1 /* 2 * Copyright (c) 2019 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef MODULES_AUDIO_PROCESSING_NS_WIENER_FILTER_H_ 12 #define MODULES_AUDIO_PROCESSING_NS_WIENER_FILTER_H_ 13 14 #include <array> 15 16 #include "api/array_view.h" 17 #include "modules/audio_processing/ns/ns_common.h" 18 #include "modules/audio_processing/ns/suppression_params.h" 19 20 namespace webrtc { 21 22 // Estimates a Wiener-filter based frequency domain noise reduction filter. 23 class WienerFilter { 24 public: 25 explicit WienerFilter(const SuppressionParams& suppression_params); 26 WienerFilter(const WienerFilter&) = delete; 27 WienerFilter& operator=(const WienerFilter&) = delete; 28 29 // Updates the filter estimate. 30 void Update( 31 int32_t num_analyzed_frames, 32 rtc::ArrayView<const float, kFftSizeBy2Plus1> noise_spectrum, 33 rtc::ArrayView<const float, kFftSizeBy2Plus1> prev_noise_spectrum, 34 rtc::ArrayView<const float, kFftSizeBy2Plus1> parametric_noise_spectrum, 35 rtc::ArrayView<const float, kFftSizeBy2Plus1> signal_spectrum); 36 37 // Compute an overall gain scaling factor. 38 float ComputeOverallScalingFactor(int32_t num_analyzed_frames, 39 float prior_speech_probability, 40 float energy_before_filtering, 41 float energy_after_filtering) const; 42 43 // Returns the filter. get_filter()44 rtc::ArrayView<const float, kFftSizeBy2Plus1> get_filter() const { 45 return filter_; 46 } 47 48 private: 49 const SuppressionParams& suppression_params_; 50 std::array<float, kFftSizeBy2Plus1> spectrum_prev_process_; 51 std::array<float, kFftSizeBy2Plus1> initial_spectral_estimate_; 52 std::array<float, kFftSizeBy2Plus1> filter_; 53 }; 54 55 } // namespace webrtc 56 57 #endif // MODULES_AUDIO_PROCESSING_NS_WIENER_FILTER_H_ 58