14c11a4712
This CL adds detection of components in the render signal that are of strong narrowband nature and therefore may cause problems for the AEC. This CL also adds functionality in the echo suppressor to suppress these signals BUG=webrtc:7967 Review-Url: https://codereview.webrtc.org/2980493002 Cr-Commit-Position: refs/heads/master@{#18968}
127 lines
4.3 KiB
C++
127 lines
4.3 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/render_signal_analyzer.h"
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#include <math.h>
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#include <algorithm>
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#include "webrtc/rtc_base/checks.h"
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namespace webrtc {
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namespace {
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constexpr size_t kCounterThreshold = 5;
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// Identifies local bands with narrow characteristics.
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void IdentifySmallNarrowBandRegions(
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const RenderBuffer& render_buffer,
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const rtc::Optional<size_t>& delay_partitions,
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std::array<size_t, kFftLengthBy2 - 1>* narrow_band_counters) {
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if (!delay_partitions) {
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narrow_band_counters->fill(0);
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return;
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}
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const std::array<float, kFftLengthBy2Plus1>& X2 =
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render_buffer.Spectrum(*delay_partitions);
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for (size_t k = 1; k < (X2.size() - 1); ++k) {
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(*narrow_band_counters)[k - 1] = X2[k] > 3 * std::max(X2[k - 1], X2[k + 1])
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? (*narrow_band_counters)[k - 1] + 1
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: 0;
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}
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}
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// Identifies whether the signal has a single strong narrow-band component.
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void IdentifyStrongNarrowBandComponent(const RenderBuffer& render_buffer,
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rtc::Optional<int>* narrow_peak_band,
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size_t* narrow_peak_counter) {
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const auto X2_latest = render_buffer.Spectrum(0);
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// Identify the spectral peak.
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const int peak_bin = static_cast<int>(
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std::max_element(X2_latest.begin(), X2_latest.end()) - X2_latest.begin());
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// Compute the level around the peak.
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float non_peak_power = 0.f;
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for (int k = std::max(5, peak_bin - 14); k < peak_bin - 4; ++k) {
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non_peak_power = std::max(X2_latest[k], non_peak_power);
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}
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for (int k = peak_bin + 5;
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k < std::min(peak_bin + 15, static_cast<int>(kFftLengthBy2Plus1)); ++k) {
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non_peak_power = std::max(X2_latest[k], non_peak_power);
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}
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// Assess the render signal strength
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const std::vector<std::vector<float>>& x_latest =
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render_buffer.MostRecentBlock();
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auto result0 = std::minmax_element(x_latest[0].begin(), x_latest[0].end());
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float max_abs = std::max(fabs(*result0.first), fabs(*result0.second));
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if (x_latest.size() > 1) {
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const auto result1 =
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std::minmax_element(x_latest[1].begin(), x_latest[1].end());
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max_abs =
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std::max(max_abs, static_cast<float>(std::max(fabs(*result1.first),
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fabs(*result1.second))));
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}
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// Detect whether the spectal peak has as strong narrowband nature.
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if (peak_bin > 6 && max_abs > 100 &&
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X2_latest[peak_bin] > 100 * non_peak_power) {
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*narrow_peak_band = rtc::Optional<int>(peak_bin);
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*narrow_peak_counter = 0;
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} else {
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if (*narrow_peak_band && ++(*narrow_peak_counter) > 7) {
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*narrow_peak_band = rtc::Optional<int>();
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}
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}
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}
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} // namespace
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RenderSignalAnalyzer::RenderSignalAnalyzer() {
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narrow_band_counters_.fill(0);
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}
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RenderSignalAnalyzer::~RenderSignalAnalyzer() = default;
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void RenderSignalAnalyzer::Update(
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const RenderBuffer& render_buffer,
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const rtc::Optional<size_t>& delay_partitions) {
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// Identify bands of narrow nature.
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IdentifySmallNarrowBandRegions(render_buffer, delay_partitions,
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&narrow_band_counters_);
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// Identify the presence of a strong narrow band.
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IdentifyStrongNarrowBandComponent(render_buffer, &narrow_peak_band_,
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&narrow_peak_counter_);
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}
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void RenderSignalAnalyzer::MaskRegionsAroundNarrowBands(
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std::array<float, kFftLengthBy2Plus1>* v) const {
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RTC_DCHECK(v);
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// Set v to zero around narrow band signal regions.
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if (narrow_band_counters_[0] > kCounterThreshold) {
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(*v)[1] = (*v)[0] = 0.f;
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}
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for (size_t k = 2; k < kFftLengthBy2 - 1; ++k) {
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if (narrow_band_counters_[k - 1] > kCounterThreshold) {
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(*v)[k - 2] = (*v)[k - 1] = (*v)[k] = (*v)[k + 1] = (*v)[k + 2] = 0.f;
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}
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}
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if (narrow_band_counters_[kFftLengthBy2 - 2] > kCounterThreshold) {
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(*v)[kFftLengthBy2] = (*v)[kFftLengthBy2 - 1] = 0.f;
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}
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}
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} // namespace webrtc
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