celt/celt_encoder.c

/* Copyright (c) 2007-2008 CSIRO
   Copyright (c) 2007-2010 Xiph.Org Foundation
   Copyright (c) 2008 Gregory Maxwell
   Written by Jean-Marc Valin and Gregory Maxwell */
/*
   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

#define CELT_ENCODER_C

#include "cpu_support.h"
#include "os_support.h"
#include "mdct.h"
#include <math.h>
#include "celt.h"
#include "pitch.h"
#include "bands.h"
#include "modes.h"
#include "entcode.h"
#include "quant_bands.h"
#include "rate.h"
#include "stack_alloc.h"
#include "mathops.h"
#include "float_cast.h"
#include <stdarg.h>
#include "celt_lpc.h"
#include "vq.h"


/** Encoder state
 @brief Encoder state
 */
struct OpusCustomEncoder {
   const OpusCustomMode *mode;     /**< Mode used by the encoder */
   int overlap;
   int channels;
   int stream_channels;

   int force_intra;
   int clip;
   int disable_pf;
   int complexity;
   int upsample;
   int start, end;

   opus_int32 bitrate;
   int vbr;
   int signalling;
   int constrained_vbr;      /* If zero, VBR can do whatever it likes with the rate */
   int loss_rate;
   int lsb_depth;
   int variable_duration;
   int lfe;
   int arch;

   /* Everything beyond this point gets cleared on a reset */
#define ENCODER_RESET_START rng

   opus_uint32 rng;
   int spread_decision;
   opus_val32 delayedIntra;
   int tonal_average;
   int lastCodedBands;
   int hf_average;
   int tapset_decision;

   int prefilter_period;
   opus_val16 prefilter_gain;
   int prefilter_tapset;
#ifdef RESYNTH
   int prefilter_period_old;
   opus_val16 prefilter_gain_old;
   int prefilter_tapset_old;
#endif
   int consec_transient;
   AnalysisInfo analysis;

   opus_val32 preemph_memE[2];
   opus_val32 preemph_memD[2];

   /* VBR-related parameters */
   opus_int32 vbr_reservoir;
   opus_int32 vbr_drift;
   opus_int32 vbr_offset;
   opus_int32 vbr_count;
   opus_val32 overlap_max;
   opus_val16 stereo_saving;
   int intensity;
   opus_val16 *energy_mask;
   opus_val16 spec_avg;

#ifdef RESYNTH
   /* +MAX_PERIOD/2 to make space for overlap */
   celt_sig syn_mem[2][2*MAX_PERIOD+MAX_PERIOD/2];
#endif

   celt_sig in_mem[1]; /* Size = channels*mode->overlap */
   /* celt_sig prefilter_mem[],  Size = channels*COMBFILTER_MAXPERIOD */
   /* opus_val16 oldBandE[],     Size = channels*mode->nbEBands */
   /* opus_val16 oldLogE[],      Size = channels*mode->nbEBands */
   /* opus_val16 oldLogE2[],     Size = channels*mode->nbEBands */
};

int celt_encoder_get_size(int channels)
{
   CELTMode *mode = opus_custom_mode_create(48000, 960, NULL);
   return opus_custom_encoder_get_size(mode, channels);
}

OPUS_CUSTOM_NOSTATIC int opus_custom_encoder_get_size(const CELTMode *mode, int channels)
{
   int size = sizeof(struct CELTEncoder)
         + (channels*mode->overlap-1)*sizeof(celt_sig)    /* celt_sig in_mem[channels*mode->overlap]; */
         + channels*COMBFILTER_MAXPERIOD*sizeof(celt_sig) /* celt_sig prefilter_mem[channels*COMBFILTER_MAXPERIOD]; */
         + 3*channels*mode->nbEBands*sizeof(opus_val16);  /* opus_val16 oldBandE[channels*mode->nbEBands]; */
                                                          /* opus_val16 oldLogE[channels*mode->nbEBands]; */
                                                          /* opus_val16 oldLogE2[channels*mode->nbEBands]; */
   return size;
}

#ifdef CUSTOM_MODES
CELTEncoder *opus_custom_encoder_create(const CELTMode *mode, int channels, int *error)
{
   int ret;
   CELTEncoder *st = (CELTEncoder *)opus_alloc(opus_custom_encoder_get_size(mode, channels));
   /* init will handle the NULL case */
   ret = opus_custom_encoder_init(st, mode, channels);
   if (ret != OPUS_OK)
   {
      opus_custom_encoder_destroy(st);
      st = NULL;
   }
   if (error)
      *error = ret;
   return st;
}
#endif /* CUSTOM_MODES */

int celt_encoder_init(CELTEncoder *st, opus_int32 sampling_rate, int channels)
{
   int ret;
   ret = opus_custom_encoder_init(st, opus_custom_mode_create(48000, 960, NULL), channels);
   if (ret != OPUS_OK)
      return ret;
   st->upsample = resampling_factor(sampling_rate);
   return OPUS_OK;
}

OPUS_CUSTOM_NOSTATIC int opus_custom_encoder_init(CELTEncoder *st, const CELTMode *mode, int channels)
{
   if (channels < 0 || channels > 2)
      return OPUS_BAD_ARG;

   if (st==NULL || mode==NULL)
      return OPUS_ALLOC_FAIL;

   OPUS_CLEAR((char*)st, opus_custom_encoder_get_size(mode, channels));

   st->mode = mode;
   st->overlap = mode->overlap;
   st->stream_channels = st->channels = channels;

   st->upsample = 1;
   st->start = 0;
   st->end = st->mode->effEBands;
   st->signalling = 1;

   st->arch = opus_select_arch();

   st->constrained_vbr = 1;
   st->clip = 1;

   st->bitrate = OPUS_BITRATE_MAX;
   st->vbr = 0;
   st->force_intra  = 0;
   st->complexity = 5;
   st->lsb_depth=24;

   opus_custom_encoder_ctl(st, OPUS_RESET_STATE);

   return OPUS_OK;
}

#ifdef CUSTOM_MODES
void opus_custom_encoder_destroy(CELTEncoder *st)
{
   opus_free(st);
}
#endif /* CUSTOM_MODES */


static int transient_analysis(const opus_val32 * OPUS_RESTRICT in, int len, int C,
                              opus_val16 *tf_estimate, int *tf_chan)
{
   int i;
   VARDECL(opus_val16, tmp);
   opus_val32 mem0,mem1;
   int is_transient = 0;
   opus_int32 mask_metric = 0;
   int c;
   opus_val16 tf_max;
   int len2;
   /* Table of 6*64/x, trained on real data to minimize the average error */
   static const unsigned char inv_table[128] = {
         255,255,156,110, 86, 70, 59, 51, 45, 40, 37, 33, 31, 28, 26, 25,
          23, 22, 21, 20, 19, 18, 17, 16, 16, 15, 15, 14, 13, 13, 12, 12,
          12, 12, 11, 11, 11, 10, 10, 10,  9,  9,  9,  9,  9,  9,  8,  8,
           8,  8,  8,  7,  7,  7,  7,  7,  7,  6,  6,  6,  6,  6,  6,  6,
           6,  6,  6,  6,  6,  6,  6,  6,  6,  5,  5,  5,  5,  5,  5,  5,
           5,  5,  5,  5,  5,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,
           4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  3,  3,
           3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  3,  2,
   };
   SAVE_STACK;
   ALLOC(tmp, len, opus_val16);

   len2=len/2;
   for (c=0;c<C;c++)
   {
      opus_val32 mean;
      opus_int32 unmask=0;
      opus_val32 norm;
      opus_val16 maxE;
      mem0=0;
      mem1=0;
      /* High-pass filter: (1 - 2*z^-1 + z^-2) / (1 - z^-1 + .5*z^-2) */
      for (i=0;i<len;i++)
      {
         opus_val32 x,y;
         x = SHR32(in[i+c*len],SIG_SHIFT);
         y = ADD32(mem0, x);
#ifdef FIXED_POINT
         mem0 = mem1 + y - SHL32(x,1);
         mem1 = x - SHR32(y,1);
#else
         mem0 = mem1 + y - 2*x;
         mem1 = x - .5f*y;
#endif
         tmp[i] = EXTRACT16(SHR32(y,2));
         /*printf("%f ", tmp[i]);*/
      }
      /*printf("\n");*/
      /* First few samples are bad because we don't propagate the memory */
      for (i=0;i<12;i++)
         tmp[i] = 0;

#ifdef FIXED_POINT
      /* Normalize tmp to max range */
      {
         int shift=0;
         shift = 14-celt_ilog2(1+celt_maxabs16(tmp, len));
         if (shift!=0)
         {
            for (i=0;i<len;i++)
               tmp[i] = SHL16(tmp[i], shift);
         }
      }
#endif

      mean=0;
      mem0=0;
      /* Grouping by two to reduce complexity */
      /* Forward pass to compute the post-echo threshold*/
      for (i=0;i<len2;i++)
      {
         opus_val16 x2 = PSHR32(MULT16_16(tmp[2*i],tmp[2*i]) + MULT16_16(tmp[2*i+1],tmp[2*i+1]),16);
         mean += x2;
#ifdef FIXED_POINT
         /* FIXME: Use PSHR16() instead */
         tmp[i] = mem0 + PSHR32(x2-mem0,4);
#else
         tmp[i] = mem0 + MULT16_16_P15(QCONST16(.0625f,15),x2-mem0);
#endif
         mem0 = tmp[i];
      }

      mem0=0;
      maxE=0;
      /* Backward pass to compute the pre-echo threshold */
      for (i=len2-1;i>=0;i--)
      {
#ifdef FIXED_POINT
         /* FIXME: Use PSHR16() instead */
         tmp[i] = mem0 + PSHR32(tmp[i]-mem0,3);
#else
         tmp[i] = mem0 + MULT16_16_P15(QCONST16(0.125f,15),tmp[i]-mem0);
#endif
         mem0 = tmp[i];
         maxE = MAX16(maxE, mem0);
      }
      /*for (i=0;i<len2;i++)printf("%f ", tmp[i]/mean);printf("\n");*/

      /* Compute the ratio of the "frame energy" over the harmonic mean of the energy.
         This essentially corresponds to a bitrate-normalized temporal noise-to-mask
         ratio */

      /* As a compromise with the old transient detector, frame energy is the
         geometric mean of the energy and half the max */
#ifdef FIXED_POINT
      /* Costs two sqrt() to avoid overflows */
      mean = MULT16_16(celt_sqrt(mean), celt_sqrt(MULT16_16(maxE,len2>>1)));
#else
      mean = celt_sqrt(mean * maxE*.5*len2);
#endif
      /* Inverse of the mean energy in Q15+6 */
      norm = SHL32(EXTEND32(len2),6+14)/ADD32(EPSILON,SHR32(mean,1));
      /* Compute harmonic mean discarding the unreliable boundaries
         The data is smooth, so we only take 1/4th of the samples */
      unmask=0;
      for (i=12;i<len2-5;i+=4)
      {
         int id;
#ifdef FIXED_POINT
         id = IMAX(0,IMIN(127,MULT16_32_Q15(tmp[i],norm))); /* Do not round to nearest */
#else
         id = IMAX(0,IMIN(127,(int)floor(64*norm*tmp[i]))); /* Do not round to nearest */
#endif
         unmask += inv_table[id];
      }
      /*printf("%d\n", unmask);*/
      /* Normalize, compensate for the 1/4th of the sample and the factor of 6 in the inverse table */
      unmask = 64*unmask*4/(6*(len2-17));
      if (unmask>mask_metric)
      {
         *tf_chan = c;
         mask_metric = unmask;
      }
   }
   is_transient = mask_metric>200;

   /* Arbitrary metric for VBR boost */
   tf_max = MAX16(0,celt_sqrt(27*mask_metric)-42);
   /* *tf_estimate = 1 + MIN16(1, sqrt(MAX16(0, tf_max-30))/20); */
   *tf_estimate = celt_sqrt(MAX16(0, SHL32(MULT16_16(QCONST16(0.0069,14),MIN16(163,tf_max)),14)-QCONST32(0.139,28)));
   /*printf("%d %f\n", tf_max, mask_metric);*/
   RESTORE_STACK;
#ifdef FUZZING
   is_transient = rand()&0x1;
#endif
   /*printf("%d %f %d\n", is_transient, (float)*tf_estimate, tf_max);*/
   return is_transient;
}

/* Looks for sudden increases of energy to decide whether we need to patch
   the transient decision */
int patch_transient_decision(opus_val16 *newE, opus_val16 *oldE, int nbEBands,
      int end, int C)
{
   int i, c;
   opus_val32 mean_diff=0;
   opus_val16 spread_old[26];
   /* Apply an aggressive (-6 dB/Bark) spreading function to the old frame to
      avoid false detection caused by irrelevant bands */
   if (C==1)
   {
      spread_old[0] = oldE[0];
      for (i=1;i<end;i++)
         spread_old[i] = MAX16(spread_old[i-1]-QCONST16(1.0f, DB_SHIFT), oldE[i]);
   } else {
      spread_old[0] = MAX16(oldE[0],oldE[nbEBands]);
      for (i=1;i<end;i++)
         spread_old[i] = MAX16(spread_old[i-1]-QCONST16(1.0f, DB_SHIFT),
                               MAX16(oldE[i],oldE[i+nbEBands]));
   }
   for (i=end-2;i>=0;i--)
      spread_old[i] = MAX16(spread_old[i], spread_old[i+1]-QCONST16(1.0f, DB_SHIFT));
   /* Compute mean increase */
   c=0; do {
      for (i=2;i<end-1;i++)
      {
         opus_val16 x1, x2;
         x1 = MAX16(0, newE[i]);
         x2 = MAX16(0, spread_old[i]);
         mean_diff = ADD32(mean_diff, EXTEND32(MAX16(0, SUB16(x1, x2))));
      }
   } while (++c<C);
   mean_diff = DIV32(mean_diff, C*(end-3));
   /*printf("%f %f %d\n", mean_diff, max_diff, count);*/
   return mean_diff > QCONST16(1.f, DB_SHIFT);
}

/** Apply window and compute the MDCT for all sub-frames and
    all channels in a frame */
static void compute_mdcts(const CELTMode *mode, int shortBlocks, celt_sig * OPUS_RESTRICT in,
                          celt_sig * OPUS_RESTRICT out, int C, int CC, int LM, int upsample)
{
   const int overlap = OVERLAP(mode);
   int N;
   int B;
   int shift;
   int i, b, c;
   if (shortBlocks)
   {
      B = shortBlocks;
      N = mode->shortMdctSize;
      shift = mode->maxLM;
   } else {
      B = 1;
      N = mode->shortMdctSize<<LM;
      shift = mode->maxLM-LM;
   }
   c=0; do {
      for (b=0;b<B;b++)
      {
         /* Interleaving the sub-frames while doing the MDCTs */
         clt_mdct_forward(&mode->mdct, in+c*(B*N+overlap)+b*N, &out[b+c*N*B], mode->window, overlap, shift, B);
      }
   } while (++c<CC);
   if (CC==2&&C==1)
   {
      for (i=0;i<B*N;i++)
         out[i] = ADD32(HALF32(out[i]), HALF32(out[B*N+i]));
   }
   if (upsample != 1)
   {
      c=0; do
      {
         int bound = B*N/upsample;
         for (i=0;i<bound;i++)
            out[c*B*N+i] *= upsample;
         for (;i<B*N;i++)
            out[c*B*N+i] = 0;
      } while (++c<C);
   }
}


void preemphasis(const opus_val16 * OPUS_RESTRICT pcmp, celt_sig * OPUS_RESTRICT inp,
                        int N, int CC, int upsample, const opus_val16 *coef, celt_sig *mem, int clip)
{
   int i;
   opus_val16 coef0;
   celt_sig m;
   int Nu;

   coef0 = coef[0];


   Nu = N/upsample;
   if (upsample!=1)
   {
      for (i=0;i<N;i++)
         inp[i] = 0;
   }
   for (i=0;i<Nu;i++)
   {
      celt_sig x;

      x = SCALEIN(pcmp[CC*i]);
#ifndef FIXED_POINT
      /* Replace NaNs with zeros */
      if (!(x==x))
         x = 0;
#endif
      inp[i*upsample] = x;
   }

#ifndef FIXED_POINT
   if (clip)
   {
      /* Clip input to avoid encoding non-portable files */
      for (i=0;i<Nu;i++)
         inp[i*upsample] = MAX32(-65536.f, MIN32(65536.f,inp[i*upsample]));
   }
#endif
   m = *mem;
#ifdef CUSTOM_MODES
   if (coef[1] != 0)
   {
      opus_val16 coef1 = coef[1];
      opus_val16 coef2 = coef[2];
      for (i=0;i<N;i++)
      {
         opus_val16 x, tmp;
         x = inp[i];
         /* Apply pre-emphasis */
         tmp = MULT16_16(coef2, x);
         inp[i] = tmp + m;
         m = MULT16_32_Q15(coef1, inp[i]) - MULT16_32_Q15(coef0, tmp);
      }
   } else
#endif
   {
      for (i=0;i<N;i++)
      {
         celt_sig x;
         x = SHL32(inp[i], SIG_SHIFT);
         /* Apply pre-emphasis */
         inp[i] = x + m;
         m = - MULT16_32_Q15(coef0, x);
      }
   }
   *mem = m;
}



static opus_val32 l1_metric(const celt_norm *tmp, int N, int LM, opus_val16 bias)
{
   int i;
   opus_val32 L1;
   L1 = 0;
   for (i=0;i<N;i++)
      L1 += EXTEND32(ABS16(tmp[i]));
   /* When in doubt, prefer good freq resolution */
   L1 = MAC16_32_Q15(L1, LM*bias, L1);
   return L1;

}

static int tf_analysis(const CELTMode *m, int len, int isTransient,
      int *tf_res, int lambda, celt_norm *X, int N0, int LM,
      int *tf_sum, opus_val16 tf_estimate, int tf_chan)
{
   int i;
   VARDECL(int, metric);
   int cost0;
   int cost1;
   VARDECL(int, path0);
   VARDECL(int, path1);
   VARDECL(celt_norm, tmp);
   VARDECL(celt_norm, tmp_1);
   int sel;
   int selcost[2];
   int tf_select=0;
   opus_val16 bias;

   SAVE_STACK;
   bias = MULT16_16_Q14(QCONST16(.04f,15), MAX16(-QCONST16(.25f,14), QCONST16(.5f,14)-tf_estimate));
   /*printf("%f ", bias);*/

   ALLOC(metric, len, int);
   ALLOC(tmp, (m->eBands[len]-m->eBands[len-1])<<LM, celt_norm);
   ALLOC(tmp_1, (m->eBands[len]-m->eBands[len-1])<<LM, celt_norm);
   ALLOC(path0, len, int);
   ALLOC(path1, len, int);

   *tf_sum = 0;
   for (i=0;i<len;i++)
   {
      int j, k, N;
      int narrow;
      opus_val32 L1, best_L1;
      int best_level=0;
      N = (m->eBands[i+1]-m->eBands[i])<<LM;
      /* band is too narrow to be split down to LM=-1 */
      narrow = (m->eBands[i+1]-m->eBands[i])==1;
      for (j=0;j<N;j++)
         tmp[j] = X[tf_chan*N0 + j+(m->eBands[i]<<LM)];
      /* Just add the right channel if we're in stereo */
      /*if (C==2)
         for (j=0;j<N;j++)
            tmp[j] = ADD16(SHR16(tmp[j], 1),SHR16(X[N0+j+(m->eBands[i]<<LM)], 1));*/
      L1 = l1_metric(tmp, N, isTransient ? LM : 0, bias);
      best_L1 = L1;
      /* Check the -1 case for transients */
      if (isTransient && !narrow)
      {
         for (j=0;j<N;j++)
            tmp_1[j] = tmp[j];
         haar1(tmp_1, N>>LM, 1<<LM);
         L1 = l1_metric(tmp_1, N, LM+1, bias);
         if (L1<best_L1)
         {
            best_L1 = L1;
            best_level = -1;
         }
      }
      /*printf ("%f ", L1);*/
      for (k=0;k<LM+!(isTransient||narrow);k++)
      {
         int B;

         if (isTransient)
            B = (LM-k-1);
         else
            B = k+1;

         haar1(tmp, N>>k, 1<<k);

         L1 = l1_metric(tmp, N, B, bias);

         if (L1 < best_L1)
         {
            best_L1 = L1;
            best_level = k+1;
         }
      }
      /*printf ("%d ", isTransient ? LM-best_level : best_level);*/
      /* metric is in Q1 to be able to select the mid-point (-0.5) for narrower bands */
      if (isTransient)
         metric[i] = 2*best_level;
      else
         metric[i] = -2*best_level;
      *tf_sum += (isTransient ? LM : 0) - metric[i]/2;
      /* For bands that can't be split to -1, set the metric to the half-way point to avoid
         biasing the decision */
      if (narrow && (metric[i]==0 || metric[i]==-2*LM))
         metric[i]-=1;
      /*printf("%d ", metric[i]);*/
   }
   /*printf("\n");*/
   /* Search for the optimal tf resolution, including tf_select */
   tf_select = 0;
   for (sel=0;sel<2;sel++)
   {
      cost0 = 0;
      cost1 = isTransient ? 0 : lambda;
      for (i=1;i<len;i++)
      {
         int curr0, curr1;
         curr0 = IMIN(cost0, cost1 + lambda);
         curr1 = IMIN(cost0 + lambda, cost1);
         cost0 = curr0 + abs(metric[i]-2*tf_select_table[LM][4*isTransient+2*sel+0]);
         cost1 = curr1 + abs(metric[i]-2*tf_select_table[LM][4*isTransient+2*sel+1]);
      }
      cost0 = IMIN(cost0, cost1);
      selcost[sel]=cost0;
   }
   /* For now, we're conservative and only allow tf_select=1 for transients.
    * If tests confirm it's useful for non-transients, we could allow it. */
   if (selcost[1]<selcost[0] && isTransient)
      tf_select=1;
   cost0 = 0;
   cost1 = isTransient ? 0 : lambda;
   /* Viterbi forward pass */
   for (i=1;i<len;i++)
   {
      int curr0, curr1;
      int from0, from1;

      from0 = cost0;
      from1 = cost1 + lambda;
      if (from0 < from1)
      {
         curr0 = from0;
         path0[i]= 0;
      } else {
         curr0 = from1;
         path0[i]= 1;
      }

      from0 = cost0 + lambda;
      from1 = cost1;
      if (from0 < from1)
      {
         curr1 = from0;
         path1[i]= 0;
      } else {
         curr1 = from1;
         path1[i]= 1;
      }
      cost0 = curr0 + abs(metric[i]-2*tf_select_table[LM][4*isTransient+2*tf_select+0]);
      cost1 = curr1 + abs(metric[i]-2*tf_select_table[LM][4*isTransient+2*tf_select+1]);
   }
   tf_res[len-1] = cost0 < cost1 ? 0 : 1;
   /* Viterbi backward pass to check the decisions */
   for (i=len-2;i>=0;i--)
   {
      if (tf_res[i+1] == 1)
         tf_res[i] = path1[i+1];
      else
         tf_res[i] = path0[i+1];
   }
   /*printf("%d %f\n", *tf_sum, tf_estimate);*/
   RESTORE_STACK;
#ifdef FUZZING
   tf_select = rand()&0x1;
   tf_res[0] = rand()&0x1;
   for (i=1;i<len;i++)
      tf_res[i] = tf_res[i-1] ^ ((rand()&0xF) == 0);
#endif
   return tf_select;
}

static void tf_encode(int start, int end, int isTransient, int *tf_res, int LM, int tf_select, ec_enc *enc)
{
   int curr, i;
   int tf_select_rsv;
   int tf_changed;
   int logp;
   opus_uint32 budget;
   opus_uint32 tell;
   budget = enc->storage*8;
   tell = ec_tell(enc);
   logp = isTransient ? 2 : 4;
   /* Reserve space to code the tf_select decision. */
   tf_select_rsv = LM>0 && tell+logp+1 <= budget;
   budget -= tf_select_rsv;
   curr = tf_changed = 0;
   for (i=start;i<end;i++)
   {
      if (tell+logp<=budget)
      {
         ec_enc_bit_logp(enc, tf_res[i] ^ curr, logp);
         tell = ec_tell(enc);
         curr = tf_res[i];
         tf_changed |= curr;
      }
      else
         tf_res[i] = curr;
      logp = isTransient ? 4 : 5;
   }
   /* Only code tf_select if it would actually make a difference. */
   if (tf_select_rsv &&
         tf_select_table[LM][4*isTransient+0+tf_changed]!=
         tf_select_table[LM][4*isTransient+2+tf_changed])
      ec_enc_bit_logp(enc, tf_select, 1);
   else
      tf_select = 0;
   for (i=start;i<end;i++)
      tf_res[i] = tf_select_table[LM][4*isTransient+2*tf_select+tf_res[i]];
   /*for(i=0;i<end;i++)printf("%d ", isTransient ? tf_res[i] : LM+tf_res[i]);printf("\n");*/
}


static int alloc_trim_analysis(const CELTMode *m, const celt_norm *X,
      const opus_val16 *bandLogE, int end, int LM, int C, int N0,
      AnalysisInfo *analysis, opus_val16 *stereo_saving, opus_val16 tf_estimate,
      int intensity, opus_val16 surround_trim)
{
   int i;
   opus_val32 diff=0;
   int c;
   int trim_index = 5;
   opus_val16 trim = QCONST16(5.f, 8);
   opus_val16 logXC, logXC2;
   if (C==2)
   {
      opus_val16 sum = 0; /* Q10 */
      opus_val16 minXC; /* Q10 */
      /* Compute inter-channel correlation for low frequencies */
      for (i=0;i<8;i++)
      {
         int j;
         opus_val32 partial = 0;
         for (j=m->eBands[i]<<LM;j<m->eBands[i+1]<<LM;j++)
            partial = MAC16_16(partial, X[j], X[N0+j]);
         sum = ADD16(sum, EXTRACT16(SHR32(partial, 18)));
      }
      sum = MULT16_16_Q15(QCONST16(1.f/8, 15), sum);
      sum = MIN16(QCONST16(1.f, 10), ABS16(sum));
      minXC = sum;
      for (i=8;i<intensity;i++)
      {
         int j;
         opus_val32 partial = 0;
         for (j=m->eBands[i]<<LM;j<m->eBands[i+1]<<LM;j++)
            partial = MAC16_16(partial, X[j], X[N0+j]);
         minXC = MIN16(minXC, ABS16(EXTRACT16(SHR32(partial, 18))));
      }
      minXC = MIN16(QCONST16(1.f, 10), ABS16(minXC));
      /*printf ("%f\n", sum);*/
      if (sum > QCONST16(.995f,10))
         trim_index-=4;
      else if (sum > QCONST16(.92f,10))
         trim_index-=3;
      else if (sum > QCONST16(.85f,10))
         trim_index-=2;
      else if (sum > QCONST16(.8f,10))
         trim_index-=1;
      /* mid-side savings estimations based on the LF average*/
      logXC = celt_log2(QCONST32(1.001f, 20)-MULT16_16(sum, sum));
      /* mid-side savings estimations based on min correlation */
      logXC2 = MAX16(HALF16(logXC), celt_log2(QCONST32(1.001f, 20)-MULT16_16(minXC, minXC)));
#ifdef FIXED_POINT
      /* Compensate for Q20 vs Q14 input and convert output to Q8 */
      logXC = PSHR32(logXC-QCONST16(6.f, DB_SHIFT),DB_SHIFT-8);
      logXC2 = PSHR32(logXC2-QCONST16(6.f, DB_SHIFT),DB_SHIFT-8);
#endif

      trim += MAX16(-QCONST16(4.f, 8), MULT16_16_Q15(QCONST16(.75f,15),logXC));
      *stereo_saving = MIN16(*stereo_saving + QCONST16(0.25f, 8), -HALF16(logXC2));
   }

   /* Estimate spectral tilt */
   c=0; do {
      for (i=0;i<end-1;i++)
      {
         diff += bandLogE[i+c*m->nbEBands]*(opus_int32)(2+2*i-end);
      }
   } while (++c<C);
   diff /= C*(end-1);
   /*printf("%f\n", diff);*/
   if (diff > QCONST16(2.f, DB_SHIFT))
      trim_index--;
   if (diff > QCONST16(8.f, DB_SHIFT))
      trim_index--;
   if (diff < -QCONST16(4.f, DB_SHIFT))
      trim_index++;
   if (diff < -QCONST16(10.f, DB_SHIFT))
      trim_index++;
   trim -= MAX16(-QCONST16(2.f, 8), MIN16(QCONST16(2.f, 8), SHR16(diff+QCONST16(1.f, DB_SHIFT),DB_SHIFT-8)/6 ));
   trim -= SHR16(surround_trim, DB_SHIFT-8);
   trim -= 2*SHR16(tf_estimate, 14-8);
#ifndef DISABLE_FLOAT_API
   if (analysis->valid)
   {
      trim -= MAX16(-QCONST16(2.f, 8), MIN16(QCONST16(2.f, 8),
            (opus_val16)(QCONST16(2.f, 8)*(analysis->tonality_slope+.05f))));
   }
#endif

#ifdef FIXED_POINT
   trim_index = PSHR32(trim, 8);
#else
   trim_index = (int)floor(.5f+trim);
#endif
   if (trim_index<0)
      trim_index = 0;
   if (trim_index>10)
      trim_index = 10;
   /*printf("%d\n", trim_index);*/
#ifdef FUZZING
   trim_index = rand()%11;
#endif
   return trim_index;
}

static int stereo_analysis(const CELTMode *m, const celt_norm *X,
      int LM, int N0)
{
   int i;
   int thetas;
   opus_val32 sumLR = EPSILON, sumMS = EPSILON;

   /* Use the L1 norm to model the entropy of the L/R signal vs the M/S signal */
   for (i=0;i<13;i++)
   {
      int j;
      for (j=m->eBands[i]<<LM;j<m->eBands[i+1]<<LM;j++)
      {
         opus_val32 L, R, M, S;
         /* We cast to 32-bit first because of the -32768 case */
         L = EXTEND32(X[j]);
         R = EXTEND32(X[N0+j]);
         M = ADD32(L, R);
         S = SUB32(L, R);
         sumLR = ADD32(sumLR, ADD32(ABS32(L), ABS32(R)));
         sumMS = ADD32(sumMS, ADD32(ABS32(M), ABS32(S)));
      }
   }
   sumMS = MULT16_32_Q15(QCONST16(0.707107f, 15), sumMS);
   thetas = 13;
   /* We don't need thetas for lower bands with LM<=1 */
   if (LM<=1)
      thetas -= 8;
   return MULT16_32_Q15((m->eBands[13]<<(LM+1))+thetas, sumMS)
         > MULT16_32_Q15(m->eBands[13]<<(LM+1), sumLR);
}

static opus_val16 dynalloc_analysis(const opus_val16 *bandLogE, const opus_val16 *bandLogE2,
      int nbEBands, int start, int end, int C, int *offsets, int lsb_depth, const opus_int16 *logN,
      int isTransient, int vbr, int constrained_vbr, const opus_int16 *eBands, int LM,
      int effectiveBytes, opus_int32 *tot_boost_, int lfe, opus_val16 *surround_dynalloc)
{
   int i, c;
   opus_int32 tot_boost=0;
   opus_val16 maxDepth;
   VARDECL(opus_val16, follower);
   VARDECL(opus_val16, noise_floor);
   SAVE_STACK;
   ALLOC(follower, C*nbEBands, opus_val16);
   ALLOC(noise_floor, C*nbEBands, opus_val16);
   for (i=0;i<nbEBands;i++)
      offsets[i] = 0;
   /* Dynamic allocation code */
   maxDepth=-QCONST16(31.9f, DB_SHIFT);
   for (i=0;i<end;i++)
   {
      /* Noise floor must take into account eMeans, the depth, the width of the bands
         and the preemphasis filter (approx. square of bark band ID) */
      noise_floor[i] = MULT16_16(QCONST16(0.0625f, DB_SHIFT),logN[i])
            +QCONST16(.5f,DB_SHIFT)+SHL16(9-lsb_depth,DB_SHIFT)-SHL16(eMeans[i],6)
            +MULT16_16(QCONST16(.0062,DB_SHIFT),(i+5)*(i+5));
   }
   c=0;do
   {
      for (i=0;i<end;i++)
         maxDepth = MAX16(maxDepth, bandLogE[c*nbEBands+i]-noise_floor[i]);
   } while (++c<C);
   /* Make sure that dynamic allocation can't make us bust the budget */
   if (effectiveBytes > 50 && LM>=1 && !lfe)
   {
      int last=0;
      c=0;do
      {
         follower[c*nbEBands] = bandLogE2[c*nbEBands];
         for (i=1;i<end;i++)
         {
            /* The last band to be at least 3 dB higher than the previous one
               is the last we'll consider. Otherwise, we run into problems on
               bandlimited signals. */
            if (bandLogE2[c*nbEBands+i] > bandLogE2[c*nbEBands+i-1]+QCONST16(.5f,DB_SHIFT))
               last=i;
            follower[c*nbEBands+i] = MIN16(follower[c*nbEBands+i-1]+QCONST16(1.5f,DB_SHIFT), bandLogE2[c*nbEBands+i]);
         }
         for (i=last-1;i>=0;i--)
            follower[c*nbEBands+i] = MIN16(follower[c*nbEBands+i], MIN16(follower[c*nbEBands+i+1]+QCONST16(2.f,DB_SHIFT), bandLogE2[c*nbEBands+i]));
         for (i=0;i<end;i++)
            follower[c*nbEBands+i] = MAX16(follower[c*nbEBands+i], noise_floor[i]);
      } while (++c<C);
      if (C==2)
      {
         for (i=start;i<end;i++)
         {
            /* Consider 24 dB "cross-talk" */
            follower[nbEBands+i] = MAX16(follower[nbEBands+i], follower[         i]-QCONST16(4.f,DB_SHIFT));
            follower[         i] = MAX16(follower[         i], follower[nbEBands+i]-QCONST16(4.f,DB_SHIFT));
            follower[i] = HALF16(MAX16(0, bandLogE[i]-follower[i]) + MAX16(0, bandLogE[nbEBands+i]-follower[nbEBands+i]));
         }
      } else {
         for (i=start;i<end;i++)
         {
            follower[i] = MAX16(0, bandLogE[i]-follower[i]);
         }
      }
      for (i=start;i<end;i++)
         follower[i] = MAX16(follower[i], surround_dynalloc[i]);
      /* For non-transient CBR/CVBR frames, halve the dynalloc contribution */
      if ((!vbr || constrained_vbr)&&!isTransient)
      {
         for (i=start;i<end;i++)
            follower[i] = HALF16(follower[i]);
      }
      for (i=start;i<end;i++)
      {
         int width;
         int boost;
         int boost_bits;

         if (i<8)
            follower[i] *= 2;
         if (i>=12)
            follower[i] = HALF16(follower[i]);
         follower[i] = MIN16(follower[i], QCONST16(4, DB_SHIFT));

         width = C*(eBands[i+1]-eBands[i])<<LM;
         if (width<6)
         {
            boost = (int)SHR32(EXTEND32(follower[i]),DB_SHIFT);
            boost_bits = boost*width<<BITRES;
         } else if (width > 48) {
            boost = (int)SHR32(EXTEND32(follower[i])*8,DB_SHIFT);
            boost_bits = (boost*width<<BITRES)/8;
         } else {
            boost = (int)SHR32(EXTEND32(follower[i])*width/6,DB_SHIFT);
            boost_bits = boost*6<<BITRES;
         }
         /* For CBR and non-transient CVBR frames, limit dynalloc to 1/4 of the bits */
         if ((!vbr || (constrained_vbr&&!isTransient))
               && (tot_boost+boost_bits)>>BITRES>>3 > effectiveBytes/4)
         {
            opus_int32 cap = ((effectiveBytes/4)<<BITRES<<3);
            offsets[i] = cap-tot_boost;
            tot_boost = cap;
            break;
         } else {
            offsets[i] = boost;
            tot_boost += boost_bits;
         }
      }
   }
   *tot_boost_ = tot_boost;
   RESTORE_STACK;
   return maxDepth;
}


static int run_prefilter(CELTEncoder *st, celt_sig *in, celt_sig *prefilter_mem, int CC, int N,
      int prefilter_tapset, int *pitch, opus_val16 *gain, int *qgain, int enabled, int nbAvailableBytes)
{
   int c;
   VARDECL(celt_sig, _pre);
   celt_sig *pre[2];
   const CELTMode *mode;
   int pitch_index;
   opus_val16 gain1;
   opus_val16 pf_threshold;
   int pf_on;
   int qg;
   SAVE_STACK;

   mode = st->mode;
   ALLOC(_pre, CC*(N+COMBFILTER_MAXPERIOD), celt_sig);

   pre[0] = _pre;
   pre[1] = _pre + (N+COMBFILTER_MAXPERIOD);


   c=0; do {
      OPUS_COPY(pre[c], prefilter_mem+c*COMBFILTER_MAXPERIOD, COMBFILTER_MAXPERIOD);
      OPUS_COPY(pre[c]+COMBFILTER_MAXPERIOD, in+c*(N+st->overlap)+st->overlap, N);
   } while (++c<CC);

   if (enabled)
   {
      VARDECL(opus_val16, pitch_buf);
      ALLOC(pitch_buf, (COMBFILTER_MAXPERIOD+N)>>1, opus_val16);

      pitch_downsample(pre, pitch_buf, COMBFILTER_MAXPERIOD+N, CC);
      /* Don't search for the fir last 1.5 octave of the range because
         there's too many false-positives due to short-term correlation */
      pitch_search(pitch_buf+(COMBFILTER_MAXPERIOD>>1), pitch_buf, N,
            COMBFILTER_MAXPERIOD-3*COMBFILTER_MINPERIOD, &pitch_index);
      pitch_index = COMBFILTER_MAXPERIOD-pitch_index;

      gain1 = remove_doubling(pitch_buf, COMBFILTER_MAXPERIOD, COMBFILTER_MINPERIOD,
            N, &pitch_index, st->prefilter_period, st->prefilter_gain);
      if (pitch_index > COMBFILTER_MAXPERIOD-2)
         pitch_index = COMBFILTER_MAXPERIOD-2;
      gain1 = MULT16_16_Q15(QCONST16(.7f,15),gain1);
      /*printf("%d %d %f %f\n", pitch_change, pitch_index, gain1, st->analysis.tonality);*/
      if (st->loss_rate>2)
         gain1 = HALF32(gain1);
      if (st->loss_rate>4)
         gain1 = HALF32(gain1);
      if (st->loss_rate>8)
         gain1 = 0;
   } else {
      gain1 = 0;
      pitch_index = COMBFILTER_MINPERIOD;
   }

   /* Gain threshold for enabling the prefilter/postfilter */
   pf_threshold = QCONST16(.2f,15);

   /* Adjusting the threshold based on rate and continuity */
   if (abs(pitch_index-st->prefilter_period)*10>pitch_index)
      pf_threshold += QCONST16(.2f,15);
   if (nbAvailableBytes<25)
      pf_threshold += QCONST16(.1f,15);
   if (nbAvailableBytes<35)
      pf_threshold += QCONST16(.1f,15);
   if (st->prefilter_gain > QCONST16(.4f,15))
      pf_threshold -= QCONST16(.1f,15);
   if (st->prefilter_gain > QCONST16(.55f,15))
      pf_threshold -= QCONST16(.1f,15);

   /* Hard threshold at 0.2 */
   pf_threshold = MAX16(pf_threshold, QCONST16(.2f,15));
   if (gain1<pf_threshold)
   {
      gain1 = 0;
      pf_on = 0;
      qg = 0;
   } else {
      /*This block is not gated by a total bits check only because
        of the nbAvailableBytes check above.*/
      if (ABS16(gain1-st->prefilter_gain)<QCONST16(.1f,15))
         gain1=st->prefilter_gain;

#ifdef FIXED_POINT
      qg = ((gain1+1536)>>10)/3-1;
#else
      qg = (int)floor(.5f+gain1*32/3)-1;
#endif
      qg = IMAX(0, IMIN(7, qg));
      gain1 = QCONST16(0.09375f,15)*(qg+1);
      pf_on = 1;
   }
   /*printf("%d %f\n", pitch_index, gain1);*/

   c=0; do {
      int offset = mode->shortMdctSize-st->overlap;
      st->prefilter_period=IMAX(st->prefilter_period, COMBFILTER_MINPERIOD);
      OPUS_COPY(in+c*(N+st->overlap), st->in_mem+c*(st->overlap), st->overlap);
      if (offset)
         comb_filter(in+c*(N+st->overlap)+st->overlap, pre[c]+COMBFILTER_MAXPERIOD,
               st->prefilter_period, st->prefilter_period, offset, -st->prefilter_gain, -st->prefilter_gain,
               st->prefilter_tapset, st->prefilter_tapset, NULL, 0);

      comb_filter(in+c*(N+st->overlap)+st->overlap+offset, pre[c]+COMBFILTER_MAXPERIOD+offset,
            st->prefilter_period, pitch_index, N-offset, -st->prefilter_gain, -gain1,
            st->prefilter_tapset, prefilter_tapset, mode->window, st->overlap);
      OPUS_COPY(st->in_mem+c*(st->overlap), in+c*(N+st->overlap)+N, st->overlap);

      if (N>COMBFILTER_MAXPERIOD)
      {
         OPUS_MOVE(prefilter_mem+c*COMBFILTER_MAXPERIOD, pre[c]+N, COMBFILTER_MAXPERIOD);
      } else {
         OPUS_MOVE(prefilter_mem+c*COMBFILTER_MAXPERIOD, prefilter_mem+c*COMBFILTER_MAXPERIOD+N, COMBFILTER_MAXPERIOD-N);
         OPUS_MOVE(prefilter_mem+c*COMBFILTER_MAXPERIOD+COMBFILTER_MAXPERIOD-N, pre[c]+COMBFILTER_MAXPERIOD, N);
      }
   } while (++c<CC);

   RESTORE_STACK;
   *gain = gain1;
   *pitch = pitch_index;
   *qgain = qg;
   return pf_on;
}

static int compute_vbr(const CELTMode *mode, AnalysisInfo *analysis, opus_int32 base_target,
      int LM, opus_int32 bitrate, int lastCodedBands, int C, int intensity,
      int constrained_vbr, opus_val16 stereo_saving, int tot_boost,
      opus_val16 tf_estimate, int pitch_change, opus_val16 maxDepth,
      int variable_duration, int lfe, int has_surround_mask, opus_val16 surround_masking,
      opus_val16 temporal_vbr)
{
   /* The target rate in 8th bits per frame */
   opus_int32 target;
   int coded_bins;
   int coded_bands;
   opus_val16 tf_calibration;
   int nbEBands;
   const opus_int16 *eBands;

   nbEBands = mode->nbEBands;
   eBands = mode->eBands;

   coded_bands = lastCodedBands ? lastCodedBands : nbEBands;
   coded_bins = eBands[coded_bands]<<LM;
   if (C==2)
      coded_bins += eBands[IMIN(intensity, coded_bands)]<<LM;

   target = base_target;

   /*printf("%f %f %f %f %d %d ", st->analysis.activity, st->analysis.tonality, tf_estimate, st->stereo_saving, tot_boost, coded_bands);*/
#ifndef DISABLE_FLOAT_API
   if (analysis->valid && analysis->activity<.4)
      target -= (opus_int32)((coded_bins<<BITRES)*(.4f-analysis->activity));
#endif
   /* Stereo savings */
   if (C==2)
   {
      int coded_stereo_bands;
      int coded_stereo_dof;
      opus_val16 max_frac;
      coded_stereo_bands = IMIN(intensity, coded_bands);
      coded_stereo_dof = (eBands[coded_stereo_bands]<<LM)-coded_stereo_bands;
      /* Maximum fraction of the bits we can save if the signal is mono. */
      max_frac = DIV32_16(MULT16_16(QCONST16(0.8f, 15), coded_stereo_dof), coded_bins);
      stereo_saving = MIN16(stereo_saving, QCONST16(1.f, 8));
      /*printf("%d %d %d ", coded_stereo_dof, coded_bins, tot_boost);*/
      target -= (opus_int32)MIN32(MULT16_32_Q15(max_frac,target),
                      SHR32(MULT16_16(stereo_saving-QCONST16(0.1f,8),(coded_stereo_dof<<BITRES)),8));
   }
   /* Boost the rate according to dynalloc (minus the dynalloc average for calibration). */
   target += tot_boost-(16<<LM);
   /* Apply transient boost, compensating for average boost. */
   tf_calibration = variable_duration==OPUS_FRAMESIZE_VARIABLE ?
                    QCONST16(0.02f,14) : QCONST16(0.04f,14);
   target += (opus_int32)SHL32(MULT16_32_Q15(tf_estimate-tf_calibration, target),1);

#ifndef DISABLE_FLOAT_API
   /* Apply tonality boost */
   if (analysis->valid && !lfe)
   {
      opus_int32 tonal_target;
      float tonal;

      /* Tonality boost (compensating for the average). */
      tonal = MAX16(0.f,analysis->tonality-.15f)-0.09f;
      tonal_target = target + (opus_int32)((coded_bins<<BITRES)*1.2f*tonal);
      if (pitch_change)
         tonal_target +=  (opus_int32)((coded_bins<<BITRES)*.8f);
      /*printf("%f %f ", analysis->tonality, tonal);*/
      target = tonal_target;
   }
#endif

   if (has_surround_mask&&!lfe)
   {
      opus_int32 surround_target = target + (opus_int32)SHR32(MULT16_16(surround_masking,coded_bins<<BITRES), DB_SHIFT);
      /*printf("%f %d %d %d %d %d %d ", surround_masking, coded_bins, st->end, st->intensity, surround_target, target, st->bitrate);*/
      target = IMAX(target/4, surround_target);
   }

   {
      opus_int32 floor_depth;
      int bins;
      bins = eBands[nbEBands-2]<<LM;
      /*floor_depth = SHR32(MULT16_16((C*bins<<BITRES),celt_log2(SHL32(MAX16(1,sample_max),13))), DB_SHIFT);*/
      floor_depth = (opus_int32)SHR32(MULT16_16((C*bins<<BITRES),maxDepth), DB_SHIFT);
      floor_depth = IMAX(floor_depth, target>>2);
      target = IMIN(target, floor_depth);
      /*printf("%f %d\n", maxDepth, floor_depth);*/
   }

   if ((!has_surround_mask||lfe) && (constrained_vbr || bitrate<64000))
   {
      opus_val16 rate_factor;
#ifdef FIXED_POINT
      rate_factor = MAX16(0,(bitrate-32000));
#else
      rate_factor = MAX16(0,(1.f/32768)*(bitrate-32000));
#endif
      if (constrained_vbr)
         rate_factor = MIN16(rate_factor, QCONST16(0.67f, 15));
      target = base_target + (opus_int32)MULT16_32_Q15(rate_factor, target-base_target);

   }

   if (!has_surround_mask && tf_estimate < QCONST16(.2f, 14))
   {
      opus_val16 amount;
      opus_val16 tvbr_factor;
      amount = MULT16_16_Q15(QCONST16(.0000031f, 30), IMAX(0, IMIN(32000, 96000-bitrate)));
      tvbr_factor = SHR32(MULT16_16(temporal_vbr, amount), DB_SHIFT);
      target += (opus_int32)MULT16_32_Q15(tvbr_factor, target);
   }

   /* Don't allow more than doubling the rate */
   target = IMIN(2*base_target, target);

   return target;
}

int celt_encode_with_ec(CELTEncoder * OPUS_RESTRICT st, const opus_val16 * pcm, int frame_size, unsigned char *compressed, int nbCompressedBytes, ec_enc *enc)
{
   int i, c, N;
   opus_int32 bits;
   ec_enc _enc;
   VARDECL(celt_sig, in);
   VARDECL(celt_sig, freq);
   VARDECL(celt_norm, X);
   VARDECL(celt_ener, bandE);
   VARDECL(opus_val16, bandLogE);
   VARDECL(opus_val16, bandLogE2);
   VARDECL(int, fine_quant);
   VARDECL(opus_val16, error);
   VARDECL(int, pulses);
   VARDECL(int, cap);
   VARDECL(int, offsets);
   VARDECL(int, fine_priority);
   VARDECL(int, tf_res);
   VARDECL(unsigned char, collapse_masks);
   celt_sig *prefilter_mem;
   opus_val16 *oldBandE, *oldLogE, *oldLogE2;
   int shortBlocks=0;
   int isTransient=0;
   const int CC = st->channels;
   const int C = st->stream_channels;
   int LM, M;
   int tf_select;
   int nbFilledBytes, nbAvailableBytes;
   int effEnd;
   int codedBands;
   int tf_sum;
   int alloc_trim;
   int pitch_index=COMBFILTER_MINPERIOD;
   opus_val16 gain1 = 0;
   int dual_stereo=0;
   int effectiveBytes;
   int dynalloc_logp;
   opus_int32 vbr_rate;
   opus_int32 total_bits;
   opus_int32 total_boost;
   opus_int32 balance;
   opus_int32 tell;
   int prefilter_tapset=0;
   int pf_on;
   int anti_collapse_rsv;
   int anti_collapse_on=0;
   int silence=0;
   int tf_chan = 0;
   opus_val16 tf_estimate;
   int pitch_change=0;
   opus_int32 tot_boost;
   opus_val32 sample_max;
   opus_val16 maxDepth;
   const OpusCustomMode *mode;
   int nbEBands;
   int overlap;
   const opus_int16 *eBands;
   int secondMdct;
   int signalBandwidth;
   int transient_got_disabled=0;
   opus_val16 surround_masking=0;
   opus_val16 temporal_vbr=0;
   opus_val16 surround_trim = 0;
   opus_int32 equiv_rate = 510000;
   VARDECL(opus_val16, surround_dynalloc);
   ALLOC_STACK;

   mode = st->mode;
   nbEBands = mode->nbEBands;
   overlap = mode->overlap;
   eBands = mode->eBands;
   tf_estimate = 0;
   if (nbCompressedBytes<2 || pcm==NULL)
     return OPUS_BAD_ARG;

   frame_size *= st->upsample;
   for (LM=0;LM<=mode->maxLM;LM++)
      if (mode->shortMdctSize<<LM==frame_size)
         break;
   if (LM>mode->maxLM)
      return OPUS_BAD_ARG;
   M=1<<LM;
   N = M*mode->shortMdctSize;

   prefilter_mem = st->in_mem+CC*(st->overlap);
   oldBandE = (opus_val16*)(st->in_mem+CC*(st->overlap+COMBFILTER_MAXPERIOD));
   oldLogE = oldBandE + CC*nbEBands;
   oldLogE2 = oldLogE + CC*nbEBands;

   if (enc==NULL)
   {
      tell=1;
      nbFilledBytes=0;
   } else {
      tell=ec_tell(enc);
      nbFilledBytes=(tell+4)>>3;
   }

#ifdef CUSTOM_MODES
   if (st->signalling && enc==NULL)
   {
      int tmp = (mode->effEBands-st->end)>>1;
      st->end = IMAX(1, mode->effEBands-tmp);
      compressed[0] = tmp<<5;
      compressed[0] |= LM<<3;
      compressed[0] |= (C==2)<<2;
      /* Convert "standard mode" to Opus header */
      if (mode->Fs==48000 && mode->shortMdctSize==120)
      {
         int c0 = toOpus(compressed[0]);
         if (c0<0)
            return OPUS_BAD_ARG;
         compressed[0] = c0;
      }
      compressed++;
      nbCompressedBytes--;
   }
#else
   celt_assert(st->signalling==0);
#endif

   /* Can't produce more than 1275 output bytes */
   nbCompressedBytes = IMIN(nbCompressedBytes,1275);
   nbAvailableBytes = nbCompressedBytes - nbFilledBytes;

   if (st->vbr && st->bitrate!=OPUS_BITRATE_MAX)
   {
      opus_int32 den=mode->Fs>>BITRES;
      vbr_rate=(st->bitrate*frame_size+(den>>1))/den;
#ifdef CUSTOM_MODES
      if (st->signalling)
         vbr_rate -= 8<<BITRES;
#endif
      effectiveBytes = vbr_rate>>(3+BITRES);
   } else {
      opus_int32 tmp;
      vbr_rate = 0;
      tmp = st->bitrate*frame_size;
      if (tell>1)
         tmp += tell;
      if (st->bitrate!=OPUS_BITRATE_MAX)
         nbCompressedBytes = IMAX(2, IMIN(nbCompressedBytes,
               (tmp+4*mode->Fs)/(8*mode->Fs)-!!st->signalling));
      effectiveBytes = nbCompressedBytes;
   }
   if (st->bitrate != OPUS_BITRATE_MAX)
      equiv_rate = st->bitrate - (40*C+20)*((400>>LM) - 50);

   if (enc==NULL)
   {
      ec_enc_init(&_enc, compressed, nbCompressedBytes);
      enc = &_enc;
   }

   if (vbr_rate>0)
   {
      /* Computes the max bit-rate allowed in VBR mode to avoid violating the
          target rate and buffering.
         We must do this up front so that bust-prevention logic triggers
          correctly if we don't have enough bits. */
      if (st->constrained_vbr)
      {
         opus_int32 vbr_bound;
         opus_int32 max_allowed;
         /* We could use any multiple of vbr_rate as bound (depending on the
             delay).
            This is clamped to ensure we use at least two bytes if the encoder
             was entirely empty, but to allow 0 in hybrid mode. */
         vbr_bound = vbr_rate;
         max_allowed = IMIN(IMAX(tell==1?2:0,
               (vbr_rate+vbr_bound-st->vbr_reservoir)>>(BITRES+3)),
               nbAvailableBytes);
         if(max_allowed < nbAvailableBytes)
         {
            nbCompressedBytes = nbFilledBytes+max_allowed;
            nbAvailableBytes = max_allowed;
            ec_enc_shrink(enc, nbCompressedBytes);
         }
      }
   }
   total_bits = nbCompressedBytes*8;

   effEnd = st->end;
   if (effEnd > mode->effEBands)
      effEnd = mode->effEBands;

   ALLOC(in, CC*(N+st->overlap), celt_sig);

   sample_max=MAX32(st->overlap_max, celt_maxabs16(pcm, C*(N-overlap)/st->upsample));
   st->overlap_max=celt_maxabs16(pcm+C*(N-overlap)/st->upsample, C*overlap/st->upsample);
   sample_max=MAX32(sample_max, st->overlap_max);
#ifdef FIXED_POINT
   silence = (sample_max==0);
#else
   silence = (sample_max <= (opus_val16)1/(1<<st->lsb_depth));
#endif
#ifdef FUZZING
   if ((rand()&0x3F)==0)
      silence = 1;
#endif
   if (tell==1)
      ec_enc_bit_logp(enc, silence, 15);
   else
      silence=0;
   if (silence)
   {
      /*In VBR mode there is no need to send more than the minimum. */
      if (vbr_rate>0)
      {
         effectiveBytes=nbCompressedBytes=IMIN(nbCompressedBytes, nbFilledBytes+2);
         total_bits=nbCompressedBytes*8;
         nbAvailableBytes=2;
         ec_enc_shrink(enc, nbCompressedBytes);
      }
      /* Pretend we've filled all the remaining bits with zeros
            (that's what the initialiser did anyway) */
      tell = nbCompressedBytes*8;
      enc->nbits_total+=tell-ec_tell(enc);
   }
   c=0; do {
      preemphasis(pcm+c, in+c*(N+st->overlap)+st->overlap, N, CC, st->upsample,
                  mode->preemph, st->preemph_memE+c, st->clip);
   } while (++c<CC);



   /* Find pitch period and gain */
   {
      int enabled;
      int qg;
      enabled = ((st->lfe&&nbAvailableBytes>3) || nbAvailableBytes>12*C) && st->start==0 && !silence && !st->disable_pf
            && st->complexity >= 5 && !(st->consec_transient && LM!=3 && st->variable_duration==OPUS_FRAMESIZE_VARIABLE);

      prefilter_tapset = st->tapset_decision;
      pf_on = run_prefilter(st, in, prefilter_mem, CC, N, prefilter_tapset, &pitch_index, &gain1, &qg, enabled, nbAvailableBytes);
      if ((gain1 > QCONST16(.4f,15) || st->prefilter_gain > QCONST16(.4f,15)) && (!st->analysis.valid || st->analysis.tonality > .3)
            && (pitch_index > 1.26*st->prefilter_period || pitch_index < .79*st->prefilter_period))
         pitch_change = 1;
      if (pf_on==0)
      {
         if(st->start==0 && tell+16<=total_bits)
            ec_enc_bit_logp(enc, 0, 1);
      } else {
         /*This block is not gated by a total bits check only because
           of the nbAvailableBytes check above.*/
         int octave;
         ec_enc_bit_logp(enc, 1, 1);
         pitch_index += 1;
         octave = EC_ILOG(pitch_index)-5;
         ec_enc_uint(enc, octave, 6);
         ec_enc_bits(enc, pitch_index-(16<<octave), 4+octave);
         pitch_index -= 1;
         ec_enc_bits(enc, qg, 3);
         ec_enc_icdf(enc, prefilter_tapset, tapset_icdf, 2);
      }
   }

   isTransient = 0;
   shortBlocks = 0;
   if (st->complexity >= 1 && !st->lfe)
   {
      isTransient = transient_analysis(in, N+st->overlap, CC,
            &tf_estimate, &tf_chan);
   }
   if (LM>0 && ec_tell(enc)+3<=total_bits)
   {
      if (isTransient)
         shortBlocks = M;
   } else {
      isTransient = 0;
      transient_got_disabled=1;
   }

   ALLOC(freq, CC*N, celt_sig); /**< Interleaved signal MDCTs */
   ALLOC(bandE,nbEBands*CC, celt_ener);
   ALLOC(bandLogE,nbEBands*CC, opus_val16);

   secondMdct = shortBlocks && st->complexity>=8;
   ALLOC(bandLogE2, C*nbEBands, opus_val16);
   if (secondMdct)
   {
      compute_mdcts(mode, 0, in, freq, C, CC, LM, st->upsample);
      compute_band_energies(mode, freq, bandE, effEnd, C, M);
      amp2Log2(mode, effEnd, st->end, bandE, bandLogE2, C);
      for (i=0;i<C*nbEBands;i++)
         bandLogE2[i] += HALF16(SHL16(LM, DB_SHIFT));
   }

   compute_mdcts(mode, shortBlocks, in, freq, C, CC, LM, st->upsample);
   if (CC==2&&C==1)
      tf_chan = 0;
   compute_band_energies(mode, freq, bandE, effEnd, C, M);

   if (st->lfe)
   {
      for (i=2;i<st->end;i++)
      {
         bandE[i] = IMIN(bandE[i], MULT16_32_Q15(QCONST16(1e-4f,15),bandE[0]));
         bandE[i] = MAX32(bandE[i], EPSILON);
      }
   }
   amp2Log2(mode, effEnd, st->end, bandE, bandLogE, C);

   ALLOC(surround_dynalloc, C*nbEBands, opus_val16);
   for(i=0;i<st->end;i++)
      surround_dynalloc[i] = 0;
   /* This computes how much masking takes place between surround channels */
   if (st->start==0&&st->energy_mask&&!st->lfe)
   {
      int mask_end;
      int midband;
      int count_dynalloc;
      opus_val32 mask_avg=0;
      opus_val32 diff=0;
      int count=0;
      mask_end = IMAX(2,st->lastCodedBands);
      for (c=0;c<C;c++)
      {
         for(i=0;i<mask_end;i++)
         {
            opus_val16 mask;
            mask = MAX16(MIN16(st->energy_mask[nbEBands*c+i],
                   QCONST16(.25f, DB_SHIFT)), -QCONST16(2.0f, DB_SHIFT));
            if (mask > 0)
               mask = HALF16(mask);
            mask_avg += MULT16_16(mask, eBands[i+1]-eBands[i]);
            count += eBands[i+1]-eBands[i];
            diff += MULT16_16(mask, 1+2*i-mask_end);
         }
      }
      mask_avg = DIV32_16(mask_avg,count);
      mask_avg += QCONST16(.2f, DB_SHIFT);
      diff = diff*6/(C*(mask_end-1)*(mask_end+1)*mask_end);
      /* Again, being conservative */
      diff = HALF32(diff);
      diff = MAX32(MIN32(diff, QCONST32(.031f, DB_SHIFT)), -QCONST32(.031f, DB_SHIFT));
      /* Find the band that's in the middle of the coded spectrum */
      for (midband=0;eBands[midband+1] < eBands[mask_end]/2;midband++);
      count_dynalloc=0;
      for(i=0;i<mask_end;i++)
      {
         opus_val32 lin;
         opus_val16 unmask;
         lin = mask_avg + diff*(i-midband);
         if (C==2)
            unmask = MAX16(st->energy_mask[i], st->energy_mask[nbEBands+i]);
         else
            unmask = st->energy_mask[i];
         unmask = MIN16(unmask, QCONST16(.0f, DB_SHIFT));
         unmask -= lin;
         if (unmask > QCONST16(.25f, DB_SHIFT))
         {
            surround_dynalloc[i] = unmask - QCONST16(.25f, DB_SHIFT);
            count_dynalloc++;
         }
      }
      if (count_dynalloc>=3)
      {
         /* If we need dynalloc in many bands, it's probably because our
            initial masking rate was too low. */
         mask_avg += QCONST16(.25f, DB_SHIFT);
         if (mask_avg>0)
         {
            /* Something went really wrong in the original calculations,
               disabling masking. */
            mask_avg = 0;
            diff = 0;
            for(i=0;i<mask_end;i++)
               surround_dynalloc[i] = 0;
         } else {
            for(i=0;i<mask_end;i++)
               surround_dynalloc[i] = MAX16(0, surround_dynalloc[i]-QCONST16(.25f, DB_SHIFT));
         }
      }
      mask_avg += QCONST16(.2f, DB_SHIFT);
      /* Convert to 1/64th units used for the trim */
      surround_trim = 64*diff;
      /*printf("%d %d ", mask_avg, surround_trim);*/
      surround_masking = mask_avg;
   }
   /* Temporal VBR (but not for LFE) */
   if (!st->lfe)
   {
      opus_val16 follow=-QCONST16(10.0f,DB_SHIFT);
      opus_val32 frame_avg=0;
      opus_val16 offset = shortBlocks?HALF16(SHL16(LM, DB_SHIFT)):0;
      for(i=st->start;i<st->end;i++)
      {
         follow = MAX16(follow-QCONST16(1.f, DB_SHIFT), bandLogE[i]-offset);
         if (C==2)
            follow = MAX16(follow, bandLogE[i+nbEBands]-offset);
         frame_avg += follow;
      }
      frame_avg /= (st->end-st->start);
      temporal_vbr = SUB16(frame_avg,st->spec_avg);
      temporal_vbr = MIN16(QCONST16(3.f, DB_SHIFT), MAX16(-QCONST16(1.5f, DB_SHIFT), temporal_vbr));
      st->spec_avg += MULT16_16_Q15(QCONST16(.02f, 15), temporal_vbr);
   }
   /*for (i=0;i<21;i++)
      printf("%f ", bandLogE[i]);
   printf("\n");*/

   if (!secondMdct)
   {
      for (i=0;i<C*nbEBands;i++)
         bandLogE2[i] = bandLogE[i];
   }

   /* Last chance to catch any transient we might have missed in the
      time-domain analysis */
   if (LM>0 && ec_tell(enc)+3<=total_bits && !isTransient && st->complexity>=5 && !st->lfe)
   {
      if (patch_transient_decision(bandLogE, oldBandE, nbEBands, st->end, C))
      {
         isTransient = 1;
         shortBlocks = M;
         compute_mdcts(mode, shortBlocks, in, freq, C, CC, LM, st->upsample);
         compute_band_energies(mode, freq, bandE, effEnd, C, M);
         amp2Log2(mode, effEnd, st->end, bandE, bandLogE, C);
         /* Compensate for the scaling of short vs long mdcts */
         for (i=0;i<C*nbEBands;i++)
            bandLogE2[i] += HALF16(SHL16(LM, DB_SHIFT));
         tf_estimate = QCONST16(.2f,14);
      }
   }

   if (LM>0 && ec_tell(enc)+3<=total_bits)
      ec_enc_bit_logp(enc, isTransient, 3);

   ALLOC(X, C*N, celt_norm);         /**< Interleaved normalised MDCTs */

   /* Band normalisation */
   normalise_bands(mode, freq, X, bandE, effEnd, C, M);

   ALLOC(tf_res, nbEBands, int);
   /* Disable variable tf resolution for hybrid and at very low bitrate */
   if (effectiveBytes>=15*C && st->start==0 && st->complexity>=2 && !st->lfe)
   {
      int lambda;
      if (effectiveBytes<40)
         lambda = 12;
      else if (effectiveBytes<60)
         lambda = 6;
      else if (effectiveBytes<100)
         lambda = 4;
      else
         lambda = 3;
      lambda*=2;
      tf_select = tf_analysis(mode, effEnd, isTransient, tf_res, lambda, X, N, LM, &tf_sum, tf_estimate, tf_chan);
      for (i=effEnd;i<st->end;i++)
         tf_res[i] = tf_res[effEnd-1];
   } else {
      tf_sum = 0;
      for (i=0;i<st->end;i++)
         tf_res[i] = isTransient;
      tf_select=0;
   }

   ALLOC(error, C*nbEBands, opus_val16);
   quant_coarse_energy(mode, st->start, st->end, effEnd, bandLogE,
         oldBandE, total_bits, error, enc,
         C, LM, nbAvailableBytes, st->force_intra,
         &st->delayedIntra, st->complexity >= 4, st->loss_rate, st->lfe);

   tf_encode(st->start, st->end, isTransient, tf_res, LM, tf_select, enc);

   if (ec_tell(enc)+4<=total_bits)
   {
      if (st->lfe)
      {
         st->tapset_decision = 0;
         st->spread_decision = SPREAD_NORMAL;
      } else if (shortBlocks || st->complexity < 3 || nbAvailableBytes < 10*C || st->start != 0)
      {
         if (st->complexity == 0)
            st->spread_decision = SPREAD_NONE;
         else
            st->spread_decision = SPREAD_NORMAL;
      } else {
         /* Disable new spreading+tapset estimator until we can show it works
            better than the old one. So far it seems like spreading_decision()
            works best. */
         if (0&&st->analysis.valid)
         {
            static const opus_val16 spread_thresholds[3] = {-QCONST16(.6f, 15), -QCONST16(.2f, 15), -QCONST16(.07f, 15)};
            static const opus_val16 spread_histeresis[3] = {QCONST16(.15f, 15), QCONST16(.07f, 15), QCONST16(.02f, 15)};
            static const opus_val16 tapset_thresholds[2] = {QCONST16(.0f, 15), QCONST16(.15f, 15)};
            static const opus_val16 tapset_histeresis[2] = {QCONST16(.1f, 15), QCONST16(.05f, 15)};
            st->spread_decision = hysteresis_decision(-st->analysis.tonality, spread_thresholds, spread_histeresis, 3, st->spread_decision);
            st->tapset_decision = hysteresis_decision(st->analysis.tonality_slope, tapset_thresholds, tapset_histeresis, 2, st->tapset_decision);
         } else {
            st->spread_decision = spreading_decision(mode, X,
                  &st->tonal_average, st->spread_decision, &st->hf_average,
                  &st->tapset_decision, pf_on&&!shortBlocks, effEnd, C, M);
         }
         /*printf("%d %d\n", st->tapset_decision, st->spread_decision);*/
         /*printf("%f %d %f %d\n\n", st->analysis.tonality, st->spread_decision, st->analysis.tonality_slope, st->tapset_decision);*/
      }
      ec_enc_icdf(enc, st->spread_decision, spread_icdf, 5);
   }

   ALLOC(offsets, nbEBands, int);

   maxDepth = dynalloc_analysis(bandLogE, bandLogE2, nbEBands, st->start, st->end, C, offsets,
         st->lsb_depth, mode->logN, isTransient, st->vbr, st->constrained_vbr,
         eBands, LM, effectiveBytes, &tot_boost, st->lfe, surround_dynalloc);
   /* For LFE, everything interesting is in the first band */
   if (st->lfe)
      offsets[0] = IMIN(8, effectiveBytes/3);
   ALLOC(cap, nbEBands, int);
   init_caps(mode,cap,LM,C);

   dynalloc_logp = 6;
   total_bits<<=BITRES;
   total_boost = 0;
   tell = ec_tell_frac(enc);
   for (i=st->start;i<st->end;i++)
   {
      int width, quanta;
      int dynalloc_loop_logp;
      int boost;
      int j;
      width = C*(eBands[i+1]-eBands[i])<<LM;
      /* quanta is 6 bits, but no more than 1 bit/sample
         and no less than 1/8 bit/sample */
      quanta = IMIN(width<<BITRES, IMAX(6<<BITRES, width));
      dynalloc_loop_logp = dynalloc_logp;
      boost = 0;
      for (j = 0; tell+(dynalloc_loop_logp<<BITRES) < total_bits-total_boost
            && boost < cap[i]; j++)
      {
         int flag;
         flag = j<offsets[i];
         ec_enc_bit_logp(enc, flag, dynalloc_loop_logp);
         tell = ec_tell_frac(enc);
         if (!flag)
            break;
         boost += quanta;
         total_boost += quanta;
         dynalloc_loop_logp = 1;
      }
      /* Making dynalloc more likely */
      if (j)
         dynalloc_logp = IMAX(2, dynalloc_logp-1);
      offsets[i] = boost;
   }

   if (C==2)
   {
      int effectiveRate;

      static const opus_val16 intensity_thresholds[21]=
      /* 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19  20  off*/
        { 16,21,23,25,27,29,31,33,35,38,42,46,50,54,58,63,68,75,84,102,130};
      static const opus_val16 intensity_histeresis[21]=
        {  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 4, 5, 6,  8, 12};

      /* Always use MS for 2.5 ms frames until we can do a better analysis */
      if (LM!=0)
         dual_stereo = stereo_analysis(mode, X, LM, N);

      /* Account for coarse energy */
      effectiveRate = (8*effectiveBytes - 80)>>LM;

      /* effectiveRate in kb/s */
      effectiveRate = 2*effectiveRate/5;

      st->intensity = hysteresis_decision((opus_val16)effectiveRate, intensity_thresholds, intensity_histeresis, 21, st->intensity);
      st->intensity = IMIN(st->end,IMAX(st->start, st->intensity));
   }

   alloc_trim = 5;
   if (tell+(6<<BITRES) <= total_bits - total_boost)
   {
      if (st->lfe)
         alloc_trim = 5;
      else
         alloc_trim = alloc_trim_analysis(mode, X, bandLogE,
            st->end, LM, C, N, &st->analysis, &st->stereo_saving, tf_estimate, st->intensity, surround_trim);
      ec_enc_icdf(enc, alloc_trim, trim_icdf, 7);
      tell = ec_tell_frac(enc);
   }

   /* Variable bitrate */
   if (vbr_rate>0)
   {
     opus_val16 alpha;
     opus_int32 delta;
     /* The target rate in 8th bits per frame */
     opus_int32 target, base_target;
     opus_int32 min_allowed;
     int lm_diff = mode->maxLM - LM;

     /* Don't attempt to use more than 510 kb/s, even for frames smaller than 20 ms.
        The CELT allocator will just not be able to use more than that anyway. */
     nbCompressedBytes = IMIN(nbCompressedBytes,1275>>(3-LM));
     base_target = vbr_rate - ((40*C+20)<<BITRES);

     if (st->constrained_vbr)
        base_target += (st->vbr_offset>>lm_diff);

     target = compute_vbr(mode, &st->analysis, base_target, LM, equiv_rate,
           st->lastCodedBands, C, st->intensity, st->constrained_vbr,
           st->stereo_saving, tot_boost, tf_estimate, pitch_change, maxDepth,
           st->variable_duration, st->lfe, st->energy_mask!=NULL, surround_masking,
           temporal_vbr);

     /* The current offset is removed from the target and the space used
        so far is added*/
     target=target+tell;
     /* In VBR mode the frame size must not be reduced so much that it would
         result in the encoder running out of bits.
        The margin of 2 bytes ensures that none of the bust-prevention logic
         in the decoder will have triggered so far. */
     min_allowed = ((tell+total_boost+(1<<(BITRES+3))-1)>>(BITRES+3)) + 2 - nbFilledBytes;

     nbAvailableBytes = (target+(1<<(BITRES+2)))>>(BITRES+3);
     nbAvailableBytes = IMAX(min_allowed,nbAvailableBytes);
     nbAvailableBytes = IMIN(nbCompressedBytes,nbAvailableBytes+nbFilledBytes) - nbFilledBytes;

     /* By how much did we "miss" the target on that frame */
     delta = target - vbr_rate;

     target=nbAvailableBytes<<(BITRES+3);

     /*If the frame is silent we don't adjust our drift, otherwise
       the encoder will shoot to very high rates after hitting a
       span of silence, but we do allow the bitres to refill.
       This means that we'll undershoot our target in CVBR/VBR modes
       on files with lots of silence. */
     if(silence)
     {
       nbAvailableBytes = 2;
       target = 2*8<<BITRES;
       delta = 0;
     }

     if (st->vbr_count < 970)
     {
        st->vbr_count++;
        alpha = celt_rcp(SHL32(EXTEND32(st->vbr_count+20),16));
     } else
        alpha = QCONST16(.001f,15);
     /* How many bits have we used in excess of what we're allowed */
     if (st->constrained_vbr)
        st->vbr_reservoir += target - vbr_rate;
     /*printf ("%d\n", st->vbr_reservoir);*/

     /* Compute the offset we need to apply in order to reach the target */
     if (st->constrained_vbr)
     {
        st->vbr_drift += (opus_int32)MULT16_32_Q15(alpha,(delta*(1<<lm_diff))-st->vbr_offset-st->vbr_drift);
        st->vbr_offset = -st->vbr_drift;
     }
     /*printf ("%d\n", st->vbr_drift);*/

     if (st->constrained_vbr && st->vbr_reservoir < 0)
     {
        /* We're under the min value -- increase rate */
        int adjust = (-st->vbr_reservoir)/(8<<BITRES);
        /* Unless we're just coding silence */
        nbAvailableBytes += silence?0:adjust;
        st->vbr_reservoir = 0;
        /*printf ("+%d\n", adjust);*/
     }
     nbCompressedBytes = IMIN(nbCompressedBytes,nbAvailableBytes+nbFilledBytes);
     /*printf("%d\n", nbCompressedBytes*50*8);*/
     /* This moves the raw bits to take into account the new compressed size */
     ec_enc_shrink(enc, nbCompressedBytes);
   }

   /* Bit allocation */
   ALLOC(fine_quant, nbEBands, int);
   ALLOC(pulses, nbEBands, int);
   ALLOC(fine_priority, nbEBands, int);

   /* bits =           packet size                    - where we are - safety*/
   bits = (((opus_int32)nbCompressedBytes*8)<<BITRES) - ec_tell_frac(enc) - 1;
   anti_collapse_rsv = isTransient&&LM>=2&&bits>=((LM+2)<<BITRES) ? (1<<BITRES) : 0;
   bits -= anti_collapse_rsv;
   signalBandwidth = st->end-1;
#ifndef DISABLE_FLOAT_API
   if (st->analysis.valid)
   {
      int min_bandwidth;
      if (equiv_rate < (opus_int32)32000*C)
         min_bandwidth = 13;
      else if (equiv_rate < (opus_int32)48000*C)
         min_bandwidth = 16;
      else if (equiv_rate < (opus_int32)60000*C)
         min_bandwidth = 18;
      else  if (equiv_rate < (opus_int32)80000*C)
         min_bandwidth = 19;
      else
         min_bandwidth = 20;
      signalBandwidth = IMAX(st->analysis.bandwidth, min_bandwidth);
   }
#endif
   if (st->lfe)
      signalBandwidth = 1;
   codedBands = compute_allocation(mode, st->start, st->end, offsets, cap,
         alloc_trim, &st->intensity, &dual_stereo, bits, &balance, pulses,
         fine_quant, fine_priority, C, LM, enc, 1, st->lastCodedBands, signalBandwidth);
   if (st->lastCodedBands)
      st->lastCodedBands = IMIN(st->lastCodedBands+1,IMAX(st->lastCodedBands-1,codedBands));
   else
      st->lastCodedBands = codedBands;

   quant_fine_energy(mode, st->start, st->end, oldBandE, error, fine_quant, enc, C);

   /* Residual quantisation */
   ALLOC(collapse_masks, C*nbEBands, unsigned char);
   quant_all_bands(1, mode, st->start, st->end, X, C==2 ? X+N : NULL, collapse_masks,
         bandE, pulses, shortBlocks, st->spread_decision, dual_stereo, st->intensity, tf_res,
         nbCompressedBytes*(8<<BITRES)-anti_collapse_rsv, balance, enc, LM, codedBands, &st->rng);

   if (anti_collapse_rsv > 0)
   {
      anti_collapse_on = st->consec_transient<2;
#ifdef FUZZING
      anti_collapse_on = rand()&0x1;
#endif
      ec_enc_bits(enc, anti_collapse_on, 1);
   }
   quant_energy_finalise(mode, st->start, st->end, oldBandE, error, fine_quant, fine_priority, nbCompressedBytes*8-ec_tell(enc), enc, C);

   if (silence)
   {
      for (i=0;i<C*nbEBands;i++)
         oldBandE[i] = -QCONST16(28.f,DB_SHIFT);
   }

#ifdef RESYNTH
   /* Re-synthesis of the coded audio if required */
   {
      celt_sig *out_mem[2];

      if (anti_collapse_on)
      {
         anti_collapse(mode, X, collapse_masks, LM, C, N,
               st->start, st->end, oldBandE, oldLogE, oldLogE2, pulses, st->rng);
      }

      if (silence)
      {
         for (i=0;i<C*N;i++)
            freq[i] = 0;
      } else {
         /* Synthesis */
         denormalise_bands(mode, X, freq, oldBandE, st->start, effEnd, C, M);
      }

      c=0; do {
         OPUS_MOVE(st->syn_mem[c], st->syn_mem[c]+N, 2*MAX_PERIOD-N+overlap/2);
      } while (++c<CC);

      if (CC==2&&C==1)
      {
         for (i=0;i<N;i++)
            freq[N+i] = freq[i];
      }

      c=0; do {
         out_mem[c] = st->syn_mem[c]+2*MAX_PERIOD-N;
      } while (++c<CC);

      compute_inv_mdcts(mode, shortBlocks, freq, out_mem, CC, LM);

      c=0; do {
         st->prefilter_period=IMAX(st->prefilter_period, COMBFILTER_MINPERIOD);
         st->prefilter_period_old=IMAX(st->prefilter_period_old, COMBFILTER_MINPERIOD);
         comb_filter(out_mem[c], out_mem[c], st->prefilter_period_old, st->prefilter_period, mode->shortMdctSize,
               st->prefilter_gain_old, st->prefilter_gain, st->prefilter_tapset_old, st->prefilter_tapset,
               mode->window, st->overlap);
         if (LM!=0)
            comb_filter(out_mem[c]+mode->shortMdctSize, out_mem[c]+mode->shortMdctSize, st->prefilter_period, pitch_index, N-mode->shortMdctSize,
                  st->prefilter_gain, gain1, st->prefilter_tapset, prefilter_tapset,
                  mode->window, overlap);
      } while (++c<CC);

      /* We reuse freq[] as scratch space for the de-emphasis */
      deemphasis(out_mem, (opus_val16*)pcm, N, CC, st->upsample, mode->preemph, st->preemph_memD, freq);
      st->prefilter_period_old = st->prefilter_period;
      st->prefilter_gain_old = st->prefilter_gain;
      st->prefilter_tapset_old = st->prefilter_tapset;
   }
#endif

   st->prefilter_period = pitch_index;
   st->prefilter_gain = gain1;
   st->prefilter_tapset = prefilter_tapset;
#ifdef RESYNTH
   if (LM!=0)
   {
      st->prefilter_period_old = st->prefilter_period;
      st->prefilter_gain_old = st->prefilter_gain;
      st->prefilter_tapset_old = st->prefilter_tapset;
   }
#endif

   if (CC==2&&C==1) {
      for (i=0;i<nbEBands;i++)
         oldBandE[nbEBands+i]=oldBandE[i];
   }

   if (!isTransient)
   {
      for (i=0;i<CC*nbEBands;i++)
         oldLogE2[i] = oldLogE[i];
      for (i=0;i<CC*nbEBands;i++)
         oldLogE[i] = oldBandE[i];
   } else {
      for (i=0;i<CC*nbEBands;i++)
         oldLogE[i] = MIN16(oldLogE[i], oldBandE[i]);
   }
   /* In case start or end were to change */
   c=0; do
   {
      for (i=0;i<st->start;i++)
      {
         oldBandE[c*nbEBands+i]=0;
         oldLogE[c*nbEBands+i]=oldLogE2[c*nbEBands+i]=-QCONST16(28.f,DB_SHIFT);
      }
      for (i=st->end;i<nbEBands;i++)
      {
         oldBandE[c*nbEBands+i]=0;
         oldLogE[c*nbEBands+i]=oldLogE2[c*nbEBands+i]=-QCONST16(28.f,DB_SHIFT);
      }
   } while (++c<CC);

   if (isTransient || transient_got_disabled)
      st->consec_transient++;
   else
      st->consec_transient=0;
   st->rng = enc->rng;

   /* If there's any room left (can only happen for very high rates),
      it's already filled with zeros */
   ec_enc_done(enc);

#ifdef CUSTOM_MODES
   if (st->signalling)
      nbCompressedBytes++;
#endif

   RESTORE_STACK;
   if (ec_get_error(enc))
      return OPUS_INTERNAL_ERROR;
   else
      return nbCompressedBytes;
}


#ifdef CUSTOM_MODES

#ifdef FIXED_POINT
int opus_custom_encode(CELTEncoder * OPUS_RESTRICT st, const opus_int16 * pcm, int frame_size, unsigned char *compressed, int nbCompressedBytes)
{
   return celt_encode_with_ec(st, pcm, frame_size, compressed, nbCompressedBytes, NULL);
}

#ifndef DISABLE_FLOAT_API
int opus_custom_encode_float(CELTEncoder * OPUS_RESTRICT st, const float * pcm, int frame_size, unsigned char *compressed, int nbCompressedBytes)
{
   int j, ret, C, N;
   VARDECL(opus_int16, in);
   ALLOC_STACK;

   if (pcm==NULL)
      return OPUS_BAD_ARG;

   C = st->channels;
   N = frame_size;
   ALLOC(in, C*N, opus_int16);

   for (j=0;j<C*N;j++)
     in[j] = FLOAT2INT16(pcm[j]);

   ret=celt_encode_with_ec(st,in,frame_size,compressed,nbCompressedBytes, NULL);
#ifdef RESYNTH
   for (j=0;j<C*N;j++)
      ((float*)pcm)[j]=in[j]*(1.f/32768.f);
#endif
   RESTORE_STACK;
   return ret;
}
#endif /* DISABLE_FLOAT_API */
#else

int opus_custom_encode(CELTEncoder * OPUS_RESTRICT st, const opus_int16 * pcm, int frame_size, unsigned char *compressed, int nbCompressedBytes)
{
   int j, ret, C, N;
   VARDECL(celt_sig, in);
   ALLOC_STACK;

   if (pcm==NULL)
      return OPUS_BAD_ARG;

   C=st->channels;
   N=frame_size;
   ALLOC(in, C*N, celt_sig);
   for (j=0;j<C*N;j++) {
     in[j] = SCALEOUT(pcm[j]);
   }

   ret = celt_encode_with_ec(st,in,frame_size,compressed,nbCompressedBytes, NULL);
#ifdef RESYNTH
   for (j=0;j<C*N;j++)
      ((opus_int16*)pcm)[j] = FLOAT2INT16(in[j]);
#endif
   RESTORE_STACK;
   return ret;
}

int opus_custom_encode_float(CELTEncoder * OPUS_RESTRICT st, const float * pcm, int frame_size, unsigned char *compressed, int nbCompressedBytes)
{
   return celt_encode_with_ec(st, pcm, frame_size, compressed, nbCompressedBytes, NULL);
}

#endif

#endif /* CUSTOM_MODES */

int opus_custom_encoder_ctl(CELTEncoder * OPUS_RESTRICT st, int request, ...)
{
   va_list ap;

   va_start(ap, request);
   switch (request)
   {
      case OPUS_SET_COMPLEXITY_REQUEST:
      {
         int value = va_arg(ap, opus_int32);
         if (value<0 || value>10)
            goto bad_arg;
         st->complexity = value;
      }
      break;
      case CELT_SET_START_BAND_REQUEST:
      {
         opus_int32 value = va_arg(ap, opus_int32);
         if (value<0 || value>=st->mode->nbEBands)
            goto bad_arg;
         st->start = value;
      }
      break;
      case CELT_SET_END_BAND_REQUEST:
      {
         opus_int32 value = va_arg(ap, opus_int32);
         if (value<1 || value>st->mode->nbEBands)
            goto bad_arg;
         st->end = value;
      }
      break;
      case CELT_SET_PREDICTION_REQUEST:
      {
         int value = va_arg(ap, opus_int32);
         if (value<0 || value>2)
            goto bad_arg;
         st->disable_pf = value<=1;
         st->force_intra = value==0;
      }
      break;
      case OPUS_SET_PACKET_LOSS_PERC_REQUEST:
      {
         int value = va_arg(ap, opus_int32);
         if (value<0 || value>100)
            goto bad_arg;
         st->loss_rate = value;
      }
      break;
      case OPUS_SET_VBR_CONSTRAINT_REQUEST:
      {
         opus_int32 value = va_arg(ap, opus_int32);
         st->constrained_vbr = value;
      }
      break;
      case OPUS_SET_VBR_REQUEST:
      {
         opus_int32 value = va_arg(ap, opus_int32);
         st->vbr = value;
      }
      break;
      case OPUS_SET_BITRATE_REQUEST:
      {
         opus_int32 value = va_arg(ap, opus_int32);
         if (value<=500 && value!=OPUS_BITRATE_MAX)
            goto bad_arg;
         value = IMIN(value, 260000*st->channels);
         st->bitrate = value;
      }
      break;
      case CELT_SET_CHANNELS_REQUEST:
      {
         opus_int32 value = va_arg(ap, opus_int32);
         if (value<1 || value>2)
            goto bad_arg;
         st->stream_channels = value;
      }
      break;
      case OPUS_SET_LSB_DEPTH_REQUEST:
      {
          opus_int32 value = va_arg(ap, opus_int32);
          if (value<8 || value>24)
             goto bad_arg;
          st->lsb_depth=value;
      }
      break;
      case OPUS_GET_LSB_DEPTH_REQUEST:
      {
          opus_int32 *value = va_arg(ap, opus_int32*);
          *value=st->lsb_depth;
      }
      break;
      case OPUS_SET_EXPERT_FRAME_DURATION_REQUEST:
      {
          opus_int32 value = va_arg(ap, opus_int32);
          st->variable_duration = value;
      }
      break;
      case OPUS_RESET_STATE:
      {
         int i;
         opus_val16 *oldBandE, *oldLogE, *oldLogE2;
         oldBandE = (opus_val16*)(st->in_mem+st->channels*(st->overlap+COMBFILTER_MAXPERIOD));
         oldLogE = oldBandE + st->channels*st->mode->nbEBands;
         oldLogE2 = oldLogE + st->channels*st->mode->nbEBands;
         OPUS_CLEAR((char*)&st->ENCODER_RESET_START,
               opus_custom_encoder_get_size(st->mode, st->channels)-
               ((char*)&st->ENCODER_RESET_START - (char*)st));
         for (i=0;i<st->channels*st->mode->nbEBands;i++)
            oldLogE[i]=oldLogE2[i]=-QCONST16(28.f,DB_SHIFT);
         st->vbr_offset = 0;
         st->delayedIntra = 1;
         st->spread_decision = SPREAD_NORMAL;
         st->tonal_average = 256;
         st->hf_average = 0;
         st->tapset_decision = 0;
      }
      break;
#ifdef CUSTOM_MODES
      case CELT_SET_INPUT_CLIPPING_REQUEST:
      {
         opus_int32 value = va_arg(ap, opus_int32);
         st->clip = value;
      }
      break;
#endif
      case CELT_SET_SIGNALLING_REQUEST:
      {
         opus_int32 value = va_arg(ap, opus_int32);
         st->signalling = value;
      }
      break;
      case CELT_SET_ANALYSIS_REQUEST:
      {
         AnalysisInfo *info = va_arg(ap, AnalysisInfo *);
         if (info)
            OPUS_COPY(&st->analysis, info, 1);
      }
      break;
      case CELT_GET_MODE_REQUEST:
      {
         const CELTMode ** value = va_arg(ap, const CELTMode**);
         if (value==0)
            goto bad_arg;
         *value=st->mode;
      }
      break;
      case OPUS_GET_FINAL_RANGE_REQUEST:
      {
         opus_uint32 * value = va_arg(ap, opus_uint32 *);
         if (value==0)
            goto bad_arg;
         *value=st->rng;
      }
      break;
      case OPUS_SET_LFE_REQUEST:
      {
          opus_int32 value = va_arg(ap, opus_int32);
          st->lfe = value;
      }
      break;
      case OPUS_SET_ENERGY_MASK_REQUEST:
      {
          opus_val16 *value = va_arg(ap, opus_val16*);
          st->energy_mask = value;
      }
      break;
      default:
         goto bad_request;
   }
   va_end(ap);
   return OPUS_OK;
bad_arg:
   va_end(ap);
   return OPUS_BAD_ARG;
bad_request:
   va_end(ap);
   return OPUS_UNIMPLEMENTED;
}