| /* |
| * 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_); |
| erle_onsets_.fill(min_erle_); |
| hold_counters_.fill(0); |
| coming_onset_.fill(true); |
| erle_time_domain_ = min_erle_; |
| hold_counter_time_domain_ = 0; |
| } |
| |
| ErleEstimator::~ErleEstimator() = default; |
| |
| void ErleEstimator::Update(rtc::ArrayView<const float> render_spectrum, |
| rtc::ArrayView<const float> capture_spectrum, |
| rtc::ArrayView<const float> subtractor_spectrum) { |
| RTC_DCHECK_EQ(kFftLengthBy2Plus1, render_spectrum.size()); |
| RTC_DCHECK_EQ(kFftLengthBy2Plus1, capture_spectrum.size()); |
| RTC_DCHECK_EQ(kFftLengthBy2Plus1, subtractor_spectrum.size()); |
| 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; |
| constexpr int kOnsetSizeBlocks = 4; |
| constexpr int kErleHold = 100; |
| constexpr int kErleOnsetHold = kErleHold + kOnsetSizeBlocks; |
| |
| auto erle_band_update = [](float erle_band, float new_erle, float alpha_inc, |
| float alpha_dec, float min_erle, float max_erle) { |
| float alpha = new_erle > erle_band ? alpha_inc : alpha_dec; |
| float erle_band_out = erle_band; |
| erle_band_out = erle_band + alpha * (new_erle - erle_band); |
| erle_band_out = rtc::SafeClamp(erle_band_out, min_erle, max_erle); |
| return erle_band_out; |
| }; |
| |
| // 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 (coming_onset_[k - 1]) { |
| hold_counters_[k - 1] = kErleOnsetHold; |
| coming_onset_[k - 1] = false; |
| } |
| if (hold_counters_[k - 1] > kErleHold) { |
| erle_onsets_[k] = erle_band_update(erle_onsets_[k], new_erle, 0.05f, |
| 0.1f, min_erle_, max_erle); |
| } else { |
| hold_counters_[k - 1] = kErleHold; |
| } |
| erle_[k] = erle_band_update(erle_[k], new_erle, 0.01f, 0.02f, min_erle_, |
| max_erle); |
| } |
| } |
| }; |
| |
| constexpr size_t kFftLengthBy4 = kFftLengthBy2 / 2; |
| erle_update(1, kFftLengthBy4, max_erle_lf_); |
| erle_update(kFftLengthBy4, kFftLengthBy2, max_erle_hf_); |
| |
| for (size_t k = 0; k < hold_counters_.size(); ++k) { |
| hold_counters_[k]--; |
| if (hold_counters_[k] <= 0) { |
| coming_onset_[k] = true; |
| if (erle_[k + 1] > erle_onsets_[k + 1]) { |
| erle_[k + 1] = std::max(erle_onsets_[k + 1], 0.97f * erle_[k + 1]); |
| RTC_DCHECK_LE(min_erle_, erle_[k + 1]); |
| } |
| } |
| } |
| |
| 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_ = kErleHold; |
| 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 |