1 /* 2 * Copyright (c) 2016 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 VIDEO_QUALITY_THRESHOLD_H_ 12 #define VIDEO_QUALITY_THRESHOLD_H_ 13 14 #include <memory> 15 16 #include "absl/types/optional.h" 17 18 namespace webrtc { 19 20 class QualityThreshold { 21 public: 22 // Both thresholds are inclusive, i.e. measurement >= high signifies a high 23 // state, while measurement <= low signifies a low state. 24 QualityThreshold(int low_threshold, 25 int high_threshold, 26 float fraction, 27 int max_measurements); 28 ~QualityThreshold(); 29 30 void AddMeasurement(int measurement); 31 absl::optional<bool> IsHigh() const; 32 absl::optional<double> CalculateVariance() const; 33 absl::optional<double> FractionHigh(int min_required_samples) const; 34 35 private: 36 const std::unique_ptr<int[]> buffer_; 37 const int max_measurements_; 38 const float fraction_; 39 const int low_threshold_; 40 const int high_threshold_; 41 int until_full_; 42 int next_index_; 43 absl::optional<bool> is_high_; 44 int sum_; 45 int count_low_; 46 int count_high_; 47 int num_high_states_; 48 int num_certain_states_; 49 }; 50 51 } // namespace webrtc 52 53 #endif // VIDEO_QUALITY_THRESHOLD_H_ 54