text: /*
   * AAC Spectral Band Replication decoding functions
   * Copyright (c) 2008-2009 Robert Swain ( rob opendot cl )
   * Copyright (c) 2009-2010 Alex Converse <alex.converse@gmail.com>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * AAC Spectral Band Replication decoding functions
   * @author Robert Swain ( rob opendot cl )
   */
  #define USE_FIXED 0
  
  #include "aac.h"
  #include "sbr.h"
  #include "aacsbr.h"
  #include "aacsbrdata.h"
  #include "fft.h"
  #include "internal.h"
  #include "aacps.h"
  #include "sbrdsp.h"
  #include "libavutil/internal.h"
  #include "libavutil/libm.h"
  #include "libavutil/avassert.h"
  #include "libavutil/mem_internal.h"
  
  #include <stdint.h>
  #include <float.h>
  #include <math.h>
  
  #if ARCH_MIPS
  #include "mips/aacsbr_mips.h"
  #endif /* ARCH_MIPS */
  
  static VLC vlc_sbr[10];
  static void aacsbr_func_ptr_init(AACSBRContext *c);
  
  static void make_bands(int16_t* bands, int start, int stop, int num_bands)
  {
      int k, previous, present;
      float base, prod;
  
      base = powf((float)stop / start, 1.0f / num_bands);
      prod = start;
      previous = start;
  
      for (k = 0; k < num_bands-1; k++) {
          prod *= base;
          present  = lrintf(prod);
          bands[k] = present - previous;
          previous = present;
      }
      bands[num_bands-1] = stop - previous;
  }
  
  /// Dequantization and stereo decoding (14496-3 sp04 p203)
  static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)
  {
      int k, e;
      int ch;
      static const double exp2_tab[2] = {1, M_SQRT2};
      if (id_aac == TYPE_CPE && sbr->bs_coupling) {
          int pan_offset = sbr->data[0].bs_amp_res ? 12 : 24;
          for (e = 1; e <= sbr->data[0].bs_num_env; e++) {
              for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {
                  float temp1, temp2, fac;
                  if (sbr->data[0].bs_amp_res) {
                      temp1 = ff_exp2fi(sbr->data[0].env_facs_q[e][k] + 7);
                      temp2 = ff_exp2fi(pan_offset - sbr->data[1].env_facs_q[e][k]);
                  }
                  else {
                      temp1 = ff_exp2fi((sbr->data[0].env_facs_q[e][k]>>1) + 7) *
                              exp2_tab[sbr->data[0].env_facs_q[e][k] & 1];
                      temp2 = ff_exp2fi((pan_offset - sbr->data[1].env_facs_q[e][k])>>1) *
                              exp2_tab[(pan_offset - sbr->data[1].env_facs_q[e][k]) & 1];
                  }
                  if (temp1 > 1E20) {
                      av_log(NULL, AV_LOG_ERROR, "envelope scalefactor overflow in dequant\n");
                      temp1 = 1;
                  }
                  fac   = temp1 / (1.0f + temp2);
                  sbr->data[0].env_facs[e][k] = fac;
                  sbr->data[1].env_facs[e][k] = fac * temp2;
              }
          }
          for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {
              for (k = 0; k < sbr->n_q; k++) {
                  float temp1 = ff_exp2fi(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs_q[e][k] + 1);
                  float temp2 = ff_exp2fi(12 - sbr->data[1].noise_facs_q[e][k]);
                  float fac;
                  av_assert0(temp1 <= 1E20);
                  fac = temp1 / (1.0f + temp2);
                  sbr->data[0].noise_facs[e][k] = fac;
                  sbr->data[1].noise_facs[e][k] = fac * temp2;
              }
          }
      } else { // SCE or one non-coupled CPE
          for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {
              for (e = 1; e <= sbr->data[ch].bs_num_env; e++)
                  for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++){
                      if (sbr->data[ch].bs_amp_res)
                          sbr->data[ch].env_facs[e][k] = ff_exp2fi(sbr->data[ch].env_facs_q[e][k] + 6);
                      else
                          sbr->data[ch].env_facs[e][k] = ff_exp2fi((sbr->data[ch].env_facs_q[e][k]>>1) + 6)
                                                         * exp2_tab[sbr->data[ch].env_facs_q[e][k] & 1];
                      if (sbr->data[ch].env_facs[e][k] > 1E20) {
                          av_log(NULL, AV_LOG_ERROR, "envelope scalefactor overflow in dequant\n");
                          sbr->data[ch].env_facs[e][k] = 1;
                      }
                  }
  
              for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)
                  for (k = 0; k < sbr->n_q; k++)
                      sbr->data[ch].noise_facs[e][k] =
                          ff_exp2fi(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs_q[e][k]);
          }
      }
  }
  
  /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering
   * (14496-3 sp04 p214)
   * Warning: This routine does not seem numerically stable.
   */
  static void sbr_hf_inverse_filter(SBRDSPContext *dsp,
                                    float (*alpha0)[2], float (*alpha1)[2],
                                    const float X_low[32][40][2], int k0)
  {
      int k;
      for (k = 0; k < k0; k++) {
          LOCAL_ALIGNED_16(float, phi, [3], [2][2]);
          float dk;
  
          dsp->autocorrelate(X_low[k], phi);
  
          dk =  phi[2][1][0] * phi[1][0][0] -
               (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;
  
          if (!dk) {
              alpha1[k][0] = 0;
              alpha1[k][1] = 0;
          } else {
              float temp_real, temp_im;
              temp_real = phi[0][0][0] * phi[1][1][0] -
                          phi[0][0][1] * phi[1][1][1] -
                          phi[0][1][0] * phi[1][0][0];
              temp_im   = phi[0][0][0] * phi[1][1][1] +
                          phi[0][0][1] * phi[1][1][0] -
                          phi[0][1][1] * phi[1][0][0];
  
              alpha1[k][0] = temp_real / dk;
              alpha1[k][1] = temp_im   / dk;
          }
  
          if (!phi[1][0][0]) {
              alpha0[k][0] = 0;
              alpha0[k][1] = 0;
          } else {
              float temp_real, temp_im;
              temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +
                                         alpha1[k][1] * phi[1][1][1];
              temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -
                                         alpha1[k][0] * phi[1][1][1];
  
              alpha0[k][0] = -temp_real / phi[1][0][0];
              alpha0[k][1] = -temp_im   / phi[1][0][0];
          }
  
          if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||
             alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {
              alpha1[k][0] = 0;
              alpha1[k][1] = 0;
              alpha0[k][0] = 0;
              alpha0[k][1] = 0;
          }
      }
  }
  
  /// Chirp Factors (14496-3 sp04 p214)
  static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)
  {
      int i;
      float new_bw;
      static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };
  
      for (i = 0; i < sbr->n_q; i++) {
          if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {
              new_bw = 0.6f;
          } else
              new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];
  
          if (new_bw < ch_data->bw_array[i]) {
              new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];
          } else
              new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];
          ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;
      }
  }
  
  /**
   * Calculation of levels of additional HF signal components (14496-3 sp04 p219)
   * and Calculation of gain (14496-3 sp04 p219)
   */
  static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,
                            SBRData *ch_data, const int e_a[2])
  {
      int e, k, m;
      // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)
      static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };
  
      for (e = 0; e < ch_data->bs_num_env; e++) {
          int delta = !((e == e_a[1]) || (e == e_a[0]));
          for (k = 0; k < sbr->n_lim; k++) {
              float gain_boost, gain_max;
              float sum[2] = { 0.0f, 0.0f };
              for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
                  const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);
                  sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);
                  sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);
                  if (!sbr->s_mapped[e][m]) {
                      sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /
                                              ((1.0f + sbr->e_curr[e][m]) *
                                               (1.0f + sbr->q_mapped[e][m] * delta)));
                  } else {
                      sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /
                                              ((1.0f + sbr->e_curr[e][m]) *
                                               (1.0f + sbr->q_mapped[e][m])));
                  }
                  sbr->gain[e][m] += FLT_MIN;
              }
              for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
                  sum[0] += sbr->e_origmapped[e][m];
                  sum[1] += sbr->e_curr[e][m];
              }
              gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));
              gain_max = FFMIN(100000.f, gain_max);
              for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
                  float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];
                  sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);
                  sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);
              }
              sum[0] = sum[1] = 0.0f;
              for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
                  sum[0] += sbr->e_origmapped[e][m];
                  sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]
                            + sbr->s_m[e][m] * sbr->s_m[e][m]
                            + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];
              }
              gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));
              gain_boost = FFMIN(1.584893192f, gain_boost);
              for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {
                  sbr->gain[e][m] *= gain_boost;
                  sbr->q_m[e][m]  *= gain_boost;
                  sbr->s_m[e][m]  *= gain_boost;
              }
          }
      }
  }
  
  /// Assembling HF Signals (14496-3 sp04 p220)
  static void sbr_hf_assemble(float Y1[38][64][2],
                              const float X_high[64][40][2],
                              SpectralBandReplication *sbr, SBRData *ch_data,
                              const int e_a[2])
  {
      int e, i, j, m;
      const int h_SL = 4 * !sbr->bs_smoothing_mode;
      const int kx = sbr->kx[1];
      const int m_max = sbr->m[1];
      static const float h_smooth[5] = {
          0.33333333333333,
          0.30150283239582,
          0.21816949906249,
          0.11516383427084,
          0.03183050093751,
      };
      float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;
      int indexnoise = ch_data->f_indexnoise;
      int indexsine  = ch_data->f_indexsine;
  
      if (sbr->reset) {
          for (i = 0; i < h_SL; i++) {
              memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));
              memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0],  m_max * sizeof(sbr->q_m[0][0]));
          }
      } else if (h_SL) {
          for (i = 0; i < 4; i++) {
              memcpy(g_temp[i + 2 * ch_data->t_env[0]],
                     g_temp[i + 2 * ch_data->t_env_num_env_old],
                     sizeof(g_temp[0]));
              memcpy(q_temp[i + 2 * ch_data->t_env[0]],
                     q_temp[i + 2 * ch_data->t_env_num_env_old],
                     sizeof(q_temp[0]));
          }
      }
  
      for (e = 0; e < ch_data->bs_num_env; e++) {
          for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {
              memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));
              memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));
          }
      }
  
      for (e = 0; e < ch_data->bs_num_env; e++) {
          for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {
              LOCAL_ALIGNED_16(float, g_filt_tab, [48]);
              LOCAL_ALIGNED_16(float, q_filt_tab, [48]);
              float *g_filt, *q_filt;
  
              if (h_SL && e != e_a[0] && e != e_a[1]) {
                  g_filt = g_filt_tab;
                  q_filt = q_filt_tab;
                  for (m = 0; m < m_max; m++) {
                      const int idx1 = i + h_SL;
                      g_filt[m] = 0.0f;
                      q_filt[m] = 0.0f;
                      for (j = 0; j <= h_SL; j++) {
                          g_filt[m] += g_temp[idx1 - j][m] * h_smooth[j];
                          q_filt[m] += q_temp[idx1 - j][m] * h_smooth[j];
                      }
                  }
              } else {
                  g_filt = g_temp[i + h_SL];
                  q_filt = q_temp[i];
              }
  
              sbr->dsp.hf_g_filt(Y1[i] + kx, X_high + kx, g_filt, m_max,
                                 i + ENVELOPE_ADJUSTMENT_OFFSET);
  
              if (e != e_a[0] && e != e_a[1]) {
                  sbr->dsp.hf_apply_noise[indexsine](Y1[i] + kx, sbr->s_m[e],
                                                     q_filt, indexnoise,
                                                     kx, m_max);
              } else {
                  int idx = indexsine&1;
                  int A = (1-((indexsine+(kx & 1))&2));
                  int B = (A^(-idx)) + idx;
                  float *out = &Y1[i][kx][idx];
                  float *in  = sbr->s_m[e];
                  for (m = 0; m+1 < m_max; m+=2) {
                      out[2*m  ] += in[m  ] * A;
                      out[2*m+2] += in[m+1] * B;
                  }
                  if(m_max&1)
                      out[2*m  ] += in[m  ] * A;
              }
              indexnoise = (indexnoise + m_max) & 0x1ff;
              indexsine = (indexsine + 1) & 3;
          }
      }
      ch_data->f_indexnoise = indexnoise;
      ch_data->f_indexsine  = indexsine;
  }
  
  #include "aacsbr_template.c"
  