1 /* 2 * Copyright (c) 2014 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_PACING_BITRATE_PROBER_H_ 12 #define WEBRTC_MODULES_PACING_BITRATE_PROBER_H_ 13 14 #include <queue> 15 16 #include "webrtc/base/basictypes.h" 17 #include "webrtc/typedefs.h" 18 19 namespace webrtc { 20 21 // Note that this class isn't thread-safe by itself and therefore relies 22 // on being protected by the caller. 23 class BitrateProber { 24 public: 25 BitrateProber(); 26 27 void SetEnabled(bool enable); 28 29 // Returns true if the prober is in a probing session, i.e., it currently 30 // wants packets to be sent out according to the time returned by 31 // TimeUntilNextProbe(). 32 bool IsProbing() const; 33 34 // Initializes a new probing session if the prober is allowed to probe. Does 35 // not initialize the prober unless the packet size is large enough to probe 36 // with. 37 void OnIncomingPacket(size_t packet_size); 38 39 // Create a cluster used to probe for |bitrate_bps| with |num_probes| number 40 // of probes. 41 void CreateProbeCluster(int bitrate_bps); 42 43 // Returns the number of milliseconds until the next probe should be sent to 44 // get accurate probing. 45 int TimeUntilNextProbe(int64_t now_ms); 46 47 // Which cluster that is currently being used for probing. 48 int CurrentClusterId() const; 49 50 // Returns the minimum number of bytes that the prober recommends for 51 // the next probe. 52 size_t RecommendedMinProbeSize() const; 53 54 // Called to report to the prober that a probe has been sent. In case of 55 // multiple packets per probe, this call would be made at the end of sending 56 // the last packet in probe. |probe_size| is the total size of all packets 57 // in probe. 58 void ProbeSent(int64_t now_ms, size_t probe_size); 59 60 private: 61 enum class ProbingState { 62 // Probing will not be triggered in this state at all times. 63 kDisabled, 64 // Probing is enabled and ready to trigger on the first packet arrival. 65 kInactive, 66 // Probe cluster is filled with the set of data rates to be probed and 67 // probes are being sent. 68 kActive, 69 // Probing is enabled, but currently suspended until an explicit trigger 70 // to start probing again. 71 kSuspended, 72 }; 73 74 // A probe cluster consists of a set of probes. Each probe in turn can be 75 // divided into a number of packets to accomodate the MTU on the network. 76 struct ProbeCluster { 77 int min_probes = 0; 78 int sent_probes = 0; 79 int min_bytes = 0; 80 int sent_bytes = 0; 81 int bitrate_bps = 0; 82 int id = -1; 83 }; 84 85 // Resets the state of the prober and clears any cluster/timing data tracked. 86 void ResetState(); 87 88 ProbingState probing_state_; 89 // Probe bitrate per packet. These are used to compute the delta relative to 90 // the previous probe packet based on the size and time when that packet was 91 // sent. 92 std::queue<ProbeCluster> clusters_; 93 // A probe can include one or more packets. 94 size_t probe_size_last_sent_; 95 // The last time a probe was sent. 96 int64_t time_last_probe_sent_ms_; 97 int next_cluster_id_; 98 }; 99 } // namespace webrtc 100 #endif // WEBRTC_MODULES_PACING_BITRATE_PROBER_H_ 101