1 /* 2 * Copyright (c) 2011 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 WEBRTC_MODULES_VIDEO_CODING_RTT_FILTER_H_ 12 #define WEBRTC_MODULES_VIDEO_CODING_RTT_FILTER_H_ 13 14 #include "webrtc/typedefs.h" 15 16 namespace webrtc { 17 18 class VCMRttFilter { 19 public: 20 VCMRttFilter(); 21 22 VCMRttFilter& operator=(const VCMRttFilter& rhs); 23 24 // Resets the filter. 25 void Reset(); 26 // Updates the filter with a new sample. 27 void Update(int64_t rttMs); 28 // A getter function for the current RTT level in ms. 29 int64_t RttMs() const; 30 31 private: 32 // The size of the drift and jump memory buffers 33 // and thus also the detection threshold for these 34 // detectors in number of samples. 35 enum { kMaxDriftJumpCount = 5 }; 36 // Detects RTT jumps by comparing the difference between 37 // samples and average to the standard deviation. 38 // Returns true if the long time statistics should be updated 39 // and false otherwise 40 bool JumpDetection(int64_t rttMs); 41 // Detects RTT drifts by comparing the difference between 42 // max and average to the standard deviation. 43 // Returns true if the long time statistics should be updated 44 // and false otherwise 45 bool DriftDetection(int64_t rttMs); 46 // Computes the short time average and maximum of the vector buf. 47 void ShortRttFilter(int64_t* buf, uint32_t length); 48 49 bool _gotNonZeroUpdate; 50 double _avgRtt; 51 double _varRtt; 52 int64_t _maxRtt; 53 uint32_t _filtFactCount; 54 const uint32_t _filtFactMax; 55 const double _jumpStdDevs; 56 const double _driftStdDevs; 57 int32_t _jumpCount; 58 int32_t _driftCount; 59 const int32_t _detectThreshold; 60 int64_t _jumpBuf[kMaxDriftJumpCount]; 61 int64_t _driftBuf[kMaxDriftJumpCount]; 62 }; 63 64 } // namespace webrtc 65 66 #endif // WEBRTC_MODULES_VIDEO_CODING_RTT_FILTER_H_ 67