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      1 /* Copyright (c) 2007-2008 CSIRO
      2    Copyright (c) 2007-2009 Xiph.Org Foundation
      3    Written by Jean-Marc Valin */
      4 /*
      5    Redistribution and use in source and binary forms, with or without
      6    modification, are permitted provided that the following conditions
      7    are met:
      8 
      9    - Redistributions of source code must retain the above copyright
     10    notice, this list of conditions and the following disclaimer.
     11 
     12    - Redistributions in binary form must reproduce the above copyright
     13    notice, this list of conditions and the following disclaimer in the
     14    documentation and/or other materials provided with the distribution.
     15 
     16    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
     20    OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     21    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     22    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     23    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     24    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     25    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     26    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 */
     28 
     29 #ifdef HAVE_CONFIG_H
     30 #include "config.h"
     31 #endif
     32 
     33 #include "quant_bands.h"
     34 #include "laplace.h"
     35 #include <math.h>
     36 #include "os_support.h"
     37 #include "arch.h"
     38 #include "mathops.h"
     39 #include "stack_alloc.h"
     40 #include "rate.h"
     41 
     42 #ifdef FIXED_POINT
     43 /* Mean energy in each band quantized in Q4 */
     44 const signed char eMeans[25] = {
     45       103,100, 92, 85, 81,
     46        77, 72, 70, 78, 75,
     47        73, 71, 78, 74, 69,
     48        72, 70, 74, 76, 71,
     49        60, 60, 60, 60, 60
     50 };
     51 #else
     52 /* Mean energy in each band quantized in Q4 and converted back to float */
     53 const opus_val16 eMeans[25] = {
     54       6.437500f, 6.250000f, 5.750000f, 5.312500f, 5.062500f,
     55       4.812500f, 4.500000f, 4.375000f, 4.875000f, 4.687500f,
     56       4.562500f, 4.437500f, 4.875000f, 4.625000f, 4.312500f,
     57       4.500000f, 4.375000f, 4.625000f, 4.750000f, 4.437500f,
     58       3.750000f, 3.750000f, 3.750000f, 3.750000f, 3.750000f
     59 };
     60 #endif
     61 /* prediction coefficients: 0.9, 0.8, 0.65, 0.5 */
     62 #ifdef FIXED_POINT
     63 static const opus_val16 pred_coef[4] = {29440, 26112, 21248, 16384};
     64 static const opus_val16 beta_coef[4] = {30147, 22282, 12124, 6554};
     65 static const opus_val16 beta_intra = 4915;
     66 #else
     67 static const opus_val16 pred_coef[4] = {29440/32768., 26112/32768., 21248/32768., 16384/32768.};
     68 static const opus_val16 beta_coef[4] = {30147/32768., 22282/32768., 12124/32768., 6554/32768.};
     69 static const opus_val16 beta_intra = 4915/32768.;
     70 #endif
     71 
     72 /*Parameters of the Laplace-like probability models used for the coarse energy.
     73   There is one pair of parameters for each frame size, prediction type
     74    (inter/intra), and band number.
     75   The first number of each pair is the probability of 0, and the second is the
     76    decay rate, both in Q8 precision.*/
     77 static const unsigned char e_prob_model[4][2][42] = {
     78    /*120 sample frames.*/
     79    {
     80       /*Inter*/
     81       {
     82           72, 127,  65, 129,  66, 128,  65, 128,  64, 128,  62, 128,  64, 128,
     83           64, 128,  92,  78,  92,  79,  92,  78,  90,  79, 116,  41, 115,  40,
     84          114,  40, 132,  26, 132,  26, 145,  17, 161,  12, 176,  10, 177,  11
     85       },
     86       /*Intra*/
     87       {
     88           24, 179,  48, 138,  54, 135,  54, 132,  53, 134,  56, 133,  55, 132,
     89           55, 132,  61, 114,  70,  96,  74,  88,  75,  88,  87,  74,  89,  66,
     90           91,  67, 100,  59, 108,  50, 120,  40, 122,  37,  97,  43,  78,  50
     91       }
     92    },
     93    /*240 sample frames.*/
     94    {
     95       /*Inter*/
     96       {
     97           83,  78,  84,  81,  88,  75,  86,  74,  87,  71,  90,  73,  93,  74,
     98           93,  74, 109,  40, 114,  36, 117,  34, 117,  34, 143,  17, 145,  18,
     99          146,  19, 162,  12, 165,  10, 178,   7, 189,   6, 190,   8, 177,   9
    100       },
    101       /*Intra*/
    102       {
    103           23, 178,  54, 115,  63, 102,  66,  98,  69,  99,  74,  89,  71,  91,
    104           73,  91,  78,  89,  86,  80,  92,  66,  93,  64, 102,  59, 103,  60,
    105          104,  60, 117,  52, 123,  44, 138,  35, 133,  31,  97,  38,  77,  45
    106       }
    107    },
    108    /*480 sample frames.*/
    109    {
    110       /*Inter*/
    111       {
    112           61,  90,  93,  60, 105,  42, 107,  41, 110,  45, 116,  38, 113,  38,
    113          112,  38, 124,  26, 132,  27, 136,  19, 140,  20, 155,  14, 159,  16,
    114          158,  18, 170,  13, 177,  10, 187,   8, 192,   6, 175,   9, 159,  10
    115       },
    116       /*Intra*/
    117       {
    118           21, 178,  59, 110,  71,  86,  75,  85,  84,  83,  91,  66,  88,  73,
    119           87,  72,  92,  75,  98,  72, 105,  58, 107,  54, 115,  52, 114,  55,
    120          112,  56, 129,  51, 132,  40, 150,  33, 140,  29,  98,  35,  77,  42
    121       }
    122    },
    123    /*960 sample frames.*/
    124    {
    125       /*Inter*/
    126       {
    127           42, 121,  96,  66, 108,  43, 111,  40, 117,  44, 123,  32, 120,  36,
    128          119,  33, 127,  33, 134,  34, 139,  21, 147,  23, 152,  20, 158,  25,
    129          154,  26, 166,  21, 173,  16, 184,  13, 184,  10, 150,  13, 139,  15
    130       },
    131       /*Intra*/
    132       {
    133           22, 178,  63, 114,  74,  82,  84,  83,  92,  82, 103,  62,  96,  72,
    134           96,  67, 101,  73, 107,  72, 113,  55, 118,  52, 125,  52, 118,  52,
    135          117,  55, 135,  49, 137,  39, 157,  32, 145,  29,  97,  33,  77,  40
    136       }
    137    }
    138 };
    139 
    140 static const unsigned char small_energy_icdf[3]={2,1,0};
    141 
    142 static opus_val32 loss_distortion(const opus_val16 *eBands, opus_val16 *oldEBands, int start, int end, int len, int C)
    143 {
    144    int c, i;
    145    opus_val32 dist = 0;
    146    c=0; do {
    147       for (i=start;i<end;i++)
    148       {
    149          opus_val16 d = SUB16(SHR16(eBands[i+c*len], 3), SHR16(oldEBands[i+c*len], 3));
    150          dist = MAC16_16(dist, d,d);
    151       }
    152    } while (++c<C);
    153    return MIN32(200,SHR32(dist,2*DB_SHIFT-6));
    154 }
    155 
    156 static int quant_coarse_energy_impl(const CELTMode *m, int start, int end,
    157       const opus_val16 *eBands, opus_val16 *oldEBands,
    158       opus_int32 budget, opus_int32 tell,
    159       const unsigned char *prob_model, opus_val16 *error, ec_enc *enc,
    160       int C, int LM, int intra, opus_val16 max_decay, int lfe)
    161 {
    162    int i, c;
    163    int badness = 0;
    164    opus_val32 prev[2] = {0,0};
    165    opus_val16 coef;
    166    opus_val16 beta;
    167 
    168    if (tell+3 <= budget)
    169       ec_enc_bit_logp(enc, intra, 3);
    170    if (intra)
    171    {
    172       coef = 0;
    173       beta = beta_intra;
    174    } else {
    175       beta = beta_coef[LM];
    176       coef = pred_coef[LM];
    177    }
    178 
    179    /* Encode at a fixed coarse resolution */
    180    for (i=start;i<end;i++)
    181    {
    182       c=0;
    183       do {
    184          int bits_left;
    185          int qi, qi0;
    186          opus_val32 q;
    187          opus_val16 x;
    188          opus_val32 f, tmp;
    189          opus_val16 oldE;
    190          opus_val16 decay_bound;
    191          x = eBands[i+c*m->nbEBands];
    192          oldE = MAX16(-QCONST16(9.f,DB_SHIFT), oldEBands[i+c*m->nbEBands]);
    193 #ifdef FIXED_POINT
    194          f = SHL32(EXTEND32(x),7) - PSHR32(MULT16_16(coef,oldE), 8) - prev[c];
    195          /* Rounding to nearest integer here is really important! */
    196          qi = (f+QCONST32(.5f,DB_SHIFT+7))>>(DB_SHIFT+7);
    197          decay_bound = EXTRACT16(MAX32(-QCONST16(28.f,DB_SHIFT),
    198                SUB32((opus_val32)oldEBands[i+c*m->nbEBands],max_decay)));
    199 #else
    200          f = x-coef*oldE-prev[c];
    201          /* Rounding to nearest integer here is really important! */
    202          qi = (int)floor(.5f+f);
    203          decay_bound = MAX16(-QCONST16(28.f,DB_SHIFT), oldEBands[i+c*m->nbEBands]) - max_decay;
    204 #endif
    205          /* Prevent the energy from going down too quickly (e.g. for bands
    206             that have just one bin) */
    207          if (qi < 0 && x < decay_bound)
    208          {
    209             qi += (int)SHR16(SUB16(decay_bound,x), DB_SHIFT);
    210             if (qi > 0)
    211                qi = 0;
    212          }
    213          qi0 = qi;
    214          /* If we don't have enough bits to encode all the energy, just assume
    215              something safe. */
    216          tell = ec_tell(enc);
    217          bits_left = budget-tell-3*C*(end-i);
    218          if (i!=start && bits_left < 30)
    219          {
    220             if (bits_left < 24)
    221                qi = IMIN(1, qi);
    222             if (bits_left < 16)
    223                qi = IMAX(-1, qi);
    224          }
    225          if (lfe && i>=2)
    226             qi = IMIN(qi, 0);
    227          if (budget-tell >= 15)
    228          {
    229             int pi;
    230             pi = 2*IMIN(i,20);
    231             ec_laplace_encode(enc, &qi,
    232                   prob_model[pi]<<7, prob_model[pi+1]<<6);
    233          }
    234          else if(budget-tell >= 2)
    235          {
    236             qi = IMAX(-1, IMIN(qi, 1));
    237             ec_enc_icdf(enc, 2*qi^-(qi<0), small_energy_icdf, 2);
    238          }
    239          else if(budget-tell >= 1)
    240          {
    241             qi = IMIN(0, qi);
    242             ec_enc_bit_logp(enc, -qi, 1);
    243          }
    244          else
    245             qi = -1;
    246          error[i+c*m->nbEBands] = PSHR32(f,7) - SHL16(qi,DB_SHIFT);
    247          badness += abs(qi0-qi);
    248          q = (opus_val32)SHL32(EXTEND32(qi),DB_SHIFT);
    249 
    250          tmp = PSHR32(MULT16_16(coef,oldE),8) + prev[c] + SHL32(q,7);
    251 #ifdef FIXED_POINT
    252          tmp = MAX32(-QCONST32(28.f, DB_SHIFT+7), tmp);
    253 #endif
    254          oldEBands[i+c*m->nbEBands] = PSHR32(tmp, 7);
    255          prev[c] = prev[c] + SHL32(q,7) - MULT16_16(beta,PSHR32(q,8));
    256       } while (++c < C);
    257    }
    258    return lfe ? 0 : badness;
    259 }
    260 
    261 void quant_coarse_energy(const CELTMode *m, int start, int end, int effEnd,
    262       const opus_val16 *eBands, opus_val16 *oldEBands, opus_uint32 budget,
    263       opus_val16 *error, ec_enc *enc, int C, int LM, int nbAvailableBytes,
    264       int force_intra, opus_val32 *delayedIntra, int two_pass, int loss_rate, int lfe)
    265 {
    266    int intra;
    267    opus_val16 max_decay;
    268    VARDECL(opus_val16, oldEBands_intra);
    269    VARDECL(opus_val16, error_intra);
    270    ec_enc enc_start_state;
    271    opus_uint32 tell;
    272    int badness1=0;
    273    opus_int32 intra_bias;
    274    opus_val32 new_distortion;
    275    SAVE_STACK;
    276 
    277    intra = force_intra || (!two_pass && *delayedIntra>2*C*(end-start) && nbAvailableBytes > (end-start)*C);
    278    intra_bias = (opus_int32)((budget**delayedIntra*loss_rate)/(C*512));
    279    new_distortion = loss_distortion(eBands, oldEBands, start, effEnd, m->nbEBands, C);
    280 
    281    tell = ec_tell(enc);
    282    if (tell+3 > budget)
    283       two_pass = intra = 0;
    284 
    285    max_decay = QCONST16(16.f,DB_SHIFT);
    286    if (end-start>10)
    287    {
    288 #ifdef FIXED_POINT
    289       max_decay = MIN32(max_decay, SHL32(EXTEND32(nbAvailableBytes),DB_SHIFT-3));
    290 #else
    291       max_decay = MIN32(max_decay, .125f*nbAvailableBytes);
    292 #endif
    293    }
    294    if (lfe)
    295       max_decay=3;
    296    enc_start_state = *enc;
    297 
    298    ALLOC(oldEBands_intra, C*m->nbEBands, opus_val16);
    299    ALLOC(error_intra, C*m->nbEBands, opus_val16);
    300    OPUS_COPY(oldEBands_intra, oldEBands, C*m->nbEBands);
    301 
    302    if (two_pass || intra)
    303    {
    304       badness1 = quant_coarse_energy_impl(m, start, end, eBands, oldEBands_intra, budget,
    305             tell, e_prob_model[LM][1], error_intra, enc, C, LM, 1, max_decay, lfe);
    306    }
    307 
    308    if (!intra)
    309    {
    310       unsigned char *intra_buf;
    311       ec_enc enc_intra_state;
    312       opus_int32 tell_intra;
    313       opus_uint32 nstart_bytes;
    314       opus_uint32 nintra_bytes;
    315       opus_uint32 save_bytes;
    316       int badness2;
    317       VARDECL(unsigned char, intra_bits);
    318 
    319       tell_intra = ec_tell_frac(enc);
    320 
    321       enc_intra_state = *enc;
    322 
    323       nstart_bytes = ec_range_bytes(&enc_start_state);
    324       nintra_bytes = ec_range_bytes(&enc_intra_state);
    325       intra_buf = ec_get_buffer(&enc_intra_state) + nstart_bytes;
    326       save_bytes = nintra_bytes-nstart_bytes;
    327       if (save_bytes == 0)
    328          save_bytes = ALLOC_NONE;
    329       ALLOC(intra_bits, save_bytes, unsigned char);
    330       /* Copy bits from intra bit-stream */
    331       OPUS_COPY(intra_bits, intra_buf, nintra_bytes - nstart_bytes);
    332 
    333       *enc = enc_start_state;
    334 
    335       badness2 = quant_coarse_energy_impl(m, start, end, eBands, oldEBands, budget,
    336             tell, e_prob_model[LM][intra], error, enc, C, LM, 0, max_decay, lfe);
    337 
    338       if (two_pass && (badness1 < badness2 || (badness1 == badness2 && ((opus_int32)ec_tell_frac(enc))+intra_bias > tell_intra)))
    339       {
    340          *enc = enc_intra_state;
    341          /* Copy intra bits to bit-stream */
    342          OPUS_COPY(intra_buf, intra_bits, nintra_bytes - nstart_bytes);
    343          OPUS_COPY(oldEBands, oldEBands_intra, C*m->nbEBands);
    344          OPUS_COPY(error, error_intra, C*m->nbEBands);
    345          intra = 1;
    346       }
    347    } else {
    348       OPUS_COPY(oldEBands, oldEBands_intra, C*m->nbEBands);
    349       OPUS_COPY(error, error_intra, C*m->nbEBands);
    350    }
    351 
    352    if (intra)
    353       *delayedIntra = new_distortion;
    354    else
    355       *delayedIntra = ADD32(MULT16_32_Q15(MULT16_16_Q15(pred_coef[LM], pred_coef[LM]),*delayedIntra),
    356             new_distortion);
    357 
    358    RESTORE_STACK;
    359 }
    360 
    361 void quant_fine_energy(const CELTMode *m, int start, int end, opus_val16 *oldEBands, opus_val16 *error, int *fine_quant, ec_enc *enc, int C)
    362 {
    363    int i, c;
    364 
    365    /* Encode finer resolution */
    366    for (i=start;i<end;i++)
    367    {
    368       opus_int16 frac = 1<<fine_quant[i];
    369       if (fine_quant[i] <= 0)
    370          continue;
    371       c=0;
    372       do {
    373          int q2;
    374          opus_val16 offset;
    375 #ifdef FIXED_POINT
    376          /* Has to be without rounding */
    377          q2 = (error[i+c*m->nbEBands]+QCONST16(.5f,DB_SHIFT))>>(DB_SHIFT-fine_quant[i]);
    378 #else
    379          q2 = (int)floor((error[i+c*m->nbEBands]+.5f)*frac);
    380 #endif
    381          if (q2 > frac-1)
    382             q2 = frac-1;
    383          if (q2<0)
    384             q2 = 0;
    385          ec_enc_bits(enc, q2, fine_quant[i]);
    386 #ifdef FIXED_POINT
    387          offset = SUB16(SHR32(SHL32(EXTEND32(q2),DB_SHIFT)+QCONST16(.5f,DB_SHIFT),fine_quant[i]),QCONST16(.5f,DB_SHIFT));
    388 #else
    389          offset = (q2+.5f)*(1<<(14-fine_quant[i]))*(1.f/16384) - .5f;
    390 #endif
    391          oldEBands[i+c*m->nbEBands] += offset;
    392          error[i+c*m->nbEBands] -= offset;
    393          /*printf ("%f ", error[i] - offset);*/
    394       } while (++c < C);
    395    }
    396 }
    397 
    398 void quant_energy_finalise(const CELTMode *m, int start, int end, opus_val16 *oldEBands, opus_val16 *error, int *fine_quant, int *fine_priority, int bits_left, ec_enc *enc, int C)
    399 {
    400    int i, prio, c;
    401 
    402    /* Use up the remaining bits */
    403    for (prio=0;prio<2;prio++)
    404    {
    405       for (i=start;i<end && bits_left>=C ;i++)
    406       {
    407          if (fine_quant[i] >= MAX_FINE_BITS || fine_priority[i]!=prio)
    408             continue;
    409          c=0;
    410          do {
    411             int q2;
    412             opus_val16 offset;
    413             q2 = error[i+c*m->nbEBands]<0 ? 0 : 1;
    414             ec_enc_bits(enc, q2, 1);
    415 #ifdef FIXED_POINT
    416             offset = SHR16(SHL16(q2,DB_SHIFT)-QCONST16(.5f,DB_SHIFT),fine_quant[i]+1);
    417 #else
    418             offset = (q2-.5f)*(1<<(14-fine_quant[i]-1))*(1.f/16384);
    419 #endif
    420             oldEBands[i+c*m->nbEBands] += offset;
    421             bits_left--;
    422          } while (++c < C);
    423       }
    424    }
    425 }
    426 
    427 void unquant_coarse_energy(const CELTMode *m, int start, int end, opus_val16 *oldEBands, int intra, ec_dec *dec, int C, int LM)
    428 {
    429    const unsigned char *prob_model = e_prob_model[LM][intra];
    430    int i, c;
    431    opus_val32 prev[2] = {0, 0};
    432    opus_val16 coef;
    433    opus_val16 beta;
    434    opus_int32 budget;
    435    opus_int32 tell;
    436 
    437    if (intra)
    438    {
    439       coef = 0;
    440       beta = beta_intra;
    441    } else {
    442       beta = beta_coef[LM];
    443       coef = pred_coef[LM];
    444    }
    445 
    446    budget = dec->storage*8;
    447 
    448    /* Decode at a fixed coarse resolution */
    449    for (i=start;i<end;i++)
    450    {
    451       c=0;
    452       do {
    453          int qi;
    454          opus_val32 q;
    455          opus_val32 tmp;
    456          /* It would be better to express this invariant as a
    457             test on C at function entry, but that isn't enough
    458             to make the static analyzer happy. */
    459          celt_assert(c<2);
    460          tell = ec_tell(dec);
    461          if(budget-tell>=15)
    462          {
    463             int pi;
    464             pi = 2*IMIN(i,20);
    465             qi = ec_laplace_decode(dec,
    466                   prob_model[pi]<<7, prob_model[pi+1]<<6);
    467          }
    468          else if(budget-tell>=2)
    469          {
    470             qi = ec_dec_icdf(dec, small_energy_icdf, 2);
    471             qi = (qi>>1)^-(qi&1);
    472          }
    473          else if(budget-tell>=1)
    474          {
    475             qi = -ec_dec_bit_logp(dec, 1);
    476          }
    477          else
    478             qi = -1;
    479          q = (opus_val32)SHL32(EXTEND32(qi),DB_SHIFT);
    480 
    481          oldEBands[i+c*m->nbEBands] = MAX16(-QCONST16(9.f,DB_SHIFT), oldEBands[i+c*m->nbEBands]);
    482          tmp = PSHR32(MULT16_16(coef,oldEBands[i+c*m->nbEBands]),8) + prev[c] + SHL32(q,7);
    483 #ifdef FIXED_POINT
    484          tmp = MAX32(-QCONST32(28.f, DB_SHIFT+7), tmp);
    485 #endif
    486          oldEBands[i+c*m->nbEBands] = PSHR32(tmp, 7);
    487          prev[c] = prev[c] + SHL32(q,7) - MULT16_16(beta,PSHR32(q,8));
    488       } while (++c < C);
    489    }
    490 }
    491 
    492 void unquant_fine_energy(const CELTMode *m, int start, int end, opus_val16 *oldEBands, int *fine_quant, ec_dec *dec, int C)
    493 {
    494    int i, c;
    495    /* Decode finer resolution */
    496    for (i=start;i<end;i++)
    497    {
    498       if (fine_quant[i] <= 0)
    499          continue;
    500       c=0;
    501       do {
    502          int q2;
    503          opus_val16 offset;
    504          q2 = ec_dec_bits(dec, fine_quant[i]);
    505 #ifdef FIXED_POINT
    506          offset = SUB16(SHR32(SHL32(EXTEND32(q2),DB_SHIFT)+QCONST16(.5f,DB_SHIFT),fine_quant[i]),QCONST16(.5f,DB_SHIFT));
    507 #else
    508          offset = (q2+.5f)*(1<<(14-fine_quant[i]))*(1.f/16384) - .5f;
    509 #endif
    510          oldEBands[i+c*m->nbEBands] += offset;
    511       } while (++c < C);
    512    }
    513 }
    514 
    515 void unquant_energy_finalise(const CELTMode *m, int start, int end, opus_val16 *oldEBands, int *fine_quant,  int *fine_priority, int bits_left, ec_dec *dec, int C)
    516 {
    517    int i, prio, c;
    518 
    519    /* Use up the remaining bits */
    520    for (prio=0;prio<2;prio++)
    521    {
    522       for (i=start;i<end && bits_left>=C ;i++)
    523       {
    524          if (fine_quant[i] >= MAX_FINE_BITS || fine_priority[i]!=prio)
    525             continue;
    526          c=0;
    527          do {
    528             int q2;
    529             opus_val16 offset;
    530             q2 = ec_dec_bits(dec, 1);
    531 #ifdef FIXED_POINT
    532             offset = SHR16(SHL16(q2,DB_SHIFT)-QCONST16(.5f,DB_SHIFT),fine_quant[i]+1);
    533 #else
    534             offset = (q2-.5f)*(1<<(14-fine_quant[i]-1))*(1.f/16384);
    535 #endif
    536             oldEBands[i+c*m->nbEBands] += offset;
    537             bits_left--;
    538          } while (++c < C);
    539       }
    540    }
    541 }
    542 
    543 void amp2Log2(const CELTMode *m, int effEnd, int end,
    544       celt_ener *bandE, opus_val16 *bandLogE, int C)
    545 {
    546    int c, i;
    547    c=0;
    548    do {
    549       for (i=0;i<effEnd;i++)
    550          bandLogE[i+c*m->nbEBands] =
    551                celt_log2(SHL32(bandE[i+c*m->nbEBands],2))
    552                - SHL16((opus_val16)eMeans[i],6);
    553       for (i=effEnd;i<end;i++)
    554          bandLogE[c*m->nbEBands+i] = -QCONST16(14.f,DB_SHIFT);
    555    } while (++c < C);
    556 }
    557