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/*
* Copyright (c) 2017 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 "modules/audio_processing/aec3/echo_remover.h"
#include <math.h>
#include <algorithm>
#include <memory>
#include <numeric>
#include <string>
#include "api/array_view.h"
#include "modules/audio_processing/aec3/aec3_common.h"
#include "modules/audio_processing/aec3/aec_state.h"
#include "modules/audio_processing/aec3/comfort_noise_generator.h"
#include "modules/audio_processing/aec3/echo_path_variability.h"
#include "modules/audio_processing/aec3/echo_remover_metrics.h"
#include "modules/audio_processing/aec3/fft_data.h"
#include "modules/audio_processing/aec3/output_selector.h"
#include "modules/audio_processing/aec3/render_buffer.h"
#include "modules/audio_processing/aec3/render_delay_buffer.h"
#include "modules/audio_processing/aec3/residual_echo_estimator.h"
#include "modules/audio_processing/aec3/subtractor.h"
#include "modules/audio_processing/aec3/suppression_filter.h"
#include "modules/audio_processing/aec3/suppression_gain.h"
#include "modules/audio_processing/logging/apm_data_dumper.h"
#include "rtc_base/atomicops.h"
#include "rtc_base/constructormagic.h"
namespace webrtc {
namespace {
void LinearEchoPower(const FftData& E,
const FftData& Y,
std::array<float, kFftLengthBy2Plus1>* S2) {
for (size_t k = 0; k < E.re.size(); ++k) {
(*S2)[k] = (Y.re[k] - E.re[k]) * (Y.re[k] - E.re[k]) +
(Y.im[k] - E.im[k]) * (Y.im[k] - E.im[k]);
}
}
// Class for removing the echo from the capture signal.
class EchoRemoverImpl final : public EchoRemover {
public:
explicit EchoRemoverImpl(const EchoCanceller3Config& config,
int sample_rate_hz);
~EchoRemoverImpl() override;
void GetMetrics(EchoControl::Metrics* metrics) const override;
// Removes the echo from a block of samples from the capture signal. The
// supplied render signal is assumed to be pre-aligned with the capture
// signal.
void ProcessCapture(const EchoPathVariability& echo_path_variability,
bool capture_signal_saturation,
const rtc::Optional<DelayEstimate>& delay_estimate,
RenderBuffer* render_buffer,
std::vector<std::vector<float>>* capture) override;
// Updates the status on whether echo leakage is detected in the output of the
// echo remover.
void UpdateEchoLeakageStatus(bool leakage_detected) override {
echo_leakage_detected_ = leakage_detected;
}
private:
static int instance_count_;
const EchoCanceller3Config config_;
const Aec3Fft fft_;
std::unique_ptr<ApmDataDumper> data_dumper_;
const Aec3Optimization optimization_;
const int sample_rate_hz_;
Subtractor subtractor_;
SuppressionGain suppression_gain_;
ComfortNoiseGenerator cng_;
SuppressionFilter suppression_filter_;
RenderSignalAnalyzer render_signal_analyzer_;
OutputSelector output_selector_;
ResidualEchoEstimator residual_echo_estimator_;
bool echo_leakage_detected_ = false;
AecState aec_state_;
EchoRemoverMetrics metrics_;
bool initial_state_ = true;
RTC_DISALLOW_COPY_AND_ASSIGN(EchoRemoverImpl);
};
int EchoRemoverImpl::instance_count_ = 0;
EchoRemoverImpl::EchoRemoverImpl(const EchoCanceller3Config& config,
int sample_rate_hz)
: config_(config),
fft_(),
data_dumper_(
new ApmDataDumper(rtc::AtomicOps::Increment(&instance_count_))),
optimization_(DetectOptimization()),
sample_rate_hz_(sample_rate_hz),
subtractor_(config, data_dumper_.get(), optimization_),
suppression_gain_(config_, optimization_),
cng_(optimization_),
suppression_filter_(sample_rate_hz_),
residual_echo_estimator_(config_),
aec_state_(config_) {
RTC_DCHECK(ValidFullBandRate(sample_rate_hz));
}
EchoRemoverImpl::~EchoRemoverImpl() = default;
void EchoRemoverImpl::GetMetrics(EchoControl::Metrics* metrics) const {
// Echo return loss (ERL) is inverted to go from gain to attenuation.
metrics->echo_return_loss = -10.0 * log10(aec_state_.ErlTimeDomain());
metrics->echo_return_loss_enhancement =
10.0 * log10(aec_state_.ErleTimeDomain());
}
void EchoRemoverImpl::ProcessCapture(
const EchoPathVariability& echo_path_variability,
bool capture_signal_saturation,
const rtc::Optional<DelayEstimate>& delay_estimate,
RenderBuffer* render_buffer,
std::vector<std::vector<float>>* capture) {
const std::vector<std::vector<float>>& x = render_buffer->Block(0);
std::vector<std::vector<float>>* y = capture;
RTC_DCHECK(render_buffer);
RTC_DCHECK(y);
RTC_DCHECK_EQ(x.size(), NumBandsForRate(sample_rate_hz_));
RTC_DCHECK_EQ(y->size(), NumBandsForRate(sample_rate_hz_));
RTC_DCHECK_EQ(x[0].size(), kBlockSize);
RTC_DCHECK_EQ((*y)[0].size(), kBlockSize);
const std::vector<float>& x0 = x[0];
std::vector<float>& y0 = (*y)[0];
data_dumper_->DumpWav("aec3_echo_remover_capture_input", kBlockSize, &y0[0],
LowestBandRate(sample_rate_hz_), 1);
data_dumper_->DumpWav("aec3_echo_remover_render_input", kBlockSize, &x0[0],
LowestBandRate(sample_rate_hz_), 1);
data_dumper_->DumpRaw("aec3_echo_remover_capture_input", y0);
data_dumper_->DumpRaw("aec3_echo_remover_render_input", x0);
aec_state_.UpdateCaptureSaturation(capture_signal_saturation);
if (echo_path_variability.AudioPathChanged()) {
subtractor_.HandleEchoPathChange(echo_path_variability);
aec_state_.HandleEchoPathChange(echo_path_variability);
initial_state_ = true;
}
std::array<float, kFftLengthBy2Plus1> Y2;
std::array<float, kFftLengthBy2Plus1> R2;
std::array<float, kFftLengthBy2Plus1> S2_linear;
std::array<float, kFftLengthBy2Plus1> G;
float high_bands_gain;
FftData Y;
FftData comfort_noise;
FftData high_band_comfort_noise;
SubtractorOutput subtractor_output;
FftData& E_main_nonwindowed = subtractor_output.E_main_nonwindowed;
auto& E2_main = subtractor_output.E2_main_nonwindowed;
auto& E2_shadow = subtractor_output.E2_shadow;
auto& e_main = subtractor_output.e_main;
// Analyze the render signal.
render_signal_analyzer_.Update(*render_buffer, aec_state_.FilterDelay());
// Perform linear echo cancellation.
if (initial_state_ && !aec_state_.InitialState()) {
subtractor_.ExitInitialState();
initial_state_ = false;
}
subtractor_.Process(*render_buffer, y0, render_signal_analyzer_, aec_state_,
&subtractor_output);
// Compute spectra.
// fft_.ZeroPaddedFft(y0, Aec3Fft::Window::kHanning, &Y);
fft_.ZeroPaddedFft(y0, Aec3Fft::Window::kRectangular, &Y);
LinearEchoPower(E_main_nonwindowed, Y, &S2_linear);
Y.Spectrum(optimization_, Y2);
// Update the AEC state information.
aec_state_.Update(delay_estimate, subtractor_.FilterFrequencyResponse(),
subtractor_.FilterImpulseResponse(),
subtractor_.ConvergedFilter(), *render_buffer, E2_main, Y2,
subtractor_output.s_main, echo_leakage_detected_);
// Choose the linear output.
output_selector_.FormLinearOutput(!aec_state_.TransparentMode(), e_main, y0);
data_dumper_->DumpWav("aec3_output_linear", kBlockSize, &y0[0],
LowestBandRate(sample_rate_hz_), 1);
data_dumper_->DumpRaw("aec3_output_linear", y0);
const auto& E2 = output_selector_.UseSubtractorOutput() ? E2_main : Y2;
// Estimate the residual echo power.
residual_echo_estimator_.Estimate(aec_state_, *render_buffer, S2_linear, Y2,
&R2);
// Estimate the comfort noise.
cng_.Compute(aec_state_, Y2, &comfort_noise, &high_band_comfort_noise);
// A choose and apply echo suppression gain.
suppression_gain_.GetGain(E2, R2, cng_.NoiseSpectrum(),
render_signal_analyzer_, aec_state_, x,
&high_bands_gain, &G);
suppression_filter_.ApplyGain(comfort_noise, high_band_comfort_noise, G,
high_bands_gain, y);
// Update the metrics.
metrics_.Update(aec_state_, cng_.NoiseSpectrum(), G);
// Update the aec state with the aec output characteristics.
aec_state_.UpdateWithOutput(y0);
// Debug outputs for the purpose of development and analysis.
data_dumper_->DumpWav("aec3_echo_estimate", kBlockSize,
&subtractor_output.s_main[0],
LowestBandRate(sample_rate_hz_), 1);
data_dumper_->DumpRaw("aec3_output", y0);
data_dumper_->DumpRaw("aec3_narrow_render",
render_signal_analyzer_.NarrowPeakBand() ? 1 : 0);
data_dumper_->DumpRaw("aec3_N2", cng_.NoiseSpectrum());
data_dumper_->DumpRaw("aec3_suppressor_gain", G);
data_dumper_->DumpWav("aec3_output",
rtc::ArrayView<const float>(&y0[0], kBlockSize),
LowestBandRate(sample_rate_hz_), 1);
data_dumper_->DumpRaw("aec3_using_subtractor_output",
output_selector_.UseSubtractorOutput() ? 1 : 0);
data_dumper_->DumpRaw("aec3_E2", E2);
data_dumper_->DumpRaw("aec3_E2_main", E2_main);
data_dumper_->DumpRaw("aec3_E2_shadow", E2_shadow);
data_dumper_->DumpRaw("aec3_S2_linear", S2_linear);
data_dumper_->DumpRaw("aec3_Y2", Y2);
data_dumper_->DumpRaw("aec3_X2", render_buffer->Spectrum(0));
data_dumper_->DumpRaw("aec3_R2", R2);
data_dumper_->DumpRaw("aec3_erle", aec_state_.Erle());
data_dumper_->DumpRaw("aec3_erl", aec_state_.Erl());
data_dumper_->DumpRaw("aec3_usable_linear_estimate",
aec_state_.UsableLinearEstimate());
data_dumper_->DumpRaw("aec3_filter_delay", aec_state_.FilterDelay());
data_dumper_->DumpRaw("aec3_capture_saturation",
aec_state_.SaturatedCapture() ? 1 : 0);
}
} // namespace
EchoRemover* EchoRemover::Create(const EchoCanceller3Config& config,
int sample_rate_hz) {
return new EchoRemoverImpl(config, sample_rate_hz);
}
} // namespace webrtc