chromium/third_party/webrtc/modules/audio_processing/ns/signal_model_estimator.cc

/*
 *  Copyright (c) 2019 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/ns/signal_model_estimator.h"

#include "modules/audio_processing/ns/fast_math.h"

namespace webrtc {

namespace {

constexpr float kOneByFftSizeBy2Plus1 = …;

// Computes the difference measure between input spectrum and a template/learned
// noise spectrum.
float ComputeSpectralDiff(
    rtc::ArrayView<const float, kFftSizeBy2Plus1> conservative_noise_spectrum,
    rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum,
    float signal_spectral_sum,
    float diff_normalization) { … }

// Updates the spectral flatness based on the input spectrum.
void UpdateSpectralFlatness(
    rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum,
    float signal_spectral_sum,
    float* spectral_flatness) { … }

// Updates the log LRT measures.
void UpdateSpectralLrt(rtc::ArrayView<const float, kFftSizeBy2Plus1> prior_snr,
                       rtc::ArrayView<const float, kFftSizeBy2Plus1> post_snr,
                       rtc::ArrayView<float, kFftSizeBy2Plus1> avg_log_lrt,
                       float* lrt) { … }

}  // namespace

SignalModelEstimator::SignalModelEstimator()
    : … { … }

void SignalModelEstimator::AdjustNormalization(int32_t num_analyzed_frames,
                                               float signal_energy) { … }

// Update the noise features.
void SignalModelEstimator::Update(
    rtc::ArrayView<const float, kFftSizeBy2Plus1> prior_snr,
    rtc::ArrayView<const float, kFftSizeBy2Plus1> post_snr,
    rtc::ArrayView<const float, kFftSizeBy2Plus1> conservative_noise_spectrum,
    rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum,
    float signal_spectral_sum,
    float signal_energy) { … }

}  // namespace webrtc