/******************************************************************************
 *                                                                            *
 * 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 <math.h>
#include <string.h>

#include "iusace_type_def.h"
#include "ixheaac_error_standards.h"
#include "ixheaace_error_codes.h"
#include "ixheaace_mps_common_define.h"
#include "iusace_cnst.h"
#include "iusace_fd_quant.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 "iusace_block_switch_const.h"
#include "iusace_block_switch_struct_def.h"
#include "iusace_signal_classifier.h"
#include "iusace_ms.h"
#include "ixheaace_adjust_threshold_data.h"
#include "iusace_fd_qc_util.h"
#include "ixheaace_sbr_header.h"
#include "ixheaace_config.h"
#include "ixheaace_asc_write.h"
#include "iusace_main.h"
#include "iusace_rom.h"

static VOID iusace_compute_pred_coef(WORD32 num_lines, WORD32 complex_coef,
                                     FLOAT64 *ptr_spec_mdct_dmx, FLOAT64 *ptr_spec_mdst_dmx,
                                     FLOAT64 *ptr_spec_mdct_mid_side, FLOAT32 *pred_coef_re,
                                     FLOAT32 *pred_coef_im, FLOAT32 *pred_coef_q_re,
                                     FLOAT32 *pred_coef_q_im, WORD32 *pred_coef_q_int_re,
                                     WORD32 *pred_coef_q_int_im) {
  LOOPIDX bin_idx;
  FLOAT32 iprod_re = 0.0f, iprod_im = 0.0f;
  FLOAT32 eps = 1.0e-6f;
  const FLOAT32 k_delta = 0.1f;
  const FLOAT32 k_max = 3.0f;
  WORD32 pred_coef_sign_re, pred_coef_sign_im;
  FLOAT32 pred_coef_abs_re, pred_coef_abs_im;
  FLOAT32 abs_dmx = 0.0f;

  for (bin_idx = 0; bin_idx < num_lines; bin_idx++) {
    /* D = Dr + jDi */
    /* D*S = (Dr + jDi)*S = Dr*S + j(Di*S) */
    /* alpha = alpha_r - jalpha_i */
    if (complex_coef == 1) {
      iprod_re += (FLOAT32)(ptr_spec_mdct_dmx[bin_idx] * ptr_spec_mdct_mid_side[bin_idx]);
      iprod_im += (FLOAT32)(ptr_spec_mdst_dmx[bin_idx] * ptr_spec_mdct_mid_side[bin_idx]);
      abs_dmx += (FLOAT32)(ptr_spec_mdct_dmx[bin_idx] * ptr_spec_mdct_dmx[bin_idx] +
                           ptr_spec_mdst_dmx[bin_idx] * ptr_spec_mdst_dmx[bin_idx]);
    } else {
      iprod_re += (FLOAT32)(ptr_spec_mdct_dmx[bin_idx] * ptr_spec_mdct_mid_side[bin_idx]);
      abs_dmx += (FLOAT32)(ptr_spec_mdct_dmx[bin_idx] * ptr_spec_mdct_dmx[bin_idx]);
    }
  }

  /* Compute real and imaginary parts of prediction coefficient  */
  *pred_coef_re = iprod_re / (abs_dmx + eps);
  pred_coef_sign_re = *pred_coef_re > 0 ? 1 : -1;
  pred_coef_abs_re = (FLOAT32)MIN(fabs(*pred_coef_re), k_max);
  *pred_coef_q_int_re = pred_coef_sign_re * (WORD32)(pred_coef_abs_re / k_delta + 0.5f);
  *pred_coef_q_re = *pred_coef_q_int_re * k_delta;

  if (complex_coef == 1) {
    *pred_coef_im = iprod_im / (abs_dmx + eps);
    pred_coef_sign_im = *pred_coef_im > 0 ? 1 : -1;
    pred_coef_abs_im = (FLOAT32)MIN(fabs(*pred_coef_im), k_max);
    *pred_coef_q_int_im = pred_coef_sign_im * (WORD32)(pred_coef_abs_im / k_delta + 0.5f);
    *pred_coef_q_im = *pred_coef_q_int_im * k_delta;
  }
}

static VOID iusace_compute_res(WORD32 num_lines, WORD32 complex_coef, FLOAT32 pred_coef_q_re,
                               FLOAT32 pred_coef_q_im, FLOAT64 *ptr_spec_mdct_dmx,
                               FLOAT64 *ptr_spec_mdst_dmx, FLOAT64 *ptr_spec_mdct_mid_side,
                               FLOAT64 *ptr_spec_mdct_res) {
  LOOPIDX i;

  for (i = 0; i < num_lines; i++) {
    /* DMX = M; E = S - alpha*DMX if pred_dir = 0 */
    /* DMX = S; E = M - alpha*DMX if pred_dir = 1 */
    if (complex_coef == 1) {
      ptr_spec_mdct_res[i] =
          (FLOAT32)(ptr_spec_mdct_mid_side[i] - pred_coef_q_re * ptr_spec_mdct_dmx[i] -
                    pred_coef_q_im * ptr_spec_mdst_dmx[i]);
    } else {
      ptr_spec_mdct_res[i] =
          (FLOAT32)(ptr_spec_mdct_mid_side[i] - pred_coef_q_re * ptr_spec_mdct_dmx[i]);
    }
  }
}

static VOID iusace_filter_and_add(const FLOAT64 *ptr_in, const WORD32 length,
                                  const FLOAT64 *ptr_filter, FLOAT64 *ptr_out,
                                  const WORD32 factor_even) {
  LOOPIDX i;
  FLOAT64 s;

  i = 0;
  s = ptr_filter[6] * ptr_in[2] + ptr_filter[5] * ptr_in[1] + ptr_filter[4] * ptr_in[0] +
      ptr_filter[3] * ptr_in[0] + ptr_filter[2] * ptr_in[1] + ptr_filter[1] * ptr_in[2] +
      ptr_filter[0] * ptr_in[3];
  ptr_out[i] += s * factor_even;
  i = 1;
  s = ptr_filter[6] * ptr_in[1] + ptr_filter[5] * ptr_in[0] + ptr_filter[4] * ptr_in[0] +
      ptr_filter[3] * ptr_in[1] + ptr_filter[2] * ptr_in[2] + ptr_filter[1] * ptr_in[3] +
      ptr_filter[0] * ptr_in[4];
  ptr_out[i] += s;
  i = 2;
  s = ptr_filter[6] * ptr_in[0] + ptr_filter[5] * ptr_in[0] + ptr_filter[4] * ptr_in[1] +
      ptr_filter[3] * ptr_in[2] + ptr_filter[2] * ptr_in[3] + ptr_filter[1] * ptr_in[4] +
      ptr_filter[0] * ptr_in[5];
  ptr_out[i] += s * factor_even;

  for (i = 3; i < length - 4; i += 2) {
    s = ptr_filter[6] * ptr_in[i - 3] + ptr_filter[5] * ptr_in[i - 2] +
        ptr_filter[4] * ptr_in[i - 1] + ptr_filter[3] * ptr_in[i] +
        ptr_filter[2] * ptr_in[i + 1] + ptr_filter[1] * ptr_in[i + 2] +
        ptr_filter[0] * ptr_in[i + 3];
    ptr_out[i] += s;
    s = ptr_filter[6] * ptr_in[i - 2] + ptr_filter[5] * ptr_in[i - 1] +
        ptr_filter[4] * ptr_in[i] + ptr_filter[3] * ptr_in[i + 1] +
        ptr_filter[2] * ptr_in[i + 2] + ptr_filter[1] * ptr_in[i + 3] +
        ptr_filter[0] * ptr_in[i + 4];
    ptr_out[i + 1] += s * factor_even;
  }

  i = length - 3;
  s = ptr_filter[6] * ptr_in[i - 3] + ptr_filter[5] * ptr_in[i - 2] +
      ptr_filter[4] * ptr_in[i - 1] + ptr_filter[3] * ptr_in[i] + ptr_filter[2] * ptr_in[i + 1] +
      ptr_filter[1] * ptr_in[i + 2] + ptr_filter[0] * ptr_in[i + 2];
  ptr_out[i] += s;
  i = length - 2;
  s = ptr_filter[6] * ptr_in[i - 3] + ptr_filter[5] * ptr_in[i - 2] +
      ptr_filter[4] * ptr_in[i - 1] + ptr_filter[3] * ptr_in[i] + ptr_filter[2] * ptr_in[i + 1] +
      ptr_filter[1] * ptr_in[i + 1] + ptr_filter[0] * ptr_in[i];
  ptr_out[i] += s * factor_even;
  i = length - 1;
  s = ptr_filter[6] * ptr_in[i - 3] + ptr_filter[5] * ptr_in[i - 2] +
      ptr_filter[4] * ptr_in[i - 1] + ptr_filter[3] * ptr_in[i] + ptr_filter[2] * ptr_in[i] +
      ptr_filter[1] * ptr_in[i - 1] + ptr_filter[0] * ptr_in[i - 2];
  ptr_out[i] += s;
}

static VOID iusace_estimate_dmx_im(const FLOAT64 *ptr_dmx_re, const FLOAT64 *ptr_dmx_re_prev,
                                   FLOAT64 *ptr_dmx_im, WORD32 window, const WORD32 w_shape,
                                   const WORD32 prev_w_shape, WORD32 num_sbk,
                                   WORD32 bins_per_sbk) {
  LOOPIDX i;
  const FLOAT64 *ptr_mdst_fcoeff_curr, *ptr_mdst_fcoeff_prev;

  switch (window) {
    case ONLY_LONG_SEQUENCE:
    case EIGHT_SHORT_SEQUENCE:
      ptr_mdst_fcoeff_curr = iusace_mdst_fcoeff_longshort_curr[prev_w_shape][w_shape];
      ptr_mdst_fcoeff_prev = iusace_mdst_fcoeff_l_s_start_left_prev[prev_w_shape];
      break;
    case LONG_START_SEQUENCE:
      ptr_mdst_fcoeff_curr = iusace_mdst_fcoeff_start_curr[prev_w_shape][w_shape];
      ptr_mdst_fcoeff_prev = iusace_mdst_fcoeff_l_s_start_left_prev[prev_w_shape];
      break;
    case LONG_STOP_SEQUENCE:
      ptr_mdst_fcoeff_curr = iusace_mdst_fcoeff_stop_cur[prev_w_shape][w_shape];
      ptr_mdst_fcoeff_prev = iusace_mdst_fcoeff_stop_stopstart_left_prev[prev_w_shape];
      break;
    case STOP_START_SEQUENCE:
      ptr_mdst_fcoeff_curr = iusace_mdst_fcoeff_stopstart_cur[prev_w_shape][w_shape];
      ptr_mdst_fcoeff_prev = iusace_mdst_fcoeff_stop_stopstart_left_prev[prev_w_shape];
      break;
    default:
      ptr_mdst_fcoeff_curr = iusace_mdst_fcoeff_stopstart_cur[prev_w_shape][w_shape];
      ptr_mdst_fcoeff_prev = iusace_mdst_fcoeff_stop_stopstart_left_prev[prev_w_shape];
      break;
  }

  for (i = 0; i < num_sbk; i++) {
    iusace_filter_and_add(ptr_dmx_re, bins_per_sbk, ptr_mdst_fcoeff_curr, ptr_dmx_im, 1);

    if (ptr_dmx_re_prev) {
      iusace_filter_and_add(ptr_dmx_re_prev, bins_per_sbk, ptr_mdst_fcoeff_prev, ptr_dmx_im, -1);
    }

    ptr_dmx_re_prev = ptr_dmx_re;
    ptr_dmx_re += bins_per_sbk;
    ptr_dmx_im += bins_per_sbk;
  }
  return;
}

static VOID iusace_usac_cplx_save_prev(FLOAT64 *ptr_mdct_spec, FLOAT64 *ptr_mdct_spec_prev,
                                       WORD32 save_zeros, WORD32 condition_2, WORD32 samp_per_bk,
                                       WORD32 bins_per_sbk) {
  WORD32 offset;

  offset = samp_per_bk - bins_per_sbk;

  if (save_zeros || condition_2) {
    memset(ptr_mdct_spec_prev + offset, 0, sizeof(FLOAT64) * bins_per_sbk);
  } else {
    memcpy(ptr_mdct_spec_prev + offset, ptr_mdct_spec + offset, sizeof(FLOAT64) * bins_per_sbk);
  }
  return;
}

static FLOAT64 iusace_compute_ipd(FLOAT64 *ptr_spec_real1, FLOAT64 *ptr_spec_imag1,
                                  FLOAT64 *ptr_spec_real2, FLOAT64 *ptr_spec_imag2,
                                  WORD32 num_lines) {
  LOOPIDX i;

  FLOAT64 ipd = 0.0f;
  FLOAT64 cross_corr_real = 0.0f, cross_corr_imag = 0.0f;

  for (i = 0; i < num_lines; i++) {
    cross_corr_real +=
        ptr_spec_real1[i] * ptr_spec_real2[i] + ptr_spec_imag1[i] * ptr_spec_imag2[i];
    cross_corr_imag +=
        -ptr_spec_imag2[i] * ptr_spec_real1[i] + ptr_spec_imag1[i] * ptr_spec_real2[i];
  }

  ipd = (FLOAT64)atan2(cross_corr_imag, cross_corr_real);
  ipd = ipd > 0 ? ipd : 2. * PI + ipd;

  return ipd;
}

static IA_ERRORCODE iusace_cplx_pred_main(
    WORD32 num_sfb, WORD32 num_window_groups, FLOAT64 *ptr_spec_mdct_mid,
    FLOAT64 *ptr_spec_mdct_side, WORD32 pred_coef_q_int_re[MAX_SHORT_WINDOWS][MAX_SFB_LONG],
    WORD32 pred_coef_q_int_im[MAX_SHORT_WINDOWS][MAX_SFB_LONG], WORD32 *pred_dir,
    ia_usac_data_struct *pstr_usac_data, ia_sfb_params_struct *pstr_sfb_prms,
    WORD32 usac_independancy_flag, ia_usac_encoder_config_struct *pstr_usac_config,
    FLOAT64 *ptr_scratch_cmpx_mdct_buf, WORD32 cplx_pred_used[MAX_SHORT_WINDOWS][MAX_SFB_LONG],
    WORD32 chn, const WORD32 *ptr_sfb_offsets, FLOAT32 nrg_mid, FLOAT32 nrg_side,
    WORD32 *ms_mask_flag) {
  LOOPIDX group, sfb, i;
  FLOAT32 pred_coef_re, pred_coef_im, pred_coef_q_re, pred_coef_q_im = 0.0f;
  const WORD32 sfb_per_pred_band = 2;
  WORD32 left = 0, right = 0, save_zeros = 0, condition_2 = 0, samp_per_bk = 0, bins_per_sbk = 0,
         num_sbk = 0;
  FLOAT64 *ptr_dmx_re_prev;
  FLOAT64 *ptr_spec_mdct_res = &ptr_scratch_cmpx_mdct_buf[0];
  const WORD32 sfb_count = num_window_groups * num_sfb;
  const WORD32 sfb_per_group = num_sfb;
  WORD32 sfb_offsets = 0, zero_flag, spec_start, spec_end;

  left = chn, right = chn + 1;

  /* Number of sub-blocks */
  if (pstr_usac_config->window_sequence[left] == EIGHT_SHORT_SEQUENCE) {
    num_sbk = MAX_SHORT_WINDOWS;
  }
  if (pstr_usac_config->window_sequence[left] == ONLY_LONG_SEQUENCE ||
      pstr_usac_config->window_sequence[left] == LONG_START_SEQUENCE ||
      pstr_usac_config->window_sequence[left] == LONG_STOP_SEQUENCE ||
      pstr_usac_config->window_sequence[left] == STOP_START_SEQUENCE) {
    num_sbk = 1;
  }

  if (num_sbk == 0) {
    return IA_EXHEAACE_EXE_FATAL_USAC_INVALID_NUM_SBK;
  }

  samp_per_bk = pstr_usac_config->ccfl;
  bins_per_sbk = samp_per_bk / num_sbk;

  /* Compute prediction direction */
  if (nrg_mid >= nrg_side) {
    *pred_dir = 0;
  } else {
    *pred_dir = 1;
  }

  if (pstr_usac_data->complex_coef[chn] == 1) {
    save_zeros = ((pstr_usac_config->window_sequence[left] == EIGHT_SHORT_SEQUENCE &&
                   pstr_usac_config->window_sequence[right] != EIGHT_SHORT_SEQUENCE) ||
                  (pstr_usac_config->window_sequence[left] != EIGHT_SHORT_SEQUENCE &&
                   pstr_usac_config->window_sequence[right] == EIGHT_SHORT_SEQUENCE));

    condition_2 = (usac_independancy_flag || pstr_usac_data->core_mode_prev[left] ||
                   pstr_usac_data->core_mode_prev[right]);

    /* Compute current frame's MDST down-mix*/
    ptr_dmx_re_prev = !(usac_independancy_flag) ? pstr_usac_data->ptr_dmx_re_save[chn] : NULL;

    memset(pstr_usac_data->ptr_dmx_im[chn], 0, sizeof(FLOAT64) * FRAME_LEN_LONG);

    iusace_estimate_dmx_im(*pred_dir == 0 ? ptr_spec_mdct_mid : ptr_spec_mdct_side,
                           ptr_dmx_re_prev, pstr_usac_data->ptr_dmx_im[chn],
                           pstr_usac_config->window_sequence[left],
                           pstr_sfb_prms->window_shape[left],
                           pstr_usac_config->window_shape_prev[left], num_sbk, bins_per_sbk);

    /* MCLT of downmix = dmx_re + j*dmx_im */
    /*  Save MDCT down-mix for use as previous frame MDCT down-mix in the next frame */
    iusace_usac_cplx_save_prev(*pred_dir == 0 ? &ptr_spec_mdct_mid[0] : &ptr_spec_mdct_side[0],
                               pstr_usac_data->ptr_dmx_re_save[chn], save_zeros, condition_2,
                               samp_per_bk, bins_per_sbk);
  }

  /* Reset buffer to zero */
  for (group = 0; group < MAX_SHORT_WINDOWS; group++) {
    memset(pred_coef_q_int_re, 0, MAX_SFB_LONG * sizeof(WORD32));
    memset(pred_coef_q_int_im, 0, MAX_SFB_LONG * sizeof(WORD32));
  }

  group = 0;
  for (sfb = 0; sfb < sfb_count; sfb += sfb_per_group, group++) {
    for (sfb_offsets = 0; sfb_offsets < sfb_per_group; sfb_offsets += sfb_per_pred_band) {
      if (cplx_pred_used[group][sfb_offsets] == 1) {
        zero_flag = (ptr_sfb_offsets[sfb + sfb_offsets + 1] != FRAME_LEN_LONG);
        spec_start = ptr_sfb_offsets[sfb + sfb_offsets];
        spec_end = (zero_flag ? ptr_sfb_offsets[sfb + sfb_offsets + 2]
                              : ptr_sfb_offsets[sfb + sfb_offsets + 1]);

        /* Calculate prediction coefficients */
        iusace_compute_pred_coef(
            spec_end - spec_start, pstr_usac_data->complex_coef[chn],
            *pred_dir == 0 ? &ptr_spec_mdct_mid[spec_start] : &ptr_spec_mdct_side[spec_start],
            pstr_usac_data->complex_coef[chn] == 1 ? &pstr_usac_data->ptr_dmx_im[chn][spec_start]
                                                   : NULL,
            *pred_dir == 0 ? &ptr_spec_mdct_side[spec_start] : &ptr_spec_mdct_mid[spec_start],
            &pred_coef_re, pstr_usac_data->complex_coef[chn] == 1 ? &pred_coef_im : NULL,
            &pred_coef_q_re, pstr_usac_data->complex_coef[chn] == 1 ? &pred_coef_q_im : NULL,
            &pred_coef_q_int_re[group][sfb_offsets],
            pstr_usac_data->complex_coef[chn] == 1 ? &pred_coef_q_int_im[group][sfb_offsets]
                                                   : NULL);

        /* Calculate residual */
        iusace_compute_res(
            spec_end - spec_start, pstr_usac_data->complex_coef[chn], pred_coef_q_re,
            pstr_usac_data->complex_coef[chn] == 1 ? pred_coef_q_im : 0,
            *pred_dir == 0 ? &ptr_spec_mdct_mid[spec_start] : &ptr_spec_mdct_side[spec_start],
            pstr_usac_data->complex_coef[chn] == 1 ? &pstr_usac_data->ptr_dmx_im[chn][spec_start]
                                                   : NULL,
            *pred_dir == 0 ? &ptr_spec_mdct_side[spec_start] : &ptr_spec_mdct_mid[spec_start],
            &ptr_spec_mdct_res[spec_start]);
      }
    }
  }

  /* Compute the prediction gain */
  FLOAT32 pred_gain = 0.f, nrg_res = 0.f;
  for (i = 0; i < pstr_usac_config->ccfl; i++) {
    nrg_res += (FLOAT32)(ptr_spec_mdct_res[i] * ptr_spec_mdct_res[i]);
  }
  pred_gain =
      10.f * log10f((*pred_dir == 0 ? nrg_side : nrg_mid) / nrg_res); /* Prediction gain in dB */

  if (pred_gain > 20.f) /* Retain complex prediction */
  {
    if (*pred_dir == 1) {
      for (i = 0; i < pstr_usac_config->ccfl; i++) {
        ptr_spec_mdct_mid[i] = ptr_spec_mdct_side[i];
        ptr_spec_mdct_side[i] = ptr_spec_mdct_res[i];
      }
    } else {
      for (i = 0; i < pstr_usac_config->ccfl; i++) {
        ptr_spec_mdct_side[i] = ptr_spec_mdct_res[i];
      }
    }
  } else /* Use M/S */
  {
    *ms_mask_flag = 0;
    /* Revert spectra to L and R */
    for (i = 0; i < pstr_usac_config->ccfl; i++) {
      ptr_spec_mdct_mid[i] = pstr_usac_data->left_chan_save[chn][i];
      ptr_spec_mdct_side[i] = pstr_usac_data->right_chan_save[chn][i];
    }
  }

  return IA_NO_ERROR;
}

IA_ERRORCODE iusace_cplx_pred_proc(
    ia_usac_data_struct *pstr_usac_data, ia_usac_encoder_config_struct *pstr_usac_config,
    WORD32 usac_independancy_flag, ia_sfb_params_struct *pstr_sfb_prms, WORD32 chn,
    ia_psy_mod_data_struct *pstr_psy_data, const WORD32 *ptr_sfb_offsets,
    FLOAT64 *ptr_scratch_cmpx_mdct_buf, FLOAT64 *ptr_ms_spec, FLOAT32 nrg_mid, FLOAT32 nrg_side) {
  IA_ERRORCODE err_code;
  FLOAT32 *ptr_sfb_enegry_left = pstr_psy_data[chn].ptr_sfb_energy_long;
  FLOAT32 *ptr_sfb_energy_right = pstr_psy_data[chn + 1].ptr_sfb_energy_long;
  const FLOAT32 *ptr_sfb_energy_mid = pstr_psy_data[chn].ptr_sfb_energy_long_ms;
  const FLOAT32 *ptr_sfb_energy_side = pstr_psy_data[chn + 1].ptr_sfb_energy_long_ms;
  FLOAT32 *ptr_sfb_thr_left = pstr_psy_data[chn].ptr_sfb_thr_long;
  FLOAT32 *ptr_sfb_thr_right = pstr_psy_data[chn + 1].ptr_sfb_thr_long;
  FLOAT32 *ptr_sfb_spread_energy_left = pstr_psy_data[chn].ptr_sfb_spreaded_energy_long;
  FLOAT32 *ptr_sfb_spread_energy_right = pstr_psy_data[chn + 1].ptr_sfb_spreaded_energy_long;
  WORD32 sfb, sfb_offsets;
  WORD32 *ptr_num_sfb = pstr_sfb_prms->num_sfb;
  WORD32 *ptr_num_window_groups = pstr_sfb_prms->num_window_groups;
  const WORD32 sfb_count = ptr_num_window_groups[chn] * ptr_num_sfb[chn];
  const WORD32 sfb_per_group = ptr_num_sfb[chn];
  WORD32 grp = 0, i, zero_flag;
  const WORD32 sfb_per_pred_band = 2;
  FLOAT32 min_thr_1, min_thr_2 = 0.0f;
  FLOAT32 temp_1 = 0, temp_2 = 0;
  ia_ms_info_struct *pstr_ms_info = &pstr_usac_data->str_ms_info[chn];

  FLOAT64 ipd;
  /* Compute IPD between L and R channels */
  ipd = iusace_compute_ipd(&pstr_usac_data->spectral_line_vector[chn][0],
                           &pstr_usac_data->mdst_spectrum[chn][0],
                           &pstr_usac_data->spectral_line_vector[chn + 1][0],
                           &pstr_usac_data->mdst_spectrum[chn + 1][0], pstr_usac_config->ccfl);

  /* Decide value of complex_coef based on IPD */
  if ((ipd > (PI / 2 - 5 * PI / 180) && ipd < (PI / 2 + 5 * PI / 180)) ||
      (ipd > (3 * PI / 2 - 5 * PI / 180) && ipd < (3 * PI / 2 + 5 * PI / 180))) {
    pstr_usac_data->complex_coef[chn] = 1;
  } else {
    pstr_usac_data->complex_coef[chn] = 0;
  }

  /* Compute M and S spectra */
  for (i = 0; i < pstr_usac_config->ccfl; i++) {
    pstr_usac_data->spectral_line_vector[chn][i] = ptr_ms_spec[i];
    pstr_usac_data->spectral_line_vector[chn + 1][i] = ptr_ms_spec[pstr_usac_config->ccfl + i];
  }

  err_code = iusace_cplx_pred_main(
      pstr_sfb_prms->num_sfb[chn], pstr_sfb_prms->num_window_groups[chn],
      pstr_usac_data->spectral_line_vector[chn], pstr_usac_data->spectral_line_vector[chn + 1],
      pstr_usac_data->pred_coef_re[chn], pstr_usac_data->pred_coef_im[chn],
      &pstr_usac_data->pred_dir_idx[chn], pstr_usac_data, pstr_sfb_prms, usac_independancy_flag,
      pstr_usac_config, ptr_scratch_cmpx_mdct_buf, pstr_usac_data->cplx_pred_used[chn], chn,
      ptr_sfb_offsets, nrg_mid, nrg_side, &pstr_ms_info->ms_mask);
  if (err_code != IA_NO_ERROR) {
    return err_code;
  }

  if (pstr_ms_info->ms_mask == 3) {
    /* Compute thresholds required for quantization (similar to that in MS coding) */
    for (sfb = 0; sfb < sfb_count; sfb += sfb_per_group, grp++) {
      for (sfb_offsets = 0; sfb_offsets < sfb_per_group; sfb_offsets += sfb_per_pred_band) {
        if (pstr_usac_data->cplx_pred_used[chn][grp][sfb_offsets] == 1) {
          zero_flag = (ptr_sfb_offsets[sfb + sfb_offsets + 1] != pstr_usac_config->ccfl);
          min_thr_1 =
              MIN(ptr_sfb_thr_left[sfb + sfb_offsets], ptr_sfb_thr_right[sfb + sfb_offsets]);
          if (zero_flag) {
            min_thr_2 = MIN(ptr_sfb_thr_left[sfb + sfb_offsets + 1],
                            ptr_sfb_thr_right[sfb + sfb_offsets + 1]);
          }

          ptr_sfb_thr_left[sfb + sfb_offsets] = ptr_sfb_thr_right[sfb + sfb_offsets] = min_thr_1;
          ptr_sfb_enegry_left[sfb + sfb_offsets] = ptr_sfb_energy_mid[sfb + sfb_offsets];
          ptr_sfb_energy_right[sfb + sfb_offsets] = ptr_sfb_energy_side[sfb + sfb_offsets];
          if (zero_flag) {
            ptr_sfb_thr_left[sfb + sfb_offsets + 1] = ptr_sfb_thr_right[sfb + sfb_offsets + 1] =
                min_thr_2;
            ptr_sfb_enegry_left[sfb + sfb_offsets + 1] =
                ptr_sfb_energy_mid[sfb + sfb_offsets + 1];
            ptr_sfb_energy_right[sfb + sfb_offsets + 1] =
                ptr_sfb_energy_side[sfb + sfb_offsets + 1];
          }
          ptr_sfb_spread_energy_left[sfb + sfb_offsets] =
              ptr_sfb_spread_energy_right[sfb + sfb_offsets] =
                  MIN(ptr_sfb_spread_energy_left[sfb + sfb_offsets],
                      ptr_sfb_spread_energy_right[sfb + sfb_offsets]) *
                  0.5f;
          if (zero_flag) {
            ptr_sfb_spread_energy_left[sfb + sfb_offsets + 1] =
                ptr_sfb_spread_energy_right[sfb + sfb_offsets + 1] =
                    MIN(ptr_sfb_spread_energy_left[sfb + sfb_offsets + 1],
                        ptr_sfb_spread_energy_right[sfb + sfb_offsets + 1]) *
                    0.5f;
          }
        }
      }
    }

    if (pstr_usac_data->pred_dir_idx[chn] == 1) {
      grp = 0;

      for (sfb = 0; sfb < sfb_count; sfb += sfb_per_group, grp++) {
        for (sfb_offsets = 0; sfb_offsets < sfb_per_group; sfb_offsets += sfb_per_pred_band) {
          zero_flag = (ptr_sfb_offsets[sfb + sfb_offsets + 1] != pstr_usac_config->ccfl);

          if (pstr_usac_data->cplx_pred_used[chn][grp][sfb_offsets] == 1) {
            temp_1 = ptr_sfb_enegry_left[sfb + sfb_offsets];
            ptr_sfb_enegry_left[sfb + sfb_offsets] = ptr_sfb_energy_right[sfb + sfb_offsets];
            ptr_sfb_energy_right[sfb + sfb_offsets] = temp_1;
            if (zero_flag) {
              temp_2 = ptr_sfb_enegry_left[sfb + sfb_offsets + 1];
              ptr_sfb_enegry_left[sfb + sfb_offsets + 1] =
                  ptr_sfb_energy_right[sfb + sfb_offsets + 1];
              ptr_sfb_energy_right[sfb + sfb_offsets + 1] = temp_2;
            }
          }
        }
      }
    }
  }
  return IA_NO_ERROR;
}