999cf2bd7c
TBR=henrik.lundin@webrtc.org BUG=webrtc:6018 Review-Url: https://codereview.webrtc.org/2720973005 Cr-Commit-Position: refs/heads/master@{#16928}
112 lines
3.5 KiB
C++
112 lines
3.5 KiB
C++
/*
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* Copyright (c) 2017 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 "webrtc/modules/audio_processing/aec3/power_echo_model.h"
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#include <string.h>
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#include <algorithm>
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#include "webrtc/base/optional.h"
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namespace webrtc {
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namespace {
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// Computes the spectral power over that last 20 frames.
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void RecentMaximum(const FftBuffer& X_buffer,
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std::array<float, kFftLengthBy2Plus1>* R2) {
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R2->fill(0.f);
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for (size_t j = 0; j < 20; ++j) {
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std::transform(R2->begin(), R2->end(), X_buffer.Spectrum(j).begin(),
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R2->begin(),
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[](float a, float b) { return std::max(a, b); });
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}
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}
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constexpr float kHInitial = 10.f;
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constexpr int kUpdateCounterInitial = 300;
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} // namespace
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PowerEchoModel::PowerEchoModel() {
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H2_.fill(CountedFloat(kHInitial, kUpdateCounterInitial));
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}
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PowerEchoModel::~PowerEchoModel() = default;
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void PowerEchoModel::HandleEchoPathChange(
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const EchoPathVariability& variability) {
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if (variability.gain_change) {
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H2_.fill(CountedFloat(kHInitial, kUpdateCounterInitial));
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}
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}
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void PowerEchoModel::EstimateEcho(
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const FftBuffer& render_buffer,
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const std::array<float, kFftLengthBy2Plus1>& capture_spectrum,
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const AecState& aec_state,
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std::array<float, kFftLengthBy2Plus1>* echo_spectrum) {
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RTC_DCHECK(echo_spectrum);
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const FftBuffer& X_buffer = render_buffer;
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const auto& Y2 = capture_spectrum;
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std::array<float, kFftLengthBy2Plus1>* S2 = echo_spectrum;
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// Choose delay to use.
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const rtc::Optional<size_t> delay =
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aec_state.FilterDelay()
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? aec_state.FilterDelay()
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: (aec_state.ExternalDelay() ? rtc::Optional<size_t>(std::min<size_t>(
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*aec_state.ExternalDelay(),
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X_buffer.Buffer().size() - 1))
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: rtc::Optional<size_t>());
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// Compute R2.
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std::array<float, kFftLengthBy2Plus1> render_max;
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if (!delay) {
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RecentMaximum(render_buffer, &render_max);
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}
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const std::array<float, kFftLengthBy2Plus1>& X2_active =
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delay ? render_buffer.Spectrum(*delay) : render_max;
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if (!aec_state.SaturatedCapture()) {
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// Corresponds of WGN of power -46dBFS.
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constexpr float kX2Min = 44015068.0f;
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const int max_update_counter_value = delay ? 300 : 500;
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std::array<float, kFftLengthBy2Plus1> new_H2;
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// new_H2 = Y2 / X2.
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std::transform(X2_active.begin(), X2_active.end(), Y2.begin(),
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new_H2.begin(),
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[&](float a, float b) { return a > kX2Min ? b / a : -1.f; });
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// Lambda for updating H2 in a maximum statistics manner.
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auto H2_updater = [&](float a, CountedFloat b) {
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if (a > 0) {
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if (a > b.value) {
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b.counter = max_update_counter_value;
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b.value = a;
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} else if (--b.counter <= 0) {
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b.value = std::max(b.value * 0.9f, 1.f);
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}
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}
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return b;
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};
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std::transform(new_H2.begin(), new_H2.end(), H2_.begin(), H2_.begin(),
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H2_updater);
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}
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// S2 = H2*X2_active.
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std::transform(H2_.begin(), H2_.end(), X2_active.begin(), S2->begin(),
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[](CountedFloat a, float b) { return a.value * b; });
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}
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} // namespace webrtc
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