/src/opus/celt/quant_bands.c

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/* Copyright (c) 2007-2008 CSIRO
   Copyright (c) 2007-2009 Xiph.Org Foundation
   Written by Jean-Marc Valin */
/*
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.

   - Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
   OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "quant_bands.h"
#include "laplace.h"
#include <math.h>
#include "os_support.h"
#include "arch.h"
#include "mathops.h"
#include "stack_alloc.h"
#include "rate.h"

#ifdef FIXED_POINT
/* Mean energy in each band quantized in Q4 */
const signed char eMeans[25] = {
      103,100, 92, 85, 81,
       77, 72, 70, 78, 75,
       73, 71, 78, 74, 69,
       72, 70, 74, 76, 71,
       60, 60, 60, 60, 60
};
#else
/* Mean energy in each band quantized in Q4 and converted back to float */
const opus_val16 eMeans[25] = {
      6.437500f, 6.250000f, 5.750000f, 5.312500f, 5.062500f,
      4.812500f, 4.500000f, 4.375000f, 4.875000f, 4.687500f,
      4.562500f, 4.437500f, 4.875000f, 4.625000f, 4.312500f,
      4.500000f, 4.375000f, 4.625000f, 4.750000f, 4.437500f,
      3.750000f, 3.750000f, 3.750000f, 3.750000f, 3.750000f
};
#endif
/* prediction coefficients: 0.9, 0.8, 0.65, 0.5 */
#ifdef FIXED_POINT
static const opus_val16 pred_coef[4] = {29440, 26112, 21248, 16384};
static const opus_val16 beta_coef[4] = {30147, 22282, 12124, 6554};
static const opus_val16 beta_intra = 4915;
#else
static const opus_val16 pred_coef[4] = {29440/32768., 26112/32768., 21248/32768., 16384/32768.};
static const opus_val16 beta_coef[4] = {30147/32768., 22282/32768., 12124/32768., 6554/32768.};
static const opus_val16 beta_intra = 4915/32768.;
#endif

/*Parameters of the Laplace-like probability models used for the coarse energy.
  There is one pair of parameters for each frame size, prediction type
   (inter/intra), and band number.
  The first number of each pair is the probability of 0, and the second is the
   decay rate, both in Q8 precision.*/
static const unsigned char e_prob_model[4][2][42] = {
   /*120 sample frames.*/
   {
      /*Inter*/
      {
          72, 127,  65, 129,  66, 128,  65, 128,  64, 128,  62, 128,  64, 128,
          64, 128,  92,  78,  92,  79,  92,  78,  90,  79, 116,  41, 115,  40,
         114,  40, 132,  26, 132,  26, 145,  17, 161,  12, 176,  10, 177,  11
      },
      /*Intra*/
      {
          24, 179,  48, 138,  54, 135,  54, 132,  53, 134,  56, 133,  55, 132,
          55, 132,  61, 114,  70,  96,  74,  88,  75,  88,  87,  74,  89,  66,
          91,  67, 100,  59, 108,  50, 120,  40, 122,  37,  97,  43,  78,  50
      }
   },
   /*240 sample frames.*/
   {
      /*Inter*/
      {
          83,  78,  84,  81,  88,  75,  86,  74,  87,  71,  90,  73,  93,  74,
          93,  74, 109,  40, 114,  36, 117,  34, 117,  34, 143,  17, 145,  18,
         146,  19, 162,  12, 165,  10, 178,   7, 189,   6, 190,   8, 177,   9
      },
      /*Intra*/
      {
          23, 178,  54, 115,  63, 102,  66,  98,  69,  99,  74,  89,  71,  91,
          73,  91,  78,  89,  86,  80,  92,  66,  93,  64, 102,  59, 103,  60,
         104,  60, 117,  52, 123,  44, 138,  35, 133,  31,  97,  38,  77,  45
      }
   },
   /*480 sample frames.*/
   {
      /*Inter*/
      {
          61,  90,  93,  60, 105,  42, 107,  41, 110,  45, 116,  38, 113,  38,
         112,  38, 124,  26, 132,  27, 136,  19, 140,  20, 155,  14, 159,  16,
         158,  18, 170,  13, 177,  10, 187,   8, 192,   6, 175,   9, 159,  10
      },
      /*Intra*/
      {
          21, 178,  59, 110,  71,  86,  75,  85,  84,  83,  91,  66,  88,  73,
          87,  72,  92,  75,  98,  72, 105,  58, 107,  54, 115,  52, 114,  55,
         112,  56, 129,  51, 132,  40, 150,  33, 140,  29,  98,  35,  77,  42
      }
   },
   /*960 sample frames.*/
   {
      /*Inter*/
      {
          42, 121,  96,  66, 108,  43, 111,  40, 117,  44, 123,  32, 120,  36,
         119,  33, 127,  33, 134,  34, 139,  21, 147,  23, 152,  20, 158,  25,
         154,  26, 166,  21, 173,  16, 184,  13, 184,  10, 150,  13, 139,  15
      },
      /*Intra*/
      {
          22, 178,  63, 114,  74,  82,  84,  83,  92,  82, 103,  62,  96,  72,
          96,  67, 101,  73, 107,  72, 113,  55, 118,  52, 125,  52, 118,  52,
         117,  55, 135,  49, 137,  39, 157,  32, 145,  29,  97,  33,  77,  40
      }
   }
};

static const unsigned char small_energy_icdf[3]={2,1,0};

static opus_val32 loss_distortion(const celt_glog *eBands, celt_glog *oldEBands, int start, int end, int len, int C)
{
   int c, i;
   opus_val32 dist = 0;
   c=0; do {
      for (i=start;i<end;i++)
      {
         celt_glog d = PSHR32(SUB32(eBands[i+c*len], oldEBands[i+c*len]), DB_SHIFT-7);
         dist = MAC16_16(dist, d,d);
      }
   } while (++c<C);
   return MIN32(200,SHR32(dist,14));
}

static int quant_coarse_energy_impl(const CELTMode *m, int start, int end,
      const celt_glog *eBands, celt_glog *oldEBands,
      opus_int32 budget, opus_int32 tell,
      const unsigned char *prob_model, celt_glog *error, ec_enc *enc,
      int C, int LM, int intra, celt_glog max_decay, int lfe)
{
   int i, c;
   int badness = 0;
   opus_val32 prev[2] = {0,0};
   opus_val16 coef;
   opus_val16 beta;

   if (tell+3 <= budget)
      ec_enc_bit_logp(enc, intra, 3);
   if (intra)
   {
      coef = 0;
      beta = beta_intra;
   } else {
      beta = beta_coef[LM];
      coef = pred_coef[LM];
   }

   /* Encode at a fixed coarse resolution */
   for (i=start;i<end;i++)
   {
      c=0;
      do {
         int bits_left;
         int qi, qi0;
         opus_val32 q;
         celt_glog x;
         opus_val32 f, tmp;
         celt_glog oldE;
         celt_glog decay_bound;
         x = eBands[i+c*m->nbEBands];
         oldE = MAXG(-GCONST(9.f), oldEBands[i+c*m->nbEBands]);
#ifdef FIXED_POINT
         f = x - MULT16_32_Q15(coef,oldE) - prev[c];
         /* Rounding to nearest integer here is really important! */
         qi = (f+QCONST32(.5f,DB_SHIFT))>>DB_SHIFT;
         decay_bound = MAXG(-GCONST(28.f), SUB32((opus_val32)oldEBands[i+c*m->nbEBands],max_decay));
#else
         f = x-coef*oldE-prev[c];
         /* Rounding to nearest integer here is really important! */
         qi = (int)floor(.5f+f);
         decay_bound = MAXG(-GCONST(28.f), oldEBands[i+c*m->nbEBands]) - max_decay;
#endif
         /* Prevent the energy from going down too quickly (e.g. for bands
            that have just one bin) */
         if (qi < 0 && x < decay_bound)
         {
            qi += (int)SHR32(SUB32(decay_bound,x), DB_SHIFT);
            if (qi > 0)
               qi = 0;
         }
         qi0 = qi;
         /* If we don't have enough bits to encode all the energy, just assume
             something safe. */
         tell = ec_tell(enc);
         bits_left = budget-tell-3*C*(end-i);
         if (i!=start && bits_left < 30)
         {
            if (bits_left < 24)
               qi = IMIN(1, qi);
            if (bits_left < 16)
               qi = IMAX(-1, qi);
         }
         if (lfe && i>=2)
            qi = IMIN(qi, 0);
         if (budget-tell >= 15)
         {
            int pi;
            pi = 2*IMIN(i,20);
            ec_laplace_encode(enc, &qi,
                  prob_model[pi]<<7, prob_model[pi+1]<<6);
         }
         else if(budget-tell >= 2)
         {
            qi = IMAX(-1, IMIN(qi, 1));
            ec_enc_icdf(enc, 2*qi^-(qi<0), small_energy_icdf, 2);
         }
         else if(budget-tell >= 1)
         {
            qi = IMIN(0, qi);
            ec_enc_bit_logp(enc, -qi, 1);
         }
         else
            qi = -1;
         error[i+c*m->nbEBands] = f - SHL32(qi,DB_SHIFT);
         badness += abs(qi0-qi);
         q = (opus_val32)SHL32(EXTEND32(qi),DB_SHIFT);

         tmp = MULT16_32_Q15(coef,oldE) + prev[c] + q;
#ifdef FIXED_POINT
         tmp = MAX32(-GCONST(28.f), tmp);
#endif
         oldEBands[i+c*m->nbEBands] = tmp;
         prev[c] = prev[c] + q - MULT16_32_Q15(beta,q);
      } while (++c < C);
   }
   return lfe ? 0 : badness;
}

void quant_coarse_energy(const CELTMode *m, int start, int end, int effEnd,
      const celt_glog *eBands, celt_glog *oldEBands, opus_uint32 budget,
      celt_glog *error, ec_enc *enc, int C, int LM, int nbAvailableBytes,
      int force_intra, opus_val32 *delayedIntra, int two_pass, int loss_rate, int lfe)
{
   int intra;
   celt_glog max_decay;
   VARDECL(celt_glog, oldEBands_intra);
   VARDECL(celt_glog, error_intra);
   ec_enc enc_start_state;
   opus_uint32 tell;
   int badness1=0;
   opus_int32 intra_bias;
   opus_val32 new_distortion;
   SAVE_STACK;

   intra = force_intra || (!two_pass && *delayedIntra>2*C*(end-start) && nbAvailableBytes > (end-start)*C);
   intra_bias = (opus_int32)((budget**delayedIntra*loss_rate)/(C*512));
   new_distortion = loss_distortion(eBands, oldEBands, start, effEnd, m->nbEBands, C);

   tell = ec_tell(enc);
   if (tell+3 > budget)
      two_pass = intra = 0;

   max_decay = GCONST(16.f);
   if (end-start>10)
   {
#ifdef FIXED_POINT
      max_decay = SHL32(MIN32(SHR32(max_decay,DB_SHIFT-3), EXTEND32(nbAvailableBytes)),DB_SHIFT-3);
#else
      max_decay = MIN32(max_decay, .125f*nbAvailableBytes);
#endif
   }
   if (lfe)
      max_decay = GCONST(3.f);
   enc_start_state = *enc;

   ALLOC(oldEBands_intra, C*m->nbEBands, celt_glog);
   ALLOC(error_intra, C*m->nbEBands, celt_glog);
   OPUS_COPY(oldEBands_intra, oldEBands, C*m->nbEBands);

   if (two_pass || intra)
   {
      badness1 = quant_coarse_energy_impl(m, start, end, eBands, oldEBands_intra, budget,
            tell, e_prob_model[LM][1], error_intra, enc, C, LM, 1, max_decay, lfe);
   }

   if (!intra)
   {
      unsigned char *intra_buf;
      ec_enc enc_intra_state;
      opus_int32 tell_intra;
      opus_uint32 nstart_bytes;
      opus_uint32 nintra_bytes;
      opus_uint32 save_bytes;
      int badness2;
      VARDECL(unsigned char, intra_bits);

      tell_intra = ec_tell_frac(enc);

      enc_intra_state = *enc;

      nstart_bytes = ec_range_bytes(&enc_start_state);
      nintra_bytes = ec_range_bytes(&enc_intra_state);
      intra_buf = ec_get_buffer(&enc_intra_state) + nstart_bytes;
      save_bytes = nintra_bytes-nstart_bytes;
      if (save_bytes == 0)
         save_bytes = ALLOC_NONE;
      ALLOC(intra_bits, save_bytes, unsigned char);
      /* Copy bits from intra bit-stream */
      OPUS_COPY(intra_bits, intra_buf, nintra_bytes - nstart_bytes);

      *enc = enc_start_state;

      badness2 = quant_coarse_energy_impl(m, start, end, eBands, oldEBands, budget,
            tell, e_prob_model[LM][intra], error, enc, C, LM, 0, max_decay, lfe);

      if (two_pass && (badness1 < badness2 || (badness1 == badness2 && ((opus_int32)ec_tell_frac(enc))+intra_bias > tell_intra)))
      {
         *enc = enc_intra_state;
         /* Copy intra bits to bit-stream */
         OPUS_COPY(intra_buf, intra_bits, nintra_bytes - nstart_bytes);
         OPUS_COPY(oldEBands, oldEBands_intra, C*m->nbEBands);
         OPUS_COPY(error, error_intra, C*m->nbEBands);
         intra = 1;
      }
   } else {
      OPUS_COPY(oldEBands, oldEBands_intra, C*m->nbEBands);
      OPUS_COPY(error, error_intra, C*m->nbEBands);
   }

   if (intra)
      *delayedIntra = new_distortion;
   else
      *delayedIntra = ADD32(MULT16_32_Q15(MULT16_16_Q15(pred_coef[LM], pred_coef[LM]),*delayedIntra),
            new_distortion);

   RESTORE_STACK;
}

void quant_fine_energy(const CELTMode *m, int start, int end, celt_glog *oldEBands, celt_glog *error, int *prev_quant, int *extra_quant, ec_enc *enc, int C)
{
   int i, c;
   /* Encode finer resolution */
   for (i=start;i<end;i++)
   {
      opus_int16 extra, prev;
      extra = 1<<extra_quant[i];
      if (extra_quant[i] <= 0)
         continue;
      if (ec_tell(enc)+C*extra_quant[i] > (opus_int32)enc->storage*8) continue;
      prev = (prev_quant!=NULL) ? prev_quant[i] : 0;
      c=0;
      do {
         int q2;
         celt_glog offset;
#ifdef FIXED_POINT
         /* Has to be without rounding */
         q2 = VSHR32(ADD32(error[i+c*m->nbEBands], SHR32(GCONST(.5f), prev)), DB_SHIFT-extra_quant[i]-prev);
#else
         q2 = (int)floor((error[i+c*m->nbEBands]*(1<<prev)+.5f)*extra);
#endif
         if (q2 > extra-1)
            q2 = extra-1;
         if (q2<0)
            q2 = 0;
         ec_enc_bits(enc, q2, extra_quant[i]);
#ifdef FIXED_POINT
         offset = SUB32(VSHR32(2*q2+1, extra_quant[i]-DB_SHIFT+1), GCONST(.5f));
         offset = SHR32(offset, prev);
#else
         offset = (q2+.5f)*(1<<(14-extra_quant[i]))*(1.f/16384) - .5f;
         offset *= (1<<(14-prev))*(1.f/16384);
#endif
         oldEBands[i+c*m->nbEBands] += offset;
         error[i+c*m->nbEBands] -= offset;
         /*printf ("%f ", error[i] - offset);*/
      } while (++c < C);
   }
}

void quant_energy_finalise(const CELTMode *m, int start, int end, celt_glog *oldEBands, celt_glog *error, int *fine_quant, int *fine_priority, int bits_left, ec_enc *enc, int C)
{
   int i, prio, c;

   /* Use up the remaining bits */
   for (prio=0;prio<2;prio++)
   {
      for (i=start;i<end && bits_left>=C ;i++)
      {
         if (fine_quant[i] >= MAX_FINE_BITS || fine_priority[i]!=prio)
            continue;
         c=0;
         do {
            int q2;
            celt_glog offset;
            q2 = error[i+c*m->nbEBands]<0 ? 0 : 1;
            ec_enc_bits(enc, q2, 1);
#ifdef FIXED_POINT
            offset = SHR32(SHL32(q2,DB_SHIFT)-GCONST(.5f),fine_quant[i]+1);
#else
            offset = (q2-.5f)*(1<<(14-fine_quant[i]-1))*(1.f/16384);
#endif
            if (oldEBands != NULL) oldEBands[i+c*m->nbEBands] += offset;
            error[i+c*m->nbEBands] -= offset;
            bits_left--;
         } while (++c < C);
      }
   }
}

void unquant_coarse_energy(const CELTMode *m, int start, int end, celt_glog *oldEBands, int intra, ec_dec *dec, int C, int LM)
{
   const unsigned char *prob_model = e_prob_model[LM][intra];
   int i, c;
   opus_val64 prev[2] = {0, 0};
   opus_val16 coef;
   opus_val16 beta;
   opus_int32 budget;
   opus_int32 tell;

   if (intra)
   {
      coef = 0;
      beta = beta_intra;
   } else {
      beta = beta_coef[LM];
      coef = pred_coef[LM];
   }

   budget = dec->storage*8;

   /* Decode at a fixed coarse resolution */
   for (i=start;i<end;i++)
   {
      c=0;
      do {
         int qi;
         opus_val32 q;
         opus_val32 tmp;
         /* It would be better to express this invariant as a
            test on C at function entry, but that isn't enough
            to make the static analyzer happy. */
         celt_sig_assert(c<2);
         tell = ec_tell(dec);
         if(budget-tell>=15)
         {
            int pi;
            pi = 2*IMIN(i,20);
            qi = ec_laplace_decode(dec,
                  prob_model[pi]<<7, prob_model[pi+1]<<6);
         }
         else if(budget-tell>=2)
         {
            qi = ec_dec_icdf(dec, small_energy_icdf, 2);
            qi = (qi>>1)^-(qi&1);
         }
         else if(budget-tell>=1)
         {
            qi = -ec_dec_bit_logp(dec, 1);
         }
         else
            qi = -1;
         q = (opus_val32)SHL32(EXTEND32(qi),DB_SHIFT);

         oldEBands[i+c*m->nbEBands] = MAXG(-GCONST(9.f), oldEBands[i+c*m->nbEBands]);
         tmp = MULT16_32_Q15(coef,oldEBands[i+c*m->nbEBands]) + prev[c] + q;
#ifdef FIXED_POINT
         tmp = MIN32(GCONST(28.f), MAX32(-GCONST(28.f), tmp));
#endif
         oldEBands[i+c*m->nbEBands] = tmp;
         prev[c] = prev[c] + q - MULT16_32_Q15(beta,q);
      } while (++c < C);
   }
}

void unquant_fine_energy(const CELTMode *m, int start, int end, celt_glog *oldEBands, int *prev_quant, int *extra_quant, ec_dec *dec, int C)
{
   int i, c;
   /* Decode finer resolution */
   for (i=start;i<end;i++)
   {
      opus_int16 extra, prev;
      extra = extra_quant[i];
      if (extra_quant[i] <= 0)
         continue;
      if (ec_tell(dec)+C*extra_quant[i] > (opus_int32)dec->storage*8) continue;
      prev = (prev_quant!=NULL) ? prev_quant[i] : 0;
      c=0;
      do {
         int q2;
         celt_glog offset;
         q2 = ec_dec_bits(dec, extra);
#ifdef FIXED_POINT
         offset = SUB32(VSHR32(2*q2+1, extra-DB_SHIFT+1), GCONST(.5f));
         offset = SHR32(offset, prev);
#else
         offset = (q2+.5f)*(1<<(14-extra))*(1.f/16384) - .5f;
         offset *= (1<<(14-prev))*(1.f/16384);
#endif
         oldEBands[i+c*m->nbEBands] += offset;
      } while (++c < C);
   }
}

void unquant_energy_finalise(const CELTMode *m, int start, int end, celt_glog *oldEBands, int *fine_quant,  int *fine_priority, int bits_left, ec_dec *dec, int C)
{
   int i, prio, c;

   /* Use up the remaining bits */
   for (prio=0;prio<2;prio++)
   {
      for (i=start;i<end && bits_left>=C ;i++)
      {
         if (fine_quant[i] >= MAX_FINE_BITS || fine_priority[i]!=prio)
            continue;
         c=0;
         do {
            int q2;
            celt_glog offset;
            q2 = ec_dec_bits(dec, 1);
#ifdef FIXED_POINT
            offset = SHR32(SHL32(q2,DB_SHIFT)-GCONST(.5f),fine_quant[i]+1);
#else
            offset = (q2-.5f)*(1<<(14-fine_quant[i]-1))*(1.f/16384);
#endif
            if (oldEBands != NULL) oldEBands[i+c*m->nbEBands] += offset;
            bits_left--;
         } while (++c < C);
      }
   }
}

void amp2Log2(const CELTMode *m, int effEnd, int end,
      celt_ener *bandE, celt_glog *bandLogE, int C)
{
   int c, i;
   c=0;
   do {
      for (i=0;i<effEnd;i++)
      {
         bandLogE[i+c*m->nbEBands] =
               celt_log2_db(bandE[i+c*m->nbEBands])
               - SHL32((celt_glog)eMeans[i],DB_SHIFT-4);
#ifdef FIXED_POINT
         /* Compensate for bandE[] being Q12 but celt_log2() taking a Q14 input. */
         bandLogE[i+c*m->nbEBands] += GCONST(2.f);
#endif
      }
      for (i=effEnd;i<end;i++)
         bandLogE[c*m->nbEBands+i] = -GCONST(14.f);
   } while (++c < C);
}

Coverage Report

Created: 2025-08-26 07:18