[feat] implementation for send side congestion controller

src/qos/delay_based_bwe.h

@@ -0,0 +1,115 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2025-01-14
+ * Copyright (c) 2025 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _DELAY_BASED_BWE_H_
+#define _DELAY_BASED_BWE_H_
+
+#include <stdint.h>
+
+#include <memory>
+#include <optional>
+#include <vector>
+
+#include "network_types.h"
+
+enum class BandwidthUsage {
+  kBwNormal = 0,
+  kBwUnderusing = 1,
+  kBwOverusing = 2,
+  kLast
+};
+
+struct BweSeparateAudioPacketsSettings {
+  static constexpr char kKey[] = "WebRTC-Bwe-SeparateAudioPackets";
+
+  BweSeparateAudioPacketsSettings() = default;
+  explicit BweSeparateAudioPacketsSettings(
+      const FieldTrialsView* key_value_config);
+
+  bool enabled = false;
+  int packet_threshold = 10;
+  int64_t time_threshold = int64_t::Seconds(1);
+
+  std::unique_ptr<StructParametersParser> Parser();
+};
+
+class DelayBasedBwe {
+ public:
+  struct Result {
+    Result();
+    ~Result() = default;
+    bool updated;
+    bool probe;
+    int64_t target_bitrate = int64_t::Zero();
+    bool recovered_from_overuse;
+    BandwidthUsage delay_detector_state;
+  };
+
+  explicit DelayBasedBwe(const FieldTrialsView* key_value_config,
+                         RtcEventLog* event_log,
+                         NetworkStatePredictor* network_state_predictor);
+
+  DelayBasedBwe() = delete;
+  DelayBasedBwe(const DelayBasedBwe&) = delete;
+  DelayBasedBwe& operator=(const DelayBasedBwe&) = delete;
+
+  virtual ~DelayBasedBwe();
+
+  Result IncomingPacketFeedbackVector(
+      const TransportPacketsFeedback& msg, std::optional<int64_t> acked_bitrate,
+      std::optional<int64_t> probe_bitrate,
+      std::optional<NetworkStateEstimate> network_estimate, bool in_alr);
+  void OnRttUpdate(int64_t avg_rtt);
+  bool LatestEstimate(std::vector<uint32_t>* ssrcs, int64_t* bitrate) const;
+  void SetStartBitrate(int64_t start_bitrate);
+  void SetMinBitrate(int64_t min_bitrate);
+  int64_t GetExpectedBwePeriod() const;
+  int64_t TriggerOveruse(int64_t at_time, std::optional<int64_t> link_capacity);
+  int64_t last_estimate() const { return prev_bitrate_; }
+  BandwidthUsage last_state() const { return prev_state_; }
+
+ private:
+  friend class GoogCcStatePrinter;
+  void IncomingPacketFeedback(const PacketResult& packet_feedback,
+                              int64_t at_time);
+  Result MaybeUpdateEstimate(std::optional<int64_t> acked_bitrate,
+                             std::optional<int64_t> probe_bitrate,
+                             std::optional<NetworkStateEstimate> state_estimate,
+                             bool recovered_from_overuse, bool in_alr,
+                             int64_t at_time);
+  // Updates the current remote rate estimate and returns true if a valid
+  // estimate exists.
+  bool UpdateEstimate(int64_t at_time, std::optional<int64_t> acked_bitrate,
+                      int64_t* target_rate);
+
+  rtc::RaceChecker network_race_;
+  RtcEventLog* const event_log_;
+  const FieldTrialsView* const key_value_config_;
+
+  // Alternatively, run two separate overuse detectors for audio and video,
+  // and fall back to the audio one if we haven't seen a video packet in a
+  // while.
+  BweSeparateAudioPacketsSettings separate_audio_;
+  int64_t audio_packets_since_last_video_;
+  int64_t last_video_packet_recv_time_;
+
+  NetworkStatePredictor* network_state_predictor_;
+  std::unique_ptr<InterArrival> video_inter_arrival_;
+  std::unique_ptr<InterArrivalDelta> video_inter_arrival_delta_;
+  std::unique_ptr<DelayIncreaseDetectorInterface> video_delay_detector_;
+  std::unique_ptr<InterArrival> audio_inter_arrival_;
+  std::unique_ptr<InterArrivalDelta> audio_inter_arrival_delta_;
+  std::unique_ptr<DelayIncreaseDetectorInterface> audio_delay_detector_;
+  DelayIncreaseDetectorInterface* active_delay_detector_;
+
+  int64_t last_seen_packet_;
+  bool uma_recorded_;
+  AimdRateControl rate_control_;
+  int64_t prev_bitrate_;
+  BandwidthUsage prev_state_;
+};
+
+#endif