Source code
Revision control
Copy as Markdown
Other Tools
/*
* 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/aec_state.h"
#include <math.h>
#include <algorithm>
#include <numeric>
#include <vector>
#include "absl/types/optional.h"
#include "api/array_view.h"
#include "modules/audio_processing/aec3/aec3_common.h"
#include "modules/audio_processing/logging/apm_data_dumper.h"
#include "rtc_base/checks.h"
#include "system_wrappers/include/field_trial.h"
namespace webrtc {
namespace {
bool DeactivateInitialStateResetAtEchoPathChange() {
return field_trial::IsEnabled(
"WebRTC-Aec3DeactivateInitialStateResetKillSwitch");
}
bool FullResetAtEchoPathChange() {
return !field_trial::IsEnabled("WebRTC-Aec3AecStateFullResetKillSwitch");
}
bool SubtractorAnalyzerResetAtEchoPathChange() {
return !field_trial::IsEnabled(
"WebRTC-Aec3AecStateSubtractorAnalyzerResetKillSwitch");
}
void ComputeAvgRenderReverb(
const SpectrumBuffer& spectrum_buffer,
int delay_blocks,
float reverb_decay,
ReverbModel* reverb_model,
rtc::ArrayView<float, kFftLengthBy2Plus1> reverb_power_spectrum) {
RTC_DCHECK(reverb_model);
const size_t num_render_channels = spectrum_buffer.buffer[0].size();
int idx_at_delay =
spectrum_buffer.OffsetIndex(spectrum_buffer.read, delay_blocks);
int idx_past = spectrum_buffer.IncIndex(idx_at_delay);
std::array<float, kFftLengthBy2Plus1> X2_data;
rtc::ArrayView<const float> X2;
if (num_render_channels > 1) {
auto average_channels =
[](size_t num_render_channels,
rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
spectrum_band_0,
rtc::ArrayView<float, kFftLengthBy2Plus1> render_power) {
std::fill(render_power.begin(), render_power.end(), 0.f);
for (size_t ch = 0; ch < num_render_channels; ++ch) {
for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
render_power[k] += spectrum_band_0[ch][k];
}
}
const float normalizer = 1.f / num_render_channels;
for (size_t k = 0; k < kFftLengthBy2Plus1; ++k) {
render_power[k] *= normalizer;
}
};
average_channels(num_render_channels, spectrum_buffer.buffer[idx_past],
X2_data);
reverb_model->UpdateReverbNoFreqShaping(
X2_data, /*power_spectrum_scaling=*/1.0f, reverb_decay);
average_channels(num_render_channels, spectrum_buffer.buffer[idx_at_delay],
X2_data);
X2 = X2_data;
} else {
reverb_model->UpdateReverbNoFreqShaping(
spectrum_buffer.buffer[idx_past][/*channel=*/0],
/*power_spectrum_scaling=*/1.0f, reverb_decay);
X2 = spectrum_buffer.buffer[idx_at_delay][/*channel=*/0];
}
rtc::ArrayView<const float, kFftLengthBy2Plus1> reverb_power =
reverb_model->reverb();
for (size_t k = 0; k < X2.size(); ++k) {
reverb_power_spectrum[k] = X2[k] + reverb_power[k];
}
}
} // namespace
std::atomic<int> AecState::instance_count_(0);
void AecState::GetResidualEchoScaling(
rtc::ArrayView<float> residual_scaling) const {
bool filter_has_had_time_to_converge;
if (config_.filter.conservative_initial_phase) {
filter_has_had_time_to_converge =
strong_not_saturated_render_blocks_ >= 1.5f * kNumBlocksPerSecond;
} else {
filter_has_had_time_to_converge =
strong_not_saturated_render_blocks_ >= 0.8f * kNumBlocksPerSecond;
}
echo_audibility_.GetResidualEchoScaling(filter_has_had_time_to_converge,
residual_scaling);
}
AecState::AecState(const EchoCanceller3Config& config,
size_t num_capture_channels)
: data_dumper_(new ApmDataDumper(instance_count_.fetch_add(1) + 1)),
config_(config),
num_capture_channels_(num_capture_channels),
deactivate_initial_state_reset_at_echo_path_change_(
DeactivateInitialStateResetAtEchoPathChange()),
full_reset_at_echo_path_change_(FullResetAtEchoPathChange()),
subtractor_analyzer_reset_at_echo_path_change_(
SubtractorAnalyzerResetAtEchoPathChange()),
initial_state_(config_),
delay_state_(config_, num_capture_channels_),
transparent_state_(TransparentMode::Create(config_)),
filter_quality_state_(config_, num_capture_channels_),
erl_estimator_(2 * kNumBlocksPerSecond),
erle_estimator_(2 * kNumBlocksPerSecond, config_, num_capture_channels_),
filter_analyzer_(config_, num_capture_channels_),
echo_audibility_(
config_.echo_audibility.use_stationarity_properties_at_init),
reverb_model_estimator_(config_, num_capture_channels_),
subtractor_output_analyzer_(num_capture_channels_) {}
AecState::~AecState() = default;
void AecState::HandleEchoPathChange(
const EchoPathVariability& echo_path_variability) {
const auto full_reset = [&]() {
filter_analyzer_.Reset();
capture_signal_saturation_ = false;
strong_not_saturated_render_blocks_ = 0;
blocks_with_active_render_ = 0;
if (!deactivate_initial_state_reset_at_echo_path_change_) {
initial_state_.Reset();
}
if (transparent_state_) {
transparent_state_->Reset();
}
erle_estimator_.Reset(true);
erl_estimator_.Reset();
filter_quality_state_.Reset();
};
// TODO(peah): Refine the reset scheme according to the type of gain and
// delay adjustment.
if (full_reset_at_echo_path_change_ &&
echo_path_variability.delay_change !=
EchoPathVariability::DelayAdjustment::kNone) {
full_reset();
} else if (echo_path_variability.gain_change) {
erle_estimator_.Reset(false);
}
if (subtractor_analyzer_reset_at_echo_path_change_) {
subtractor_output_analyzer_.HandleEchoPathChange();
}
}
void AecState::Update(
const absl::optional<DelayEstimate>& external_delay,
rtc::ArrayView<const std::vector<std::array<float, kFftLengthBy2Plus1>>>
adaptive_filter_frequency_responses,
rtc::ArrayView<const std::vector<float>> adaptive_filter_impulse_responses,
const RenderBuffer& render_buffer,
rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> E2_refined,
rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> Y2,
rtc::ArrayView<const SubtractorOutput> subtractor_output) {
RTC_DCHECK_EQ(num_capture_channels_, Y2.size());
RTC_DCHECK_EQ(num_capture_channels_, subtractor_output.size());
RTC_DCHECK_EQ(num_capture_channels_,
adaptive_filter_frequency_responses.size());
RTC_DCHECK_EQ(num_capture_channels_,
adaptive_filter_impulse_responses.size());
// Analyze the filter outputs and filters.
bool any_filter_converged;
bool any_coarse_filter_converged;
bool all_filters_diverged;
subtractor_output_analyzer_.Update(subtractor_output, &any_filter_converged,
&any_coarse_filter_converged,
&all_filters_diverged);
bool any_filter_consistent;
float max_echo_path_gain;
filter_analyzer_.Update(adaptive_filter_impulse_responses, render_buffer,
&any_filter_consistent, &max_echo_path_gain);
// Estimate the direct path delay of the filter.
if (config_.filter.use_linear_filter) {
delay_state_.Update(filter_analyzer_.FilterDelaysBlocks(), external_delay,
strong_not_saturated_render_blocks_);
}
const Block& aligned_render_block =
render_buffer.GetBlock(-delay_state_.MinDirectPathFilterDelay());
// Update render counters.
bool active_render = false;
for (int ch = 0; ch < aligned_render_block.NumChannels(); ++ch) {
const float render_energy =
std::inner_product(aligned_render_block.begin(/*block=*/0, ch),
aligned_render_block.end(/*block=*/0, ch),
aligned_render_block.begin(/*block=*/0, ch), 0.f);
if (render_energy > (config_.render_levels.active_render_limit *
config_.render_levels.active_render_limit) *
kFftLengthBy2) {
active_render = true;
break;
}
}
blocks_with_active_render_ += active_render ? 1 : 0;
strong_not_saturated_render_blocks_ +=
active_render && !SaturatedCapture() ? 1 : 0;
std::array<float, kFftLengthBy2Plus1> avg_render_spectrum_with_reverb;
ComputeAvgRenderReverb(render_buffer.GetSpectrumBuffer(),
delay_state_.MinDirectPathFilterDelay(),
ReverbDecay(/*mild=*/false), &avg_render_reverb_,
avg_render_spectrum_with_reverb);
if (config_.echo_audibility.use_stationarity_properties) {
// Update the echo audibility evaluator.
echo_audibility_.Update(render_buffer, avg_render_reverb_.reverb(),
delay_state_.MinDirectPathFilterDelay(),
delay_state_.ExternalDelayReported());
}
// Update the ERL and ERLE measures.
if (initial_state_.TransitionTriggered()) {
erle_estimator_.Reset(false);
}
erle_estimator_.Update(render_buffer, adaptive_filter_frequency_responses,
avg_render_spectrum_with_reverb, Y2, E2_refined,
subtractor_output_analyzer_.ConvergedFilters());
erl_estimator_.Update(
subtractor_output_analyzer_.ConvergedFilters(),
render_buffer.Spectrum(delay_state_.MinDirectPathFilterDelay()), Y2);
// Detect and flag echo saturation.
if (config_.ep_strength.echo_can_saturate) {
saturation_detector_.Update(aligned_render_block, SaturatedCapture(),
UsableLinearEstimate(), subtractor_output,
max_echo_path_gain);
} else {
RTC_DCHECK(!saturation_detector_.SaturatedEcho());
}
// Update the decision on whether to use the initial state parameter set.
initial_state_.Update(active_render, SaturatedCapture());
// Detect whether the transparent mode should be activated.
if (transparent_state_) {
transparent_state_->Update(
delay_state_.MinDirectPathFilterDelay(), any_filter_consistent,
any_filter_converged, any_coarse_filter_converged, all_filters_diverged,
active_render, SaturatedCapture());
}
// Analyze the quality of the filter.
filter_quality_state_.Update(active_render, TransparentModeActive(),
SaturatedCapture(), external_delay,
any_filter_converged);
// Update the reverb estimate.
const bool stationary_block =
config_.echo_audibility.use_stationarity_properties &&
echo_audibility_.IsBlockStationary();
reverb_model_estimator_.Update(
filter_analyzer_.GetAdjustedFilters(),
adaptive_filter_frequency_responses,
erle_estimator_.GetInstLinearQualityEstimates(),
delay_state_.DirectPathFilterDelays(),
filter_quality_state_.UsableLinearFilterOutputs(), stationary_block);
erle_estimator_.Dump(data_dumper_);
reverb_model_estimator_.Dump(data_dumper_.get());
data_dumper_->DumpRaw("aec3_active_render", active_render);
data_dumper_->DumpRaw("aec3_erl", Erl());
data_dumper_->DumpRaw("aec3_erl_time_domain", ErlTimeDomain());
data_dumper_->DumpRaw("aec3_erle", Erle(/*onset_compensated=*/false)[0]);
data_dumper_->DumpRaw("aec3_erle_onset_compensated",
Erle(/*onset_compensated=*/true)[0]);
data_dumper_->DumpRaw("aec3_usable_linear_estimate", UsableLinearEstimate());
data_dumper_->DumpRaw("aec3_transparent_mode", TransparentModeActive());
data_dumper_->DumpRaw("aec3_filter_delay",
filter_analyzer_.MinFilterDelayBlocks());
data_dumper_->DumpRaw("aec3_any_filter_consistent", any_filter_consistent);
data_dumper_->DumpRaw("aec3_initial_state",
initial_state_.InitialStateActive());
data_dumper_->DumpRaw("aec3_capture_saturation", SaturatedCapture());
data_dumper_->DumpRaw("aec3_echo_saturation", SaturatedEcho());
data_dumper_->DumpRaw("aec3_any_filter_converged", any_filter_converged);
data_dumper_->DumpRaw("aec3_any_coarse_filter_converged",
any_coarse_filter_converged);
data_dumper_->DumpRaw("aec3_all_filters_diverged", all_filters_diverged);
data_dumper_->DumpRaw("aec3_external_delay_avaliable",
external_delay ? 1 : 0);
data_dumper_->DumpRaw("aec3_filter_tail_freq_resp_est",
GetReverbFrequencyResponse());
data_dumper_->DumpRaw("aec3_subtractor_y2", subtractor_output[0].y2);
data_dumper_->DumpRaw("aec3_subtractor_e2_coarse",
subtractor_output[0].e2_coarse);
data_dumper_->DumpRaw("aec3_subtractor_e2_refined",
subtractor_output[0].e2_refined);
}
AecState::InitialState::InitialState(const EchoCanceller3Config& config)
: conservative_initial_phase_(config.filter.conservative_initial_phase),
initial_state_seconds_(config.filter.initial_state_seconds) {
Reset();
}
void AecState::InitialState::InitialState::Reset() {
initial_state_ = true;
strong_not_saturated_render_blocks_ = 0;
}
void AecState::InitialState::InitialState::Update(bool active_render,
bool saturated_capture) {
strong_not_saturated_render_blocks_ +=
active_render && !saturated_capture ? 1 : 0;
// Flag whether the initial state is still active.
bool prev_initial_state = initial_state_;
if (conservative_initial_phase_) {
initial_state_ =
strong_not_saturated_render_blocks_ < 5 * kNumBlocksPerSecond;
} else {
initial_state_ = strong_not_saturated_render_blocks_ <
initial_state_seconds_ * kNumBlocksPerSecond;
}
// Flag whether the transition from the initial state has started.
transition_triggered_ = !initial_state_ && prev_initial_state;
}
AecState::FilterDelay::FilterDelay(const EchoCanceller3Config& config,
size_t num_capture_channels)
: delay_headroom_blocks_(config.delay.delay_headroom_samples / kBlockSize),
filter_delays_blocks_(num_capture_channels, delay_headroom_blocks_),
min_filter_delay_(delay_headroom_blocks_) {}
void AecState::FilterDelay::Update(
rtc::ArrayView<const int> analyzer_filter_delay_estimates_blocks,
const absl::optional<DelayEstimate>& external_delay,
size_t blocks_with_proper_filter_adaptation) {
// Update the delay based on the external delay.
if (external_delay &&
(!external_delay_ || external_delay_->delay != external_delay->delay)) {
external_delay_ = external_delay;
external_delay_reported_ = true;
}
// Override the estimated delay if it is not certain that the filter has had
// time to converge.
const bool delay_estimator_may_not_have_converged =
blocks_with_proper_filter_adaptation < 2 * kNumBlocksPerSecond;
if (delay_estimator_may_not_have_converged && external_delay_) {
const int delay_guess = delay_headroom_blocks_;
std::fill(filter_delays_blocks_.begin(), filter_delays_blocks_.end(),
delay_guess);
} else {
RTC_DCHECK_EQ(filter_delays_blocks_.size(),
analyzer_filter_delay_estimates_blocks.size());
std::copy(analyzer_filter_delay_estimates_blocks.begin(),
analyzer_filter_delay_estimates_blocks.end(),
filter_delays_blocks_.begin());
}
min_filter_delay_ = *std::min_element(filter_delays_blocks_.begin(),
filter_delays_blocks_.end());
}
AecState::FilteringQualityAnalyzer::FilteringQualityAnalyzer(
const EchoCanceller3Config& config,
size_t num_capture_channels)
: use_linear_filter_(config.filter.use_linear_filter),
usable_linear_filter_estimates_(num_capture_channels, false) {}
void AecState::FilteringQualityAnalyzer::Reset() {
std::fill(usable_linear_filter_estimates_.begin(),
usable_linear_filter_estimates_.end(), false);
overall_usable_linear_estimates_ = false;
filter_update_blocks_since_reset_ = 0;
}
void AecState::FilteringQualityAnalyzer::Update(
bool active_render,
bool transparent_mode,
bool saturated_capture,
const absl::optional<DelayEstimate>& external_delay,
bool any_filter_converged) {
// Update blocks counter.
const bool filter_update = active_render && !saturated_capture;
filter_update_blocks_since_reset_ += filter_update ? 1 : 0;
filter_update_blocks_since_start_ += filter_update ? 1 : 0;
// Store convergence flag when observed.
convergence_seen_ = convergence_seen_ || any_filter_converged;
// Verify requirements for achieving a decent filter. The requirements for
// filter adaptation at call startup are more restrictive than after an
// in-call reset.
const bool sufficient_data_to_converge_at_startup =
filter_update_blocks_since_start_ > kNumBlocksPerSecond * 0.4f;
const bool sufficient_data_to_converge_at_reset =
sufficient_data_to_converge_at_startup &&
filter_update_blocks_since_reset_ > kNumBlocksPerSecond * 0.2f;
// The linear filter can only be used if it has had time to converge.
overall_usable_linear_estimates_ = sufficient_data_to_converge_at_startup &&
sufficient_data_to_converge_at_reset;
// The linear filter can only be used if an external delay or convergence have
// been identified
overall_usable_linear_estimates_ =
overall_usable_linear_estimates_ && (external_delay || convergence_seen_);
// If transparent mode is on, deactivate usign the linear filter.
overall_usable_linear_estimates_ =
overall_usable_linear_estimates_ && !transparent_mode;
if (use_linear_filter_) {
std::fill(usable_linear_filter_estimates_.begin(),
usable_linear_filter_estimates_.end(),
overall_usable_linear_estimates_);
}
}
void AecState::SaturationDetector::Update(
const Block& x,
bool saturated_capture,
bool usable_linear_estimate,
rtc::ArrayView<const SubtractorOutput> subtractor_output,
float echo_path_gain) {
saturated_echo_ = false;
if (!saturated_capture) {
return;
}
if (usable_linear_estimate) {
constexpr float kSaturationThreshold = 20000.f;
for (size_t ch = 0; ch < subtractor_output.size(); ++ch) {
saturated_echo_ =
saturated_echo_ ||
(subtractor_output[ch].s_refined_max_abs > kSaturationThreshold ||
subtractor_output[ch].s_coarse_max_abs > kSaturationThreshold);
}
} else {
float max_sample = 0.f;
for (int ch = 0; ch < x.NumChannels(); ++ch) {
rtc::ArrayView<const float, kBlockSize> x_ch = x.View(/*band=*/0, ch);
for (float sample : x_ch) {
max_sample = std::max(max_sample, fabsf(sample));
}
}
const float kMargin = 10.f;
float peak_echo_amplitude = max_sample * echo_path_gain * kMargin;
saturated_echo_ = saturated_echo_ || peak_echo_amplitude > 32000;
}
}
} // namespace webrtc