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/*
* 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.
*/
#ifndef MODULES_AUDIO_PROCESSING_NS_NOISE_ESTIMATOR_H_
#define MODULES_AUDIO_PROCESSING_NS_NOISE_ESTIMATOR_H_
#include <array>
#include "api/array_view.h"
#include "modules/audio_processing/ns/ns_common.h"
#include "modules/audio_processing/ns/quantile_noise_estimator.h"
#include "modules/audio_processing/ns/suppression_params.h"
namespace webrtc {
// Class for estimating the spectral characteristics of the noise in an incoming
// signal.
class NoiseEstimator {
public:
explicit NoiseEstimator(const SuppressionParams& suppression_params);
// Prepare the estimator for analysis of a new frame.
void PrepareAnalysis();
// Performs the first step of the estimator update.
void PreUpdate(int32_t num_analyzed_frames,
rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum,
float signal_spectral_sum);
// Performs the second step of the estimator update.
void PostUpdate(
rtc::ArrayView<const float> speech_probability,
rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum);
// Returns the noise spectral estimate.
rtc::ArrayView<const float, kFftSizeBy2Plus1> get_noise_spectrum() const {
return noise_spectrum_;
}
// Returns the noise from the previous frame.
rtc::ArrayView<const float, kFftSizeBy2Plus1> get_prev_noise_spectrum()
const {
return prev_noise_spectrum_;
}
// Returns a noise spectral estimate based on white and pink noise parameters.
rtc::ArrayView<const float, kFftSizeBy2Plus1> get_parametric_noise_spectrum()
const {
return parametric_noise_spectrum_;
}
rtc::ArrayView<const float, kFftSizeBy2Plus1>
get_conservative_noise_spectrum() const {
return conservative_noise_spectrum_;
}
private:
const SuppressionParams& suppression_params_;
float white_noise_level_ = 0.f;
float pink_noise_numerator_ = 0.f;
float pink_noise_exp_ = 0.f;
std::array<float, kFftSizeBy2Plus1> prev_noise_spectrum_;
std::array<float, kFftSizeBy2Plus1> conservative_noise_spectrum_;
std::array<float, kFftSizeBy2Plus1> parametric_noise_spectrum_;
std::array<float, kFftSizeBy2Plus1> noise_spectrum_;
QuantileNoiseEstimator quantile_noise_estimator_;
};
} // namespace webrtc
#endif // MODULES_AUDIO_PROCESSING_NS_NOISE_ESTIMATOR_H_