chincpl >> ch) & 1) {
                  if (dithflag[ch])
#ifndef LIBA52_FIXED
                      samples[ch][i] = (scale_factor[exp[i]] *
                                    cplco[ch] * dither_gen (state));
#else
                      COEFF (samples[ch][i], dither_gen (state),
                           cplco[ch], scale_factor, exp[i]);
#endif
                  else
                      samples[ch][i] = 0;
                }
            i++;
            continue;

          case -1:
            if (quant->q1_ptr >= 0) {
                cplcoeff = quant->q1[quant->q1_ptr--];
                break;
            } else {
                int code;

                code = bitstream_get (state, 5);

                quant->q1_ptr = 1;
                quant->q1[0] = q_1_2[code];
                quant->q1[1] = q_1_1[code];
                cplcoeff = q_1_0[code];
                break;
            }

          case -2:
            if (quant->q2_ptr >= 0) {
                cplcoeff = quant->q2[quant->q2_ptr--];
                break;
            } else {
                int code;

                code = bitstream_get (state, 7);

                quant->q2_ptr = 1;
                quant->q2[0] = q_2_2[code];
                quant->q2[1] = q_2_1[code];
                cplcoeff = q_2_0[code];
                break;
            }

          case 3:
            cplcoeff = q_3[bitstream_get (state, 3)];
            break;

          case -3:
            if (quant->q4_ptr == 0) {
                quant->q4_ptr = -1;
                cplcoeff = quant->q4;
                break;
            } else {
                int code;

                code = bitstream_get (state, 7);

                quant->q4_ptr = 0;
                quant->q4 = q_4_1[code];
                cplcoeff = q_4_0[code];
                break;
            }

          case 4:
            cplcoeff = q_5[bitstream_get (state, 4)];
            break;

          default:
            cplcoeff = bitstream_get_2 (state, bapi) << (16 - bapi);
          }
#ifndef LIBA52_FIXED
          cplcoeff *= scale_factor[exp[i]];
#endif
          for (ch = 0; ch < nfchans; ch++)
             if ((state->chincpl >> ch) & 1)
#ifndef LIBA52_FIXED
                samples[ch][i] = cplcoeff * cplco[ch];
#else
                COEFF (samples[ch][i], cplcoeff, cplco[ch],
                     scale_factor, exp[i]);
#endif
          i++;
      }
    }
}

int a52_block (a52_state_t * state)
{
    static const uint8_t nfchans_tbl[] = {2, 1, 2, 3, 3, 4, 4, 5, 1, 1, 2};
    static int rematrix_band[4] = {25, 37, 61, 253};
    int i, nfchans, chaninfo;
    uint8_t cplexpstr, chexpstr[5], lfeexpstr, do_bit_alloc, done_cpl;
    uint8_t blksw[5], dithflag[5];
    level_t coeff[5];
    int chanbias;
    quantizer_set_t quant;
    sample_t * samples;

    nfchans = nfchans_tbl[state->acmod];

    for (i = 0; i < nfchans; i++)
      blksw[i] = bitstream_get (state, 1);

    for (i = 0; i < nfchans; i++)
      dithflag[i] = bitstream_get (state, 1);

    chaninfo = !state->acmod;
    do {
      if (bitstream_get (state, 1)) {     /* dynrnge */
          int dynrng;

          dynrng = bitstream_get_2 (state, 8);
          if (state->dynrnge) {
            level_t range;

#if !defined(LIBA52_FIXED)
            range = ((((dynrng & 0x1f) | 0x20) << 13) *
                   scale_factor[3 - (dynrng >> 5)]);
#else
            range = ((dynrng & 0x1f) | 0x20) << (21 + (dynrng >> 5));
#endif
            if (state->dynrngcall)
                range = state->dynrngcall (range, state->dynrngdata);
            state->dynrng = MUL_L (state->level, range);
          }
      }
    } while (chaninfo--);

    if (bitstream_get (state, 1)) { /* cplstre */
      state->chincpl = 0;
      if (bitstream_get (state, 1)) {     /* cplinu */
          static uint8_t bndtab[16] = {31, 35, 37, 39, 41, 42, 43, 44,
                               45, 45, 46, 46, 47, 47, 48, 48};
          int cplbegf;
          int cplendf;
          int ncplsubnd;

          for (i = 0; i < nfchans; i++)
            state->chincpl |= bitstream_get (state, 1) << i;
          switch (state->acmod) {
          case 0: case 1:
            return 1;
          case 2:
            state->phsflginu = bitstream_get (state, 1);
          }
          cplbegf = bitstream_get (state, 4);
          cplendf = bitstream_get (state, 4);

          if (cplendf + 3 - cplbegf < 0)
            return 1;
          state->ncplbnd = ncplsubnd = cplendf + 3 - cplbegf;
          state->cplstrtbnd = bndtab[cplbegf];
          state->cplstrtmant = cplbegf * 12 + 37;
          state->cplendmant = cplendf * 12 + 73;

          state->cplbndstrc = 0;
          for (i = 0; i < ncplsubnd - 1; i++)
            if (bitstream_get (state, 1)) {
                state->cplbndstrc |= 1 << i;
                state->ncplbnd--;
            }
      }
    }

    if (state->chincpl) {     /* cplinu */
      int j, cplcoe;

      cplcoe = 0;
      for (i = 0; i < nfchans; i++)
          if ((state->chincpl) >> i & 1)
            if (bitstream_get (state, 1)) {     /* cplcoe */
                int mstrcplco, cplcoexp, cplcomant;

                cplcoe = 1;
                mstrcplco = 3 * bitstream_get (state, 2);
                for (j = 0; j < state->ncplbnd; j++) {
                  cplcoexp = bitstream_get (state, 4);
                  cplcomant = bitstream_get (state, 4);
                  if (cplcoexp == 15)
                      cplcomant <<= 14;
                  else
                      cplcomant = (cplcomant | 0x10) << 13;
#ifndef LIBA52_FIXED
                  state->cplco[i][j] =
                      cplcomant * scale_factor[cplcoexp + mstrcplco];
#else
                  state->cplco[i][j] = (cplcomant << 11) >> (cplcoexp + mstrcplco);
#endif

                }
            }
      if ((state->acmod == 2) && state->phsflginu && cplcoe)
          for (j = 0; j < state->ncplbnd; j++)
            if (bitstream_get (state, 1)) /* phsflg */
                state->cplco[1][j] = -state->cplco[1][j];
    }

    if ((state->acmod == 2) && (bitstream_get (state, 1))) {      /* rematstr */
      int end;

      state->rematflg = 0;
      end = (state->chincpl) ? state->cplstrtmant : 253;    /* cplinu */
      i = 0;
      do
          state->rematflg |= bitstream_get (state, 1) << i;
      while (rematrix_band[i++] < end);
    }

    cplexpstr = EXP_REUSE;
    lfeexpstr = EXP_REUSE;
    if (state->chincpl) /* cplinu */
      cplexpstr = bitstream_get (state, 2);
    for (i = 0; i < nfchans; i++)
      chexpstr[i] = bitstream_get (state, 2);
    if (state->lfeon)
      lfeexpstr = bitstream_get (state, 1);

    for (i = 0; i < nfchans; i++)
      if (chexpstr[i] != EXP_REUSE) {
          if ((state->chincpl >> i) & 1)
            state->endmant[i] = state->cplstrtmant;
          else {
            int chbwcod;

            chbwcod = bitstream_get (state, 6);
            if (chbwcod > 60)
                return 1;
            state->endmant[i] = chbwcod * 3 + 73;
          }
      }

    do_bit_alloc = 0;

    if (cplexpstr != EXP_REUSE) {
      int cplabsexp, ncplgrps;

      do_bit_alloc = 64;
      ncplgrps = ((state->cplendmant - state->cplstrtmant) /
                (3 << (cplexpstr - 1)));
      cplabsexp = bitstream_get (state, 4) << 1;
      if (parse_exponents (state, cplexpstr, ncplgrps, cplabsexp,
                       state->cpl_expbap.exp + state->cplstrtmant))
          return 1;
    }
    for (i = 0; i < nfchans; i++)
      if (chexpstr[i] != EXP_REUSE) {
          int grp_size, nchgrps;

          do_bit_alloc |= 1 << i;
          grp_size = 3 << (chexpstr[i] - 1);
          nchgrps = (state->endmant[i] + grp_size - 4) / grp_size;
          state->fbw_expbap[i].exp[0] = bitstream_get (state, 4);
          if (parse_exponents (state, chexpstr[i], nchgrps,
                         state->fbw_expbap[i].exp[0],
                         state->fbw_expbap[i].exp + 1))
            return 1;
          bitstream_get (state, 2); /* gainrng */
      }
    if (lfeexpstr != EXP_REUSE) {
      do_bit_alloc |= 32;
      state->lfe_expbap.exp[0] = bitstream_get (state, 4);
      if (parse_exponents (state, lfeexpstr, 2, state->lfe_expbap.exp[0],
                       state->lfe_expbap.exp + 1))
          return 1;
    }

    if (bitstream_get (state, 1)) { /* baie */
      do_bit_alloc = 127;
      state->bai = bitstream_get (state, 11);
    }
    if (bitstream_get (state, 1)) { /* snroffste */
      do_bit_alloc = 127;
      state->csnroffst = bitstream_get (state, 6);
      if (state->chincpl)     /* cplinu */
          state->cplba.bai = bitstream_get (state, 7);
      for (i = 0; i < nfchans; i++)
          state->ba[i].bai = bitstream_get (state, 7);
      if (state->lfeon)
          state->lfeba.bai = bitstream_get (state, 7);
    }
    if ((state->chincpl) && (bitstream_get (state, 1))) { /* cplleake */
      do_bit_alloc |= 64;
      state->cplfleak = 9 - bitstream_get (state, 3);
      state->cplsleak = 9 - bitstream_get (state, 3);
    }

    if (bitstream_get (state, 1)) { /* deltbaie */
      do_bit_alloc = 127;
      if (state->chincpl)     /* cplinu */
          state->cplba.deltbae = bitstream_get (state, 2);
      for (i = 0; i < nfchans; i++)
          state->ba[i].deltbae = bitstream_get (state, 2);
      if (state->chincpl &&   /* cplinu */
          (state->cplba.deltbae == DELTA_BIT_NEW) &&
          parse_deltba (state, state->cplba.deltba))
          return 1;
      for (i = 0; i < nfchans; i++)
          if ((state->ba[i].deltbae == DELTA_BIT_NEW) &&
            parse_deltba (state, state->ba[i].deltba))
            return 1;
    }

    if (do_bit_alloc) {
      if (zero_snr_offsets (nfchans, state)) {
          memset (state->cpl_expbap.bap, 0, sizeof (state->cpl_expbap.bap));
          for (i = 0; i < nfchans; i++)
            memset (state->fbw_expbap[i].bap, 0,
                  sizeof (state->fbw_expbap[i].bap));
          memset (state->lfe_expbap.bap, 0, sizeof (state->lfe_expbap.bap));
      } else {
          if (state->chincpl && (do_bit_alloc & 64))  /* cplinu */
            a52_bit_allocate (state, &state->cplba, state->cplstrtbnd,
                          state->cplstrtmant, state->cplendmant,
                          state->cplfleak << 8, state->cplsleak << 8,
                          &state->cpl_expbap);
          for (i = 0; i < nfchans; i++)
            if (do_bit_alloc & (1 << i))
                a52_bit_allocate (state, state->ba + i, 0, 0,
                              state->endmant[i], 0, 0,
                              state->fbw_expbap +i);
          if (state->lfeon && (do_bit_alloc & 32)) {
            state->lfeba.deltbae = DELTA_BIT_NONE;
            a52_bit_allocate (state, &state->lfeba, 0, 0, 7, 0, 0,
                          &state->lfe_expbap);
          }
      }
    }

    if (bitstream_get (state, 1)) { /* skiple */
      i = bitstream_get (state, 9); /* skipl */
      while (i--)
          bitstream_get (state, 8);
    }

    samples = state->samples;
    if (state->output & A52_LFE)
      samples += 256;   /* shift for LFE channel */

    chanbias = a52_downmix_coeff (coeff, state->acmod, state->output,
                          state->dynrng, state->clev, state->slev);

    quant.q1_ptr = quant.q2_ptr = quant.q4_ptr = -1;
    done_cpl = 0;

    for (i = 0; i < nfchans; i++) {
      int j;

      coeff_get (state, samples + 256 * i, state->fbw_expbap +i, &quant,
               coeff[i], dithflag[i], state->endmant[i]);

      if ((state->chincpl >> i) & 1) {
          if (!done_cpl) {
            done_cpl = 1;
            coeff_get_coupling (state, nfchans, coeff,
                            (sample_t (*)[256])samples, &quant,
                            dithflag);
          }
          j = state->cplendmant;
      } else
          j = state->endmant[i];
      do
          (samples + 256 * i)[j] = 0;
      while (++j < 256);
    }

    if (state->acmod == 2) {
      int j, end, band, rematflg;

      end = ((state->endmant[0] < state->endmant[1]) ?
             state->endmant[0] : state->endmant[1]);

      i = 0;
      j = 13;
      rematflg = state->rematflg;
      do {
          if (! (rematflg & 1)) {
            rematflg >>= 1;
            j = rematrix_band[i++];
            continue;
          }
          rematflg >>= 1;
          band = rematrix_band[i++];
          if (band > end)
            band = end;
          do {
            sample_t tmp0, tmp1;

            tmp0 = samples[j];
            tmp1 = (samples+256)[j];
            samples[j] = tmp0 + tmp1;
            (samples+256)[j] = tmp0 - tmp1;
          } while (++j < band);
      } while (j < end);
    }

    if (state->lfeon) {
      if (state->output & A52_LFE) {
          coeff_get (state, samples - 256, &state->lfe_expbap, &quant,
                   state->dynrng, 0, 7);
          for (i = 7; i < 256; i++)
            (samples-256)[i] = 0;
          a52_imdct_512 (samples - 256, samples + 1536 - 256, state->bias);
      } else {
          /* just skip the LFE coefficients */
          coeff_get (state, samples + 1280, &state->lfe_expbap, &quant,
                   0, 0, 7);
      }
    }

    i = 0;
    if (nfchans_tbl[state->output & A52_CHANNEL_MASK] < nfchans)
      for (i = 1; i < nfchans; i++)
          if (blksw[i] != blksw[0])
            break;

    if (i < nfchans) {
      if (state->downmixed) {
          state->downmixed = 0;
          a52_upmix (samples + 1536, state->acmod, state->output);
      }

      for (i = 0; i < nfchans; i++) {
          sample_t bias;

          bias = 0;
          if (!(chanbias & (1 << i)))
            bias = state->bias;

          if (coeff[i]) {
            if (blksw[i])
                a52_imdct_256 (samples + 256 * i, samples + 1536 + 256 * i,
                           bias);
            else
                a52_imdct_512 (samples + 256 * i, samples + 1536 + 256 * i,
                           bias);
          } else {
            int j;

            for (j = 0; j < 256; j++)
                (samples + 256 * i)[j] = bias;
          }
      }

      a52_downmix (samples, state->acmod, state->output, state->bias,
                 state->clev, state->slev);
    } else {
      nfchans = nfchans_tbl[state->output & A52_CHANNEL_MASK];

      a52_downmix (samples, state->acmod, state->output, 0,
                 state->clev, state->slev);

      if (!state->downmixed) {
          state->downmixed = 1;
          a52_downmix (samples + 1536, state->acmod, state->output, 0,
                   state->clev, state->slev);
      }

      if (blksw[0])
          for (i = 0; i < nfchans; i++)
            a52_imdct_256 (samples + 256 * i, samples + 1536 + 256 * i,
                         state->bias);
      else
          for (i = 0; i < nfchans; i++)
            a52_imdct_512 (samples + 256 * i, samples + 1536 + 256 * i,
                         state->bias);
    }

    return 0;
}

void a52_free (a52_state_t * state)
{
    free (state->samples);
    free (state);
}

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