Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
       3             :  *
       4             :  *  Use of this source code is governed by a BSD-style license
       5             :  *  that can be found in the LICENSE file in the root of the source
       6             :  *  tree. An additional intellectual property rights grant can be found
       7             :  *  in the file PATENTS.  All contributing project authors may
       8             :  *  be found in the AUTHORS file in the root of the source tree.
       9             :  */
      10             : 
      11             : #include "settings.h"
      12             : #include "fft.h"
      13             : #include "codec.h"
      14             : #include "os_specific_inline.h"
      15             : #include <math.h>
      16             : 
      17           0 : void WebRtcIsac_InitTransform(TransformTables* tables) {
      18             :   int k;
      19             :   double fact, phase;
      20             : 
      21           0 :   fact = PI / (FRAMESAMPLES_HALF);
      22           0 :   phase = 0.0;
      23           0 :   for (k = 0; k < FRAMESAMPLES_HALF; k++) {
      24           0 :     tables->costab1[k] = cos(phase);
      25           0 :     tables->sintab1[k] = sin(phase);
      26           0 :     phase += fact;
      27             :   }
      28             : 
      29           0 :   fact = PI * ((double) (FRAMESAMPLES_HALF - 1)) / ((double) FRAMESAMPLES_HALF);
      30           0 :   phase = 0.5 * fact;
      31           0 :   for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
      32           0 :     tables->costab2[k] = cos(phase);
      33           0 :     tables->sintab2[k] = sin(phase);
      34           0 :     phase += fact;
      35             :   }
      36           0 : }
      37             : 
      38           0 : void WebRtcIsac_Time2Spec(const TransformTables* tables,
      39             :                           double* inre1,
      40             :                           double* inre2,
      41             :                           int16_t* outreQ7,
      42             :                           int16_t* outimQ7,
      43             :                           FFTstr* fftstr_obj) {
      44             :   int k;
      45             :   int dims[1];
      46             :   double tmp1r, tmp1i, xr, xi, yr, yi, fact;
      47             :   double tmpre[FRAMESAMPLES_HALF], tmpim[FRAMESAMPLES_HALF];
      48             : 
      49             : 
      50           0 :   dims[0] = FRAMESAMPLES_HALF;
      51             : 
      52             : 
      53             :   /* Multiply with complex exponentials and combine into one complex vector */
      54           0 :   fact = 0.5 / sqrt(FRAMESAMPLES_HALF);
      55           0 :   for (k = 0; k < FRAMESAMPLES_HALF; k++) {
      56           0 :     tmp1r = tables->costab1[k];
      57           0 :     tmp1i = tables->sintab1[k];
      58           0 :     tmpre[k] = (inre1[k] * tmp1r + inre2[k] * tmp1i) * fact;
      59           0 :     tmpim[k] = (inre2[k] * tmp1r - inre1[k] * tmp1i) * fact;
      60             :   }
      61             : 
      62             : 
      63             :   /* Get DFT */
      64           0 :   WebRtcIsac_Fftns(1, dims, tmpre, tmpim, -1, 1.0, fftstr_obj);
      65             : 
      66             :   /* Use symmetry to separate into two complex vectors and center frames in time around zero */
      67           0 :   for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
      68           0 :     xr = tmpre[k] + tmpre[FRAMESAMPLES_HALF - 1 - k];
      69           0 :     yi = -tmpre[k] + tmpre[FRAMESAMPLES_HALF - 1 - k];
      70           0 :     xi = tmpim[k] - tmpim[FRAMESAMPLES_HALF - 1 - k];
      71           0 :     yr = tmpim[k] + tmpim[FRAMESAMPLES_HALF - 1 - k];
      72             : 
      73           0 :     tmp1r = tables->costab2[k];
      74           0 :     tmp1i = tables->sintab2[k];
      75           0 :     outreQ7[k] = (int16_t)WebRtcIsac_lrint((xr * tmp1r - xi * tmp1i) * 128.0);
      76           0 :     outimQ7[k] = (int16_t)WebRtcIsac_lrint((xr * tmp1i + xi * tmp1r) * 128.0);
      77           0 :     outreQ7[FRAMESAMPLES_HALF - 1 - k] = (int16_t)WebRtcIsac_lrint((-yr * tmp1i - yi * tmp1r) * 128.0);
      78           0 :     outimQ7[FRAMESAMPLES_HALF - 1 - k] = (int16_t)WebRtcIsac_lrint((-yr * tmp1r + yi * tmp1i) * 128.0);
      79             :   }
      80           0 : }
      81             : 
      82           0 : void WebRtcIsac_Spec2time(const TransformTables* tables,
      83             :                           double* inre,
      84             :                           double* inim,
      85             :                           double* outre1,
      86             :                           double* outre2,
      87             :                           FFTstr* fftstr_obj) {
      88             :   int k;
      89             :   double tmp1r, tmp1i, xr, xi, yr, yi, fact;
      90             : 
      91             :   int dims;
      92             : 
      93           0 :   dims = FRAMESAMPLES_HALF;
      94             : 
      95           0 :   for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
      96             :     /* Move zero in time to beginning of frames */
      97           0 :     tmp1r = tables->costab2[k];
      98           0 :     tmp1i = tables->sintab2[k];
      99           0 :     xr = inre[k] * tmp1r + inim[k] * tmp1i;
     100           0 :     xi = inim[k] * tmp1r - inre[k] * tmp1i;
     101           0 :     yr = -inim[FRAMESAMPLES_HALF - 1 - k] * tmp1r - inre[FRAMESAMPLES_HALF - 1 - k] * tmp1i;
     102           0 :     yi = -inre[FRAMESAMPLES_HALF - 1 - k] * tmp1r + inim[FRAMESAMPLES_HALF - 1 - k] * tmp1i;
     103             : 
     104             :     /* Combine into one vector,  z = x + j * y */
     105           0 :     outre1[k] = xr - yi;
     106           0 :     outre1[FRAMESAMPLES_HALF - 1 - k] = xr + yi;
     107           0 :     outre2[k] = xi + yr;
     108           0 :     outre2[FRAMESAMPLES_HALF - 1 - k] = -xi + yr;
     109             :   }
     110             : 
     111             : 
     112             :   /* Get IDFT */
     113           0 :   WebRtcIsac_Fftns(1, &dims, outre1, outre2, 1, FRAMESAMPLES_HALF, fftstr_obj);
     114             : 
     115             : 
     116             :   /* Demodulate and separate */
     117           0 :   fact = sqrt(FRAMESAMPLES_HALF);
     118           0 :   for (k = 0; k < FRAMESAMPLES_HALF; k++) {
     119           0 :     tmp1r = tables->costab1[k];
     120           0 :     tmp1i = tables->sintab1[k];
     121           0 :     xr = (outre1[k] * tmp1r - outre2[k] * tmp1i) * fact;
     122           0 :     outre2[k] = (outre2[k] * tmp1r + outre1[k] * tmp1i) * fact;
     123           0 :     outre1[k] = xr;
     124             :   }
     125           0 : }