1/*
2 *  Copyright (c) 2013 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_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_
12#define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_
13
14#include <cstddef>
15
16#include "webrtc/base/constructormagic.h"
17#include "webrtc/typedefs.h"
18
19namespace webrtc {
20
21// Helper class to compute the inter-arrival time delta and the size delta
22// between two timestamp groups. A timestamp is a 32 bit unsigned number with
23// a client defined rate.
24class InterArrival {
25 public:
26  // A timestamp group is defined as all packets with a timestamp which are at
27  // most timestamp_group_length_ticks older than the first timestamp in that
28  // group.
29  InterArrival(uint32_t timestamp_group_length_ticks,
30               double timestamp_to_ms_coeff,
31               bool enable_burst_grouping);
32
33  // This function returns true if a delta was computed, or false if the current
34  // group is still incomplete or if only one group has been completed.
35  // |timestamp| is the timestamp.
36  // |arrival_time_ms| is the local time at which the packet arrived.
37  // |packet_size| is the size of the packet.
38  // |timestamp_delta| (output) is the computed timestamp delta.
39  // |arrival_time_delta_ms| (output) is the computed arrival-time delta.
40  // |packet_size_delta| (output) is the computed size delta.
41  bool ComputeDeltas(uint32_t timestamp,
42                     int64_t arrival_time_ms,
43                     size_t packet_size,
44                     uint32_t* timestamp_delta,
45                     int64_t* arrival_time_delta_ms,
46                     int* packet_size_delta);
47
48 private:
49  struct TimestampGroup {
50    TimestampGroup()
51        : size(0),
52          first_timestamp(0),
53          timestamp(0),
54          complete_time_ms(-1) {}
55
56    bool IsFirstPacket() const {
57      return complete_time_ms == -1;
58    }
59
60    size_t size;
61    uint32_t first_timestamp;
62    uint32_t timestamp;
63    int64_t complete_time_ms;
64  };
65
66  // Returns true if the packet with timestamp |timestamp| arrived in order.
67  bool PacketInOrder(uint32_t timestamp);
68
69  // Returns true if the last packet was the end of the current batch and the
70  // packet with |timestamp| is the first of a new batch.
71  bool NewTimestampGroup(int64_t arrival_time_ms, uint32_t timestamp) const;
72
73  bool BelongsToBurst(int64_t arrival_time_ms, uint32_t timestamp) const;
74
75  const uint32_t kTimestampGroupLengthTicks;
76  TimestampGroup current_timestamp_group_;
77  TimestampGroup prev_timestamp_group_;
78  double timestamp_to_ms_coeff_;
79  bool burst_grouping_;
80
81  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(InterArrival);
82};
83}  // namespace webrtc
84
85#endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_
86