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 <math.h>
12
13 #include "modules/audio_coding/codecs/isac/main/source/settings.h"
14 #include "modules/audio_coding/codecs/isac/main/source/codec.h"
15 #include "modules/audio_coding/codecs/isac/main/source/os_specific_inline.h"
16 #include "modules/third_party/fft/fft.h"
17
WebRtcIsac_InitTransform(TransformTables * tables)18 void WebRtcIsac_InitTransform(TransformTables* tables) {
19 int k;
20 double fact, phase;
21
22 fact = PI / (FRAMESAMPLES_HALF);
23 phase = 0.0;
24 for (k = 0; k < FRAMESAMPLES_HALF; k++) {
25 tables->costab1[k] = cos(phase);
26 tables->sintab1[k] = sin(phase);
27 phase += fact;
28 }
29
30 fact = PI * ((double) (FRAMESAMPLES_HALF - 1)) / ((double) FRAMESAMPLES_HALF);
31 phase = 0.5 * fact;
32 for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
33 tables->costab2[k] = cos(phase);
34 tables->sintab2[k] = sin(phase);
35 phase += fact;
36 }
37 }
38
WebRtcIsac_Time2Spec(const TransformTables * tables,double * inre1,double * inre2,int16_t * outreQ7,int16_t * outimQ7,FFTstr * fftstr_obj)39 void WebRtcIsac_Time2Spec(const TransformTables* tables,
40 double* inre1,
41 double* inre2,
42 int16_t* outreQ7,
43 int16_t* outimQ7,
44 FFTstr* fftstr_obj) {
45 int k;
46 int dims[1];
47 double tmp1r, tmp1i, xr, xi, yr, yi, fact;
48 double tmpre[FRAMESAMPLES_HALF], tmpim[FRAMESAMPLES_HALF];
49
50
51 dims[0] = FRAMESAMPLES_HALF;
52
53
54 /* Multiply with complex exponentials and combine into one complex vector */
55 fact = 0.5 / sqrt(FRAMESAMPLES_HALF);
56 for (k = 0; k < FRAMESAMPLES_HALF; k++) {
57 tmp1r = tables->costab1[k];
58 tmp1i = tables->sintab1[k];
59 tmpre[k] = (inre1[k] * tmp1r + inre2[k] * tmp1i) * fact;
60 tmpim[k] = (inre2[k] * tmp1r - inre1[k] * tmp1i) * fact;
61 }
62
63
64 /* Get DFT */
65 WebRtcIsac_Fftns(1, dims, tmpre, tmpim, -1, 1.0, fftstr_obj);
66
67 /* Use symmetry to separate into two complex vectors and center frames in time around zero */
68 for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
69 xr = tmpre[k] + tmpre[FRAMESAMPLES_HALF - 1 - k];
70 yi = -tmpre[k] + tmpre[FRAMESAMPLES_HALF - 1 - k];
71 xi = tmpim[k] - tmpim[FRAMESAMPLES_HALF - 1 - k];
72 yr = tmpim[k] + tmpim[FRAMESAMPLES_HALF - 1 - k];
73
74 tmp1r = tables->costab2[k];
75 tmp1i = tables->sintab2[k];
76 outreQ7[k] = (int16_t)WebRtcIsac_lrint((xr * tmp1r - xi * tmp1i) * 128.0);
77 outimQ7[k] = (int16_t)WebRtcIsac_lrint((xr * tmp1i + xi * tmp1r) * 128.0);
78 outreQ7[FRAMESAMPLES_HALF - 1 - k] = (int16_t)WebRtcIsac_lrint((-yr * tmp1i - yi * tmp1r) * 128.0);
79 outimQ7[FRAMESAMPLES_HALF - 1 - k] = (int16_t)WebRtcIsac_lrint((-yr * tmp1r + yi * tmp1i) * 128.0);
80 }
81 }
82
WebRtcIsac_Spec2time(const TransformTables * tables,double * inre,double * inim,double * outre1,double * outre2,FFTstr * fftstr_obj)83 void WebRtcIsac_Spec2time(const TransformTables* tables,
84 double* inre,
85 double* inim,
86 double* outre1,
87 double* outre2,
88 FFTstr* fftstr_obj) {
89 int k;
90 double tmp1r, tmp1i, xr, xi, yr, yi, fact;
91
92 int dims;
93
94 dims = FRAMESAMPLES_HALF;
95
96 for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
97 /* Move zero in time to beginning of frames */
98 tmp1r = tables->costab2[k];
99 tmp1i = tables->sintab2[k];
100 xr = inre[k] * tmp1r + inim[k] * tmp1i;
101 xi = inim[k] * tmp1r - inre[k] * tmp1i;
102 yr = -inim[FRAMESAMPLES_HALF - 1 - k] * tmp1r - inre[FRAMESAMPLES_HALF - 1 - k] * tmp1i;
103 yi = -inre[FRAMESAMPLES_HALF - 1 - k] * tmp1r + inim[FRAMESAMPLES_HALF - 1 - k] * tmp1i;
104
105 /* Combine into one vector, z = x + j * y */
106 outre1[k] = xr - yi;
107 outre1[FRAMESAMPLES_HALF - 1 - k] = xr + yi;
108 outre2[k] = xi + yr;
109 outre2[FRAMESAMPLES_HALF - 1 - k] = -xi + yr;
110 }
111
112
113 /* Get IDFT */
114 WebRtcIsac_Fftns(1, &dims, outre1, outre2, 1, FRAMESAMPLES_HALF, fftstr_obj);
115
116
117 /* Demodulate and separate */
118 fact = sqrt(FRAMESAMPLES_HALF);
119 for (k = 0; k < FRAMESAMPLES_HALF; k++) {
120 tmp1r = tables->costab1[k];
121 tmp1i = tables->sintab1[k];
122 xr = (outre1[k] * tmp1r - outre2[k] * tmp1i) * fact;
123 outre2[k] = (outre2[k] * tmp1r + outre1[k] * tmp1i) * fact;
124 outre1[k] = xr;
125 }
126 }
127