blob: b2849db18af6894699f246a3e5cb51cbef46fc52 [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/erl_estimator.h"
#include <algorithm>
#include <numeric>
namespace webrtc {
namespace {
constexpr float kMinErl = 0.01f;
constexpr float kMaxErl = 1000.f;
} // namespace
ErlEstimator::ErlEstimator() {
erl_.fill(kMaxErl);
hold_counters_.fill(0);
erl_time_domain_ = kMaxErl;
hold_counter_time_domain_ = 0;
}
ErlEstimator::~ErlEstimator() = default;
void ErlEstimator::Update(rtc::ArrayView<const float> render_spectrum,
rtc::ArrayView<const float> capture_spectrum) {
RTC_DCHECK_EQ(kFftLengthBy2Plus1, render_spectrum.size());
RTC_DCHECK_EQ(kFftLengthBy2Plus1, capture_spectrum.size());
const auto& X2 = render_spectrum;
const auto& Y2 = capture_spectrum;
// Corresponds to WGN of power -46 dBFS.
constexpr float kX2Min = 44015068.0f;
// Update the estimates in a maximum statistics manner.
for (size_t k = 1; k < kFftLengthBy2; ++k) {
if (X2[k] > kX2Min) {
const float new_erl = Y2[k] / X2[k];
if (new_erl < erl_[k]) {
hold_counters_[k - 1] = 1000;
erl_[k] += 0.1f * (new_erl - erl_[k]);
erl_[k] = std::max(erl_[k], kMinErl);
}
}
}
std::for_each(hold_counters_.begin(), hold_counters_.end(),
[](int& a) { --a; });
std::transform(hold_counters_.begin(), hold_counters_.end(), erl_.begin() + 1,
erl_.begin() + 1, [](int a, float b) {
return a > 0 ? b : std::min(kMaxErl, 2.f * b);
});
erl_[0] = erl_[1];
erl_[kFftLengthBy2] = erl_[kFftLengthBy2 - 1];
// Compute ERL over all frequency bins.
const float X2_sum = std::accumulate(X2.begin(), X2.end(), 0.0f);
if (X2_sum > kX2Min * X2.size()) {
const float Y2_sum = std::accumulate(Y2.begin(), Y2.end(), 0.0f);
const float new_erl = Y2_sum / X2_sum;
if (new_erl < erl_time_domain_) {
hold_counter_time_domain_ = 1000;
erl_time_domain_ += 0.1f * (new_erl - erl_time_domain_);
erl_time_domain_ = std::max(erl_time_domain_, kMinErl);
}
}
--hold_counter_time_domain_;
erl_time_domain_ = (hold_counter_time_domain_ > 0)
? erl_time_domain_
: std::min(kMaxErl, 2.f * erl_time_domain_);
}
} // namespace webrtc