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 MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_ 12 #define MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_ 13 14 #include <stddef.h> 15 #include <stdint.h> 16 17 #include "rtc_base/constructor_magic.h" 18 19 namespace 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. 24 class InterArrival { 25 public: 26 // After this many packet groups received out of order InterArrival will 27 // reset, assuming that clocks have made a jump. 28 static constexpr int kReorderedResetThreshold = 3; 29 static constexpr int64_t kArrivalTimeOffsetThresholdMs = 3000; 30 31 // A timestamp group is defined as all packets with a timestamp which are at 32 // most timestamp_group_length_ticks older than the first timestamp in that 33 // group. 34 InterArrival(uint32_t timestamp_group_length_ticks, 35 double timestamp_to_ms_coeff, 36 bool enable_burst_grouping); 37 38 // This function returns true if a delta was computed, or false if the current 39 // group is still incomplete or if only one group has been completed. 40 // |timestamp| is the timestamp. 41 // |arrival_time_ms| is the local time at which the packet arrived. 42 // |packet_size| is the size of the packet. 43 // |timestamp_delta| (output) is the computed timestamp delta. 44 // |arrival_time_delta_ms| (output) is the computed arrival-time delta. 45 // |packet_size_delta| (output) is the computed size delta. 46 bool ComputeDeltas(uint32_t timestamp, 47 int64_t arrival_time_ms, 48 int64_t system_time_ms, 49 size_t packet_size, 50 uint32_t* timestamp_delta, 51 int64_t* arrival_time_delta_ms, 52 int* packet_size_delta); 53 54 private: 55 struct TimestampGroup { TimestampGroupTimestampGroup56 TimestampGroup() 57 : size(0), 58 first_timestamp(0), 59 timestamp(0), 60 first_arrival_ms(-1), 61 complete_time_ms(-1) {} 62 IsFirstPacketTimestampGroup63 bool IsFirstPacket() const { return complete_time_ms == -1; } 64 65 size_t size; 66 uint32_t first_timestamp; 67 uint32_t timestamp; 68 int64_t first_arrival_ms; 69 int64_t complete_time_ms; 70 int64_t last_system_time_ms; 71 }; 72 73 // Returns true if the packet with timestamp |timestamp| arrived in order. 74 bool PacketInOrder(uint32_t timestamp); 75 76 // Returns true if the last packet was the end of the current batch and the 77 // packet with |timestamp| is the first of a new batch. 78 bool NewTimestampGroup(int64_t arrival_time_ms, uint32_t timestamp) const; 79 80 bool BelongsToBurst(int64_t arrival_time_ms, uint32_t timestamp) const; 81 82 void Reset(); 83 84 const uint32_t kTimestampGroupLengthTicks; 85 TimestampGroup current_timestamp_group_; 86 TimestampGroup prev_timestamp_group_; 87 double timestamp_to_ms_coeff_; 88 bool burst_grouping_; 89 int num_consecutive_reordered_packets_; 90 91 RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(InterArrival); 92 }; 93 } // namespace webrtc 94 95 #endif // MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_ 96