From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- .../aec3/residual_echo_estimator.cc | 379 +++++++++++++++++++++ 1 file changed, 379 insertions(+) create mode 100644 third_party/libwebrtc/modules/audio_processing/aec3/residual_echo_estimator.cc (limited to 'third_party/libwebrtc/modules/audio_processing/aec3/residual_echo_estimator.cc') diff --git a/third_party/libwebrtc/modules/audio_processing/aec3/residual_echo_estimator.cc b/third_party/libwebrtc/modules/audio_processing/aec3/residual_echo_estimator.cc new file mode 100644 index 0000000000..640a3e3cb9 --- /dev/null +++ b/third_party/libwebrtc/modules/audio_processing/aec3/residual_echo_estimator.cc @@ -0,0 +1,379 @@ +/* + * 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/residual_echo_estimator.h" + +#include + +#include +#include + +#include "api/array_view.h" +#include "modules/audio_processing/aec3/reverb_model.h" +#include "rtc_base/checks.h" +#include "system_wrappers/include/field_trial.h" + +namespace webrtc { +namespace { + +constexpr float kDefaultTransparentModeGain = 0.01f; + +float GetTransparentModeGain() { + return kDefaultTransparentModeGain; +} + +float GetEarlyReflectionsDefaultModeGain( + const EchoCanceller3Config::EpStrength& config) { + if (field_trial::IsEnabled("WebRTC-Aec3UseLowEarlyReflectionsDefaultGain")) { + return 0.1f; + } + return config.default_gain; +} + +float GetLateReflectionsDefaultModeGain( + const EchoCanceller3Config::EpStrength& config) { + if (field_trial::IsEnabled("WebRTC-Aec3UseLowLateReflectionsDefaultGain")) { + return 0.1f; + } + return config.default_gain; +} + +bool UseErleOnsetCompensationInDominantNearend( + const EchoCanceller3Config::EpStrength& config) { + return config.erle_onset_compensation_in_dominant_nearend || + field_trial::IsEnabled( + "WebRTC-Aec3UseErleOnsetCompensationInDominantNearend"); +} + +// Computes the indexes that will be used for computing spectral power over +// the blocks surrounding the delay. +void GetRenderIndexesToAnalyze( + const SpectrumBuffer& spectrum_buffer, + const EchoCanceller3Config::EchoModel& echo_model, + int filter_delay_blocks, + int* idx_start, + int* idx_stop) { + RTC_DCHECK(idx_start); + RTC_DCHECK(idx_stop); + size_t window_start; + size_t window_end; + window_start = + std::max(0, filter_delay_blocks - + static_cast(echo_model.render_pre_window_size)); + window_end = filter_delay_blocks + + static_cast(echo_model.render_post_window_size); + *idx_start = spectrum_buffer.OffsetIndex(spectrum_buffer.read, window_start); + *idx_stop = spectrum_buffer.OffsetIndex(spectrum_buffer.read, window_end + 1); +} + +// Estimates the residual echo power based on the echo return loss enhancement +// (ERLE) and the linear power estimate. +void LinearEstimate( + rtc::ArrayView> S2_linear, + rtc::ArrayView> erle, + rtc::ArrayView> R2) { + RTC_DCHECK_EQ(S2_linear.size(), erle.size()); + RTC_DCHECK_EQ(S2_linear.size(), R2.size()); + + const size_t num_capture_channels = R2.size(); + for (size_t ch = 0; ch < num_capture_channels; ++ch) { + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + RTC_DCHECK_LT(0.f, erle[ch][k]); + R2[ch][k] = S2_linear[ch][k] / erle[ch][k]; + } + } +} + +// Estimates the residual echo power based on the estimate of the echo path +// gain. +void NonLinearEstimate( + float echo_path_gain, + const std::array& X2, + rtc::ArrayView> R2) { + const size_t num_capture_channels = R2.size(); + for (size_t ch = 0; ch < num_capture_channels; ++ch) { + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + R2[ch][k] = X2[k] * echo_path_gain; + } + } +} + +// Applies a soft noise gate to the echo generating power. +void ApplyNoiseGate(const EchoCanceller3Config::EchoModel& config, + rtc::ArrayView X2) { + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + if (config.noise_gate_power > X2[k]) { + X2[k] = std::max(0.f, X2[k] - config.noise_gate_slope * + (config.noise_gate_power - X2[k])); + } + } +} + +// Estimates the echo generating signal power as gated maximal power over a +// time window. +void EchoGeneratingPower(size_t num_render_channels, + const SpectrumBuffer& spectrum_buffer, + const EchoCanceller3Config::EchoModel& echo_model, + int filter_delay_blocks, + rtc::ArrayView X2) { + int idx_stop; + int idx_start; + GetRenderIndexesToAnalyze(spectrum_buffer, echo_model, filter_delay_blocks, + &idx_start, &idx_stop); + + std::fill(X2.begin(), X2.end(), 0.f); + if (num_render_channels == 1) { + for (int k = idx_start; k != idx_stop; k = spectrum_buffer.IncIndex(k)) { + for (size_t j = 0; j < kFftLengthBy2Plus1; ++j) { + X2[j] = std::max(X2[j], spectrum_buffer.buffer[k][/*channel=*/0][j]); + } + } + } else { + for (int k = idx_start; k != idx_stop; k = spectrum_buffer.IncIndex(k)) { + std::array render_power; + render_power.fill(0.f); + for (size_t ch = 0; ch < num_render_channels; ++ch) { + const auto& channel_power = spectrum_buffer.buffer[k][ch]; + for (size_t j = 0; j < kFftLengthBy2Plus1; ++j) { + render_power[j] += channel_power[j]; + } + } + for (size_t j = 0; j < kFftLengthBy2Plus1; ++j) { + X2[j] = std::max(X2[j], render_power[j]); + } + } + } +} + +} // namespace + +ResidualEchoEstimator::ResidualEchoEstimator(const EchoCanceller3Config& config, + size_t num_render_channels) + : config_(config), + num_render_channels_(num_render_channels), + early_reflections_transparent_mode_gain_(GetTransparentModeGain()), + late_reflections_transparent_mode_gain_(GetTransparentModeGain()), + early_reflections_general_gain_( + GetEarlyReflectionsDefaultModeGain(config_.ep_strength)), + late_reflections_general_gain_( + GetLateReflectionsDefaultModeGain(config_.ep_strength)), + erle_onset_compensation_in_dominant_nearend_( + UseErleOnsetCompensationInDominantNearend(config_.ep_strength)) { + Reset(); +} + +ResidualEchoEstimator::~ResidualEchoEstimator() = default; + +void ResidualEchoEstimator::Estimate( + const AecState& aec_state, + const RenderBuffer& render_buffer, + rtc::ArrayView> S2_linear, + rtc::ArrayView> Y2, + bool dominant_nearend, + rtc::ArrayView> R2, + rtc::ArrayView> R2_unbounded) { + RTC_DCHECK_EQ(R2.size(), Y2.size()); + RTC_DCHECK_EQ(R2.size(), S2_linear.size()); + + const size_t num_capture_channels = R2.size(); + + // Estimate the power of the stationary noise in the render signal. + UpdateRenderNoisePower(render_buffer); + + // Estimate the residual echo power. + if (aec_state.UsableLinearEstimate()) { + // When there is saturated echo, assume the same spectral content as is + // present in the microphone signal. + if (aec_state.SaturatedEcho()) { + for (size_t ch = 0; ch < num_capture_channels; ++ch) { + std::copy(Y2[ch].begin(), Y2[ch].end(), R2[ch].begin()); + std::copy(Y2[ch].begin(), Y2[ch].end(), R2_unbounded[ch].begin()); + } + } else { + const bool onset_compensated = + erle_onset_compensation_in_dominant_nearend_ || !dominant_nearend; + LinearEstimate(S2_linear, aec_state.Erle(onset_compensated), R2); + LinearEstimate(S2_linear, aec_state.ErleUnbounded(), R2_unbounded); + } + + UpdateReverb(ReverbType::kLinear, aec_state, render_buffer, + dominant_nearend); + AddReverb(R2); + AddReverb(R2_unbounded); + } else { + const float echo_path_gain = + GetEchoPathGain(aec_state, /*gain_for_early_reflections=*/true); + + // When there is saturated echo, assume the same spectral content as is + // present in the microphone signal. + if (aec_state.SaturatedEcho()) { + for (size_t ch = 0; ch < num_capture_channels; ++ch) { + std::copy(Y2[ch].begin(), Y2[ch].end(), R2[ch].begin()); + std::copy(Y2[ch].begin(), Y2[ch].end(), R2_unbounded[ch].begin()); + } + } else { + // Estimate the echo generating signal power. + std::array X2; + EchoGeneratingPower(num_render_channels_, + render_buffer.GetSpectrumBuffer(), config_.echo_model, + aec_state.MinDirectPathFilterDelay(), X2); + if (!aec_state.UseStationarityProperties()) { + ApplyNoiseGate(config_.echo_model, X2); + } + + // Subtract the stationary noise power to avoid stationary noise causing + // excessive echo suppression. + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + X2[k] -= config_.echo_model.stationary_gate_slope * X2_noise_floor_[k]; + X2[k] = std::max(0.f, X2[k]); + } + + NonLinearEstimate(echo_path_gain, X2, R2); + NonLinearEstimate(echo_path_gain, X2, R2_unbounded); + } + + if (config_.echo_model.model_reverb_in_nonlinear_mode && + !aec_state.TransparentModeActive()) { + UpdateReverb(ReverbType::kNonLinear, aec_state, render_buffer, + dominant_nearend); + AddReverb(R2); + AddReverb(R2_unbounded); + } + } + + if (aec_state.UseStationarityProperties()) { + // Scale the echo according to echo audibility. + std::array residual_scaling; + aec_state.GetResidualEchoScaling(residual_scaling); + for (size_t ch = 0; ch < num_capture_channels; ++ch) { + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + R2[ch][k] *= residual_scaling[k]; + R2_unbounded[ch][k] *= residual_scaling[k]; + } + } + } +} + +void ResidualEchoEstimator::Reset() { + echo_reverb_.Reset(); + X2_noise_floor_counter_.fill(config_.echo_model.noise_floor_hold); + X2_noise_floor_.fill(config_.echo_model.min_noise_floor_power); +} + +void ResidualEchoEstimator::UpdateRenderNoisePower( + const RenderBuffer& render_buffer) { + std::array render_power_data; + rtc::ArrayView> X2 = + render_buffer.Spectrum(0); + rtc::ArrayView render_power = + X2[/*channel=*/0]; + if (num_render_channels_ > 1) { + render_power_data.fill(0.f); + for (size_t ch = 0; ch < num_render_channels_; ++ch) { + const auto& channel_power = X2[ch]; + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + render_power_data[k] += channel_power[k]; + } + } + render_power = render_power_data; + } + + // Estimate the stationary noise power in a minimum statistics manner. + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + // Decrease rapidly. + if (render_power[k] < X2_noise_floor_[k]) { + X2_noise_floor_[k] = render_power[k]; + X2_noise_floor_counter_[k] = 0; + } else { + // Increase in a delayed, leaky manner. + if (X2_noise_floor_counter_[k] >= + static_cast(config_.echo_model.noise_floor_hold)) { + X2_noise_floor_[k] = std::max(X2_noise_floor_[k] * 1.1f, + config_.echo_model.min_noise_floor_power); + } else { + ++X2_noise_floor_counter_[k]; + } + } + } +} + +// Updates the reverb estimation. +void ResidualEchoEstimator::UpdateReverb(ReverbType reverb_type, + const AecState& aec_state, + const RenderBuffer& render_buffer, + bool dominant_nearend) { + // Choose reverb partition based on what type of echo power model is used. + const size_t first_reverb_partition = + reverb_type == ReverbType::kLinear + ? aec_state.FilterLengthBlocks() + 1 + : aec_state.MinDirectPathFilterDelay() + 1; + + // Compute render power for the reverb. + std::array render_power_data; + rtc::ArrayView> X2 = + render_buffer.Spectrum(first_reverb_partition); + rtc::ArrayView render_power = + X2[/*channel=*/0]; + if (num_render_channels_ > 1) { + render_power_data.fill(0.f); + for (size_t ch = 0; ch < num_render_channels_; ++ch) { + const auto& channel_power = X2[ch]; + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + render_power_data[k] += channel_power[k]; + } + } + render_power = render_power_data; + } + + // Update the reverb estimate. + float reverb_decay = aec_state.ReverbDecay(/*mild=*/dominant_nearend); + if (reverb_type == ReverbType::kLinear) { + echo_reverb_.UpdateReverb( + render_power, aec_state.GetReverbFrequencyResponse(), reverb_decay); + } else { + const float echo_path_gain = + GetEchoPathGain(aec_state, /*gain_for_early_reflections=*/false); + echo_reverb_.UpdateReverbNoFreqShaping(render_power, echo_path_gain, + reverb_decay); + } +} +// Adds the estimated power of the reverb to the residual echo power. +void ResidualEchoEstimator::AddReverb( + rtc::ArrayView> R2) const { + const size_t num_capture_channels = R2.size(); + + // Add the reverb power. + rtc::ArrayView reverb_power = + echo_reverb_.reverb(); + for (size_t ch = 0; ch < num_capture_channels; ++ch) { + for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) { + R2[ch][k] += reverb_power[k]; + } + } +} + +// Chooses the echo path gain to use. +float ResidualEchoEstimator::GetEchoPathGain( + const AecState& aec_state, + bool gain_for_early_reflections) const { + float gain_amplitude; + if (aec_state.TransparentModeActive()) { + gain_amplitude = gain_for_early_reflections + ? early_reflections_transparent_mode_gain_ + : late_reflections_transparent_mode_gain_; + } else { + gain_amplitude = gain_for_early_reflections + ? early_reflections_general_gain_ + : late_reflections_general_gain_; + } + return gain_amplitude * gain_amplitude; +} + +} // namespace webrtc -- cgit v1.2.3