blob: 385e6dd7e634940ed2dc38d19f74d6798c38a91d [file] [log] [blame]
/*
* 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/erle_estimator.h"
#include <algorithm>
#include <numeric>
#include "rtc_base/numerics/safe_minmax.h"
namespace webrtc {
ErleEstimator::ErleEstimator(float min_erle,
float max_erle_lf,
float max_erle_hf)
: min_erle_(min_erle),
max_erle_lf_(max_erle_lf),
max_erle_hf_(max_erle_hf) {
erle_.fill(min_erle_);
hold_counters_.fill(0);
erle_time_domain_ = min_erle_;
hold_counter_time_domain_ = 0;
}
ErleEstimator::~ErleEstimator() = default;
void ErleEstimator::Update(
const std::array<float, kFftLengthBy2Plus1>& render_spectrum,
const std::array<float, kFftLengthBy2Plus1>& capture_spectrum,
const std::array<float, kFftLengthBy2Plus1>& subtractor_spectrum) {
const auto& X2 = render_spectrum;
const auto& Y2 = capture_spectrum;
const auto& E2 = subtractor_spectrum;
// Corresponds of WGN of power -46 dBFS.
constexpr float kX2Min = 44015068.0f;
// Update the estimates in a clamped minimum statistics manner.
auto erle_update = [&](size_t start, size_t stop, float max_erle) {
for (size_t k = start; k < stop; ++k) {
if (X2[k] > kX2Min && E2[k] > 0.f) {
const float new_erle = Y2[k] / E2[k];
if (new_erle > erle_[k]) {
hold_counters_[k - 1] = 100;
erle_[k] += 0.1f * (new_erle - erle_[k]);
erle_[k] = rtc::SafeClamp(erle_[k], min_erle_, max_erle);
}
}
}
};
erle_update(1, kFftLengthBy2 / 2, max_erle_lf_);
erle_update(kFftLengthBy2 / 2, kFftLengthBy2, max_erle_hf_);
std::for_each(hold_counters_.begin(), hold_counters_.end(),
[](int& a) { --a; });
std::transform(hold_counters_.begin(), hold_counters_.end(),
erle_.begin() + 1, erle_.begin() + 1, [&](int a, float b) {
return a > 0 ? b : std::max(min_erle_, 0.97f * b);
});
erle_[0] = erle_[1];
erle_[kFftLengthBy2] = erle_[kFftLengthBy2 - 1];
// Compute ERLE over all frequency bins.
const float X2_sum = std::accumulate(X2.begin(), X2.end(), 0.0f);
const float E2_sum = std::accumulate(E2.begin(), E2.end(), 0.0f);
if (X2_sum > kX2Min * X2.size() && E2_sum > 0.f) {
const float Y2_sum = std::accumulate(Y2.begin(), Y2.end(), 0.0f);
const float new_erle = Y2_sum / E2_sum;
if (new_erle > erle_time_domain_) {
hold_counter_time_domain_ = 100;
erle_time_domain_ += 0.1f * (new_erle - erle_time_domain_);
erle_time_domain_ =
rtc::SafeClamp(erle_time_domain_, min_erle_, max_erle_lf_);
}
}
--hold_counter_time_domain_;
erle_time_domain_ = (hold_counter_time_domain_ > 0)
? erle_time_domain_
: std::max(min_erle_, 0.97f * erle_time_domain_);
}
} // namespace webrtc