xref: /aosp_15_r20/external/libxaac/encoder/ixheaace_fd_qc_adjthr.c (revision 15dc779a375ca8b5125643b829a8aa4b70d7f451)

/******************************************************************************
 *                                                                            *
 * Copyright (C) 2023 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *****************************************************************************
 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
 */

#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <limits.h>
#include <float.h>
#include "iusace_type_def.h"
#include "ixheaac_error_standards.h"
#include "ixheaace_error_codes.h"
#include "ixheaace_psy_const.h"
#include "ixheaace_tns.h"
#include "ixheaace_tns_params.h"
#include "ixheaace_rom.h"
#include "iusace_block_switch_const.h"
#include "iusace_cnst.h"
#include "iusace_rom.h"
#include "ixheaace_mps_common_define.h"
#include "iusace_bitbuffer.h"
#include "impd_drc_common_enc.h"
#include "impd_drc_uni_drc.h"
#include "impd_drc_api.h"
#include "impd_drc_uni_drc_eq.h"
#include "impd_drc_uni_drc_filter_bank.h"
#include "impd_drc_gain_enc.h"
#include "impd_drc_struct_def.h"

#include "ixheaace_memory_standards.h"
#include "iusace_tns_usac.h"
#include "iusace_psy_mod.h"
#include "iusace_config.h"
#include "ixheaace_adjust_threshold_data.h"
#include "iusace_fd_qc_util.h"
#include "iusace_fd_qc_adjthr.h"
#include "ixheaace_aac_constants.h"
#include "ixheaace_sbr_def.h"

FLOAT32 iusace_bits_to_pe(const FLOAT32 bits) { return (bits * 1.18f); }

VOID iusace_adj_thr_init(ia_adj_thr_elem_struct *pstr_adj_thr_ele, const FLOAT32 mean_pe,
                         WORD32 ch_bitrate) {
  ia_min_snr_adapt_param_struct *pstr_min_snr_params =
      &pstr_adj_thr_ele->str_min_snr_adapt_params;

  pstr_adj_thr_ele->pe_min = (FLOAT32)0.8f * mean_pe;
  pstr_adj_thr_ele->pe_max = (FLOAT32)1.2f * mean_pe;
  pstr_adj_thr_ele->pe_offset = 0.0f;

  if (ch_bitrate < 32000) {
    pstr_adj_thr_ele->pe_offset =
        MAX((FLOAT32)50.0f, (FLOAT32)(100.0f) - (FLOAT32)(100.0f / 32000) * (FLOAT32)ch_bitrate);
  }

  if (ch_bitrate > 20000) {
    pstr_adj_thr_ele->str_ah_param.modify_min_snr = TRUE;
    pstr_adj_thr_ele->str_ah_param.start_sfb_long = 15;
    pstr_adj_thr_ele->str_ah_param.start_sfb_short = 3;
  } else {
    pstr_adj_thr_ele->str_ah_param.modify_min_snr = FALSE;
    pstr_adj_thr_ele->str_ah_param.start_sfb_long = 0;
    pstr_adj_thr_ele->str_ah_param.start_sfb_short = 0;
  }

  pstr_min_snr_params->max_red = (FLOAT32)0.25f;

  pstr_min_snr_params->start_ratio = (FLOAT32)10.0f;

  pstr_min_snr_params->max_ratio = (FLOAT32)1000.0f;

  pstr_min_snr_params->red_ratio_fac =
      (1.0f - pstr_min_snr_params->max_red) /
      (10.0f * (FLOAT32)log10(pstr_min_snr_params->start_ratio / pstr_min_snr_params->max_ratio));

  pstr_min_snr_params->red_offs = 1.0f - pstr_min_snr_params->red_ratio_fac * 10.0f *
                                             (FLOAT32)log10(pstr_min_snr_params->start_ratio);

  pstr_adj_thr_ele->pe_last = (FLOAT32)0.0f;
  pstr_adj_thr_ele->dyn_bits_last = 0;
  pstr_adj_thr_ele->pe_correction_fac = (FLOAT32)1.0f;
}

static VOID iusace_calc_sfb_pe_data(ia_qc_pe_data_struct *pstr_qc_pe_data,
                                    ia_psy_mod_out_data_struct *pstr_psy_out, WORD32 num_channels,
                                    WORD32 chn) {
  WORD32 ch, idx = 0;
  WORD32 scf_band_grp;
  FLOAT32 num_lines;
  FLOAT32 ld_thr, ld_ratio;
  WORD32 i = 0, scf;
  WORD32 sfb_count;
  WORD32 scf_band_per_grp;
  WORD32 max_sfb_per_grp;
  FLOAT32 *ptr_sfb_energy;
  FLOAT32 *ptr_sfb_thr;
  ia_qc_pe_chan_data_struct *str_qc_pe_chan_data;

  pstr_qc_pe_data->pe = pstr_qc_pe_data->offset;
  pstr_qc_pe_data->const_part = 0.0f;
  pstr_qc_pe_data->num_active_lines = 0.0f;

  for (ch = chn; ch < chn + num_channels; ch++) {
    sfb_count = pstr_psy_out[ch].sfb_count;
    scf_band_per_grp = pstr_psy_out[ch].sfb_per_group;
    max_sfb_per_grp = pstr_psy_out[ch].max_sfb_per_grp;
    ptr_sfb_energy = pstr_psy_out[ch].ptr_sfb_energy;
    ptr_sfb_thr = pstr_psy_out[ch].ptr_sfb_thr;
    str_qc_pe_chan_data = &pstr_qc_pe_data->pe_ch_data[idx];
    str_qc_pe_chan_data->pe = 0;
    str_qc_pe_chan_data->num_active_lines = 0;
    str_qc_pe_chan_data->const_part = 0;

    for (scf_band_grp = 0; scf_band_grp < sfb_count; scf_band_grp += scf_band_per_grp) {
      i = scf_band_grp;
      for (scf = max_sfb_per_grp - 1; scf >= 0; scf--, i++) {
        if (ptr_sfb_energy[i] > ptr_sfb_thr[i]) {
          ld_thr = (FLOAT32)log(ptr_sfb_thr[i]) * LOG2_1;
          ld_ratio = str_qc_pe_chan_data->sfb_ld_energy[i] - ld_thr;
          num_lines = str_qc_pe_chan_data->sfb_lines[i];
          if (ld_ratio >= PE_C1) {
            str_qc_pe_chan_data->sfb_pe[i] = num_lines * ld_ratio;
            str_qc_pe_chan_data->sfb_const_part[i] =
                num_lines * str_qc_pe_chan_data->sfb_ld_energy[i];
          } else {
            str_qc_pe_chan_data->sfb_pe[i] = num_lines * (PE_C2 + PE_C3 * ld_ratio);
            str_qc_pe_chan_data->sfb_const_part[i] =
                num_lines * (PE_C2 + PE_C3 * str_qc_pe_chan_data->sfb_ld_energy[i]);
            num_lines = num_lines * PE_C3;
          }
          str_qc_pe_chan_data->num_sfb_active_lines[i] = num_lines;
        } else {
          str_qc_pe_chan_data->sfb_pe[i] = 0.0f;
          str_qc_pe_chan_data->sfb_const_part[i] = 0.0f;
          str_qc_pe_chan_data->num_sfb_active_lines[i] = 0.0;
        }

        str_qc_pe_chan_data->pe += str_qc_pe_chan_data->sfb_pe[i];
        str_qc_pe_chan_data->const_part += str_qc_pe_chan_data->sfb_const_part[i];
        str_qc_pe_chan_data->num_active_lines += str_qc_pe_chan_data->num_sfb_active_lines[i];
      }
    }
    pstr_qc_pe_data->pe += str_qc_pe_chan_data->pe;
    pstr_qc_pe_data->const_part += str_qc_pe_chan_data->const_part;
    pstr_qc_pe_data->num_active_lines += str_qc_pe_chan_data->num_active_lines;
    pstr_psy_out[ch].pe = pstr_qc_pe_data->pe;
    idx++;
  }
  return;
}

static VOID iusace_adj_pe_minmax(const FLOAT32 curr_pe, FLOAT32 *pe_min, FLOAT32 *pe_max) {
  FLOAT32 min_hi_fac = 0.3f, max_hi_fac = 1.0f, min_low_fac = 0.14f, max_low_fac = 0.07f;
  FLOAT32 diff;
  FLOAT32 min_diff = curr_pe * (FLOAT32)0.1666666667f;

  if (curr_pe > *pe_max) {
    diff = (curr_pe - *pe_max);
    *pe_min += diff * min_hi_fac;
    *pe_max += diff * max_hi_fac;
  } else {
    if (curr_pe < *pe_min) {
      diff = (*pe_min - curr_pe);
      *pe_min -= diff * min_low_fac;
      *pe_max -= diff * max_low_fac;
    } else {
      *pe_min += (curr_pe - *pe_min) * min_hi_fac;
      *pe_max -= (*pe_max - curr_pe) * max_low_fac;
    }
  }

  if ((*pe_max - *pe_min) < min_diff) {
    FLOAT32 low_part, high_part;
    low_part = MAX((FLOAT32)0.0f, curr_pe - *pe_min);
    high_part = MAX((FLOAT32)0.0f, *pe_max - curr_pe);
    *pe_max = curr_pe + high_part / (low_part + high_part) * min_diff;
    *pe_min = curr_pe - low_part / (low_part + high_part) * min_diff;
    *pe_min = MAX((FLOAT32)0.0f, *pe_min);
  }

  return;
}

static FLOAT32 iusace_bitres_calc_bitfac(const WORD32 bitres_bits, const WORD32 max_bitres_bits,
                                         const FLOAT32 pe, const WORD32 win_seq,
                                         const WORD32 avg_bits, const FLOAT32 max_bit_fac,
                                         ia_adj_thr_elem_struct *pstr_adj_thr_elem) {
  FLOAT32 pex;
  FLOAT32 fill_lvl = 0.0f;
  FLOAT32 bit_save, bit_spend, bitres_factor;

  if (max_bitres_bits) {
    fill_lvl = (FLOAT32)bitres_bits / max_bitres_bits;
  }

  if (win_seq != EIGHT_SHORT_SEQUENCE) {
    fill_lvl = MAX(fill_lvl, CLIP_SAVE_LO_LONG);
    fill_lvl = MIN(fill_lvl, CLIP_SAVE_HI_LONG);
    bit_save = MAX_BITS_SAVE_LONG - (BITS_SAVE_RATIO_LONG * (fill_lvl - CLIP_SAVE_LO_LONG));
    bit_spend = MIN_BITS_SPEND_LONG + (BITS_SPEND_RATIO_LONG * (fill_lvl - CLIP_SPEND_LO_LONG));
  } else {
    fill_lvl = MAX(fill_lvl, CLIP_SPEND_LO_SHORT);
    fill_lvl = MIN(fill_lvl, CLIP_SPEND_HI_SHORT);
    bit_save = MAX_BITS_SAVE_SHORT - (BITS_SAVE_RATIO_SHORT * (fill_lvl - CLIP_SAVE_LO_SHORT));
    bit_spend =
        MIN_BITS_SPEND_SHORT + (BITS_SPEND_RATIO_SHORT * (fill_lvl - CLIP_SPEND_LO_SHORT));
  }

  pex = MAX(pe, pstr_adj_thr_elem->pe_min);
  pex = MIN(pex, pstr_adj_thr_elem->pe_max);

  bitres_factor =
      (FLOAT32)1.0f - bit_save +
      ((bit_spend + bit_save) / (pstr_adj_thr_elem->pe_max - pstr_adj_thr_elem->pe_min)) *
          (pex - pstr_adj_thr_elem->pe_min);
  bitres_factor = MIN(bitres_factor,
                      (FLOAT32)1.0f - (FLOAT32)0.3f + (FLOAT32)bitres_bits / (FLOAT32)avg_bits);

  bitres_factor = MIN(bitres_factor, max_bit_fac);
  iusace_adj_pe_minmax(pe, &pstr_adj_thr_elem->pe_min, &pstr_adj_thr_elem->pe_max);

  return bitres_factor;
}

static VOID iusace_calc_pe_correction(FLOAT32 *correction_fac, const FLOAT32 pe_act,
                                      const FLOAT32 pe_last, const WORD32 bits_prev) {
  if ((bits_prev > 0) && (pe_act < (FLOAT32)1.5f * pe_last) &&
      (pe_act > (FLOAT32)0.7f * pe_last) &&
      ((FLOAT32)1.2f * iusace_bits_to_pe((FLOAT32)bits_prev) > pe_last) &&
      ((FLOAT32)0.65f * iusace_bits_to_pe((FLOAT32)bits_prev) < pe_last)) {
    FLOAT32 new_fac = pe_last / iusace_bits_to_pe((FLOAT32)bits_prev);

    if (new_fac < (FLOAT32)1.0f) {
      new_fac = MIN((FLOAT32)1.1f * new_fac, (FLOAT32)1.0f);
      new_fac = MAX(new_fac, (FLOAT32)0.85f);
    } else {
      new_fac = MAX((FLOAT32)0.9f * new_fac, (FLOAT32)1.0f);
      new_fac = MIN(new_fac, (FLOAT32)1.15f);
    }
    if (((new_fac > (FLOAT32)1.0f) && (*correction_fac < (FLOAT32)1.0f)) ||
        ((new_fac < (FLOAT32)1.0f) && (*correction_fac > (FLOAT32)1.0f))) {
      *correction_fac = (FLOAT32)1.0f;
    }

    if ((*correction_fac < (FLOAT32)1.0f && new_fac < *correction_fac) ||
        (*correction_fac > (FLOAT32)1.0f && new_fac > *correction_fac))
      *correction_fac = (FLOAT32)0.85f * (*correction_fac) + (FLOAT32)0.15f * new_fac;
    else
      *correction_fac = (FLOAT32)0.7f * (*correction_fac) + (FLOAT32)0.3f * new_fac;

    *correction_fac = MIN(*correction_fac, (FLOAT32)1.15f);
    *correction_fac = MAX(*correction_fac, (FLOAT32)0.85f);
  } else {
    *correction_fac = (FLOAT32)1.0f;
  }

  return;
}

static VOID iusace_calc_thr_exp(FLOAT32 **thr_exp, ia_psy_mod_out_data_struct *pstr_psy_out,
                                WORD32 num_chans, WORD32 chn) {
  WORD32 sfb, ch, scf_band_grp, idx = 0;
  ia_psy_mod_out_data_struct *pstr_psy_chan_out;
  FLOAT32 *scf_band_thr;
  FLOAT32 *ptr_thr_exp;
  for (ch = chn; ch < chn + num_chans; ch++) {
    pstr_psy_chan_out = &pstr_psy_out[ch];
    ptr_thr_exp = thr_exp[idx];
    for (scf_band_grp = 0; scf_band_grp < pstr_psy_chan_out->sfb_count;
         scf_band_grp += pstr_psy_chan_out->sfb_per_group) {
      FLOAT32 *thr_exp1 = &ptr_thr_exp[scf_band_grp];
      scf_band_thr = &pstr_psy_chan_out->ptr_sfb_thr[scf_band_grp];
      for (sfb = 0; sfb < pstr_psy_chan_out->max_sfb_per_grp; sfb++) {
        thr_exp1[sfb] = (FLOAT32)pow(*scf_band_thr++, RED_EXP_VAL);
      }
    }
    idx++;
  }

  return;
}

static VOID iusace_adapt_min_snr(ia_psy_mod_out_data_struct *pstr_psy_out,
                                 ia_min_snr_adapt_param_struct *pstr_min_snr_params,
                                 WORD32 num_chans, WORD32 chn) {
  WORD32 num_sfb = 0, ch, scf_band_cnt, sfb_off, sfb;
  FLOAT32 avg_energy = 0.0f, db_ratio, min_snr_red;
  WORD32 i;
  for (ch = chn; ch < chn + num_chans; ch++) {
    ia_psy_mod_out_data_struct *pstr_psy_chan_out = &pstr_psy_out[ch];

    num_sfb = 0;
    avg_energy = 0;
    scf_band_cnt = pstr_psy_chan_out->max_sfb_per_grp;

    for (sfb_off = 0; sfb_off < pstr_psy_chan_out->sfb_count;
         sfb_off += pstr_psy_chan_out->sfb_per_group) {
      FLOAT32 *sfb_energy = &pstr_psy_chan_out->ptr_sfb_energy[sfb_off];
      for (sfb = scf_band_cnt - 1; sfb >= 0; sfb--) {
        avg_energy += sfb_energy[sfb];
      }
      num_sfb += scf_band_cnt;
    }

    if (num_sfb > 0) {
      avg_energy /= num_sfb;
    }

    for (sfb_off = 0; sfb_off < pstr_psy_chan_out->sfb_count;
         sfb_off += pstr_psy_chan_out->sfb_per_group) {
      i = sfb_off;
      for (sfb = scf_band_cnt - 1; sfb >= 0; sfb--, i++) {
        if (pstr_min_snr_params->start_ratio * pstr_psy_chan_out->ptr_sfb_energy[i] <
            avg_energy) {
          db_ratio =
              (FLOAT32)(10.0 * log10((MIN_FLT_VAL + avg_energy) /
                                     (MIN_FLT_VAL + pstr_psy_chan_out->ptr_sfb_energy[i])));
          min_snr_red =
              pstr_min_snr_params->red_offs + pstr_min_snr_params->red_ratio_fac * db_ratio;
          min_snr_red = MAX(min_snr_red, pstr_min_snr_params->max_red);
          pstr_psy_chan_out->sfb_min_snr[i] =
              (FLOAT32)pow(pstr_psy_out[ch].sfb_min_snr[i], min_snr_red);
          pstr_psy_chan_out->sfb_min_snr[i] = MIN(MIN_SNR_LIMIT, pstr_psy_out[ch].sfb_min_snr[i]);
        }
      }
    }
  }

  return;
}

static VOID iusace_init_avoid_hole_flag(WORD32 **ah_flag,
                                        ia_psy_mod_out_data_struct *pstr_psy_out,
                                        ia_ah_param_struct *pstr_ah_param, WORD32 num_chans,
                                        WORD32 chn) {
  WORD32 ch, idx;
  FLOAT32 sfb_energy;
  FLOAT32 scale_spread_energy;
  WORD32 scf_band_grp, sfb, scf_band;
  FLOAT32 *ptr_scf_band_spread_energy, *ptr_scf_band_energy, *ptr_scf_band_min_snr;
  for (ch = chn; ch < chn + num_chans; ch++) {
    ia_psy_mod_out_data_struct *pstr_psy_chan_out = &pstr_psy_out[ch];

    if (pstr_psy_chan_out->window_sequence != EIGHT_SHORT_SEQUENCE) {
      scale_spread_energy = 0.5f;
    } else {
      scale_spread_energy = 0.63f;
    }

    for (scf_band_grp = 0; scf_band_grp < pstr_psy_chan_out->sfb_count;
         scf_band_grp += pstr_psy_chan_out->sfb_per_group) {
      ptr_scf_band_spread_energy = &pstr_psy_chan_out->ptr_sfb_spread_energy[scf_band_grp];
      sfb = pstr_psy_chan_out->max_sfb_per_grp;
      for (scf_band = sfb - 1; scf_band >= 0; scf_band--) {
        *ptr_scf_band_spread_energy = *ptr_scf_band_spread_energy * scale_spread_energy;
        ptr_scf_band_spread_energy++;
      }
    }
  }

  if (pstr_ah_param->modify_min_snr) {
    for (ch = chn; ch < chn + num_chans; ch++) {
      ia_psy_mod_out_data_struct *pstr_psy_chan_out = &pstr_psy_out[ch];
      ptr_scf_band_energy = pstr_psy_chan_out->ptr_sfb_energy;

      ptr_scf_band_min_snr = pstr_psy_chan_out->sfb_min_snr;

      for (scf_band_grp = 0; scf_band_grp < pstr_psy_chan_out->sfb_count;
           scf_band_grp += pstr_psy_chan_out->sfb_per_group) {
        for (scf_band = 0; scf_band < pstr_psy_chan_out->max_sfb_per_grp; scf_band++) {
          FLOAT32 sfb_en_m1, sfb_en_p1, avg_energy;
          if (scf_band > 0) {
            sfb_en_m1 = ptr_scf_band_energy[scf_band_grp + scf_band - 1];
          } else {
            sfb_en_m1 = ptr_scf_band_energy[scf_band_grp];
          }
          if (scf_band < pstr_psy_chan_out->max_sfb_per_grp - 1)
            sfb_en_p1 = ptr_scf_band_energy[scf_band_grp + scf_band + 1];
          else
            sfb_en_p1 = ptr_scf_band_energy[scf_band_grp + scf_band];

          avg_energy = (sfb_en_m1 + sfb_en_p1) / (FLOAT32)2.0f;
          sfb_energy = ptr_scf_band_energy[scf_band_grp + scf_band];

          if (sfb_energy > avg_energy) {
            FLOAT32 temp_min_snr = MAX((FLOAT32)0.8f * avg_energy / sfb_energy, (FLOAT32)0.316f);
            if (pstr_psy_chan_out->window_sequence != EIGHT_SHORT_SEQUENCE)
              temp_min_snr = MAX(temp_min_snr, (FLOAT32)0.316f);
            else
              temp_min_snr = MAX(temp_min_snr, (FLOAT32)0.5f);
            ptr_scf_band_min_snr[scf_band_grp + scf_band] =
                MIN(ptr_scf_band_min_snr[scf_band_grp + scf_band], temp_min_snr);
          }

          if (((FLOAT32)2.0f * sfb_energy < avg_energy) && (sfb_energy > (FLOAT32)0.0f)) {
            FLOAT32 temp_min_snr = avg_energy / ((FLOAT32)2.0f * sfb_energy) *
                                   ptr_scf_band_min_snr[scf_band_grp + scf_band];
            temp_min_snr = MIN((FLOAT32)0.8f, temp_min_snr);
            ptr_scf_band_min_snr[scf_band_grp + scf_band] =
                MIN(temp_min_snr, ptr_scf_band_min_snr[scf_band_grp + scf_band] * (FLOAT32)3.16f);
          }
        }
      }
    }
  }

  if (num_chans == 2) {
    ia_psy_mod_out_data_struct *psy_out_mid = &pstr_psy_out[chn];
    ia_psy_mod_out_data_struct *psy_out_side = &pstr_psy_out[chn + 1];

    for (sfb = 0; sfb < psy_out_mid->sfb_count; sfb++) {
      if (pstr_psy_out[chn].ms_used[sfb]) {
        FLOAT32 sfb_en_mid = psy_out_mid->ptr_sfb_energy[sfb];
        FLOAT32 sfb_en_side = psy_out_side->ptr_sfb_energy[sfb];
        FLOAT32 max_sfb_en = MAX(sfb_en_mid, sfb_en_side);
        FLOAT32 max_thr = 0.25f * psy_out_mid->sfb_min_snr[sfb] * max_sfb_en;

        psy_out_mid->sfb_min_snr[sfb] = (FLOAT32)MAX(
            psy_out_mid->sfb_min_snr[sfb],
            MIN(MAX_FLT_VAL, ((double)max_thr / (MIN_FLT_VAL + (double)sfb_en_mid))));

        if (psy_out_mid->ptr_sfb_energy[sfb] <= 1.0f) {
          psy_out_mid->ptr_sfb_energy[sfb] = MIN(psy_out_mid->ptr_sfb_energy[sfb], 0.8f);
        }

        psy_out_side->sfb_min_snr[sfb] = (FLOAT32)MAX(
            psy_out_side->sfb_min_snr[sfb],
            MIN(MAX_FLT_VAL, ((double)max_thr / (MIN_FLT_VAL + (double)sfb_en_side))));

        if (psy_out_side->sfb_min_snr[sfb] <= 1.0f) {
          psy_out_side->sfb_min_snr[sfb] = MIN(psy_out_side->sfb_min_snr[sfb], 0.8f);
        }

        if (sfb_en_mid > psy_out_mid->ptr_sfb_spread_energy[sfb]) {
          psy_out_side->ptr_sfb_spread_energy[sfb] = 0.9f * sfb_en_side;
        }

        if (sfb_en_side > psy_out_side->ptr_sfb_spread_energy[sfb]) {
          psy_out_mid->ptr_sfb_spread_energy[sfb] = 0.9f * sfb_en_mid;
        }
      }
    }
  }
  idx = 0;
  for (ch = chn; ch < chn + num_chans; ch++) {
    ia_psy_mod_out_data_struct *pstr_psy_chan_out = &pstr_psy_out[ch];
    for (scf_band_grp = 0; scf_band_grp < pstr_psy_chan_out->sfb_count;
         scf_band_grp += pstr_psy_chan_out->sfb_per_group) {
      for (scf_band = 0; scf_band < pstr_psy_chan_out->max_sfb_per_grp; scf_band++) {
        if (pstr_psy_chan_out->ptr_sfb_spread_energy[scf_band_grp + scf_band] >
                pstr_psy_chan_out->ptr_sfb_energy[scf_band_grp + scf_band] ||
            pstr_psy_chan_out->sfb_min_snr[scf_band_grp + scf_band] > (float)1.0) {
          ah_flag[idx][scf_band_grp + scf_band] = NO_AH;
        } else {
          ah_flag[idx][scf_band_grp + scf_band] = AH_INACTIVE;
        }
      }

      for (scf_band = pstr_psy_chan_out->max_sfb_per_grp;
           scf_band < pstr_psy_chan_out->sfb_per_group; scf_band++) {
        ah_flag[idx][scf_band_grp + scf_band] = NO_AH;
      }
    }
    idx++;
  }

  return;
}

static VOID iusace_reduce_thr(ia_psy_mod_out_data_struct *pstr_psy_out, WORD32 **ah_flag,
                              FLOAT32 **thr_exp, const FLOAT32 red_value, WORD32 num_channels,
                              WORD32 chn) {
  WORD32 ch, sfb_group, sfb, idx = 0;
  FLOAT32 sfb_energy, sfb_threshold, sfb_thr_reduced;
  FLOAT32 *sfb_energy_fix, *sfb_threshold_fix, *sfb_min_snr_fix, *thr_exp_fix;
  for (ch = chn; ch < chn + num_channels; ch++) {
    ia_psy_mod_out_data_struct *pstr_psy_chan_out = &pstr_psy_out[ch];
    sfb_energy_fix = pstr_psy_chan_out->ptr_sfb_energy;
    sfb_threshold_fix = pstr_psy_chan_out->ptr_sfb_thr;
    sfb_min_snr_fix = pstr_psy_chan_out->sfb_min_snr;
    thr_exp_fix = &thr_exp[idx][0];
    for (sfb_group = 0; sfb_group < pstr_psy_chan_out->sfb_count;
         sfb_group += pstr_psy_chan_out->sfb_per_group) {
      for (sfb = 0; sfb < pstr_psy_chan_out->max_sfb_per_grp; sfb++) {
        sfb_energy = sfb_energy_fix[sfb_group + sfb];
        sfb_threshold = sfb_threshold_fix[sfb_group + sfb];
        if (sfb_energy > sfb_threshold) {
          sfb_thr_reduced =
              (FLOAT32)pow((thr_exp_fix[sfb_group + sfb] + red_value), INV_RED_EXP_VAL);

          if ((sfb_thr_reduced > sfb_min_snr_fix[sfb_group + sfb] * sfb_energy) &&
              (ah_flag[idx][sfb_group + sfb] != NO_AH)) {
            sfb_thr_reduced = MAX(sfb_min_snr_fix[sfb_group + sfb] * sfb_energy, sfb_threshold);
            ah_flag[idx][sfb_group + sfb] = AH_ACTIVE;
          }
          sfb_threshold_fix[sfb_group + sfb] = sfb_thr_reduced;
        }
      }
    }
    idx++;
  }

  return;
}

static VOID iusace_calc_pe_no_active_holes(FLOAT32 *pe, FLOAT32 *const_part,
                                           FLOAT32 *nactive_lines,
                                           ia_qc_pe_data_struct *pstr_qs_pe_data,
                                           WORD32 **ah_flag,
                                           ia_psy_mod_out_data_struct *pstr_psy_out,
                                           WORD32 num_channels, WORD32 chn) {
  WORD32 ch, sfb_group, sfb, idx = 0;
  *pe = 0.0f;
  *const_part = 0.0f;
  *nactive_lines = 0;
  for (ch = chn; ch < chn + num_channels; ch++) {
    ia_psy_mod_out_data_struct *pstr_psy_chan_out = &pstr_psy_out[ch];
    ia_qc_pe_chan_data_struct *pe_channel_data = &pstr_qs_pe_data->pe_ch_data[idx];

    for (sfb_group = 0; sfb_group < pstr_psy_chan_out->sfb_count;
         sfb_group += pstr_psy_chan_out->sfb_per_group) {
      for (sfb = 0; sfb < pstr_psy_chan_out->max_sfb_per_grp; sfb++) {
        if (ah_flag[idx][sfb_group + sfb] < AH_ACTIVE) {
          *pe += pe_channel_data->sfb_pe[sfb_group + sfb];
          *const_part += pe_channel_data->sfb_const_part[sfb_group + sfb];
          *nactive_lines += pe_channel_data->num_sfb_active_lines[sfb_group + sfb];
        }
      }
    }
    idx++;
  }

  return;
}

static IA_ERRORCODE iusace_correct_thr(ia_psy_mod_out_data_struct *pstr_psy_out, WORD32 **ah_flag,
                                       ia_qc_pe_data_struct *pstr_qs_pe_data, FLOAT32 **thr_exp,
                                       const FLOAT32 red_value, const FLOAT32 delta_pe,
                                       WORD32 num_channels, WORD32 chn, UWORD8 *ptr_scratch) {
  WORD32 i, ch, sfb_group, sfb, idx = 0;
  FLOAT32 delta_sfb_pe;
  FLOAT32 thr_factor;
  FLOAT32 norm_factor[2] = {0};
  FLOAT32 *sfb_pe_factors[2];
  for (i = 0; i < 2; i++) {
    sfb_pe_factors[i] = (FLOAT32 *)ptr_scratch;
    ptr_scratch += (MAX_NUM_GROUPED_SFB) * sizeof(sfb_pe_factors[0][0]);
  }
  FLOAT32 sfb_en, sfb_thr, sfb_thr_reduced;
  FLOAT32 *p_thr_exp;
  FLOAT32 *p_sfb_energy, *p_sfb_thr, *p_sfb_min_snr;
  ia_psy_mod_out_data_struct *pstr_psy_chan_out = NULL;
  ia_qc_pe_chan_data_struct *pe_channel_data = NULL;

  for (ch = chn; ch < chn + num_channels; ch++) {
    if (idx >= IXHEAACE_MAX_CH_IN_BS_ELE) {
      return IA_EXHEAACE_EXE_FATAL_USAC_INVALID_NUM_CHANNEL;
    }
    pstr_psy_chan_out = &pstr_psy_out[ch];
    pe_channel_data = &pstr_qs_pe_data->pe_ch_data[idx];
    norm_factor[idx] = MIN_FLT_VAL;
    p_thr_exp = thr_exp[idx];

    for (sfb_group = 0; sfb_group < pstr_psy_chan_out->sfb_count;
         sfb_group += pstr_psy_chan_out->sfb_per_group) {
      for (sfb = 0; sfb < pstr_psy_chan_out->max_sfb_per_grp; sfb++) {
        if ((ah_flag[idx][sfb_group + sfb] < AH_ACTIVE) || (delta_pe > 0)) {
          sfb_pe_factors[idx][sfb_group + sfb] =
              pe_channel_data->num_sfb_active_lines[sfb_group + sfb] /
              (p_thr_exp[sfb_group + sfb] + red_value);
          norm_factor[idx] += sfb_pe_factors[idx][sfb_group + sfb];
        } else {
          sfb_pe_factors[idx][sfb_group + sfb] = 0.0f;
        }
      }
    }
    idx++;
  }
  if (num_channels > 1) {
    norm_factor[0] = norm_factor[0] + norm_factor[1];
  }
  norm_factor[0] = 1.0f / norm_factor[0];
  idx = 0;
  for (ch = chn; ch < chn + num_channels; ch++) {
    if (idx >= IXHEAACE_MAX_CH_IN_BS_ELE) {
      return IA_EXHEAACE_EXE_FATAL_USAC_INVALID_NUM_CHANNEL;
    }
    pstr_psy_chan_out = &pstr_psy_out[ch];
    pe_channel_data = &pstr_qs_pe_data->pe_ch_data[idx];
    p_sfb_energy = pstr_psy_chan_out->ptr_sfb_energy;
    p_sfb_thr = pstr_psy_chan_out->ptr_sfb_thr;
    p_sfb_min_snr = pstr_psy_chan_out->sfb_min_snr;

    for (sfb_group = 0; sfb_group < pstr_psy_chan_out->sfb_count;
         sfb_group += pstr_psy_chan_out->sfb_per_group) {
      i = sfb_group;
      for (sfb = pstr_psy_chan_out->max_sfb_per_grp - 1; sfb >= 0; sfb--, i++) {
        delta_sfb_pe = sfb_pe_factors[idx][i] * norm_factor[0] * delta_pe;
        if (pe_channel_data->num_sfb_active_lines[i] > (FLOAT32)0.5f) {
          sfb_en = p_sfb_energy[i];
          sfb_thr = p_sfb_thr[i];
          thr_factor = MIN(-delta_sfb_pe / pe_channel_data->num_sfb_active_lines[i], 20.f);
          thr_factor = (FLOAT32)pow(2.0f, thr_factor);
          sfb_thr_reduced = sfb_thr * thr_factor;

          if ((sfb_thr_reduced > p_sfb_min_snr[i] * sfb_en) && (ah_flag[idx][i] == AH_INACTIVE)) {
            sfb_thr_reduced = MAX(p_sfb_min_snr[i] * sfb_en, sfb_thr);
            ah_flag[idx][i] = AH_ACTIVE;
          }
          p_sfb_thr[i] = sfb_thr_reduced;
        }
      }
    }
    idx++;
  }

  return IA_NO_ERROR;
}

static VOID iusace_reduce_min_snr(ia_psy_mod_out_data_struct *pstr_psy_out,
                                  ia_qc_pe_data_struct *pstr_qs_pe_data, WORD32 **ah_flag,
                                  const FLOAT32 desired_pe, WORD32 num_channels, WORD32 chn) {
  WORD32 sfb, sfb_sub_win, ch, idx;
  FLOAT32 delta_pe;

  sfb_sub_win = pstr_psy_out[chn].max_sfb_per_grp;

  while (pstr_qs_pe_data->pe > desired_pe && sfb_sub_win > 0) {
    sfb_sub_win--;
    for (sfb = sfb_sub_win; sfb < pstr_psy_out[chn].sfb_count;
         sfb += pstr_psy_out[chn].sfb_per_group) {
      idx = 0;
      for (ch = chn; ch < chn + num_channels; ch++) {
        if (ah_flag[idx][sfb] != NO_AH && pstr_psy_out[ch].sfb_min_snr[sfb] < MIN_SNR_LIMIT) {
          pstr_psy_out[ch].sfb_min_snr[sfb] = MIN_SNR_LIMIT;
          pstr_psy_out[ch].ptr_sfb_thr[sfb] =
              pstr_psy_out[ch].ptr_sfb_energy[sfb] * pstr_psy_out[ch].sfb_min_snr[sfb];
          delta_pe = pstr_qs_pe_data->pe_ch_data[idx].sfb_lines[sfb] * 1.5f -
                     pstr_qs_pe_data->pe_ch_data[idx].sfb_pe[sfb];
          pstr_qs_pe_data->pe += delta_pe;
          pstr_qs_pe_data->pe_ch_data[idx].pe += delta_pe;
        }
        idx++;
      }
      if (pstr_qs_pe_data->pe <= desired_pe) break;
    }
  }

  return;
}

static VOID iusace_allow_more_holes(ia_psy_mod_out_data_struct *pstr_psy_out,
                                    ia_qc_pe_data_struct *pstr_qs_pe_data, WORD32 **ah_flag,
                                    const ia_ah_param_struct *str_ah_param,
                                    const FLOAT32 desired_pe, WORD32 num_channels, WORD32 chn,
                                    UWORD8 *ptr_scratch) {
  WORD32 sfb, ch, idx;
  FLOAT32 act_pe = pstr_qs_pe_data->pe;

  if (num_channels == 2 &&
      pstr_psy_out[chn].window_sequence == pstr_psy_out[chn + 1].window_sequence) {
    ia_psy_mod_out_data_struct *psy_out_left = &pstr_psy_out[chn];
    ia_psy_mod_out_data_struct *psy_out_right = &pstr_psy_out[chn + 1];

    for (sfb = 0; sfb < psy_out_left->sfb_count; sfb++) {
      if (pstr_psy_out[chn].ms_used[sfb]) {
        if (ah_flag[1][sfb] != NO_AH &&
            0.4f * psy_out_left->sfb_min_snr[sfb] * psy_out_left->ptr_sfb_energy[sfb] >
                psy_out_right->ptr_sfb_energy[sfb]) {
          ah_flag[1][sfb] = NO_AH;

          psy_out_right->ptr_sfb_thr[sfb] = 2.0f * psy_out_right->ptr_sfb_energy[sfb];

          act_pe -= pstr_qs_pe_data->pe_ch_data[1].sfb_pe[sfb];
        } else {
          if (ah_flag[0][sfb] != NO_AH &&
              0.4f * psy_out_right->sfb_min_snr[sfb] * psy_out_right->ptr_sfb_energy[sfb] >
                  psy_out_left->ptr_sfb_energy[sfb]) {
            ah_flag[0][sfb] = NO_AH;

            psy_out_left->ptr_sfb_thr[sfb] = 2.0f * psy_out_left->ptr_sfb_energy[sfb];

            act_pe -= pstr_qs_pe_data->pe_ch_data[0].sfb_pe[sfb];
          }
        }
        if (act_pe < desired_pe) break;
      }
    }
  }
  if (act_pe > desired_pe) {
    WORD32 *start_sfb = (WORD32 *)ptr_scratch;
    memset(start_sfb, 0, MAX_TIME_CHANNELS * sizeof(start_sfb[0]));
    FLOAT32 average_energy, min_energy;
    WORD32 ah_cnt;
    WORD32 en_idx;
    FLOAT32 energy[4];
    WORD32 min_sfb, max_sfb;
    WORD32 done;
    for (ch = chn; ch < chn + num_channels; ch++) {
      if (pstr_psy_out[ch].window_sequence != EIGHT_SHORT_SEQUENCE)
        start_sfb[ch] = str_ah_param->start_sfb_long;
      else
        start_sfb[ch] = str_ah_param->start_sfb_short;
    }

    average_energy = 0.0f;
    min_energy = MAX_FLT_VAL;
    ah_cnt = 0;
    idx = 0;
    for (ch = chn; ch < chn + num_channels; ch++) {
      ia_psy_mod_out_data_struct *pstr_psy_chan_out = &pstr_psy_out[ch];
      for (sfb = start_sfb[ch]; sfb < pstr_psy_chan_out->sfb_count; sfb++) {
        if ((ah_flag[idx][sfb] != NO_AH) &&
            (pstr_psy_chan_out->ptr_sfb_energy[sfb] > pstr_psy_chan_out->ptr_sfb_thr[sfb])) {
          min_energy = MIN(min_energy, pstr_psy_chan_out->ptr_sfb_energy[sfb]);
          average_energy += pstr_psy_chan_out->ptr_sfb_energy[sfb];
          ah_cnt++;
        }
      }
      idx++;
    }

    average_energy = MIN(MAX_FLT_VAL, average_energy / (ah_cnt + MIN_FLT_VAL));

    for (en_idx = 0; en_idx < 4; en_idx++) {
      energy[en_idx] = min_energy * (FLOAT32)pow(average_energy / (min_energy + MIN_FLT_VAL),
                                                 (2 * en_idx + 1) / 7.0f);
    }
    max_sfb = pstr_psy_out[chn].sfb_count - 1;
    min_sfb = start_sfb[chn];

    if (num_channels == 2) {
      max_sfb = MAX(max_sfb, pstr_psy_out[chn + 1].sfb_count - 1);

      min_sfb = MIN(min_sfb, start_sfb[chn + 1]);
    }

    sfb = max_sfb;
    en_idx = 0;
    done = 0;
    while (!done) {
      idx = 0;
      for (ch = chn; ch < chn + num_channels; ch++) {
        ia_psy_mod_out_data_struct *pstr_psy_chan_out = &pstr_psy_out[ch];
        if (sfb >= start_sfb[ch] && sfb < pstr_psy_chan_out->sfb_count) {
          if (ah_flag[idx][sfb] != NO_AH &&
              pstr_psy_chan_out->ptr_sfb_energy[sfb] < energy[en_idx]) {
            ah_flag[idx][sfb] = NO_AH;
            pstr_psy_chan_out->ptr_sfb_thr[sfb] = 2.0f * pstr_psy_chan_out->ptr_sfb_energy[sfb];
            act_pe -= pstr_qs_pe_data->pe_ch_data[idx].sfb_pe[sfb];
          }

          if (act_pe < desired_pe) {
            done = 1;
            break;
          }
        }
        idx++;
      }
      sfb--;
      if (sfb < min_sfb) {
        sfb = max_sfb;
        en_idx++;
        if (en_idx >= 4) {
          done = 1;
        }
      }
    }
  }

  return;
}

static IA_ERRORCODE iusace_adapt_thr_to_pe(ia_psy_mod_out_data_struct *pstr_psy_out,
                                           ia_qc_pe_data_struct *pstr_qs_pe_data,
                                           const FLOAT32 desired_pe,
                                           ia_ah_param_struct *str_ah_param,
                                           ia_min_snr_adapt_param_struct *msa_param,
                                           WORD32 num_channels, WORD32 chn, UWORD8 *ptr_scratch) {
  IA_ERRORCODE err_code;
  FLOAT32 no_red_pe, red_pe, red_pe_no_ah;
  FLOAT32 const_part, const_part_no_ah;
  FLOAT32 nactive_lines, nactive_lines_no_ah;
  FLOAT32 desired_pe_no_ah;
  FLOAT32 redval = 0.0f;
  WORD32 *ah_flag[2];
  WORD32 iteration;
  for (WORD32 i = 0; i < 2; i++) {
    ah_flag[i] = (WORD32 *)ptr_scratch;
    ptr_scratch += (MAX_NUM_GROUPED_SFB) * sizeof(ah_flag[0][0]);
  }
  FLOAT32 *thr_exp[2];
  for (WORD32 i = 0; i < 2; i++) {
    thr_exp[i] = (FLOAT32 *)ptr_scratch;
    ptr_scratch += (MAX_NUM_GROUPED_SFB) * sizeof(thr_exp[0][0]);
  }

  iusace_calc_thr_exp(thr_exp, pstr_psy_out, num_channels, chn);
  iusace_adapt_min_snr(pstr_psy_out, msa_param, num_channels, chn);
  iusace_init_avoid_hole_flag(ah_flag, pstr_psy_out, str_ah_param, num_channels, chn);

  no_red_pe = pstr_qs_pe_data->pe;
  const_part = pstr_qs_pe_data->const_part;
  nactive_lines = pstr_qs_pe_data->num_active_lines;
  if (nactive_lines > FLT_EPSILON) {
    FLOAT32 avg_thr_exp = (FLOAT32)pow(2.0f, (const_part - no_red_pe) /
                  (INV_RED_EXP_VAL * nactive_lines));
    redval = (FLOAT32)pow(2.0f, (const_part - desired_pe) / (INV_RED_EXP_VAL * nactive_lines)) -
             avg_thr_exp;
    redval = MAX(0.0f, redval);
    iusace_reduce_thr(pstr_psy_out, ah_flag, thr_exp, redval, num_channels, chn);
  }

  iusace_calc_sfb_pe_data(pstr_qs_pe_data, pstr_psy_out, num_channels, chn);
  red_pe = pstr_qs_pe_data->pe;

  iteration = 0;
  do {
    iusace_calc_pe_no_active_holes(&red_pe_no_ah, &const_part_no_ah, &nactive_lines_no_ah,
                                   pstr_qs_pe_data, ah_flag, pstr_psy_out, num_channels, chn);

    desired_pe_no_ah = MAX(desired_pe - (red_pe - red_pe_no_ah), 0);
    if (nactive_lines_no_ah > FLT_EPSILON) {
      FLOAT32 avg_thr_exp = (FLOAT32)pow(
          2.0f, (const_part_no_ah - red_pe_no_ah) / (INV_RED_EXP_VAL * nactive_lines_no_ah));
      redval += (FLOAT32)pow(2.0f, (const_part_no_ah - desired_pe_no_ah) /
                                       (INV_RED_EXP_VAL * nactive_lines_no_ah)) -
                avg_thr_exp;
      redval = MAX(0.0f, redval);
      iusace_reduce_thr(pstr_psy_out, ah_flag, thr_exp, redval, num_channels, chn);
    }

    iusace_calc_sfb_pe_data(pstr_qs_pe_data, pstr_psy_out, num_channels, chn);
    red_pe = pstr_qs_pe_data->pe;
    iteration++;
  } while ((fabs(red_pe - desired_pe) > (0.05f) * desired_pe) && (iteration < 2));
  if (red_pe < 1.15f * desired_pe) {
    err_code = iusace_correct_thr(pstr_psy_out, ah_flag, pstr_qs_pe_data, thr_exp, redval,
                                  desired_pe - red_pe, num_channels, chn, ptr_scratch);
    if (err_code != IA_NO_ERROR) {
      return err_code;
    }
  } else {
    iusace_reduce_min_snr(pstr_psy_out, pstr_qs_pe_data, ah_flag, 1.05f * desired_pe,
                          num_channels, chn);
    iusace_allow_more_holes(pstr_psy_out, pstr_qs_pe_data, ah_flag, str_ah_param,
                            1.05f * desired_pe, num_channels, chn, ptr_scratch);
  }

  return IA_NO_ERROR;
}

IA_ERRORCODE iusace_adj_thr(ia_adj_thr_elem_struct *pstr_adj_thr_elem,
                            ia_psy_mod_out_data_struct *pstr_psy_out, FLOAT32 *ch_bit_dist,
                            ia_qc_out_data_struct *pstr_qc_out, const WORD32 avg_bits,
                            const WORD32 bitres_bits, const WORD32 max_bitres_bits,
                            const WORD32 side_info_bits, FLOAT32 *max_bit_fac,
                            WORD32 num_channels, WORD32 chn, iusace_scratch_mem *pstr_scratch) {
  IA_ERRORCODE err_code;
  FLOAT32 no_red_pe, granted_pe, granted_pe_corr;
  WORD32 curr_win_sequence;
  ia_qc_pe_data_struct *pstr_qc_pe_data = (ia_qc_pe_data_struct *)pstr_scratch->ptr_fd_scratch;
  pUWORD8 ptr_scratch = pstr_scratch->ptr_fd_scratch + sizeof(ia_qc_pe_data_struct);
  FLOAT32 bit_factor;
  WORD32 ch;

  pstr_qc_pe_data->pe_ch_data[0].sfb_lines = pstr_scratch->ptr_sfb_num_relevant_lines[0];
  pstr_qc_pe_data->pe_ch_data[0].sfb_ld_energy = pstr_scratch->ptr_sfb_ld_energy[0];
  if (num_channels == 2) {
    pstr_qc_pe_data->pe_ch_data[1].sfb_lines = pstr_scratch->ptr_sfb_num_relevant_lines[1];
    pstr_qc_pe_data->pe_ch_data[1].sfb_ld_energy = pstr_scratch->ptr_sfb_ld_energy[1];
  }
  pstr_qc_pe_data->offset = pstr_adj_thr_elem->pe_offset;

  iusace_calc_sfb_pe_data(pstr_qc_pe_data, pstr_psy_out, num_channels, chn);
  no_red_pe = pstr_qc_pe_data->pe;

  curr_win_sequence = ONLY_LONG_SEQUENCE;
  if (num_channels == 2) {
    if ((pstr_psy_out[chn].window_sequence == EIGHT_SHORT_SEQUENCE) ||
        (pstr_psy_out[chn + 1].window_sequence == EIGHT_SHORT_SEQUENCE)) {
      curr_win_sequence = EIGHT_SHORT_SEQUENCE;
    }
  } else {
    curr_win_sequence = pstr_psy_out[chn].window_sequence;
  }

  bit_factor =
      iusace_bitres_calc_bitfac(bitres_bits, max_bitres_bits, no_red_pe + 5.0f * side_info_bits,
                                curr_win_sequence, avg_bits, *max_bit_fac, pstr_adj_thr_elem);
  granted_pe = bit_factor * iusace_bits_to_pe((FLOAT32)avg_bits);
  iusace_calc_pe_correction(&(pstr_adj_thr_elem->pe_correction_fac), MIN(granted_pe, no_red_pe),
                            pstr_adj_thr_elem->pe_last, pstr_adj_thr_elem->dyn_bits_last);
  granted_pe_corr = granted_pe * pstr_adj_thr_elem->pe_correction_fac;

  if (granted_pe_corr < no_red_pe) {
    err_code = iusace_adapt_thr_to_pe(
        pstr_psy_out, pstr_qc_pe_data, granted_pe_corr, &pstr_adj_thr_elem->str_ah_param,
        &pstr_adj_thr_elem->str_min_snr_adapt_params, num_channels, chn, ptr_scratch);
    if (err_code != IA_NO_ERROR) {
      return err_code;
    }
  }

  for (ch = 0; ch < num_channels; ch++) {
    FLOAT32 tmp_var, temp1;
    if (pstr_qc_pe_data->pe) {
      tmp_var = 1.0f - num_channels * 0.2f;
      temp1 = pstr_qc_pe_data->pe_ch_data[ch].pe / pstr_qc_pe_data->pe;
      temp1 = temp1 * tmp_var;
      ch_bit_dist[ch] = temp1 + 0.2f;
      if (ch_bit_dist[ch] < 0.2f) ch_bit_dist[ch] = 0.2f;
    } else {
      ch_bit_dist[ch] = 0.2f;
    }
  }

  pstr_qc_out->pe = no_red_pe;
  pstr_adj_thr_elem->pe_last = granted_pe;

  return IA_NO_ERROR;
}

VOID iusace_calc_form_fac_per_chan(ia_psy_mod_out_data_struct *pstr_psy_out_chan,
                                   iusace_scratch_mem *pstr_scratch, WORD32 i_ch) {
  WORD32 i, j, sfb_offs;
  WORD32 sfb, sfb_width;
  FLOAT32 *ptr_sfb_form_factor = pstr_scratch->ptr_sfb_form_fac[i_ch];
  FLOAT32 *ptr_sfb_num_relevant_lines = pstr_scratch->ptr_sfb_num_relevant_lines[i_ch];
  FLOAT32 *ptr_sfb_ld_energy = pstr_scratch->ptr_sfb_ld_energy[i_ch];
  FLOAT64 spec_coef = 0;

  memset(ptr_sfb_num_relevant_lines, 0, sizeof(FLOAT32) * pstr_psy_out_chan->sfb_count);

  for (sfb_offs = 0; sfb_offs < pstr_psy_out_chan->sfb_count;
       sfb_offs += pstr_psy_out_chan->sfb_per_group) {
    i = sfb_offs;
    for (sfb = 0; sfb < pstr_psy_out_chan->max_sfb_per_grp; sfb++, i++) {
      ptr_sfb_form_factor[i] = MIN_FLT_VAL;
      if (pstr_psy_out_chan->ptr_sfb_energy[i] > pstr_psy_out_chan->ptr_sfb_thr[i]) {
        FLOAT32 avg_form_factor;

        for (j = pstr_psy_out_chan->sfb_offsets[i]; j < pstr_psy_out_chan->sfb_offsets[i + 1];
             j++) {
          spec_coef = fabs(pstr_psy_out_chan->ptr_spec_coeffs[j]);
          if (spec_coef < EPS && spec_coef != 0) spec_coef = EPS;
          ptr_sfb_form_factor[i] += (FLOAT32)sqrt(spec_coef);
        }

        sfb_width = pstr_psy_out_chan->sfb_offsets[i + 1] - pstr_psy_out_chan->sfb_offsets[i];
        avg_form_factor =
            (FLOAT32)pow(pstr_psy_out_chan->ptr_sfb_energy[i] / (FLOAT32)sfb_width, 0.25);
        ptr_sfb_num_relevant_lines[i] = ptr_sfb_form_factor[i] / avg_form_factor;
        ptr_sfb_ld_energy[i] = (FLOAT32)(log(pstr_psy_out_chan->ptr_sfb_energy[i]) * LOG2_1);
      }
    }
  }

  return;
}

VOID iusace_quantize_lines(const WORD32 gain, const WORD32 num_lines, FLOAT32 *ptr_exp_spectrum,
                           WORD16 *ptr_quant_spectrum, FLOAT32 *ptr_mdct_spec) {
  FLOAT32 quantizer;
  FLOAT32 k = 0.4054f;
  WORD32 line;

  quantizer = ixheaace_fd_quant_table[gain + 128];
  for (line = 0; line < num_lines; line++) {
    FLOAT32 tmp = ptr_mdct_spec[line];
    if (tmp < 0.0f) {
      ptr_exp_spectrum[line] = (FLOAT32)sqrt(-tmp);
      ptr_exp_spectrum[line] *= (FLOAT32)sqrt(ptr_exp_spectrum[line]);
      ptr_quant_spectrum[line] = -(WORD16)(k + quantizer * ptr_exp_spectrum[line]);
    } else {
      ptr_exp_spectrum[line] = (FLOAT32)sqrt(tmp);
      ptr_exp_spectrum[line] *= (FLOAT32)sqrt(ptr_exp_spectrum[line]);
      ptr_quant_spectrum[line] = (WORD16)(k + quantizer * ptr_exp_spectrum[line]);
    }
  }
  return;
}

VOID iusace_calculate_exp_spec(const WORD32 num_lines, FLOAT32 *ptr_exp_spectrum,
                               FLOAT32 *ptr_mdct_spec) {
  WORD32 line;

  for (line = 0; line < num_lines; line++) {
    ptr_exp_spectrum[line] = (FLOAT32)sqrt(fabs(ptr_mdct_spec[line]));
    ptr_exp_spectrum[line] *= (FLOAT32)sqrt(ptr_exp_spectrum[line]);
  }
  return;
}

static WORD32 iusace_scf_delta_bit_count(WORD32 delta) {
  if (delta > 60) {
    return (iusace_huffman_code_table[120][0]);
  }
  if (delta < -60) {
    return (iusace_huffman_code_table[0][0]);
  }
  return (iusace_huffman_code_table[delta + 60][0]);
}

static WORD32 iusace_count_single_scf_bits(WORD32 scf, WORD32 left_scf, WORD32 right_scf) {
  WORD32 scf_bits;

  scf_bits =
      iusace_scf_delta_bit_count(left_scf - scf) + iusace_scf_delta_bit_count(scf - right_scf);

  return scf_bits;
}

static FLOAT32 iusace_calc_single_spec_pe(WORD32 scf, FLOAT32 sfb_const_pe_part,
                                          FLOAT32 num_lines) {
  FLOAT32 spec_pe;
  FLOAT32 ld_ratio;

  ld_ratio = sfb_const_pe_part - (FLOAT32)0.375f * (FLOAT32)scf;

  if (ld_ratio >= PE_C1) {
    spec_pe = (FLOAT32)0.7f * num_lines * ld_ratio;
  } else {
    spec_pe = (FLOAT32)0.7f * num_lines * (PE_C2 + PE_C3 * ld_ratio);
  }

  return spec_pe;
}

static WORD32 iusace_count_scf_bits_diff(WORD16 *ptr_sfb_prev, WORD16 *ptr_sfb_new,
                                         WORD32 sfb_count, WORD32 start_sfb, WORD32 stop_sfb) {
  WORD32 scf_bits_diff = 0;
  WORD32 sfb = 0, sfb_last;
  WORD32 sfb_prev, sfb_next;

  sfb_last = start_sfb;

  while ((sfb_last < stop_sfb) && (ptr_sfb_prev[sfb_last] == SHRT_MIN)) {
    sfb_last++;
  }

  sfb_prev = start_sfb - 1;

  while ((sfb_prev >= 0) && (ptr_sfb_prev[sfb_prev] == SHRT_MIN)) {
    sfb_prev--;
  }

  if (sfb_prev >= 0) {
    scf_bits_diff += iusace_scf_delta_bit_count(ptr_sfb_new[sfb_prev] - ptr_sfb_new[sfb_last]) -
                     iusace_scf_delta_bit_count(ptr_sfb_prev[sfb_prev] - ptr_sfb_prev[sfb_last]);
  }

  for (sfb = sfb_last + 1; sfb < stop_sfb; sfb++) {
    if (ptr_sfb_prev[sfb] != SHRT_MIN) {
      scf_bits_diff += iusace_scf_delta_bit_count(ptr_sfb_new[sfb_last] - ptr_sfb_new[sfb]) -
                       iusace_scf_delta_bit_count(ptr_sfb_prev[sfb_last] - ptr_sfb_prev[sfb]);

      sfb_last = sfb;
    }
  }

  sfb_next = stop_sfb;

  while ((sfb_next < sfb_count) && (ptr_sfb_prev[sfb_next] == SHRT_MIN)) {
    sfb_next++;
  }

  if (sfb_next < sfb_count) {
    scf_bits_diff += iusace_scf_delta_bit_count(ptr_sfb_new[sfb_last] - ptr_sfb_new[sfb_next]) -
                     iusace_scf_delta_bit_count(ptr_sfb_prev[sfb_last] - ptr_sfb_prev[sfb_next]);
  }

  return scf_bits_diff;
}

static FLOAT32 iusace_calc_spec_pe_diff(ia_psy_mod_out_data_struct *pstr_psy_out,
                                        WORD16 *scf_prev, WORD16 *scf_new,
                                        FLOAT32 *ptr_sfb_const_pe_part, FLOAT32 *ptr_sfb_form_fac,
                                        FLOAT32 *ptr_sfb_num_rel_lines, WORD32 start_sfb,
                                        WORD32 stop_sfb) {
  FLOAT32 spec_pe_diff = 0.0f;
  WORD32 sfb;

  for (sfb = start_sfb; sfb < stop_sfb; sfb++) {
    if (scf_prev[sfb] != SHRT_MIN) {
      FLOAT32 ld_ratio_prev, ld_ratio_new, pe_prev, pe_new;

      if (ptr_sfb_const_pe_part[sfb] == MIN_FLT_VAL) {
        ptr_sfb_const_pe_part[sfb] = (FLOAT32)log(pstr_psy_out->ptr_sfb_energy[sfb] *
                                                  (FLOAT32)6.75f / ptr_sfb_form_fac[sfb]) *
                                     LOG2_1;
      }

      ld_ratio_prev = ptr_sfb_const_pe_part[sfb] - 0.375f * scf_prev[sfb];
      ld_ratio_new = ptr_sfb_const_pe_part[sfb] - 0.375f * scf_new[sfb];

      if (ld_ratio_prev >= PE_C1) {
        pe_prev = ld_ratio_prev;
      } else {
        pe_prev = PE_C2 + PE_C3 * ld_ratio_prev;
      }

      if (ld_ratio_new >= PE_C1) {
        pe_new = ld_ratio_new;
      } else {
        pe_new = PE_C2 + PE_C3 * ld_ratio_new;
      }

      spec_pe_diff += (FLOAT32)0.7f * ptr_sfb_num_rel_lines[sfb] * (pe_new - pe_prev);
    }
  }

  return spec_pe_diff;
}

FLOAT32 iusace_calc_sfb_dist(const FLOAT32 *ptr_spec, const FLOAT32 *ptr_exp_spec,
                             WORD16 *ptr_quant_spec, WORD32 sfb_width, WORD32 gain) {
  WORD32 i;
  FLOAT32 dist = 0;
  FLOAT32 k = 0.4054f;
  FLOAT32 quantizer = ixheaace_fd_quant_table[gain + 128];
  FLOAT32 inv_quantizer = ixheaace_fd_inv_quant_table[gain + 128];

  for (i = 0; i < sfb_width; i++) {
    FLOAT32 iq_val;
    FLOAT32 diff;

    ptr_quant_spec[i] = (WORD16)(k + quantizer * ptr_exp_spec[i]);

    if (ptr_quant_spec[i] < 64) {
      iq_val = ixheaace_pow_4_3_table[ptr_quant_spec[i]] * inv_quantizer;
    } else {
      iq_val = (FLOAT32)((pow((FLOAT32)abs(ptr_quant_spec[i]), 4.0f / 3.0f)) * inv_quantizer);
    }

    diff = (FLOAT32)fabs(ptr_spec[i]) - iq_val;

    dist += diff * diff;
  }

  return dist;
}

static WORD16 iusace_improve_scf(FLOAT32 *ptr_spec, FLOAT32 *ptr_exp_spec, WORD16 *ptr_quant_spec,
                                 WORD16 *ptr_quant_spec_temp, WORD32 sfb_width, FLOAT32 threshold,
                                 WORD16 scf, WORD16 min_scf, FLOAT32 *dist,
                                 WORD16 *ptr_min_calc_scf) {
  FLOAT32 sfb_dist;
  WORD16 best_scf = scf;
  WORD32 j;

  sfb_dist = iusace_calc_sfb_dist(ptr_spec, ptr_exp_spec, ptr_quant_spec, sfb_width, scf);

  *ptr_min_calc_scf = scf;

  if (sfb_dist > (1.25 * threshold)) {
    WORD16 estimated_scf = scf;
    FLOAT32 best_sfb_dist = sfb_dist;
    WORD32 count;

    count = 0;

    while ((sfb_dist > (1.25 * threshold)) && (count++ < SCF_COUNT_LIMIT_THREE)) {
      scf++;

      sfb_dist =
          iusace_calc_sfb_dist(ptr_spec, ptr_exp_spec, ptr_quant_spec_temp, sfb_width, scf);

      if (sfb_dist < best_sfb_dist) {
        best_scf = scf;
        best_sfb_dist = sfb_dist;

        memcpy(ptr_quant_spec, ptr_quant_spec_temp, sfb_width * sizeof(WORD16));
      }
    }

    count = 0;
    scf = estimated_scf;
    sfb_dist = best_sfb_dist;

    while ((sfb_dist > (1.25 * threshold)) && (count++ < SCF_COUNT_LIMIT_ONE) &&
      (scf > min_scf)) {
      scf--;

      sfb_dist =
          iusace_calc_sfb_dist(ptr_spec, ptr_exp_spec, ptr_quant_spec_temp, sfb_width, scf);

      if (sfb_dist < best_sfb_dist) {
        best_scf = scf;
        best_sfb_dist = sfb_dist;

        memcpy(ptr_quant_spec, ptr_quant_spec_temp, sfb_width * sizeof(WORD16));
      }
      *ptr_min_calc_scf = scf;
    }
    *dist = best_sfb_dist;
  } else {
    FLOAT32 best_sfb_dist = sfb_dist;
    FLOAT32 allowed_sfb_dist = MIN(sfb_dist * 1.25f, threshold);
    WORD32 count;

    for (count = 0; count < SCF_COUNT_LIMIT_THREE; count++) {
      scf++;

      sfb_dist =
          iusace_calc_sfb_dist(ptr_spec, ptr_exp_spec, ptr_quant_spec_temp, sfb_width, scf);

      if (sfb_dist < allowed_sfb_dist) {
        *ptr_min_calc_scf = best_scf + 1;

        best_scf = scf;
        best_sfb_dist = sfb_dist;
        memcpy(ptr_quant_spec, ptr_quant_spec_temp, sfb_width * sizeof(WORD16));
      }
    }
    *dist = best_sfb_dist;
  }

  for (j = 0; j < sfb_width; j++) {
    if (ptr_spec[j] < 0) {
      ptr_quant_spec[j] = -ptr_quant_spec[j];
    }
  }

  return best_scf;
}

static VOID iusace_assimilate_single_scf(ia_psy_mod_out_data_struct *pstr_psy_out,
                                         FLOAT32 *ptr_exp_spec, WORD16 *ptr_quant_spec,
                                         WORD16 *ptr_quant_spec_temp, WORD16 *scf,
                                         WORD16 *ptr_min_scf, FLOAT32 *ptr_sfb_dist,
                                         FLOAT32 *ptr_sfb_const_pe_part,
                                         FLOAT32 *ptr_sfb_form_fac, FLOAT32 *ptr_sfb_num_lines,
                                         WORD16 *ptr_min_calc_scf, FLOAT32 *ptr_mdct_spec_float) {
  WORD32 sfb_prev, sfb_act, sfb_next;
  WORD16 scf_act = 0, *scf_prev, *scf_next, min_scf, max_scf;
  WORD32 sfb_width, sfb_offs;
  FLOAT32 energy;
  FLOAT32 sfb_pe_prev, sfb_pe_new;
  FLOAT32 sfb_dist_new;
  WORD32 j;
  WORD32 success = 0;
  FLOAT32 delta_pe = 0.0f, delta_pe_new, delta_pe_temp;
  WORD16 prev_scf_last[MAX_NUM_GROUPED_SFB], prev_scf_next[MAX_NUM_GROUPED_SFB];
  FLOAT32 delta_pe_last[MAX_NUM_GROUPED_SFB];
  WORD32 update_min_scf;

  for (j = 0; j < pstr_psy_out->sfb_count; j++) {
    prev_scf_last[j] = SHRT_MAX;
    prev_scf_next[j] = SHRT_MAX;
    delta_pe_last[j] = MAX_FLT_VAL;
  }

  sfb_prev = -1;
  sfb_act = -1;
  sfb_next = -1;
  scf_prev = 0;
  scf_next = 0;
  min_scf = SHRT_MAX;
  max_scf = SHRT_MAX;

  do {
    sfb_next++;

    while ((sfb_next < pstr_psy_out->sfb_count) && (scf[sfb_next] == SHRT_MIN)) {
      sfb_next++;
    }

    if ((sfb_prev >= 0) && (sfb_act >= 0) && (sfb_next < pstr_psy_out->sfb_count)) {
      scf_act = scf[sfb_act];

      scf_prev = scf + sfb_prev;
      scf_next = scf + sfb_next;

      min_scf = MIN(*scf_prev, *scf_next);

      max_scf = MAX(*scf_prev, *scf_next);
    } else {
      if ((sfb_prev == -1) && (sfb_act >= 0) && (sfb_next < pstr_psy_out->sfb_count)) {
        scf_act = scf[sfb_act];

        scf_prev = &scf_act;

        scf_next = scf + sfb_next;

        min_scf = *scf_next;

        max_scf = *scf_next;
      } else {
        if ((sfb_prev >= 0) && (sfb_act >= 0) && (sfb_next == pstr_psy_out->sfb_count)) {
          scf_act = scf[sfb_act];

          scf_prev = scf + sfb_prev;

          scf_next = &scf_act;

          min_scf = *scf_prev;

          max_scf = *scf_prev;
        }
      }
    }

    if (sfb_act >= 0) {
      min_scf = MAX(min_scf, ptr_min_scf[sfb_act]);
    }

    if ((sfb_act >= 0) && (sfb_prev >= 0 || sfb_next < pstr_psy_out->sfb_count) &&
        (scf_act > min_scf) && (scf_act <= min_scf + MAX_SCF_DELTA) &&
        (scf_act >= max_scf - MAX_SCF_DELTA) &&
        (*scf_prev != prev_scf_last[sfb_act] || *scf_next != prev_scf_next[sfb_act] ||
         delta_pe < delta_pe_last[sfb_act])) {
      success = 0;

      sfb_width = pstr_psy_out->sfb_offsets[sfb_act + 1] - pstr_psy_out->sfb_offsets[sfb_act];

      sfb_offs = pstr_psy_out->sfb_offsets[sfb_act];

      energy = pstr_psy_out->ptr_sfb_energy[sfb_act];

      if (ptr_sfb_const_pe_part[sfb_act] == MIN_FLT_VAL) {
        ptr_sfb_const_pe_part[sfb_act] =
            (FLOAT32)log(energy * (FLOAT32)6.75f / ptr_sfb_form_fac[sfb_act]) * LOG2_1;
      }

      sfb_pe_prev = iusace_calc_single_spec_pe(scf_act, ptr_sfb_const_pe_part[sfb_act],
                                               ptr_sfb_num_lines[sfb_act]) +
                    iusace_count_single_scf_bits(scf_act, *scf_prev, *scf_next);

      delta_pe_new = delta_pe;
      update_min_scf = 1;

      do {
        scf_act--;

        if (scf_act < ptr_min_calc_scf[sfb_act] && scf_act >= max_scf - MAX_SCF_DELTA) {
          sfb_pe_new = iusace_calc_single_spec_pe(scf_act, ptr_sfb_const_pe_part[sfb_act],
                                                  ptr_sfb_num_lines[sfb_act]) +
                       (FLOAT32)iusace_count_single_scf_bits(scf_act, *scf_prev, *scf_next);

          delta_pe_temp = delta_pe + sfb_pe_new - sfb_pe_prev;

          if (delta_pe_temp < (FLOAT32)10.0f) {
            sfb_dist_new =
                iusace_calc_sfb_dist(ptr_mdct_spec_float + sfb_offs, ptr_exp_spec + sfb_offs,
                                     ptr_quant_spec_temp + sfb_offs, sfb_width, scf_act);

            if (sfb_dist_new < ptr_sfb_dist[sfb_act]) {
              scf[sfb_act] = scf_act;
              ptr_sfb_dist[sfb_act] = sfb_dist_new;

              for (j = sfb_offs; j < sfb_offs + sfb_width; j++) {
                ptr_quant_spec[j] = ptr_quant_spec_temp[j];

                if (ptr_mdct_spec_float[j] < 0.0f) {
                  ptr_quant_spec[j] = -ptr_quant_spec[j];
                }
              }
              delta_pe_new = delta_pe_temp;
              success = 1;
            }

            if (update_min_scf) {
              ptr_min_calc_scf[sfb_act] = scf_act;
            }
          } else {
            update_min_scf = 0;
          }
        }
      } while (scf_act > min_scf);

      delta_pe = delta_pe_new;

      prev_scf_last[sfb_act] = *scf_prev;
      prev_scf_next[sfb_act] = *scf_next;
      delta_pe_last[sfb_act] = delta_pe;
    }

    if (success) {
      sfb_prev = -1;
      sfb_act = -1;
      sfb_next = -1;
      scf_prev = 0;
      scf_next = 0;
      min_scf = SHRT_MAX;
      max_scf = SHRT_MAX;
      success = 0;
    } else {
      sfb_prev = sfb_act;
      sfb_act = sfb_next;
    }
  } while (sfb_next < pstr_psy_out->sfb_count);
  return;
}

static VOID iusace_assimilate_multiple_scf(ia_psy_mod_out_data_struct *pstr_psy_out,
                                           FLOAT32 *ptr_exp_spec, WORD16 *ptr_quant_spec,
                                           WORD16 *ptr_quant_spec_temp, WORD16 *ptr_scf,
                                           WORD16 *ptr_min_scf, FLOAT32 *ptr_sfb_dist,
                                           FLOAT32 *ptr_sfb_const_pe_part,
                                           FLOAT32 *ptr_sfb_form_fac, FLOAT32 *ptr_sfb_num_lines,
                                           FLOAT32 *ptr_mdct_spec_float, pUWORD8 pstr_scratch) {
  WORD32 sfb, start_sfb, stop_sfb;
  WORD16 scf_temp[MAX_NUM_GROUPED_SFB], min_scf, max_scf, scf_act;
  WORD32 possible_region_found;
  WORD32 sfb_width, sfb_offs, j;
  FLOAT32 prev_dist_sum, new_dist_sum;
  WORD32 delta_scf_bits;
  FLOAT32 delta_spec_pe;
  FLOAT32 delta_pe = 0.0f, delta_pe_new;
  WORD32 sfb_count = pstr_psy_out->sfb_count;
  FLOAT32 *sfb_dist_new = (FLOAT32 *)pstr_scratch;
  min_scf = SHRT_MAX;
  max_scf = SHRT_MIN;

  for (sfb = 0; sfb < sfb_count; sfb++) {
    if (ptr_scf[sfb] != SHRT_MIN) {
      min_scf = MIN(min_scf, ptr_scf[sfb]);

      max_scf = MAX(max_scf, ptr_scf[sfb]);
    }
  }

  if (max_scf != SHRT_MIN && max_scf <= min_scf + MAX_SCF_DELTA) {
    scf_act = max_scf;

    do {
      scf_act--;

      memcpy(scf_temp, ptr_scf, MAX_NUM_GROUPED_SFB * sizeof(WORD16));

      stop_sfb = 0;

      do {
        sfb = stop_sfb;

        while (sfb < sfb_count && (ptr_scf[sfb] == SHRT_MIN || ptr_scf[sfb] <= scf_act)) {
          sfb++;
        }

        start_sfb = sfb;

        sfb++;

        while (sfb < sfb_count && (ptr_scf[sfb] == SHRT_MIN || ptr_scf[sfb] > scf_act)) {
          sfb++;
        }

        stop_sfb = sfb;

        possible_region_found = 0;

        if (start_sfb < sfb_count) {
          possible_region_found = 1;

          for (sfb = start_sfb; sfb < stop_sfb; sfb++) {
            if (ptr_scf[sfb] != SHRT_MIN) {
              if (scf_act < ptr_min_scf[sfb]) {
                possible_region_found = 0;
                break;
              }
            }
          }
        }

        if (possible_region_found) {
          for (sfb = start_sfb; sfb < stop_sfb; sfb++) {
            if (scf_temp[sfb] != SHRT_MIN) {
              scf_temp[sfb] = scf_act;
            }
          }

          delta_scf_bits =
              iusace_count_scf_bits_diff(ptr_scf, scf_temp, sfb_count, start_sfb, stop_sfb);

          delta_spec_pe =
              iusace_calc_spec_pe_diff(pstr_psy_out, ptr_scf, scf_temp, ptr_sfb_const_pe_part,
                                       ptr_sfb_form_fac, ptr_sfb_num_lines, start_sfb, stop_sfb);

          delta_pe_new = delta_pe + (FLOAT32)delta_scf_bits + delta_spec_pe;

          if (delta_pe_new < (FLOAT32)10.0f) {
            prev_dist_sum = new_dist_sum = 0.0f;

            for (sfb = start_sfb; sfb < stop_sfb; sfb++) {
              if (scf_temp[sfb] != SHRT_MIN) {
                prev_dist_sum += ptr_sfb_dist[sfb];

                sfb_width = pstr_psy_out->sfb_offsets[sfb + 1] - pstr_psy_out->sfb_offsets[sfb];

                sfb_offs = pstr_psy_out->sfb_offsets[sfb];

                sfb_dist_new[sfb] =
                    iusace_calc_sfb_dist(ptr_mdct_spec_float + sfb_offs, ptr_exp_spec + sfb_offs,
                                         ptr_quant_spec_temp + sfb_offs, sfb_width, scf_act);

                if (sfb_dist_new[sfb] > pstr_psy_out->ptr_sfb_thr[sfb]) {
                  new_dist_sum = (FLOAT32)2.0f * prev_dist_sum;
                  break;
                }

                new_dist_sum += sfb_dist_new[sfb];
              }
            }

            if (new_dist_sum < prev_dist_sum) {
              delta_pe = delta_pe_new;

              for (sfb = start_sfb; sfb < stop_sfb; sfb++) {
                if (ptr_scf[sfb] != SHRT_MIN) {
                  sfb_width = pstr_psy_out->sfb_offsets[sfb + 1] - pstr_psy_out->sfb_offsets[sfb];

                  sfb_offs = pstr_psy_out->sfb_offsets[sfb];
                  ptr_scf[sfb] = scf_act;
                  ptr_sfb_dist[sfb] = sfb_dist_new[sfb];

                  for (j = sfb_offs; j < sfb_offs + sfb_width; j++) {
                    ptr_quant_spec[j] = ptr_quant_spec_temp[j];

                    if (ptr_mdct_spec_float[j] < 0.0f) {
                      ptr_quant_spec[j] = -ptr_quant_spec[j];
                    }
                  }
                }
              }
            }
          }
        }

      } while (stop_sfb <= sfb_count);

    } while (scf_act > min_scf);
  }
  return;
}

VOID iusace_estimate_scfs_chan(ia_psy_mod_out_data_struct *pstr_psy_out,
                               ia_qc_out_chan_struct *str_qc_out_chan, WORD32 num_channels,
                               WORD32 chn, iusace_scratch_mem *pstr_scratch) {
  WORD16 *ptr_scalefactor;
  WORD32 *global_gain;
  FLOAT32 *p_sfb_form_factor;
  FLOAT32 *p_sfb_num_relevant_lines;
  WORD16 *ptr_quant_spec;
  WORD32 i, ch, j, idx = 0;
  FLOAT32 thresh, energy, energy_part, thr_part;
  FLOAT32 scf_float;
  WORD16 scf_int = 0, min_scf = 0, max_scf = 0;
  FLOAT64 max_spec = 0.0f;
  WORD16 min_sf_max_quant[MAX_NUM_GROUPED_SFB] = {0};
  pUWORD8 ptr_scratch = pstr_scratch->ptr_fd_scratch;
  FLOAT32 *ptr_sfb_dist = (FLOAT32 *)ptr_scratch;
  ptr_scratch += MAX_NUM_GROUPED_SFB * sizeof(ptr_sfb_dist[0]);
  WORD16 min_calc_scf[MAX_NUM_GROUPED_SFB] = {0};

  WORD16 *ptr_quant_spec_temp = pstr_scratch->p_adjthr_quant_spec_temp;
  FLOAT32 *ptr_exp_spec = pstr_scratch->p_adjthr_ptr_exp_spec;
  FLOAT32 *ptr_mdct_spec_float = pstr_scratch->p_adjthr_mdct_spec_float;
  FLOAT32 *sfb_const_pe_part = (FLOAT32 *)ptr_scratch;

  FLOAT32 **ptr_sfb_form_factor = &pstr_scratch->ptr_sfb_form_fac[0];
  FLOAT32 **ptr_sfb_num_relevant_lines = &pstr_scratch->ptr_sfb_num_relevant_lines[0];

  ptr_scratch += MAX_NUM_GROUPED_SFB * sizeof(sfb_const_pe_part[0]);

  memset(ptr_quant_spec_temp, 0, FRAME_LEN_LONG * sizeof(WORD16));
  memset(ptr_mdct_spec_float, 0, FRAME_LEN_LONG * sizeof(FLOAT32));
  memset(ptr_exp_spec, 0, FRAME_LEN_LONG * sizeof(FLOAT32));
  memset(ptr_sfb_dist, 0, MAX_NUM_GROUPED_SFB * sizeof(FLOAT32));
  for (ch = chn; ch < chn + num_channels; ch++) {
    ia_psy_mod_out_data_struct *ptr_psy_out = &pstr_psy_out[ch];
    str_qc_out_chan[idx].global_gain = 0;

    memset(str_qc_out_chan[idx].scalefactor, 0,
           sizeof(str_qc_out_chan[idx].scalefactor[0]) * pstr_psy_out[ch].sfb_count);
    memset(str_qc_out_chan[idx].quant_spec, 0,
           sizeof(str_qc_out_chan[idx].quant_spec[0]) * FRAME_LEN_LONG);

    ptr_scalefactor = str_qc_out_chan[idx].scalefactor;
    global_gain = &str_qc_out_chan[idx].global_gain;
    p_sfb_form_factor = &ptr_sfb_form_factor[idx][0];
    p_sfb_num_relevant_lines = &ptr_sfb_num_relevant_lines[idx][0];
    ptr_quant_spec = str_qc_out_chan[idx].quant_spec;
    for (i = 0; i < ptr_psy_out->sfb_count; i++) {
      thresh = ptr_psy_out->ptr_sfb_thr[i];
      energy = ptr_psy_out->ptr_sfb_energy[i];
      max_spec = 0.0;

      for (j = ptr_psy_out->sfb_offsets[i]; j < ptr_psy_out->sfb_offsets[i + 1]; j++) {
        max_spec = MAX(max_spec, fabs(ptr_psy_out->ptr_spec_coeffs[j]));
      }

      ptr_scalefactor[i] = MIN_SHRT_VAL;
      min_sf_max_quant[i] = MIN_SHRT_VAL;

      if ((max_spec > 0.0) && (energy > thresh) && (p_sfb_form_factor[i] != MIN_FLT_VAL)) {
        energy_part = (FLOAT32)log10(p_sfb_form_factor[i] + FLT_EPSILON);

        thr_part = (FLOAT32)log10(6.75 * thresh + MIN_FLT_VAL);
        scf_float = 8.8585f * (thr_part - energy_part);
        scf_int = (WORD16)floor(scf_float);
        min_sf_max_quant[i] = (WORD16)ceil(C1_SF + C2_SF * log(max_spec));
        scf_int = MAX(scf_int, min_sf_max_quant[i]);
        scf_int = MAX(scf_int, MIN_GAIN_INDEX);
        scf_int = MIN(scf_int, (MAX_GAIN_INDEX - SCF_COUNT_LIMIT_THREE));
        for (j = 0; j < ptr_psy_out->sfb_offsets[i + 1] - ptr_psy_out->sfb_offsets[i]; j++) {
          ptr_exp_spec[ptr_psy_out->sfb_offsets[i] + j] =
              (FLOAT32)(ptr_psy_out->ptr_spec_coeffs[ptr_psy_out->sfb_offsets[i] + j]);
          ptr_mdct_spec_float[ptr_psy_out->sfb_offsets[i] + j] =
              (FLOAT32)(ptr_psy_out->ptr_spec_coeffs[ptr_psy_out->sfb_offsets[i] + j]);
        }

        iusace_calculate_exp_spec(ptr_psy_out->sfb_offsets[i + 1] - ptr_psy_out->sfb_offsets[i],
                                  ptr_exp_spec + ptr_psy_out->sfb_offsets[i],
                                  ptr_mdct_spec_float + ptr_psy_out->sfb_offsets[i]);

        scf_int = iusace_improve_scf(
            ptr_mdct_spec_float + ptr_psy_out->sfb_offsets[i],
            ptr_exp_spec + ptr_psy_out->sfb_offsets[i],
            ptr_quant_spec + ptr_psy_out->sfb_offsets[i],
            ptr_quant_spec_temp + ptr_psy_out->sfb_offsets[i],
            ptr_psy_out->sfb_offsets[i + 1] - ptr_psy_out->sfb_offsets[i], thresh, scf_int,
            min_sf_max_quant[i], &ptr_sfb_dist[i], &min_calc_scf[i]);

        ptr_scalefactor[i] = scf_int;
      }
    }

    for (i = 0; i < ptr_psy_out->sfb_count; i++) {
      sfb_const_pe_part[i] = MIN_FLT_VAL;
    }

    iusace_assimilate_single_scf(ptr_psy_out, ptr_exp_spec, ptr_quant_spec, ptr_quant_spec_temp,
                                 ptr_scalefactor, min_sf_max_quant, ptr_sfb_dist,
                                 sfb_const_pe_part, p_sfb_form_factor, p_sfb_num_relevant_lines,
                                 min_calc_scf, ptr_mdct_spec_float);

    iusace_assimilate_multiple_scf(ptr_psy_out, ptr_exp_spec, ptr_quant_spec, ptr_quant_spec_temp,
                                   ptr_scalefactor, min_sf_max_quant, ptr_sfb_dist,
                                   sfb_const_pe_part, p_sfb_form_factor, p_sfb_num_relevant_lines,
                                   ptr_mdct_spec_float, ptr_scratch);

    max_scf = MIN_SHRT_VAL;
    min_scf = MAX_SHRT_VAL;
    for (i = 0; i < ptr_psy_out->sfb_count; i++) {
      if (max_scf < ptr_scalefactor[i]) {
        max_scf = ptr_scalefactor[i];
      }
      if ((ptr_scalefactor[i] != MIN_SHRT_VAL) && (min_scf > ptr_scalefactor[i])) {
        min_scf = ptr_scalefactor[i];
      }
    }

    for (i = 0; i < pstr_psy_out[ch].sfb_count; i++) {
      if ((ptr_scalefactor[i] != MIN_SHRT_VAL) &&
          (min_scf + MAX_SCF_DELTA) < ptr_scalefactor[i]) {
        ptr_scalefactor[i] = min_scf + MAX_SCF_DELTA;

        iusace_calc_sfb_dist(ptr_mdct_spec_float + ptr_psy_out->sfb_offsets[i],
                             ptr_exp_spec + ptr_psy_out->sfb_offsets[i],
                             ptr_quant_spec + ptr_psy_out->sfb_offsets[i],
                             ptr_psy_out->sfb_offsets[i + 1] - ptr_psy_out->sfb_offsets[i],
                             ptr_scalefactor[i]);
      }
    }

    max_scf = MIN((min_scf + MAX_SCF_DELTA), max_scf);

    if (max_scf > MIN_SHRT_VAL) {
      *global_gain = max_scf;
      for (i = 0; i < ptr_psy_out->sfb_count; i++) {
        if (ptr_scalefactor[i] == MIN_SHRT_VAL) {
          ptr_scalefactor[i] = 0;
          memset(
              &ptr_psy_out->ptr_spec_coeffs[ptr_psy_out->sfb_offsets[i]], 0,
              (ptr_psy_out->sfb_offsets[i + 1] - ptr_psy_out->sfb_offsets[i]) * sizeof(FLOAT64));
        } else {
          ptr_scalefactor[i] = max_scf - ptr_scalefactor[i];
        }
      }
    } else {
      *global_gain = 0;
      for (i = 0; i < ptr_psy_out->sfb_count; i++) {
        ptr_scalefactor[i] = 0;
        memset(&ptr_psy_out->ptr_spec_coeffs[ptr_psy_out->sfb_offsets[i]], 0,
               (ptr_psy_out->sfb_offsets[i + 1] - ptr_psy_out->sfb_offsets[i]) * sizeof(FLOAT64));
      }
    }
    idx++;
  }

  return;
}