/******************************************************************************

 *                                                                            *

 * 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 <stdlib.h>

#include <string.h>

#include "ixheaac_type_def.h"

#include "ixheaace_bitbuffer.h"

#include "iusace_tns_usac.h"

#include "iusace_cnst.h"

#include "ixheaace_sbr_def.h"

#include "ixheaace_resampler.h"

#include "ixheaace_sbr_hbe.h"

#include "ixheaace_sbr_hbe_fft.h"

#include "ixheaace_error_codes.h"

#include "ixheaace_common_rom.h"

#include "ixheaac_error_standards.h"

#include "ixheaac_constants.h"

#include "ixheaac_esbr_rom.h"

static FLOAT32 *ixheaace_map_prot_filter(WORD32 filt_length) {

  switch (filt_length) {

    case 4:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[0];

      break;

    case 8:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[40];

      break;

    case 12:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[120];

      break;

    case 16:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[240];

      break;

    case 20:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[400];

      break;

    case 24:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[600];

      break;

    case 28:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff_28_36[0];

      break;

    case 32:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[840];

      break;

    case 36:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff_28_36[280];

      break;

    case 40:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[1160];

      break;

    case 44:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[1560];

      break;

    default:

      return (FLOAT32 *)&ixheaac_sub_samp_qmf_window_coeff[0];

  }

}

/**

 * Calculate frequency domain window according to 23003-3:2012, 7.5.3.1 eSBR - Tool description

 */

static VOID ixheaace_create_dft_hbe_window(FLOAT32 *ptr_win, WORD32 x_over_bin1,

                                           WORD32 x_over_bin2, WORD32 ts, WORD32 size) {

  const FLOAT32 *ptr_freq_domain_win = NULL;

  WORD32 n;

  if (ts == 12) {

    ptr_freq_domain_win = &ixheaac_dft_hbe_window_ts_12[0];

  } else {

    ptr_freq_domain_win = &ixheaac_dft_hbe_window_ts_18[0];

  }

  for (n = 0; n < (x_over_bin1 - ts / 2); n++) {

    ptr_win[n] = 0;

  }

  for (n = (x_over_bin1 - ts / 2); n <= (x_over_bin1 + ts / 2); n++) {

    ptr_win[n] = (FLOAT32)ptr_freq_domain_win[n - (x_over_bin1 - ts / 2)];

  }

  for (n = (x_over_bin1 + ts / 2 + 1); n < (x_over_bin2 - ts / 2); n++) {

    ptr_win[n] = (FLOAT32)1.0f;

  }

  for (n = (x_over_bin2 - ts / 2); n <= (x_over_bin2 + ts / 2); n++) {

    ptr_win[n] = (FLOAT32)1.0f - ptr_freq_domain_win[n - (x_over_bin2 - ts / 2)];

  }

  for (n = (x_over_bin2 + ts / 2 + 1); n < size; n++) {

    ptr_win[n] = 0.0f;

  }

}

static IA_ERRORCODE ixheaace_calc_anal_synth_window(WORD32 fft_size, FLOAT32 *ptr_window) {

  FLOAT32 sin_pi_2_n = 0.0f;

  FLOAT32 cos_pi_2_n = 0.0f;

  FLOAT32 *ptr_sin_pi_n_by_n = NULL;

  WORD32 hop_stride = 1;

  WORD32 i, j;

  WORD32 l_fft_stride = 512;

  switch (fft_size) {

    case 64:

      hop_stride = 16;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_1024[0];

      sin_pi_2_n = ptr_sin_pi_n_by_n[hop_stride >> 1];

      cos_pi_2_n = ptr_sin_pi_n_by_n[512 + (hop_stride >> 1)];

      l_fft_stride = 512;

      break;

    case 128:

      hop_stride = 8;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_1024[0];

      sin_pi_2_n = ptr_sin_pi_n_by_n[hop_stride >> 1];

      cos_pi_2_n = ptr_sin_pi_n_by_n[512 + (hop_stride >> 1)];

      l_fft_stride = 512;

      break;

    case 256:

      hop_stride = 4;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_1024[0];

      sin_pi_2_n = ptr_sin_pi_n_by_n[hop_stride >> 1];

      cos_pi_2_n = ptr_sin_pi_n_by_n[512 + (hop_stride >> 1)];

      l_fft_stride = 512;

      break;

    case 512:

      hop_stride = 2;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_1024[0];

      sin_pi_2_n = ptr_sin_pi_n_by_n[1];

      cos_pi_2_n = ptr_sin_pi_n_by_n[512 + 1];

      l_fft_stride = 512;

      break;

    case 1024:

      hop_stride = 1;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_1024[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[0];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[1];

      l_fft_stride = 512;

      break;

    case 192:

      hop_stride = 4;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_768[0];

      sin_pi_2_n = ptr_sin_pi_n_by_n[hop_stride >> 1];

      cos_pi_2_n = ptr_sin_pi_n_by_n[384 + (hop_stride >> 1)];

      l_fft_stride = 384;

      break;

    case 384:

      hop_stride = 2;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_768[0];

      sin_pi_2_n = ptr_sin_pi_n_by_n[1];

      cos_pi_2_n = ptr_sin_pi_n_by_n[384 + 1];

      l_fft_stride = 384;

      break;

    case 768:

      hop_stride = 1;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_768[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[8];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[9];

      l_fft_stride = 384;

      break;

    case 320:

      hop_stride = 3;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_960[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[16];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[17];

      l_fft_stride = 480;

      break;

    case 960:

      hop_stride = 1;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_960[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[2];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[3];

      l_fft_stride = 480;

      break;

    case 448:

      hop_stride = 2;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_896[0];

      sin_pi_2_n = ptr_sin_pi_n_by_n[1];

      cos_pi_2_n = ptr_sin_pi_n_by_n[448 + 1];

      l_fft_stride = 448;

      break;

    case 896:

      hop_stride = 1;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_896[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[4];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[5];

      l_fft_stride = 448;

      break;

    case 576:

      hop_stride = 1;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_576[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[14];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[15];

      l_fft_stride = 288;

      break;

    case 640:

      hop_stride = 1;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_640[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[12];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[13];

      l_fft_stride = 320;

      break;

    case 704:

      hop_stride = 1;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_704[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[10];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[11];

      l_fft_stride = 352;

      break;

    case 832:

      hop_stride = 1;

      ptr_sin_pi_n_by_n = (FLOAT32 *)&ixheaac_sine_pi_n_by_832[0];

      sin_pi_2_n = ixheaac_sine_pi_by_2_N[6];

      cos_pi_2_n = ixheaac_sine_pi_by_2_N[7];

      l_fft_stride = 416;

      break;

    default:

      return IA_EXHEAACE_EXE_FATAL_USAC_INVALID_MAPPING;

  }

  /*calculate Window*/

  for (i = 0, j = 0; j < (fft_size >> 1); i += hop_stride, j++) {

    FLOAT32 cos_val = ptr_sin_pi_n_by_n[i + l_fft_stride];

    FLOAT32 sin_val = ptr_sin_pi_n_by_n[i];

    ptr_window[j] = cos_val * sin_pi_2_n + sin_val * cos_pi_2_n;

  }

  for (; j < fft_size; j++, i += hop_stride) {

    FLOAT32 cos_val = ptr_sin_pi_n_by_n[i - l_fft_stride];

    FLOAT32 sin_val = ptr_sin_pi_n_by_n[i];

    ptr_window[j] = sin_val * cos_pi_2_n - cos_val * sin_pi_2_n;

  }

  return IA_NO_ERROR;

}

VOID ixheaace_esbr_hbe_data_init(ixheaace_str_esbr_hbe_txposer *pstr_esbr_hbe_txposer,

                                 const WORD32 num_aac_samples, WORD32 samp_fac_4_flag,

                                 const WORD32 num_out_samples, VOID *ptr_persistent_hbe_mem,

                                 WORD32 *ptr_total_persistant) {

  WORD32 used_persistent = 0;

  if (pstr_esbr_hbe_txposer) {

    memset(pstr_esbr_hbe_txposer, 0, sizeof(ixheaace_str_esbr_hbe_txposer));

    pstr_esbr_hbe_txposer->core_frame_length = num_aac_samples;

    pstr_esbr_hbe_txposer->no_bins = num_out_samples / IXHEAACE_NUM_QMF_SYNTH_CHANNELS;

    pstr_esbr_hbe_txposer->hbe_qmf_in_len = pstr_esbr_hbe_txposer->no_bins;

    pstr_esbr_hbe_txposer->hbe_qmf_out_len = 2 * pstr_esbr_hbe_txposer->hbe_qmf_in_len;

    pstr_esbr_hbe_txposer->ptr_input_buf = (FLOAT32 *)ptr_persistent_hbe_mem;

    used_persistent += (num_aac_samples + IXHEAACE_NUM_QMF_SYNTH_CHANNELS) *

                       sizeof(pstr_esbr_hbe_txposer->ptr_input_buf[0]);

    pstr_esbr_hbe_txposer->upsamp_4_flag = samp_fac_4_flag;

    if (pstr_esbr_hbe_txposer) {

      pstr_esbr_hbe_txposer->fft_size[0] = num_aac_samples;

      pstr_esbr_hbe_txposer->fft_size[1] = (int)(IXHEAACE_FD_OVERSAMPLING_FAC * num_aac_samples);

      /*

        Worst Case Memory requirements for DFT based HBE.

        analysis ptr_win = num_aac_samples * sizeof(float)          = 1024 * sizeof(FLOAT32)

        synthesis ptr_win = num_aac_samples * sizeof(float)         = 1024 * sizeof(FLOAT32)

        ptr_spectrum = num_aac_samples * sizeof(float) * 1.5        = 1536 * sizeof(FLOAT32)

        spectrumTransposed = num_aac_samples * sizeof(float)    = 1536 * sizeof(FLOAT32)

        ptr_mag                                                     = 1536 * sizeof(FLOAT32)

        ptr_phase                                                   = 1536 * sizeof(FLOAT32)

        pstr_esbr_hbe_txposer->inBuf                            = 2048 * sizeof(FLOAT32)

        pstr_esbr_hbe_txposer->outBuf                           = 4096 * sizeof(FLOAT32)

        fd_win_buf                                                   = 2560 * 3 * sizeof(FLOAT32)

        Total ~ (1024 * 2 + 1536 * 4 + 2048 * 1 + 4096 * 1 + 2560 * 3) * sizeof(FLOAT32)

        = 22016 * sizeof(FLOAT32)

       */

      pstr_esbr_hbe_txposer->ptr_spectrum = &pstr_esbr_hbe_txposer->spectrum_buf[0];

      pstr_esbr_hbe_txposer->ptr_spectrum_tx = &pstr_esbr_hbe_txposer->spectrum_transposed_buf[0];

      pstr_esbr_hbe_txposer->ptr_mag = &pstr_esbr_hbe_txposer->mag_buf[0];

      pstr_esbr_hbe_txposer->ptr_phase = &pstr_esbr_hbe_txposer->phase_buf[0];

      pstr_esbr_hbe_txposer->ptr_output_buf = &pstr_esbr_hbe_txposer->output_buf[0];

    }

  }

  *ptr_total_persistant = used_persistent;

}

IA_ERRORCODE ixheaace_dft_hbe_data_reinit(ixheaace_str_esbr_hbe_txposer *pstr_hbe_txposer) {

  WORD32 sfb;

  WORD32 patch;

  WORD32 i;

  WORD32 temp_start;

  FLOAT32 fb_ratio;

  WORD32 stop_patch;

  WORD32 in_hop_size_divisor = 8;

  static const WORD32 trans_samp[2] = {12, 18}; /* FD transition samples */

  WORD32 err = IA_NO_ERROR;

  pstr_hbe_txposer->start_band = pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_LOW][0];

  pstr_hbe_txposer->end_band =

      pstr_hbe_txposer

          ->ptr_freq_band_tab[IXHEAACE_LOW][pstr_hbe_txposer->num_sf_bands[IXHEAACE_LOW]];

  pstr_hbe_txposer->esbr_hq = 1;

  pstr_hbe_txposer->synth_size = 4 * ((pstr_hbe_txposer->start_band + 4) / 8 + 1);

  pstr_hbe_txposer->k_start = ixheaac_start_subband2kL_tbl[pstr_hbe_txposer->start_band];

  fb_ratio = pstr_hbe_txposer->synth_size / 32.0f;

  pstr_hbe_txposer->ana_fft_size[0] = (WORD32)(fb_ratio * pstr_hbe_txposer->fft_size[0]);

  pstr_hbe_txposer->ana_fft_size[1] = (WORD32)(fb_ratio * pstr_hbe_txposer->fft_size[1]);

  pstr_hbe_txposer->in_hop_size = pstr_hbe_txposer->ana_fft_size[0] / in_hop_size_divisor;

  pstr_hbe_txposer->ptr_syn_win = (FLOAT32 *)&pstr_hbe_txposer->synthesis_window_buf[0];

  pstr_hbe_txposer->ptr_ana_win = (FLOAT32 *)&pstr_hbe_txposer->analysis_window_buf[0];

  err = ixheaace_calc_anal_synth_window(pstr_hbe_txposer->ana_fft_size[0],

                                        pstr_hbe_txposer->ptr_ana_win);

  if (err) {

    return err;

  }

  memset(pstr_hbe_txposer->synth_buf, 0, sizeof(pstr_hbe_txposer->synth_buf));

  pstr_hbe_txposer->ptr_syn_win_coeff = ixheaace_map_prot_filter(pstr_hbe_txposer->synth_size);

  temp_start = 2 * ((pstr_hbe_txposer->start_band - 1) / 2); /* Largest start band */

  pstr_hbe_txposer->analy_size =

      4 * ((min(64, pstr_hbe_txposer->end_band + 1) - temp_start - 1) / 4 +

           1); /* Quantize in steps of 4 */

  pstr_hbe_txposer->a_start = temp_start - max(0, temp_start + pstr_hbe_txposer->analy_size - 64);

  fb_ratio = pstr_hbe_txposer->analy_size / 64.0f;

  pstr_hbe_txposer->syn_fft_size[0] = (WORD32)(fb_ratio * pstr_hbe_txposer->fft_size[0]);

  pstr_hbe_txposer->syn_fft_size[1] = (WORD32)(fb_ratio * pstr_hbe_txposer->fft_size[1]);

  pstr_hbe_txposer->out_hop_size = 2 * pstr_hbe_txposer->syn_fft_size[0] / in_hop_size_divisor;

  err = ixheaace_calc_anal_synth_window(pstr_hbe_txposer->syn_fft_size[0],

                                        pstr_hbe_txposer->ptr_syn_win);

  if (err) {

    return err;

  }

  pstr_hbe_txposer->ptr_ana_win_coeff = ixheaace_map_prot_filter(pstr_hbe_txposer->analy_size);

  /* calculation of x_over_bin array and x_over_qmf array */

  memset(&pstr_hbe_txposer->x_over_qmf[0], 0, sizeof(pstr_hbe_txposer->x_over_qmf));

  for (i = 0; i < IXHEAACE_MAX_STRETCH; i++) {

    memset(&pstr_hbe_txposer->x_over_bin[i][0], 0,

           2 * sizeof(pstr_hbe_txposer->x_over_bin[i][0]));

  }

  sfb = 0;

  stop_patch = IXHEAACE_MAX_STRETCH;

  switch (pstr_hbe_txposer->synth_size) {

    case 4:

      pstr_hbe_txposer->ptr_syn_cos_tab = (FLOAT32 *)ixheaac_synth_cos_table_kl_4;

      pstr_hbe_txposer->ixheaace_real_synth_fft = &ixheaac_real_synth_fft_p2;

      break;

    case 8:

      pstr_hbe_txposer->ptr_syn_cos_tab = (FLOAT32 *)ixheaac_synth_cos_table_kl_8;

      pstr_hbe_txposer->ixheaace_real_synth_fft = &ixheaac_real_synth_fft_p2;

      break;

    case 12:

      pstr_hbe_txposer->ptr_syn_cos_tab = (FLOAT32 *)ixheaac_synth_cos_table_kl_12;

      pstr_hbe_txposer->ixheaace_real_synth_fft = &ixheaac_real_synth_fft_p3;

      break;

    case 16:

      pstr_hbe_txposer->ptr_syn_cos_tab = (FLOAT32 *)ixheaac_synth_cos_table_kl_16;

      pstr_hbe_txposer->ixheaace_real_synth_fft = &ixheaac_real_synth_fft_p2;

      break;

    case 20:

      pstr_hbe_txposer->ptr_syn_cos_tab = (FLOAT32 *)ixheaac_synth_cos_table_kl_20;

      break;

    case 28:

      pstr_hbe_txposer->ptr_syn_cos_tab = (FLOAT32 *)ixheaac_synth_cos_table_kl_20;

      break;

    default:

      pstr_hbe_txposer->ptr_syn_cos_tab = (FLOAT32 *)ixheaac_synth_cos_table_kl_4;

      pstr_hbe_txposer->ixheaace_real_synth_fft = &ixheaac_real_synth_fft_p2;

  }

  {

    WORD32 l, k, L = pstr_hbe_txposer->analy_size;

    for (k = 0; k < L; k++) {

      for (l = 0; l < 2 * L; l++) {

        pstr_hbe_txposer->str_dft_hbe_anal_coeff.real[k][l] =

            (FLOAT32)cos(PI / (2 * L) *

                         ((k + 0.5) * (2 * l - L / 64.0) - L / 64.0 * pstr_hbe_txposer->a_start));

        pstr_hbe_txposer->str_dft_hbe_anal_coeff.imag[k][l] =

            (FLOAT32)sin(PI / (2 * L) *

                         ((k + 0.5) * (2 * l - L / 64.0) - L / 64.0 * pstr_hbe_txposer->a_start));

      }

    }

  }

  for (patch = 1; patch <= stop_patch; patch++) {

    while (sfb <= pstr_hbe_txposer->num_sf_bands[IXHEAACE_LOW] &&

           pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_LOW][sfb] <=

               patch * pstr_hbe_txposer->start_band)

      sfb++;

    if (sfb <= pstr_hbe_txposer->num_sf_bands[IXHEAACE_LOW]) {

      /* If the distance is larger than three QMF bands - try aligning to high resolution

       * frequency bands instead. */

      if ((patch * pstr_hbe_txposer->start_band -

           pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_LOW][sfb - 1]) <= 3) {

        pstr_hbe_txposer->x_over_qmf[patch - 1] =

            pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_LOW][sfb - 1];

        if (patch <= IXHEAACE_MAX_STRETCH) {

          pstr_hbe_txposer->x_over_bin[patch - 1][0] =

              (WORD32)(pstr_hbe_txposer->fft_size[0] *

                           pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_LOW][sfb - 1] / 128 +

                       0.5);

          pstr_hbe_txposer->x_over_bin[patch - 1][1] =

              (WORD32)(pstr_hbe_txposer->fft_size[1] *

                           pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_LOW][sfb - 1] / 128 +

                       0.5);

        }

      } else {

        WORD32 sfb_idx = 0;

        while (sfb_idx <= pstr_hbe_txposer->num_sf_bands[IXHEAACE_HIGH] &&

               pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_HIGH][sfb_idx] <=

                   patch * pstr_hbe_txposer->start_band)

          sfb_idx++;

        pstr_hbe_txposer->x_over_qmf[patch - 1] =

            pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_HIGH][sfb_idx - 1];

        if (patch <= IXHEAACE_MAX_STRETCH) {

          pstr_hbe_txposer->x_over_bin[patch - 1][0] =

              (WORD32)(pstr_hbe_txposer->fft_size[0] *

                           pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_HIGH][sfb_idx - 1] / 128 +

                       0.5);

          pstr_hbe_txposer->x_over_bin[patch - 1][1] =

              (WORD32)(pstr_hbe_txposer->fft_size[1] *

                           pstr_hbe_txposer->ptr_freq_band_tab[IXHEAACE_HIGH][sfb_idx - 1] / 128 +

                       0.5);

        }

      }

    } else {

      pstr_hbe_txposer->x_over_qmf[patch - 1] = pstr_hbe_txposer->end_band;

      if (patch <= IXHEAACE_MAX_STRETCH) {

        pstr_hbe_txposer->x_over_bin[patch - 1][0] =

            (WORD32)(pstr_hbe_txposer->fft_size[0] * pstr_hbe_txposer->end_band / 128 + 0.5);

        pstr_hbe_txposer->x_over_bin[patch - 1][1] =

            (WORD32)(pstr_hbe_txposer->fft_size[1] * pstr_hbe_txposer->end_band / 128 + 0.5);

      }

      pstr_hbe_txposer->max_stretch = min(patch, IXHEAACE_MAX_STRETCH);

      break;

    }

  }

  /* calculation of frequency domain windows */

  for (patch = 0; patch < pstr_hbe_txposer->max_stretch - 1; patch++) {

    for (i = 0; i < 2; i++) {

      ixheaace_create_dft_hbe_window(pstr_hbe_txposer->fd_win_buf[patch][i],

                                     pstr_hbe_txposer->x_over_bin[patch][i],

                                     pstr_hbe_txposer->x_over_bin[patch + 1][i], trans_samp[i],

                                     pstr_hbe_txposer->fft_size[i]);

    }

  }

  return err;

}

static VOID ixheaace_dft_hbe_apply_win(const FLOAT32 *ptr_x, const FLOAT32 *ptr_y, FLOAT32 *ptr_z,

                                       WORD32 n) {

  WORD32 i;

  for (i = 0; i < n; i++) {

    ptr_z[i] = ptr_x[i] * ptr_y[i];

  }

}

VOID ixheaace_dft_hbe_fft_memmove(FLOAT32 *ptr_spectrum, WORD32 size) {

  WORD32 n = 0;

  while (n < size / 2) {

    FLOAT32 tmp = ptr_spectrum[n];

    ptr_spectrum[n] = ptr_spectrum[n + size / 2];

    ptr_spectrum[n + size / 2] = tmp;

    n++;

  }

}

VOID ixheaace_karth2polar(FLOAT32 *ptr_spectrum, FLOAT32 *ptr_mag, FLOAT32 *ptr_phase,

                          WORD32 fft_size) {

  WORD32 n;

  for (n = 1; n < fft_size / 2; n++) {

    ptr_phase[n] = (FLOAT32)atan2(ptr_spectrum[2 * n + 1], ptr_spectrum[2 * n]);

    ptr_mag[n] = (FLOAT32)sqrt(ptr_spectrum[2 * n] * ptr_spectrum[2 * n] +

                               ptr_spectrum[2 * n + 1] * ptr_spectrum[2 * n + 1]);

  }

  if (ptr_spectrum[0] < 0) {

    ptr_phase[0] = (FLOAT32)acos(-1);

    ptr_mag[0] = -ptr_spectrum[0];

  } else {

    ptr_phase[0] = 0;

    ptr_mag[0] = ptr_spectrum[0];

  }

  if (ptr_spectrum[1] < 0) {

    ptr_phase[fft_size / 2] = (FLOAT32)acos(-1);

    ptr_mag[fft_size / 2] = -ptr_spectrum[1];

  } else {

    ptr_phase[fft_size / 2] = 0;

    ptr_mag[fft_size / 2] = ptr_spectrum[1];

  }

}

VOID ixheaace_hbe_fft_tab(ixheaace_str_esbr_hbe_txposer *pstr_hbe_txposer) {

  WORD32 oversampling_flag = pstr_hbe_txposer->oversampling_flag;

  WORD32 ana_fft_size = pstr_hbe_txposer->ana_fft_size[oversampling_flag];

  WORD32 syn_fft_size = pstr_hbe_txposer->syn_fft_size[oversampling_flag];

  switch (ana_fft_size) {

    case 576:

      pstr_hbe_txposer->ptr_ana_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_576;

      break;

    case 384:

      pstr_hbe_txposer->ptr_ana_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_384;

      break;

    case 512:

      pstr_hbe_txposer->ptr_ana_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_512;

      break;

    case 768:

      pstr_hbe_txposer->ptr_ana_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_768;

      break;

    default:

      break;

  }

  switch (syn_fft_size) {

    case 448:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_448;

      break;

    case 512:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_512;

      break;

    case 768:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_768;

      break;

    case 672:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_672;

      break;

    default:

      break;

  }

}

IA_ERRORCODE ixheaace_hbe_fft_map(ixheaace_str_esbr_hbe_txposer *pstr_hbe_txposer) {

  WORD32 oversampling_flag = pstr_hbe_txposer->oversampling_flag;

  WORD32 ana_fft_size = pstr_hbe_txposer->ana_fft_size[oversampling_flag];

  WORD32 syn_fft_size = pstr_hbe_txposer->syn_fft_size[oversampling_flag];

  switch (ana_fft_size) {

    case 576:

      pstr_hbe_txposer->ptr_ana_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_576;

      pstr_hbe_txposer->ixheaace_hbe_anal_fft = &ixheaace_hbe_apply_fft_288;

      break;

    case 384:

      pstr_hbe_txposer->ptr_ana_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_384;

      pstr_hbe_txposer->ixheaace_hbe_anal_fft = &ixheaace_hbe_apply_cfftn_gen;

      break;

    case 512:

      pstr_hbe_txposer->ptr_ana_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_512;

      pstr_hbe_txposer->ixheaace_hbe_anal_fft = &ixheaace_hbe_apply_cfftn;

      break;

    case 768:

      pstr_hbe_txposer->ptr_ana_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_768;

      pstr_hbe_txposer->ixheaace_hbe_anal_fft = &ixheaace_hbe_apply_cfftn_gen;

      break;

    default:

      return IA_EXHEAACE_EXE_FATAL_USAC_INVALID_MAPPING;

      break;

  }

  switch (syn_fft_size) {

    case 448:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_448;

      pstr_hbe_txposer->ixheaace_hbe_synth_ifft = &ixheaace_hbe_apply_ifft_224;

      break;

    case 512:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_512;

      pstr_hbe_txposer->ixheaace_hbe_synth_ifft = &ixheaace_hbe_apply_cfftn;

      break;

    case 576:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_576;

      pstr_hbe_txposer->ixheaace_hbe_synth_ifft = &ixheaace_hbe_apply_fft_288;

      break;

    case 768:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_768;

      pstr_hbe_txposer->ixheaace_hbe_synth_ifft = &ixheaace_hbe_apply_cfftn_gen;

      break;

    case 672:

      pstr_hbe_txposer->ptr_syn_cos_sin_tab = (FLOAT32 *)ixheaac_sin_cos_672;

      pstr_hbe_txposer->ixheaace_hbe_synth_ifft = &ixheaace_hbe_apply_ifft_336;

      break;

    default:

      return IA_EXHEAACE_EXE_FATAL_USAC_INVALID_MAPPING;

      break;

  }

  return IA_NO_ERROR;

}

VOID ia_dft_hbe_apply_polar_t2(WORD32 T, ixheaace_str_esbr_hbe_txposer *pstr_hbe_txposer,

                               WORD32 pitch_in_bins, WORD out_transform_size) {

  WORD32 tr;

  WORD32 ti;

  WORD32 m_tr = 0;

  WORD32 p, i;

  FLOAT32 mag_t;

  FLOAT32 phase_t;

  FLOAT32 m_val;

  FLOAT32(*fd_win_buf)[3][3][1536] = &pstr_hbe_txposer->fd_win_buf;

  FLOAT32 *ptr_phase = pstr_hbe_txposer->ptr_phase;

  WORD32 oversampling_flag = pstr_hbe_txposer->oversampling_flag;

  WORD32 fft_size = pstr_hbe_txposer->fft_size[oversampling_flag];

  FLOAT32 *ptr_spectrum_tx = pstr_hbe_txposer->ptr_spectrum_tx;

  FLOAT32 *ptr_mag = pstr_hbe_txposer->ptr_mag;

  /* pitch_in_bins is given with the resolution of a 1536 point FFT */

  FLOAT32 p_flt = fft_size * pitch_in_bins / 1536.0f;

  p = (WORD32)p_flt;

  FLOAT32 q_thr = 4.0f;

  if (T < 2) {

    // To avoid invalid access by fd_win_buf

    T = 2;

  }

  i = 0;

  while (i <= out_transform_size) {

    WORD32 utk = i;

    mag_t = (*fd_win_buf)[T - 2][oversampling_flag][i] * ptr_mag[utk];

    phase_t = T * ptr_phase[utk];

    if (phase_t == 0.0) {

      ptr_spectrum_tx[2 * i] += mag_t;

    } else {

      ptr_spectrum_tx[2 * i] += mag_t * (FLOAT32)cos(phase_t);

      ptr_spectrum_tx[2 * i + 1] += mag_t * (FLOAT32)sin(phase_t);

    }

    if (p > 0) {

      m_val = 0;

      for (tr = 1; tr < T; tr++) {

        FLOAT32 temp;

        ti = (WORD32)((2.0f * i - tr * p_flt) / T + 0.5f);

        if ((ti < 0) || (ti + p > fft_size / 2)) continue;

        temp = min(ptr_mag[ti], ptr_mag[ti + p]);

        if (temp > m_val) {

          m_val = temp;

          m_tr = tr;

          utk = ti;

        }

      } /* for tr */

      if (m_val > q_thr * ptr_mag[2 * i / T]) {

        mag_t = (*fd_win_buf)[T - 2][oversampling_flag][i] * ((FLOAT32)sqrt(ptr_mag[utk])) *

                ((FLOAT32)sqrt(ptr_mag[utk + p]));

        phase_t = ((FLOAT32)(T - m_tr)) * ptr_phase[utk] + ((FLOAT32)m_tr) * ptr_phase[utk + p];

        ptr_spectrum_tx[2 * i] += mag_t * ((FLOAT32)cos(phase_t));

        ptr_spectrum_tx[2 * i + 1] += mag_t * ((FLOAT32)sin(phase_t));

      }

    }

    i++;

  }

}

VOID ia_dft_hbe_apply_polar_t_3(WORD32 T, ixheaace_str_esbr_hbe_txposer *pstr_hbe_txposer,

                                WORD32 pitch_in_bins, WORD out_transform_size) {

  WORD32 tr;

  WORD32 ti;

  WORD32 m_tr = 0;

  WORD32 p, i;

  FLOAT32 mag_t = 0.0f;

  FLOAT32 phase_t;

  FLOAT32 m_val;

  FLOAT32(*fd_win_buf)[3][3][1536] = &pstr_hbe_txposer->fd_win_buf;

  FLOAT32 *ptr_phase = pstr_hbe_txposer->ptr_phase;

  WORD32 oversampling_flag = pstr_hbe_txposer->oversampling_flag;

  WORD32 fft_size = pstr_hbe_txposer->fft_size[oversampling_flag];

  FLOAT32 *ptr_spectrum_tx = pstr_hbe_txposer->ptr_spectrum_tx;

  FLOAT32 *ptr_mag = pstr_hbe_txposer->ptr_mag;

  /* pitch_in_bins is given with the resolution of a 1536 point FFT */

  FLOAT32 p_flt = fft_size * pitch_in_bins / 1536.0f;

  p = (WORD32)p_flt;

  FLOAT32 q_thr = 4.0f;

  if (T < 3) {

    // To avoid invalid access by fd_win_buf

    T = 3;

  }

  i = 0;

  while (i <= out_transform_size) {

    WORD32 utk = 2 * i / T;

    FLOAT32 ptk = (2.0f * i / T) - utk;

    FLOAT32 k;

    if (i % 3 == 0) {

      mag_t = (*fd_win_buf)[T - 2][oversampling_flag][i] * ptr_mag[utk];

    } else if (i % 3 == 1) {

      k = (FLOAT32)cbrt(ptr_mag[utk]);

      mag_t =

          (*fd_win_buf)[T - 2][oversampling_flag][i] * k * (FLOAT32)pow(ptr_mag[utk + 1], ptk);

    } else if (i % 3 == 2) {

      k = (FLOAT32)cbrt(ptr_mag[utk + 1]);

      mag_t =

          (*fd_win_buf)[T - 2][oversampling_flag][i] * (FLOAT32)pow(ptr_mag[utk], 1.0 - ptk) * k;

    }

    phase_t = T * ((1 - ptk) * ptr_phase[utk] + ptk * ptr_phase[utk + 1]);

    ptr_spectrum_tx[2 * i] += mag_t * (FLOAT32)cos(phase_t);

    ptr_spectrum_tx[2 * i + 1] += mag_t * (FLOAT32)sin(phase_t);

    if (p > 0) {

      m_val = 0;

      for (tr = 1; tr < T; tr++) {

        FLOAT32 temp;

        ti = (WORD32)((2.0f * i - tr * p_flt) / T + 0.5f);

        if ((ti < 0) || (ti + p > fft_size / 2)) continue;

        temp = min(ptr_mag[ti], ptr_mag[ti + p]);

        if (temp > m_val) {

          m_val = temp;

          m_tr = tr;

          utk = ti;

        }

      } /* for tr */

      if (m_val > q_thr * ptr_mag[2 * i / T]) {

        FLOAT32 r = (FLOAT32)m_tr / T;

        switch (m_tr) {

          case 1:

            k = (FLOAT32)(cbrt((FLOAT32)ptr_mag[utk + p]));

            mag_t = (*fd_win_buf)[T - 2][oversampling_flag][i] *

                    (FLOAT32)pow(ptr_mag[utk], 1.0 - r) * k;

            phase_t = (T - m_tr) * ptr_phase[utk] + ptr_phase[utk + p];

            break;

          case 2:

            k = (FLOAT32)(cbrt((FLOAT32)ptr_mag[utk]));

            mag_t = (*fd_win_buf)[T - 2][oversampling_flag][i] * k *

                    (FLOAT32)pow(ptr_mag[utk + p], r);

            phase_t = ptr_phase[utk] + m_tr * ptr_phase[utk + p];

            break;

        }

        ptr_spectrum_tx[2 * i] += mag_t * (FLOAT32)cos(phase_t);

        ptr_spectrum_tx[2 * i + 1] += mag_t * (FLOAT32)sin(phase_t);

      }

    }

    i++;

  }

}

VOID ia_dft_hbe_apply_polar_t(WORD32 T, ixheaace_str_esbr_hbe_txposer *pstr_hbe_txposer,

                              WORD32 pitch_in_bins, WORD out_transform_size) {

  WORD32 tr;

  WORD32 ti;

  WORD32 m_tr = 0;

  WORD32 p, i;

  FLOAT32 mag_t;

  FLOAT32 phase_t;

  FLOAT32 m_val;

  FLOAT32(*fd_win_buf)[3][3][1536] = &pstr_hbe_txposer->fd_win_buf;

  FLOAT32 *ptr_phase = pstr_hbe_txposer->ptr_phase;

  WORD32 oversampling_flag = pstr_hbe_txposer->oversampling_flag;

  WORD32 fft_size = pstr_hbe_txposer->fft_size[oversampling_flag];

  FLOAT32 *ptr_spectrum_tx = pstr_hbe_txposer->ptr_spectrum_tx;

  FLOAT32 *ptr_mag = pstr_hbe_txposer->ptr_mag;

  /* pitch_in_bins is given with the resolution of a 1536 point FFT */

  FLOAT32 p_flt = fft_size * pitch_in_bins / 1536.0f;

  p = (WORD32)p_flt;

  FLOAT32 q_thr = 4.0f;

  if (T < 2) {

    // To avoid invalid access by fd_win_buf

    T = 2;

  }

  for (i = 0; i <= out_transform_size; i++) {

    WORD32 utk = 2 * i / T;

    FLOAT32 ptk = (2.0f * i / T) - utk;

    mag_t = (*fd_win_buf)[T - 2][oversampling_flag][i] * (FLOAT32)pow(ptr_mag[utk], 1.0f - ptk) *

            (FLOAT32)pow(ptr_mag[utk + 1], ptk);

    phase_t = T * ((1 - ptk) * ptr_phase[utk] + ptk * ptr_phase[utk + 1]);

    ptr_spectrum_tx[2 * i] += mag_t * (FLOAT32)cos(phase_t);

    ptr_spectrum_tx[2 * i + 1] += mag_t * (FLOAT32)sin(phase_t);

    if (p > 0) {

      m_val = 0;

      for (tr = 1; tr < T; tr++) {

        FLOAT32 temp;

        ti = (WORD32)((2.0f * i - tr * p_flt) / T + 0.5f);

        if ((ti < 0) || (ti + p > fft_size / 2)) continue;

        temp = min(ptr_mag[ti], ptr_mag[ti + p]);

        if (temp > m_val) {

          m_val = temp;

          m_tr = tr;

          utk = ti;

        }

      } /* for tr */

      if (m_val > q_thr * ptr_mag[2 * i / T]) {

        FLOAT32 r = (FLOAT32)m_tr / T;

        mag_t = (*fd_win_buf)[T - 2][oversampling_flag][i] * (FLOAT32)pow(ptr_mag[utk], 1.0 - r) *

                (FLOAT32)pow(ptr_mag[utk + p], r);

        phase_t = (T - m_tr) * ptr_phase[utk] + m_tr * ptr_phase[utk + p];

        ptr_spectrum_tx[2 * i] += mag_t * (FLOAT32)cos(phase_t);

        ptr_spectrum_tx[2 * i + 1] += mag_t * (FLOAT32)sin(phase_t);

      }

    }

  }

}

IA_ERRORCODE ixheaace_dft_hbe_apply(ixheaace_str_esbr_hbe_txposer *pstr_hbe_txposer,

                                    FLOAT32 qmf_buf_real[][64], FLOAT32 qmf_buf_imag[][64],

                                    WORD32 num_columns, FLOAT32 pv_qmf_buf_real[][64],

                                    FLOAT32 pv_qmf_buf_imag[][64], WORD32 pitch_in_bins,

                                    FLOAT32 *ptr_dft_hbe_scratch_buf) {

  WORD32 in_offset = 0;

  WORD32 out_offset = 0;

  WORD32 in_hop_size = pstr_hbe_txposer->in_hop_size;

  WORD32 oversampling_flag = pstr_hbe_txposer->oversampling_flag;

  WORD32 fft_size = pstr_hbe_txposer->fft_size[oversampling_flag];

  WORD32 out_hop_size = pstr_hbe_txposer->out_hop_size;

  WORD32 num_in_samples = num_columns * pstr_hbe_txposer->synth_size;

  WORD32 ana_fft_size = pstr_hbe_txposer->ana_fft_size[oversampling_flag];

  WORD32 syn_fft_size = pstr_hbe_txposer->syn_fft_size[oversampling_flag];

  WORD32 ana_pad_size = (ana_fft_size - pstr_hbe_txposer->ana_fft_size[0]) / 2;

  WORD32 syn_pad_size = (syn_fft_size - pstr_hbe_txposer->syn_fft_size[0]) / 2;

  FLOAT32 *ptr_input_buf = pstr_hbe_txposer->ptr_input_buf;

  FLOAT32 *ptr_output_buf = pstr_hbe_txposer->ptr_output_buf;

  FLOAT32 *ptr_spectrum = pstr_hbe_txposer->ptr_spectrum;

  FLOAT32 *ptr_spectrum_tx = pstr_hbe_txposer->ptr_spectrum_tx;

  FLOAT32 *ptr_mag = pstr_hbe_txposer->ptr_mag;

  FLOAT32 *ptr_phase = pstr_hbe_txposer->ptr_phase;

  WORD32 i, T;

  FLOAT32 *ptr_cos_fft;

  FLOAT32 *ptr_cos_ifft;

  WORD32 ana_fft_offset = pstr_hbe_txposer->k_start * fft_size / 32;

  WORD32 syn_fft_offset = pstr_hbe_txposer->a_start * fft_size / 64;

  /* pitch_in_bins is given with the resolution of a 1536 point FFT */

  WORD32 err_code = IA_NO_ERROR;

  memcpy(pstr_hbe_txposer->ptr_input_buf,

         pstr_hbe_txposer->ptr_input_buf + pstr_hbe_txposer->ana_fft_size[0],

         pstr_hbe_txposer->ana_fft_size[0] * sizeof(pstr_hbe_txposer->ptr_input_buf[0]));

  err_code = ixheaace_real_synth_filt(pstr_hbe_txposer, num_columns, qmf_buf_real, qmf_buf_imag);

  if (err_code) {

    return err_code;

  }

  memcpy(ptr_output_buf, ptr_output_buf + 2 * pstr_hbe_txposer->syn_fft_size[0],

         2 * pstr_hbe_txposer->syn_fft_size[0] * sizeof(ptr_output_buf[0]));

  memset(ptr_output_buf + 2 * pstr_hbe_txposer->syn_fft_size[0], 0,

         2 * pstr_hbe_txposer->syn_fft_size[0] * sizeof(ptr_output_buf[0]));

  err_code = ixheaace_hbe_fft_map(pstr_hbe_txposer);

  if (err_code) {

    return err_code;

  }

  while (in_offset < num_in_samples) {

    memset(ptr_spectrum, 0, fft_size * sizeof(ptr_spectrum[0]));

    memset(ptr_spectrum_tx, 0, ((fft_size + 2) * sizeof(ptr_spectrum_tx[0])));

    memset(ptr_mag, 0, (fft_size / 2 + 2) * sizeof(ptr_mag[0]));

    memset(ptr_phase, 0, (fft_size / 2 + 2) * sizeof(ptr_phase[0]));

    ixheaace_dft_hbe_apply_win(ptr_input_buf + in_offset, pstr_hbe_txposer->ptr_ana_win,

                               ptr_spectrum + ana_pad_size + ana_fft_offset,

                               pstr_hbe_txposer->ana_fft_size[0]);

    ixheaace_dft_hbe_fft_memmove(ptr_spectrum + ana_fft_offset, ana_fft_size);

    {

      WORD32 len = ana_fft_size;

      ptr_cos_fft = pstr_hbe_txposer->ptr_ana_cos_sin_tab;

      FLOAT32 *ptr_fft_data = ptr_spectrum + ana_fft_offset;

      FLOAT32 tmp1, tmp2, tmp3, tmp4;

      (*(pstr_hbe_txposer->ixheaace_hbe_anal_fft))(ptr_fft_data, ptr_dft_hbe_scratch_buf, len / 2,

                                                   -1);

      tmp1 = ptr_fft_data[0] + ptr_fft_data[1];

      ptr_fft_data[1] = ptr_fft_data[0] - ptr_fft_data[1];

      ptr_fft_data[0] = tmp1;

      i = 1;

      while (i <= (len / 4 + (len % 4) / 2)) {

        tmp1 = ptr_fft_data[2 * i] - ptr_fft_data[len - 2 * i];

        tmp2 = ptr_fft_data[2 * i + 1] + ptr_fft_data[len - 2 * i + 1];

        tmp3 = (*(ptr_cos_fft)) * tmp1 - (*(ptr_cos_fft + 1)) * tmp2;

        tmp4 = (*(ptr_cos_fft + 1)) * tmp1 + (*(ptr_cos_fft)) * tmp2;

        ptr_cos_fft = ptr_cos_fft + 2;

        tmp1 = ptr_fft_data[2 * i] + ptr_fft_data[len - 2 * i];

        tmp2 = ptr_fft_data[2 * i + 1] - ptr_fft_data[len - 2 * i + 1];

        ptr_fft_data[2 * i + 0] = 0.5f * (tmp1 - tmp3);

        ptr_fft_data[2 * i + 1] = 0.5f * (tmp2 - tmp4);

        ptr_fft_data[len - 2 * i + 0] = 0.5f * (tmp1 + tmp3);

        ptr_fft_data[len - 2 * i + 1] = -0.5f * (tmp2 + tmp4);

        ++i;

      }

    }

    ixheaace_karth2polar(ptr_spectrum + ana_fft_offset, ptr_mag + ana_fft_offset / 2,

                         ptr_phase + ana_fft_offset / 2, ana_fft_size);

    for (T = 2; T <= pstr_hbe_txposer->max_stretch; T++) {

      /* max_stretch cannot be greater than 4. So, T can be 2 to 4*/

      WORD32 out_transform_size;

      /* 0<i<fft_size/2 */

      out_transform_size = (fft_size / 2);

      switch (T) {

        case 2:

          ia_dft_hbe_apply_polar_t2(T, pstr_hbe_txposer, pitch_in_bins, out_transform_size);

          break;

        case 3:

          ia_dft_hbe_apply_polar_t_3(T, pstr_hbe_txposer, pitch_in_bins, out_transform_size);

          break;

        default:

          ia_dft_hbe_apply_polar_t(T, pstr_hbe_txposer, pitch_in_bins, out_transform_size);

      }

    } /* for T */

    ptr_spectrum_tx[syn_fft_offset + 1] =

        ptr_spectrum_tx[syn_fft_offset + syn_fft_size]; /* Move Nyquist bin to bin 1 for RFFTN */

    {

      WORD32 len = syn_fft_size;

      ptr_cos_ifft = pstr_hbe_txposer->ptr_syn_cos_sin_tab;

      FLOAT32 *ptr_fft_data = ptr_spectrum_tx + syn_fft_offset;

      FLOAT32 tmp1, tmp2, tmp3, tmp4;

      FLOAT32 scale = 1.0f / len;

      tmp1 = ptr_fft_data[0] + ptr_fft_data[1];

      ptr_fft_data[1] = scale * (ptr_fft_data[0] - ptr_fft_data[1]);

      ptr_fft_data[0] = scale * tmp1;

      for (i = 1; i <= (len / 4 + (len % 4) / 2); ++i) {

        tmp1 = ptr_fft_data[2 * i] - ptr_fft_data[len - 2 * i];

        tmp2 = ptr_fft_data[2 * i + 1] + ptr_fft_data[len - 2 * i + 1];

        tmp3 = (*(ptr_cos_ifft)) * tmp1 + (*(ptr_cos_ifft + 1)) * tmp2;

        tmp4 = -(*(ptr_cos_ifft + 1)) * tmp1 + (*(ptr_cos_ifft)) * tmp2;

        ptr_cos_ifft = ptr_cos_ifft + 2;

        tmp1 = ptr_fft_data[2 * i] + ptr_fft_data[len - 2 * i];