/* * Copyright (c) 2014 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 MODULES_PACING_BITRATE_PROBER_H_ #define MODULES_PACING_BITRATE_PROBER_H_ #include #include #include #include "api/transport/field_trial_based_config.h" #include "api/transport/network_types.h" #include "rtc_base/experiments/field_trial_parser.h" namespace webrtc { class RtcEventLog; struct BitrateProberConfig { explicit BitrateProberConfig(const FieldTrialsView* key_value_config); BitrateProberConfig(const BitrateProberConfig&) = default; BitrateProberConfig& operator=(const BitrateProberConfig&) = default; ~BitrateProberConfig() = default; // A minimum interval between probes to allow scheduling to be feasible. FieldTrialParameter min_probe_delta; // Maximum amount of time each probe can be delayed. FieldTrialParameter max_probe_delay; // This is used to start sending a probe after a large enough packet. // The min packet size is scaled with the bitrate we're probing at. // This defines the max min packet size, meaning that on high bitrates // a packet of at least this size is needed to trigger sending a probe. FieldTrialParameter min_packet_size; // If true, `min_packet_size` is ignored. bool allow_start_probing_immediately = false; }; // Note that this class isn't thread-safe by itself and therefore relies // on being protected by the caller. class BitrateProber { public: explicit BitrateProber(const FieldTrialsView& field_trials); ~BitrateProber() = default; void SetEnabled(bool enable); void SetAllowProbeWithoutMediaPacket(bool allow); // Returns true if the prober is in a probing session, i.e., it currently // wants packets to be sent out according to the time returned by // TimeUntilNextProbe(). bool is_probing() const { return probing_state_ == ProbingState::kActive; } // Initializes a new probing session if the prober is allowed to probe. Does // not initialize the prober unless the packet size is large enough to probe // with. void OnIncomingPacket(DataSize packet_size); // Create a cluster used to probe. void CreateProbeCluster(const ProbeClusterConfig& cluster_config); // Returns the time at which the next probe should be sent to get accurate // probing. If probing is not desired at this time, Timestamp::PlusInfinity() // will be returned. // TODO(bugs.webrtc.org/11780): Remove `now` argument when old mode is gone. Timestamp NextProbeTime(Timestamp now) const; // Information about the current probing cluster. absl::optional CurrentCluster(Timestamp now); // Returns the minimum number of bytes that the prober recommends for // the next probe, or zero if not probing. A probe can consist of multiple // packets that are sent back to back. DataSize RecommendedMinProbeSize() const; // Called to report to the prober that a probe has been sent. In case of // multiple packets per probe, this call would be made at the end of sending // the last packet in probe. `size` is the total size of all packets in probe. void ProbeSent(Timestamp now, DataSize size); private: enum class ProbingState { // Probing will not be triggered in this state at all times. kDisabled, // Probing is enabled and ready to trigger on the first packet arrival if // there is a probe cluster. kInactive, // Probe cluster is filled with the set of data rates to be probed and // probes are being sent. kActive, }; // A probe cluster consists of a set of probes. Each probe in turn can be // divided into a number of packets to accommodate the MTU on the network. struct ProbeCluster { PacedPacketInfo pace_info; int sent_probes = 0; int sent_bytes = 0; Timestamp requested_at = Timestamp::MinusInfinity(); Timestamp started_at = Timestamp::MinusInfinity(); int retries = 0; }; Timestamp CalculateNextProbeTime(const ProbeCluster& cluster) const; void MaybeSetActiveState(DataSize packet_size); bool ReadyToSetActiveState(DataSize packet_size) const; ProbingState probing_state_; // Probe bitrate per packet. These are used to compute the delta relative to // the previous probe packet based on the size and time when that packet was // sent. std::queue clusters_; // Time the next probe should be sent when in kActive state. Timestamp next_probe_time_; BitrateProberConfig config_; }; } // namespace webrtc #endif // MODULES_PACING_BITRATE_PROBER_H_