chromium/third_party/webrtc/modules/audio_processing/aec3/signal_dependent_erle_estimator.cc

/*
 *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "modules/audio_processing/aec3/signal_dependent_erle_estimator.h"

#include <algorithm>
#include <functional>
#include <numeric>

#include "modules/audio_processing/aec3/spectrum_buffer.h"
#include "rtc_base/numerics/safe_minmax.h"

namespace webrtc {

namespace {

constexpr std::array<size_t, SignalDependentErleEstimator::kSubbands + 1>
    kBandBoundaries = …;

std::array<size_t, kFftLengthBy2Plus1> FormSubbandMap() { … }

// Defines the size in blocks of the sections that are used for dividing the
// linear filter. The sections are split in a non-linear manner so that lower
// sections that typically represent the direct path have a larger resolution
// than the higher sections which typically represent more reverberant acoustic
// paths.
std::vector<size_t> DefineFilterSectionSizes(size_t delay_headroom_blocks,
                                             size_t num_blocks,
                                             size_t num_sections) { … }

// Forms the limits in blocks for each filter section. Those sections
// are used for analyzing the echo estimates and investigating which
// linear filter sections contribute most to the echo estimate energy.
std::vector<size_t> SetSectionsBoundaries(size_t delay_headroom_blocks,
                                          size_t num_blocks,
                                          size_t num_sections) { … }

std::array<float, SignalDependentErleEstimator::kSubbands>
SetMaxErleSubbands(float max_erle_l, float max_erle_h, size_t limit_subband_l) { … }

}  // namespace

SignalDependentErleEstimator::SignalDependentErleEstimator(
    const EchoCanceller3Config& config,
    size_t num_capture_channels)
    : … { … }

SignalDependentErleEstimator::~SignalDependentErleEstimator() = default;

void SignalDependentErleEstimator::Reset() { … }

// Updates the Erle estimate by analyzing the current input signals. It takes
// the render buffer and the filter frequency response in order to do an
// estimation of the number of sections of the linear filter that are needed
// for getting the majority of the energy in the echo estimate. Based on that
// number of sections, it updates the erle estimation by introducing a
// correction factor to the erle that is given as an input to this method.
void SignalDependentErleEstimator::Update(
    const RenderBuffer& render_buffer,
    rtc::ArrayView<const std::vector<std::array<float, kFftLengthBy2Plus1>>>
        filter_frequency_responses,
    rtc::ArrayView<const float, kFftLengthBy2Plus1> X2,
    rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> Y2,
    rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> E2,
    rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> average_erle,
    rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>>
        average_erle_onset_compensated,
    const std::vector<bool>& converged_filters) { … }

void SignalDependentErleEstimator::Dump(
    const std::unique_ptr<ApmDataDumper>& data_dumper) const { … }

// Estimates for each band the smallest number of sections in the filter that
// together constitute 90% of the estimated echo energy.
void SignalDependentErleEstimator::ComputeNumberOfActiveFilterSections(
    const RenderBuffer& render_buffer,
    rtc::ArrayView<const std::vector<std::array<float, kFftLengthBy2Plus1>>>
        filter_frequency_responses) { … }

void SignalDependentErleEstimator::UpdateCorrectionFactors(
    rtc::ArrayView<const float, kFftLengthBy2Plus1> X2,
    rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> Y2,
    rtc::ArrayView<const std::array<float, kFftLengthBy2Plus1>> E2,
    const std::vector<bool>& converged_filters) { … }

void SignalDependentErleEstimator::ComputeEchoEstimatePerFilterSection(
    const RenderBuffer& render_buffer,
    rtc::ArrayView<const std::vector<std::array<float, kFftLengthBy2Plus1>>>
        filter_frequency_responses) { … }

void SignalDependentErleEstimator::ComputeActiveFilterSections() { … }
}  // namespace webrtc