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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "settings.h"
#include "fft.h"
#include "codec.h"
#include "os_specific_inline.h"
#include <math.h>
static double costab1[FRAMESAMPLES_HALF];
static double sintab1[FRAMESAMPLES_HALF];
static double costab2[FRAMESAMPLES_QUARTER];
static double sintab2[FRAMESAMPLES_QUARTER];
void WebRtcIsac_InitTransform()
{
int k;
double fact, phase;
fact = PI / (FRAMESAMPLES_HALF);
phase = 0.0;
for (k = 0; k < FRAMESAMPLES_HALF; k++) {
costab1[k] = cos(phase);
sintab1[k] = sin(phase);
phase += fact;
}
fact = PI * ((double) (FRAMESAMPLES_HALF - 1)) / ((double) FRAMESAMPLES_HALF);
phase = 0.5 * fact;
for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
costab2[k] = cos(phase);
sintab2[k] = sin(phase);
phase += fact;
}
}
void WebRtcIsac_Time2Spec(double *inre1,
double *inre2,
WebRtc_Word16 *outreQ7,
WebRtc_Word16 *outimQ7,
FFTstr *fftstr_obj)
{
int k;
int dims[1];
double tmp1r, tmp1i, xr, xi, yr, yi, fact;
double tmpre[FRAMESAMPLES_HALF], tmpim[FRAMESAMPLES_HALF];
dims[0] = FRAMESAMPLES_HALF;
/* Multiply with complex exponentials and combine into one complex vector */
fact = 0.5 / sqrt(FRAMESAMPLES_HALF);
for (k = 0; k < FRAMESAMPLES_HALF; k++) {
tmp1r = costab1[k];
tmp1i = sintab1[k];
tmpre[k] = (inre1[k] * tmp1r + inre2[k] * tmp1i) * fact;
tmpim[k] = (inre2[k] * tmp1r - inre1[k] * tmp1i) * fact;
}
/* Get DFT */
WebRtcIsac_Fftns(1, dims, tmpre, tmpim, -1, 1.0, fftstr_obj);
/* Use symmetry to separate into two complex vectors and center frames in time around zero */
for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
xr = tmpre[k] + tmpre[FRAMESAMPLES_HALF - 1 - k];
yi = -tmpre[k] + tmpre[FRAMESAMPLES_HALF - 1 - k];
xi = tmpim[k] - tmpim[FRAMESAMPLES_HALF - 1 - k];
yr = tmpim[k] + tmpim[FRAMESAMPLES_HALF - 1 - k];
tmp1r = costab2[k];
tmp1i = sintab2[k];
outreQ7[k] = (WebRtc_Word16)WebRtcIsac_lrint((xr * tmp1r - xi * tmp1i) * 128.0);
outimQ7[k] = (WebRtc_Word16)WebRtcIsac_lrint((xr * tmp1i + xi * tmp1r) * 128.0);
outreQ7[FRAMESAMPLES_HALF - 1 - k] = (WebRtc_Word16)WebRtcIsac_lrint((-yr * tmp1i - yi * tmp1r) * 128.0);
outimQ7[FRAMESAMPLES_HALF - 1 - k] = (WebRtc_Word16)WebRtcIsac_lrint((-yr * tmp1r + yi * tmp1i) * 128.0);
}
}
void WebRtcIsac_Spec2time(double *inre, double *inim, double *outre1, double *outre2, FFTstr *fftstr_obj)
{
int k;
double tmp1r, tmp1i, xr, xi, yr, yi, fact;
int dims;
dims = FRAMESAMPLES_HALF;
for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
/* Move zero in time to beginning of frames */
tmp1r = costab2[k];
tmp1i = sintab2[k];
xr = inre[k] * tmp1r + inim[k] * tmp1i;
xi = inim[k] * tmp1r - inre[k] * tmp1i;
yr = -inim[FRAMESAMPLES_HALF - 1 - k] * tmp1r - inre[FRAMESAMPLES_HALF - 1 - k] * tmp1i;
yi = -inre[FRAMESAMPLES_HALF - 1 - k] * tmp1r + inim[FRAMESAMPLES_HALF - 1 - k] * tmp1i;
/* Combine into one vector, z = x + j * y */
outre1[k] = xr - yi;
outre1[FRAMESAMPLES_HALF - 1 - k] = xr + yi;
outre2[k] = xi + yr;
outre2[FRAMESAMPLES_HALF - 1 - k] = -xi + yr;
}
/* Get IDFT */
WebRtcIsac_Fftns(1, &dims, outre1, outre2, 1, FRAMESAMPLES_HALF, fftstr_obj);
/* Demodulate and separate */
fact = sqrt(FRAMESAMPLES_HALF);
for (k = 0; k < FRAMESAMPLES_HALF; k++) {
tmp1r = costab1[k];
tmp1i = sintab1[k];
xr = (outre1[k] * tmp1r - outre2[k] * tmp1i) * fact;
outre2[k] = (outre2[k] * tmp1r + outre1[k] * tmp1i) * fact;
outre1[k] = xr;
}
}
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