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1 /*
2  *  Copyright (c) 2017 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 #ifndef MODULES_AUDIO_PROCESSING_AEC3_FFT_DATA_H_
12 #define MODULES_AUDIO_PROCESSING_AEC3_FFT_DATA_H_
13 
14 // Defines WEBRTC_ARCH_X86_FAMILY, used below.
15 #include "rtc_base/system/arch.h"
16 
17 #if defined(WEBRTC_ARCH_X86_FAMILY)
18 #include <emmintrin.h>
19 #endif
20 #include <algorithm>
21 #include <array>
22 
23 #include "api/array_view.h"
24 #include "modules/audio_processing/aec3/aec3_common.h"
25 
26 namespace webrtc {
27 
28 // Struct that holds imaginary data produced from 128 point real-valued FFTs.
29 struct FftData {
30   // Copies the data in src.
AssignFftData31   void Assign(const FftData& src) {
32     std::copy(src.re.begin(), src.re.end(), re.begin());
33     std::copy(src.im.begin(), src.im.end(), im.begin());
34     im[0] = im[kFftLengthBy2] = 0;
35   }
36 
37   // Clears all the imaginary.
ClearFftData38   void Clear() {
39     re.fill(0.f);
40     im.fill(0.f);
41   }
42 
43   // Computes the power spectrum of the data.
SpectrumFftData44   void Spectrum(Aec3Optimization optimization,
45                 rtc::ArrayView<float> power_spectrum) const {
46     RTC_DCHECK_EQ(kFftLengthBy2Plus1, power_spectrum.size());
47     switch (optimization) {
48 #if defined(WEBRTC_ARCH_X86_FAMILY)
49       case Aec3Optimization::kSse2: {
50         constexpr int kNumFourBinBands = kFftLengthBy2 / 4;
51         constexpr int kLimit = kNumFourBinBands * 4;
52         for (size_t k = 0; k < kLimit; k += 4) {
53           const __m128 r = _mm_loadu_ps(&re[k]);
54           const __m128 i = _mm_loadu_ps(&im[k]);
55           const __m128 ii = _mm_mul_ps(i, i);
56           const __m128 rr = _mm_mul_ps(r, r);
57           const __m128 rrii = _mm_add_ps(rr, ii);
58           _mm_storeu_ps(&power_spectrum[k], rrii);
59         }
60         power_spectrum[kFftLengthBy2] = re[kFftLengthBy2] * re[kFftLengthBy2] +
61                                         im[kFftLengthBy2] * im[kFftLengthBy2];
62       } break;
63 #endif
64       default:
65         std::transform(re.begin(), re.end(), im.begin(), power_spectrum.begin(),
66                        [](float a, float b) { return a * a + b * b; });
67     }
68   }
69 
70   // Copy the data from an interleaved array.
CopyFromPackedArrayFftData71   void CopyFromPackedArray(const std::array<float, kFftLength>& v) {
72     re[0] = v[0];
73     re[kFftLengthBy2] = v[1];
74     im[0] = im[kFftLengthBy2] = 0;
75     for (size_t k = 1, j = 2; k < kFftLengthBy2; ++k) {
76       re[k] = v[j++];
77       im[k] = v[j++];
78     }
79   }
80 
81   // Copies the data into an interleaved array.
CopyToPackedArrayFftData82   void CopyToPackedArray(std::array<float, kFftLength>* v) const {
83     RTC_DCHECK(v);
84     (*v)[0] = re[0];
85     (*v)[1] = re[kFftLengthBy2];
86     for (size_t k = 1, j = 2; k < kFftLengthBy2; ++k) {
87       (*v)[j++] = re[k];
88       (*v)[j++] = im[k];
89     }
90   }
91 
92   std::array<float, kFftLengthBy2Plus1> re;
93   std::array<float, kFftLengthBy2Plus1> im;
94 };
95 
96 }  // namespace webrtc
97 
98 #endif  // MODULES_AUDIO_PROCESSING_AEC3_FFT_DATA_H_
99