Line data    Source code

       1             : /******************************************************************************
       2             : *                        ETSI TS 103 634 V1.5.1                               *
       3             : *              Low Complexity Communication Codec Plus (LC3plus)              *
       4             : *                                                                             *
       5             : * Copyright licence is solely granted through ETSI Intellectual Property      *
       6             : * Rights Policy, 3rd April 2019. No patent licence is granted by implication, *
       7             : * estoppel or otherwise.                                                      *
       8             : ******************************************************************************/
       9             : 
      10             : #include "options.h"
      11             : #include "wmc_auto.h"
      12             : #include "functions.h"
      13             : 
      14           0 : void processNearNyquistdetector_fl(LC3_INT16* near_nyquist_flag, const LC3_INT fs_idx, const LC3_INT near_nyquist_index,
      15             :                                    const LC3_INT bands_number, const LC3_FLOAT* ener         , const LC3_INT16 frame_dms, const LC3_INT16 hrmode)                               
      16             : {
      17           0 :     *near_nyquist_flag = 0;
      18           0 :     if (hrmode == 0){
      19           0 :         if (fs_idx < 4)
      20             :         { 
      21           0 :             LC3_INT   i = 0;
      22           0 :             LC3_FLOAT ener_low = FLT_EPSILON, ener_high = 0;
      23             : 
      24           0 :             for (i=0; i<near_nyquist_index; i++)
      25             :             {
      26           0 :                 ener_low += ener[i];
      27             :             }
      28             : 
      29           0 :             for (i=near_nyquist_index; i<bands_number; i++)
      30             :             {
      31           0 :                 ener_high += ener[i];
      32             :             }
      33             : 
      34           0 :             if (ener_high > NN_thresh * ener_low){
      35           0 :                 *near_nyquist_flag = 1;
      36             :             }
      37             :         }
      38             :     } 
      39             :     else // hrmode == 1 
      40             :     {
      41             :         // inverse spectral flatness = mean(energy) ./ 2^(mean(log2(energy)));
      42           0 :         LC3_INT32 td_thresh, i = 0;
      43           0 :         LC3_FLOAT mean_ener = 0, mean_ener_log2 = 0, inv_flatness = 0;
      44             : 
      45           0 :         switch (frame_dms)
      46             :         {
      47           0 :         case 25:
      48           0 :             td_thresh = TD_HR_thresh_2_5ms;
      49           0 :             break;
      50           0 :         case 50:
      51           0 :             td_thresh = TD_HR_thresh_5ms;
      52           0 :             break;
      53           0 :         case 75:
      54           0 :             td_thresh = TD_HR_thresh_7_5ms;
      55           0 :             break;
      56           0 :         default:                             /* 100 */
      57           0 :             td_thresh = TD_HR_thresh_10ms;
      58           0 :             break;
      59             :         }
      60             : 
      61             :         // calculate arithmetic mean
      62           0 :         for (i = 0; i < bands_number; i++)
      63             :         {
      64           0 :             mean_ener += ener[i];
      65             :         }
      66           0 :         mean_ener = mean_ener / bands_number;
      67             : 
      68             :         // calculate geometric mean
      69           0 :         for (i = 0; i < bands_number; i++)
      70             :         {    
      71           0 :             if (ener[i] != 0) {
      72           0 :                 mean_ener_log2 += LC3_LOGTWO(ener[i]);
      73             :             }
      74             :         }
      75           0 :         mean_ener_log2 = mean_ener_log2 / bands_number;
      76             : 
      77           0 :         inv_flatness = mean_ener / LC3_POW(2,mean_ener_log2);
      78             : 
      79           0 :         if (inv_flatness > td_thresh) {
      80           0 :             *near_nyquist_flag = 1;
      81             :         } 
      82             :     }
      83           0 : }