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 19 class VCMRttFilter 20 { 21 public: 22 VCMRttFilter(); 23 24 VCMRttFilter& operator=(const VCMRttFilter& rhs); 25 26 // Resets the filter. 27 void Reset(); 28 // Updates the filter with a new sample. 29 void Update(uint32_t rttMs); 30 // A getter function for the current RTT level in ms. 31 uint32_t RttMs() const; 32 33 private: 34 // The size of the drift and jump memory buffers 35 // and thus also the detection threshold for these 36 // detectors in number of samples. 37 enum { kMaxDriftJumpCount = 5 }; 38 // Detects RTT jumps by comparing the difference between 39 // samples and average to the standard deviation. 40 // Returns true if the long time statistics should be updated 41 // and false otherwise 42 bool JumpDetection(uint32_t rttMs); 43 // Detects RTT drifts by comparing the difference between 44 // max and average to the standard deviation. 45 // Returns true if the long time statistics should be updated 46 // and false otherwise 47 bool DriftDetection(uint32_t rttMs); 48 // Computes the short time average and maximum of the vector buf. 49 void ShortRttFilter(uint32_t* buf, uint32_t length); 50 51 bool _gotNonZeroUpdate; 52 double _avgRtt; 53 double _varRtt; 54 uint32_t _maxRtt; 55 uint32_t _filtFactCount; 56 const uint32_t _filtFactMax; 57 const double _jumpStdDevs; 58 const double _driftStdDevs; 59 int32_t _jumpCount; 60 int32_t _driftCount; 61 const int32_t _detectThreshold; 62 uint32_t _jumpBuf[kMaxDriftJumpCount]; 63 uint32_t _driftBuf[kMaxDriftJumpCount]; 64 }; 65 66 } // namespace webrtc 67 68 #endif // WEBRTC_MODULES_VIDEO_CODING_RTT_FILTER_H_ 69