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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 
11 #ifndef MODULES_CONGESTION_CONTROLLER_PCC_MONITOR_INTERVAL_H_
12 #define MODULES_CONGESTION_CONTROLLER_PCC_MONITOR_INTERVAL_H_
13 
14 #include <vector>
15 
16 #include "api/transport/network_types.h"
17 #include "api/units/data_rate.h"
18 #include "api/units/data_size.h"
19 #include "api/units/time_delta.h"
20 #include "api/units/timestamp.h"
21 
22 namespace webrtc {
23 namespace pcc {
24 
25 // PCC divides time into consecutive monitor intervals which are used to test
26 // consequences for performance of sending at a certain rate.
27 class PccMonitorInterval {
28  public:
29   PccMonitorInterval(DataRate target_sending_rate,
30                      Timestamp start_time,
31                      TimeDelta duration);
32   ~PccMonitorInterval();
33   PccMonitorInterval(const PccMonitorInterval& other);
34   void OnPacketsFeedback(const std::vector<PacketResult>& packets_results);
35   // Returns true if got complete information about packets.
36   // Notice, this only happens when received feedback about the first packet
37   // which were sent after the end of the monitor interval. If such event
38   // doesn't occur, we don't mind anyway and stay in the same state.
39   bool IsFeedbackCollectionDone() const;
40   Timestamp GetEndTime() const;
41 
42   double GetLossRate() const;
43   // Estimates the gradient using linear regression on the 2-dimensional
44   // dataset (sampled packets delay, time of sampling).
45   double ComputeDelayGradient(double delay_gradient_threshold) const;
46   DataRate GetTargetSendingRate() const;
47   // How fast receiving side gets packets.
48   DataRate GetTransmittedPacketsRate() const;
49 
50  private:
51   struct ReceivedPacket {
52     TimeDelta delay;
53     Timestamp sent_time;
54   };
55   // Target bitrate used to generate and pace the outgoing packets.
56   // Actually sent bitrate might not match the target exactly.
57   DataRate target_sending_rate_;
58   // Start time is not included into interval while end time is included.
59   Timestamp start_time_;
60   TimeDelta interval_duration_;
61   // Vectors below updates while receiving feedback.
62   std::vector<ReceivedPacket> received_packets_;
63   std::vector<Timestamp> lost_packets_sent_time_;
64   DataSize received_packets_size_;
65   bool feedback_collection_done_;
66 };
67 
68 }  // namespace pcc
69 }  // namespace webrtc
70 
71 #endif  // MODULES_CONGESTION_CONTROLLER_PCC_MONITOR_INTERVAL_H_
72