1 /* 2 * Copyright (c) 2018 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_AEC3_REVERB_DECAY_ESTIMATOR_H_ 12 #define MODULES_AUDIO_PROCESSING_AEC3_REVERB_DECAY_ESTIMATOR_H_ 13 14 #include <array> 15 #include <vector> 16 17 #include "absl/types/optional.h" 18 #include "api/array_view.h" 19 #include "modules/audio_processing/aec3/aec3_common.h" // kMaxAdaptiveFilter... 20 21 namespace webrtc { 22 23 class ApmDataDumper; 24 struct EchoCanceller3Config; 25 26 // Class for estimating the decay of the late reverb. 27 class ReverbDecayEstimator { 28 public: 29 explicit ReverbDecayEstimator(const EchoCanceller3Config& config); 30 ~ReverbDecayEstimator(); 31 // Updates the decay estimate. 32 void Update(rtc::ArrayView<const float> filter, 33 const absl::optional<float>& filter_quality, 34 int filter_delay_blocks, 35 bool usable_linear_filter, 36 bool stationary_signal); 37 // Returns the decay for the exponential model. Decay()38 float Decay() const { return decay_; } 39 // Dumps debug data. 40 void Dump(ApmDataDumper* data_dumper) const; 41 42 private: 43 void EstimateDecay(rtc::ArrayView<const float> filter, int peak_block); 44 void AnalyzeFilter(rtc::ArrayView<const float> filter); 45 46 void ResetDecayEstimation(); 47 48 // Class for estimating the decay of the late reverb from the linear filter. 49 class LateReverbLinearRegressor { 50 public: 51 // Resets the estimator to receive a specified number of data points. 52 void Reset(int num_data_points); 53 // Accumulates estimation data. 54 void Accumulate(float z); 55 // Estimates the decay. 56 float Estimate(); 57 // Returns whether an estimate is available. EstimateAvailable()58 bool EstimateAvailable() const { return n_ == N_ && N_ != 0; } 59 60 public: 61 float nz_ = 0.f; 62 float nn_ = 0.f; 63 float count_ = 0.f; 64 int N_ = 0; 65 int n_ = 0; 66 }; 67 68 // Class for identifying the length of the early reverb from the linear 69 // filter. For identifying the early reverberations, the impulse response is 70 // divided in sections and the tilt of each section is computed by a linear 71 // regressor. 72 class EarlyReverbLengthEstimator { 73 public: 74 explicit EarlyReverbLengthEstimator(int max_blocks); 75 ~EarlyReverbLengthEstimator(); 76 77 // Resets the estimator. 78 void Reset(); 79 // Accumulates estimation data. 80 void Accumulate(float value, float smoothing); 81 // Estimates the size in blocks of the early reverb. 82 int Estimate(); 83 // Dumps debug data. 84 void Dump(ApmDataDumper* data_dumper) const; 85 86 private: 87 std::vector<float> numerators_smooth_; 88 std::vector<float> numerators_; 89 int coefficients_counter_; 90 int block_counter_ = 0; 91 int n_sections_ = 0; 92 }; 93 94 const int filter_length_blocks_; 95 const int filter_length_coefficients_; 96 const bool use_adaptive_echo_decay_; 97 LateReverbLinearRegressor late_reverb_decay_estimator_; 98 EarlyReverbLengthEstimator early_reverb_estimator_; 99 int late_reverb_start_; 100 int late_reverb_end_; 101 int block_to_analyze_ = 0; 102 int estimation_region_candidate_size_ = 0; 103 bool estimation_region_identified_ = false; 104 std::vector<float> previous_gains_; 105 float decay_; 106 float tail_gain_ = 0.f; 107 float smoothing_constant_ = 0.f; 108 }; 109 110 } // namespace webrtc 111 112 #endif // MODULES_AUDIO_PROCESSING_AEC3_REVERB_DECAY_ESTIMATOR_H_ 113