76 lines
3.0 KiB
C++
76 lines
3.0 KiB
C++
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/*
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* Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/audio_processing/aec3/dominant_nearend_detector.h"
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#include <numeric>
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namespace webrtc {
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DominantNearendDetector::DominantNearendDetector(
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const EchoCanceller3Config::Suppressor::DominantNearendDetection& config,
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size_t num_capture_channels)
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: enr_threshold_(config.enr_threshold),
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enr_exit_threshold_(config.enr_exit_threshold),
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snr_threshold_(config.snr_threshold),
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hold_duration_(config.hold_duration),
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trigger_threshold_(config.trigger_threshold),
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use_during_initial_phase_(config.use_during_initial_phase),
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num_capture_channels_(num_capture_channels),
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trigger_counters_(num_capture_channels_),
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hold_counters_(num_capture_channels_) {}
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void DominantNearendDetector::Update(
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rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
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nearend_spectrum,
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rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
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residual_echo_spectrum,
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rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
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comfort_noise_spectrum,
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bool initial_state) {
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nearend_state_ = false;
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auto low_frequency_energy = [](rtc::ArrayView<const float> spectrum) {
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RTC_DCHECK_LE(16, spectrum.size());
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return std::accumulate(spectrum.begin() + 1, spectrum.begin() + 16, 0.f);
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};
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for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
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const float ne_sum = low_frequency_energy(nearend_spectrum[ch]);
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const float echo_sum = low_frequency_energy(residual_echo_spectrum[ch]);
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const float noise_sum = low_frequency_energy(comfort_noise_spectrum[ch]);
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// Detect strong active nearend if the nearend is sufficiently stronger than
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// the echo and the nearend noise.
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if ((!initial_state || use_during_initial_phase_) &&
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echo_sum < enr_threshold_ * ne_sum &&
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ne_sum > snr_threshold_ * noise_sum) {
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if (++trigger_counters_[ch] >= trigger_threshold_) {
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// After a period of strong active nearend activity, flag nearend mode.
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hold_counters_[ch] = hold_duration_;
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trigger_counters_[ch] = trigger_threshold_;
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}
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} else {
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// Forget previously detected strong active nearend activity.
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trigger_counters_[ch] = std::max(0, trigger_counters_[ch] - 1);
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}
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// Exit nearend-state early at strong echo.
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if (echo_sum > enr_exit_threshold_ * ne_sum &&
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echo_sum > snr_threshold_ * noise_sum) {
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hold_counters_[ch] = 0;
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}
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// Remain in any nearend mode for a certain duration.
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hold_counters_[ch] = std::max(0, hold_counters_[ch] - 1);
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nearend_state_ = nearend_state_ || hold_counters_[ch] > 0;
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}
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}
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} // namespace webrtc
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