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 #include "typedefs.h"  // NOLINT(build/include)
15 #if defined(WEBRTC_ARCH_X86_FAMILY)
16 #include <emmintrin.h>
17 #endif
18 #include <algorithm>
19 #include <array>
20 
21 #include "api/array_view.h"
22 #include "modules/audio_processing/aec3/aec3_common.h"
23 
24 namespace webrtc {
25 
26 // Struct that holds imaginary data produced from 128 point real-valued FFTs.
27 struct FftData {
28   // Copies the data in src.
AssignFftData29   void Assign(const FftData& src) {
30     std::copy(src.re.begin(), src.re.end(), re.begin());
31     std::copy(src.im.begin(), src.im.end(), im.begin());
32     im[0] = im[kFftLengthBy2] = 0;
33   }
34 
35   // Clears all the imaginary.
ClearFftData36   void Clear() {
37     re.fill(0.f);
38     im.fill(0.f);
39   }
40 
41   // Computes the power spectrum of the data.
SpectrumFftData42   void Spectrum(Aec3Optimization optimization,
43                 std::array<float, kFftLengthBy2Plus1>* power_spectrum) const {
44     RTC_DCHECK(power_spectrum);
45     switch (optimization) {
46 #if defined(WEBRTC_ARCH_X86_FAMILY)
47       case Aec3Optimization::kSse2: {
48         constexpr int kNumFourBinBands = kFftLengthBy2 / 4;
49         constexpr int kLimit = kNumFourBinBands * 4;
50         for (size_t k = 0; k < kLimit; k += 4) {
51           const __m128 r = _mm_loadu_ps(&re[k]);
52           const __m128 i = _mm_loadu_ps(&im[k]);
53           const __m128 ii = _mm_mul_ps(i, i);
54           const __m128 rr = _mm_mul_ps(r, r);
55           const __m128 rrii = _mm_add_ps(rr, ii);
56           _mm_storeu_ps(&(*power_spectrum)[k], rrii);
57         }
58         (*power_spectrum)[kFftLengthBy2] =
59             re[kFftLengthBy2] * re[kFftLengthBy2] +
60             im[kFftLengthBy2] * im[kFftLengthBy2];
61       } break;
62 #endif
63       default:
64         std::transform(re.begin(), re.end(), im.begin(),
65                        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