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/*
* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef CALL_RECEIVE_TIME_CALCULATOR_H_
#define CALL_RECEIVE_TIME_CALCULATOR_H_
#include <stdint.h>
#include <memory>
#include "api/field_trials_view.h"
#include "api/units/time_delta.h"
#include "rtc_base/experiments/field_trial_parser.h"
namespace webrtc {
struct ReceiveTimeCalculatorConfig {
explicit ReceiveTimeCalculatorConfig(const FieldTrialsView& field_trials);
ReceiveTimeCalculatorConfig(const ReceiveTimeCalculatorConfig&);
ReceiveTimeCalculatorConfig& operator=(const ReceiveTimeCalculatorConfig&) =
default;
~ReceiveTimeCalculatorConfig();
FieldTrialParameter<TimeDelta> max_packet_time_repair;
FieldTrialParameter<TimeDelta> stall_threshold;
FieldTrialParameter<TimeDelta> tolerance;
FieldTrialParameter<TimeDelta> max_stall;
};
// The receive time calculator serves the purpose of combining packet time
// stamps with a safely incremental clock. This assumes that the packet time
// stamps are based on lower layer timestamps that have more accurate time
// increments since they are based on the exact receive time. They might
// however, have large jumps due to clock resets in the system. To compensate
// this they are combined with a safe clock source that is guaranteed to be
// consistent, but it will not be able to measure the exact time when a packet
// is received.
class ReceiveTimeCalculator {
public:
static std::unique_ptr<ReceiveTimeCalculator> CreateFromFieldTrial(
const FieldTrialsView& field_trials);
explicit ReceiveTimeCalculator(const FieldTrialsView& field_trials);
int64_t ReconcileReceiveTimes(int64_t packet_time_us_,
int64_t system_time_us_,
int64_t safe_time_us_);
private:
int64_t last_corrected_time_us_ = -1;
int64_t last_packet_time_us_ = -1;
int64_t last_system_time_us_ = -1;
int64_t last_safe_time_us_ = -1;
int64_t total_system_time_passed_us_ = 0;
int64_t static_clock_offset_us_ = 0;
int64_t small_reset_during_stall_ = false;
ReceiveTimeCalculatorConfig config_;
};
} // namespace webrtc
#endif // CALL_RECEIVE_TIME_CALCULATOR_H_
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