receive_time_calculator.h (2524B)
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 #ifndef CALL_RECEIVE_TIME_CALCULATOR_H_ 11 #define CALL_RECEIVE_TIME_CALCULATOR_H_ 12 13 #include <stdint.h> 14 15 #include <memory> 16 17 #include "api/field_trials_view.h" 18 #include "api/units/time_delta.h" 19 #include "rtc_base/experiments/field_trial_parser.h" 20 21 namespace webrtc { 22 23 struct ReceiveTimeCalculatorConfig { 24 explicit ReceiveTimeCalculatorConfig(const FieldTrialsView& field_trials); 25 ReceiveTimeCalculatorConfig(const ReceiveTimeCalculatorConfig&); 26 ReceiveTimeCalculatorConfig& operator=(const ReceiveTimeCalculatorConfig&) = 27 default; 28 ~ReceiveTimeCalculatorConfig(); 29 FieldTrialParameter<TimeDelta> max_packet_time_repair; 30 FieldTrialParameter<TimeDelta> stall_threshold; 31 FieldTrialParameter<TimeDelta> tolerance; 32 FieldTrialParameter<TimeDelta> max_stall; 33 }; 34 35 // The receive time calculator serves the purpose of combining packet time 36 // stamps with a safely incremental clock. This assumes that the packet time 37 // stamps are based on lower layer timestamps that have more accurate time 38 // increments since they are based on the exact receive time. They might 39 // however, have large jumps due to clock resets in the system. To compensate 40 // this they are combined with a safe clock source that is guaranteed to be 41 // consistent, but it will not be able to measure the exact time when a packet 42 // is received. 43 class ReceiveTimeCalculator { 44 public: 45 static std::unique_ptr<ReceiveTimeCalculator> CreateFromFieldTrial( 46 const FieldTrialsView& field_trials); 47 explicit ReceiveTimeCalculator(const FieldTrialsView& field_trials); 48 int64_t ReconcileReceiveTimes(int64_t packet_time_us_, 49 int64_t system_time_us_, 50 int64_t safe_time_us_); 51 52 private: 53 int64_t last_corrected_time_us_ = -1; 54 int64_t last_packet_time_us_ = -1; 55 int64_t last_system_time_us_ = -1; 56 int64_t last_safe_time_us_ = -1; 57 int64_t total_system_time_passed_us_ = 0; 58 int64_t static_clock_offset_us_ = 0; 59 int64_t small_reset_during_stall_ = false; 60 ReceiveTimeCalculatorConfig config_; 61 }; 62 } // namespace webrtc 63 #endif // CALL_RECEIVE_TIME_CALCULATOR_H_