71 lines
2.8 KiB
C++
71 lines
2.8 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/subband_nearend_detector.h"
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#include <numeric>
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namespace webrtc {
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SubbandNearendDetector::SubbandNearendDetector(
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const EchoCanceller3Config::Suppressor::SubbandNearendDetection& config,
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size_t num_capture_channels)
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: config_(config),
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num_capture_channels_(num_capture_channels),
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nearend_smoothers_(num_capture_channels_,
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aec3::MovingAverage(kFftLengthBy2Plus1,
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config_.nearend_average_blocks)),
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one_over_subband_length1_(
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1.f / (config_.subband1.high - config_.subband1.low + 1)),
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one_over_subband_length2_(
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1.f / (config_.subband2.high - config_.subband2.low + 1)) {}
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void SubbandNearendDetector::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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for (size_t ch = 0; ch < num_capture_channels_; ++ch) {
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const std::array<float, kFftLengthBy2Plus1>& noise =
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comfort_noise_spectrum[ch];
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std::array<float, kFftLengthBy2Plus1> nearend;
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nearend_smoothers_[ch].Average(nearend_spectrum[ch], nearend);
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// Noise power of the first region.
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float noise_power =
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std::accumulate(noise.begin() + config_.subband1.low,
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noise.begin() + config_.subband1.high + 1, 0.f) *
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one_over_subband_length1_;
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// Nearend power of the first region.
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float nearend_power_subband1 =
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std::accumulate(nearend.begin() + config_.subband1.low,
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nearend.begin() + config_.subband1.high + 1, 0.f) *
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one_over_subband_length1_;
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// Nearend power of the second region.
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float nearend_power_subband2 =
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std::accumulate(nearend.begin() + config_.subband2.low,
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nearend.begin() + config_.subband2.high + 1, 0.f) *
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one_over_subband_length2_;
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// One channel is sufficient to trigger nearend state.
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nearend_state_ =
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nearend_state_ ||
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(nearend_power_subband1 <
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config_.nearend_threshold * nearend_power_subband2 &&
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(nearend_power_subband1 > config_.snr_threshold * noise_power));
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}
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}
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} // namespace webrtc
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