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In this work we introduce some changes on how the reverberation model for AEC3 is applied. Currently, the exponential modelling of the tails is applied over the linear echo estimates. That might result in an overestimation of the reverberation tails under certain conditions. In this work, the reverberation model is instead applied over an estimate of the energies at the tails of the linear estimate. Additionally, the stationary estimator is changed so it does not disable the aec immediately after a burst of activity. Bug: webrtc:9384,webrtc:9400,chromium:852257 Change-Id: Ia486694ed326cfe231fc688877c0b9b6e2c450ff Reviewed-on: https://webrtc-review.googlesource.com/82161 Reviewed-by: Per Åhgren <peah@webrtc.org> Commit-Queue: Jesus de Vicente Pena <devicentepena@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23599}
70 lines
2.2 KiB
C++
70 lines
2.2 KiB
C++
/*
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* Copyright (c) 2018 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/reverb_model_fallback.h"
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#include <algorithm>
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#include <functional>
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#include "modules/audio_processing/aec3/aec3_common.h"
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#include "rtc_base/checks.h"
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namespace webrtc {
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ReverbModelFallback::ReverbModelFallback(size_t length_blocks)
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: S2_old_(length_blocks) {
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Reset();
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}
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ReverbModelFallback::~ReverbModelFallback() = default;
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void ReverbModelFallback::Reset() {
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R2_reverb_.fill(0.f);
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for (auto& S2_k : S2_old_) {
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S2_k.fill(0.f);
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}
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}
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void ReverbModelFallback::AddEchoReverb(
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const std::array<float, kFftLengthBy2Plus1>& S2,
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size_t delay,
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float reverb_decay_factor,
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std::array<float, kFftLengthBy2Plus1>* R2) {
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// Compute the decay factor for how much the echo has decayed before leaving
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// the region covered by the linear model.
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auto integer_power = [](float base, int exp) {
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float result = 1.f;
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for (int k = 0; k < exp; ++k) {
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result *= base;
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}
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return result;
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};
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RTC_DCHECK_LE(delay, S2_old_.size());
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const float reverb_decay_for_delay =
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integer_power(reverb_decay_factor, S2_old_.size() - delay);
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// Update the estimate of the reverberant residual echo power.
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S2_old_index_ = S2_old_index_ > 0 ? S2_old_index_ - 1 : S2_old_.size() - 1;
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const auto& S2_end = S2_old_[S2_old_index_];
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std::transform(
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S2_end.begin(), S2_end.end(), R2_reverb_.begin(), R2_reverb_.begin(),
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[reverb_decay_for_delay, reverb_decay_factor](float a, float b) {
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return (b + a * reverb_decay_for_delay) * reverb_decay_factor;
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});
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// Update the buffer of old echo powers.
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std::copy(S2.begin(), S2.end(), S2_old_[S2_old_index_].begin());
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// Add the power of the echo reverb to the residual echo power.
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std::transform(R2->begin(), R2->end(), R2_reverb_.begin(), R2->begin(),
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std::plus<float>());
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}
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} // namespace webrtc
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