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/*
* Copyright (c) 2018 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/subband_erle_estimator.h"
#include <algorithm>
#include <functional>
#include "rtc_base/checks.h"
#include "rtc_base/numerics/safe_minmax.h"
#include "system_wrappers/include/field_trial.h"
namespace webrtc {
namespace {
constexpr float kX2BandEnergyThreshold = 44015068.0f;
constexpr int kBlocksToHoldErle = 100;
constexpr int kBlocksForOnsetDetection = kBlocksToHoldErle + 150;
constexpr int kPointsToAccumulate = 6;
std::array<float, kFftLengthBy2Plus1> SetMaxErleBands(float max_erle_l,
float max_erle_h) {
std::array<float, kFftLengthBy2Plus1> max_erle;
std::fill(max_erle.begin(), max_erle.begin() + kFftLengthBy2 / 2, max_erle_l);
std::fill(max_erle.begin() + kFftLengthBy2 / 2, max_erle.end(), max_erle_h);
return max_erle;
}
bool EnableMinErleDuringOnsets() {
return !field_trial::IsEnabled("WebRTC-Aec3MinErleDuringOnsetsKillSwitch");
}
} // namespace
SubbandErleEstimator::SubbandErleEstimator(const EchoCanceller3Config& config,
size_t num_capture_channels)
: use_onset_detection_(config.erle.onset_detection),
min_erle_(config.erle.min),
max_erle_(SetMaxErleBands(config.erle.max_l, config.erle.max_h)),
use_min_erle_during_onsets_(EnableMinErleDuringOnsets()),
accum_spectra_(num_capture_channels),
erle_(num_capture_channels),
erle_onset_compensated_(num_capture_channels),
erle_unbounded_(num_capture_channels),
erle_during_onsets_(num_capture_channels),
coming_onset_(num_capture_channels),
hold_counters_(num_capture_channels) {
Reset();
}
SubbandErleEstimator::~SubbandErleEstimator() = default;
void SubbandErleEstimator::Reset() {
const size_t num_capture_channels = erle_.size();
for (size_t ch = 0; ch < num_capture_channels; ++ch) {
erle_[ch].fill(min_erle_);
erle_onset_compensated_[ch].fill(min_erle_);
erle_unbounded_[ch].fill(min_erle_);
erle_during_onsets_[ch].fill(min_erle_);
coming_onset_[ch].fill(true);
hold_counters_[ch].fill(0);
}
ResetAccumulatedSpectra();
}
void SubbandErleEstimator::Update(
rtc::ArrayView<const float, kFftLengthBy2Plus1> X2,
rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> Y2,
rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> E2,
const std::vector<bool>& converged_filters) {
UpdateAccumulatedSpectra(X2, Y2, E2, converged_filters);
UpdateBands(converged_filters);
if (use_onset_detection_) {
DecreaseErlePerBandForLowRenderSignals();
}
const size_t num_capture_channels = erle_.size();
for (size_t ch = 0; ch < num_capture_channels; ++ch) {
auto& erle = erle_[ch];
erle[0] = erle[1];
erle[kFftLengthBy2] = erle[kFftLengthBy2 - 1];
auto& erle_oc = erle_onset_compensated_[ch];
erle_oc[0] = erle_oc[1];
erle_oc[kFftLengthBy2] = erle_oc[kFftLengthBy2 - 1];
auto& erle_u = erle_unbounded_[ch];
erle_u[0] = erle_u[1];
erle_u[kFftLengthBy2] = erle_u[kFftLengthBy2 - 1];
}
}
void SubbandErleEstimator::Dump(
const std::unique_ptr<ApmDataDumper>& data_dumper) const {
data_dumper->DumpRaw("aec3_erle_onset", ErleDuringOnsets()[0]);
}
void SubbandErleEstimator::UpdateBands(
const std::vector<bool>& converged_filters) {
const int num_capture_channels = static_cast<int>(accum_spectra_.Y2.size());
for (int ch = 0; ch < num_capture_channels; ++ch) {
// Note that the use of the converged_filter flag already imposed
// a minimum of the erle that can be estimated as that flag would
// be false if the filter is performing poorly.
if (!converged_filters[ch]) {
continue;
}
if (accum_spectra_.num_points[ch] != kPointsToAccumulate) {
continue;
}
std::array<float, kFftLengthBy2> new_erle;
std::array<bool, kFftLengthBy2> is_erle_updated;
is_erle_updated.fill(false);
for (size_t k = 1; k < kFftLengthBy2; ++k) {
if (accum_spectra_.E2[ch][k] > 0.f) {
new_erle[k] = accum_spectra_.Y2[ch][k] / accum_spectra_.E2[ch][k];
is_erle_updated[k] = true;
}
}
if (use_onset_detection_) {
for (size_t k = 1; k < kFftLengthBy2; ++k) {
if (is_erle_updated[k] && !accum_spectra_.low_render_energy[ch][k]) {
if (coming_onset_[ch][k]) {
coming_onset_[ch][k] = false;
if (!use_min_erle_during_onsets_) {
float alpha =
new_erle[k] < erle_during_onsets_[ch][k] ? 0.3f : 0.15f;
erle_during_onsets_[ch][k] = rtc::SafeClamp(
erle_during_onsets_[ch][k] +
alpha * (new_erle[k] - erle_during_onsets_[ch][k]),
min_erle_, max_erle_[k]);
}
}
hold_counters_[ch][k] = kBlocksForOnsetDetection;
}
}
}
auto update_erle_band = [](float& erle, float new_erle,
bool low_render_energy, float min_erle,
float max_erle) {
float alpha = 0.05f;
if (new_erle < erle) {
alpha = low_render_energy ? 0.f : 0.1f;
}
erle =
rtc::SafeClamp(erle + alpha * (new_erle - erle), min_erle, max_erle);
};
for (size_t k = 1; k < kFftLengthBy2; ++k) {
if (is_erle_updated[k]) {
const bool low_render_energy = accum_spectra_.low_render_energy[ch][k];
update_erle_band(erle_[ch][k], new_erle[k], low_render_energy,
min_erle_, max_erle_[k]);
if (use_onset_detection_) {
update_erle_band(erle_onset_compensated_[ch][k], new_erle[k],
low_render_energy, min_erle_, max_erle_[k]);
}
// Virtually unbounded ERLE.
constexpr float kUnboundedErleMax = 100000.0f;
update_erle_band(erle_unbounded_[ch][k], new_erle[k], low_render_energy,
min_erle_, kUnboundedErleMax);
}
}
}
}
void SubbandErleEstimator::DecreaseErlePerBandForLowRenderSignals() {
const int num_capture_channels = static_cast<int>(accum_spectra_.Y2.size());
for (int ch = 0; ch < num_capture_channels; ++ch) {
for (size_t k = 1; k < kFftLengthBy2; ++k) {
--hold_counters_[ch][k];
if (hold_counters_[ch][k] <=
(kBlocksForOnsetDetection - kBlocksToHoldErle)) {
if (erle_onset_compensated_[ch][k] > erle_during_onsets_[ch][k]) {
erle_onset_compensated_[ch][k] =
std::max(erle_during_onsets_[ch][k],
0.97f * erle_onset_compensated_[ch][k]);
RTC_DCHECK_LE(min_erle_, erle_onset_compensated_[ch][k]);
}
if (hold_counters_[ch][k] <= 0) {
coming_onset_[ch][k] = true;
hold_counters_[ch][k] = 0;
}
}
}
}
}
void SubbandErleEstimator::ResetAccumulatedSpectra() {
for (size_t ch = 0; ch < erle_during_onsets_.size(); ++ch) {
accum_spectra_.Y2[ch].fill(0.f);
accum_spectra_.E2[ch].fill(0.f);
accum_spectra_.num_points[ch] = 0;
accum_spectra_.low_render_energy[ch].fill(false);
}
}
void SubbandErleEstimator::UpdateAccumulatedSpectra(
rtc::ArrayView<const float, kFftLengthBy2Plus1> X2,
rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> Y2,
rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> E2,
const std::vector<bool>& converged_filters) {
auto& st = accum_spectra_;
RTC_DCHECK_EQ(st.E2.size(), E2.size());
RTC_DCHECK_EQ(st.E2.size(), E2.size());
const int num_capture_channels = static_cast<int>(Y2.size());
for (int ch = 0; ch < num_capture_channels; ++ch) {
// Note that the use of the converged_filter flag already imposed
// a minimum of the erle that can be estimated as that flag would
// be false if the filter is performing poorly.
if (!converged_filters[ch]) {
continue;
}
if (st.num_points[ch] == kPointsToAccumulate) {
st.num_points[ch] = 0;
st.Y2[ch].fill(0.f);
st.E2[ch].fill(0.f);
st.low_render_energy[ch].fill(false);
}
std::transform(Y2[ch].begin(), Y2[ch].end(), st.Y2[ch].begin(),
st.Y2[ch].begin(), std::plus<float>());
std::transform(E2[ch].begin(), E2[ch].end(), st.E2[ch].begin(),
st.E2[ch].begin(), std::plus<float>());
for (size_t k = 0; k < X2.size(); ++k) {
st.low_render_energy[ch][k] =
st.low_render_energy[ch][k] || X2[k] < kX2BandEnergyThreshold;
}
++st.num_points[ch];
}
}
} // namespace webrtc