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 #include "modules/audio_processing/aec3/subtractor.h"
12
13 #include <algorithm>
14 #include <numeric>
15
16 #include "api/array_view.h"
17 #include "modules/audio_processing/logging/apm_data_dumper.h"
18 #include "rtc_base/checks.h"
19 #include "rtc_base/numerics/safe_minmax.h"
20
21 namespace webrtc {
22
23 namespace {
24
PredictionError(const Aec3Fft & fft,const FftData & S,rtc::ArrayView<const float> y,std::array<float,kBlockSize> * e,FftData * E,std::array<float,kBlockSize> * s)25 void PredictionError(const Aec3Fft& fft,
26 const FftData& S,
27 rtc::ArrayView<const float> y,
28 std::array<float, kBlockSize>* e,
29 FftData* E,
30 std::array<float, kBlockSize>* s) {
31 std::array<float, kFftLength> s_scratch;
32 fft.Ifft(S, &s_scratch);
33 constexpr float kScale = 1.0f / kFftLengthBy2;
34 std::transform(y.begin(), y.end(), s_scratch.begin() + kFftLengthBy2,
35 e->begin(), [&](float a, float b) { return a - b * kScale; });
36 std::for_each(e->begin(), e->end(),
37 [](float& a) { a = rtc::SafeClamp(a, -32768.f, 32767.f); });
38 fft.ZeroPaddedFft(*e, E);
39
40 if (s) {
41 for (size_t k = 0; k < s->size(); ++k) {
42 (*s)[k] = kScale * s_scratch[k + kFftLengthBy2];
43 }
44 }
45 }
46 } // namespace
47
Subtractor(ApmDataDumper * data_dumper,Aec3Optimization optimization)48 Subtractor::Subtractor(ApmDataDumper* data_dumper,
49 Aec3Optimization optimization)
50 : fft_(),
51 data_dumper_(data_dumper),
52 optimization_(optimization),
53 main_filter_(kAdaptiveFilterLength, optimization, data_dumper_),
54 shadow_filter_(kAdaptiveFilterLength, optimization, data_dumper_) {
55 RTC_DCHECK(data_dumper_);
56 }
57
58 Subtractor::~Subtractor() = default;
59
HandleEchoPathChange(const EchoPathVariability & echo_path_variability)60 void Subtractor::HandleEchoPathChange(
61 const EchoPathVariability& echo_path_variability) {
62 if (echo_path_variability.delay_change) {
63 main_filter_.HandleEchoPathChange();
64 shadow_filter_.HandleEchoPathChange();
65 G_main_.HandleEchoPathChange();
66 G_shadow_.HandleEchoPathChange();
67 converged_filter_ = false;
68 }
69 }
70
Process(const RenderBuffer & render_buffer,const rtc::ArrayView<const float> capture,const RenderSignalAnalyzer & render_signal_analyzer,const AecState & aec_state,SubtractorOutput * output)71 void Subtractor::Process(const RenderBuffer& render_buffer,
72 const rtc::ArrayView<const float> capture,
73 const RenderSignalAnalyzer& render_signal_analyzer,
74 const AecState& aec_state,
75 SubtractorOutput* output) {
76 RTC_DCHECK_EQ(kBlockSize, capture.size());
77 rtc::ArrayView<const float> y = capture;
78 FftData& E_main = output->E_main;
79 FftData E_shadow;
80 std::array<float, kBlockSize>& e_main = output->e_main;
81 std::array<float, kBlockSize>& e_shadow = output->e_shadow;
82
83 FftData S;
84 FftData& G = S;
85
86 // Form the output of the main filter.
87 main_filter_.Filter(render_buffer, &S);
88 PredictionError(fft_, S, y, &e_main, &E_main, &output->s_main);
89
90 // Form the output of the shadow filter.
91 shadow_filter_.Filter(render_buffer, &S);
92 PredictionError(fft_, S, y, &e_shadow, &E_shadow, nullptr);
93
94
95 if (!converged_filter_) {
96 const auto sum_of_squares = [](float a, float b) { return a + b * b; };
97 const float e2_main =
98 std::accumulate(e_main.begin(), e_main.end(), 0.f, sum_of_squares);
99 const float e2_shadow =
100 std::accumulate(e_shadow.begin(), e_shadow.end(), 0.f, sum_of_squares);
101 const float y2 = std::accumulate(y.begin(), y.end(), 0.f, sum_of_squares);
102
103 if (y2 > kBlockSize * 50.f * 50.f) {
104 converged_filter_ = (e2_main > 0.3 * y2 || e2_shadow > 0.1 * y2);
105 }
106 }
107
108 // Compute spectra for future use.
109 E_main.Spectrum(optimization_, &output->E2_main);
110 E_shadow.Spectrum(optimization_, &output->E2_shadow);
111
112 // Update the main filter.
113 G_main_.Compute(render_buffer, render_signal_analyzer, *output, main_filter_,
114 aec_state.SaturatedCapture(), &G);
115 main_filter_.Adapt(render_buffer, G);
116 data_dumper_->DumpRaw("aec3_subtractor_G_main", G.re);
117 data_dumper_->DumpRaw("aec3_subtractor_G_main", G.im);
118
119 // Update the shadow filter.
120 G_shadow_.Compute(render_buffer, render_signal_analyzer, E_shadow,
121 shadow_filter_.SizePartitions(),
122 aec_state.SaturatedCapture(), &G);
123 shadow_filter_.Adapt(render_buffer, G);
124
125 data_dumper_->DumpRaw("aec3_subtractor_G_shadow", G.re);
126 data_dumper_->DumpRaw("aec3_subtractor_G_shadow", G.im);
127
128 main_filter_.DumpFilter("aec3_subtractor_H_main");
129 shadow_filter_.DumpFilter("aec3_subtractor_H_shadow");
130 }
131
132 } // namespace webrtc
133