[fix] fix congestion control module

src/common/api/media_types.h

@@ -0,0 +1,42 @@
+/*
+ *  Copyright 2016 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 API_MEDIA_TYPES_H_
+#define API_MEDIA_TYPES_H_
+
+#include <string>
+
+// The cricket and webrtc have separate definitions for what a media type is.
+// They're not compatible. Watch out for this.
+
+namespace cricket {
+
+enum MediaType {
+  MEDIA_TYPE_AUDIO,
+  MEDIA_TYPE_VIDEO,
+  MEDIA_TYPE_DATA,
+  MEDIA_TYPE_UNSUPPORTED
+};
+
+extern const char kMediaTypeAudio[];
+extern const char kMediaTypeVideo[];
+extern const char kMediaTypeData[];
+
+std::string MediaTypeToString(MediaType type);
+
+}  // namespace cricket
+
+namespace webrtc {
+
+enum class MediaType { ANY, AUDIO, VIDEO, DATA };
+
+}  // namespace webrtc
+
+#endif  // API_MEDIA_TYPES_H_

src/common/api/network_state_predictor.h

@@ -0,0 +1,51 @@
+/*
+ *  Copyright (c) 2019 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 API_NETWORK_STATE_PREDICTOR_H_
+#define API_NETWORK_STATE_PREDICTOR_H_
+
+#include <cstdint>
+#include <memory>
+
+#include "api/transport/bandwidth_usage.h"
+
+namespace webrtc {
+
+// TODO(yinwa): work in progress. API in class NetworkStatePredictor should not
+// be used by other users until this comment is removed.
+
+// NetworkStatePredictor predict network state based on current network metrics.
+// Usage:
+// Setup by calling Initialize.
+// For each update, call Update. Update returns network state
+// prediction.
+class NetworkStatePredictor {
+ public:
+  virtual ~NetworkStatePredictor() {}
+
+  // Returns current network state prediction.
+  // Inputs:  send_time_ms - packet send time.
+  //          arrival_time_ms - packet arrival time.
+  //          network_state - computed network state.
+  virtual BandwidthUsage Update(int64_t send_time_ms,
+                                int64_t arrival_time_ms,
+                                BandwidthUsage network_state) = 0;
+};
+
+class NetworkStatePredictorFactoryInterface {
+ public:
+  virtual std::unique_ptr<NetworkStatePredictor>
+  CreateNetworkStatePredictor() = 0;
+  virtual ~NetworkStatePredictorFactoryInterface() = default;
+};
+
+}  // namespace webrtc
+
+#endif  // API_NETWORK_STATE_PREDICTOR_H_

src/common/api/transport/network_control.h

@@ -0,0 +1,124 @@
+/*
+ *  Copyright (c) 2018 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 API_TRANSPORT_NETWORK_CONTROL_H_
+#define API_TRANSPORT_NETWORK_CONTROL_H_
+
+#include <memory>
+#include <optional>
+
+#include "api/transport/network_types.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+
+namespace webrtc {
+
+class TargetTransferRateObserver {
+ public:
+  virtual ~TargetTransferRateObserver() = default;
+  // Called to indicate target transfer rate as well as giving information about
+  // the current estimate of network parameters.
+  virtual void OnTargetTransferRate(TargetTransferRate) = 0;
+  // Called to provide updates to the expected target rate in case it changes
+  // before the first call to OnTargetTransferRate.
+  virtual void OnStartRateUpdate(DataRate) {}
+};
+
+// Configuration sent to factory create function. The parameters here are
+// optional to use for a network controller implementation.
+struct NetworkControllerConfig {
+  explicit NetworkControllerConfig() {}
+
+  // The initial constraints to start with, these can be changed at any later
+  // time by calls to OnTargetRateConstraints. Note that the starting rate
+  // has to be set initially to provide a starting state for the network
+  // controller, even though the field is marked as optional.
+  TargetRateConstraints constraints;
+  // Initial stream specific configuration, these are changed at any later time
+  // by calls to OnStreamsConfig.
+  StreamsConfig stream_based_config;
+};
+
+// NetworkControllerInterface is implemented by network controllers. A network
+// controller is a class that uses information about network state and traffic
+// to estimate network parameters such as round trip time and bandwidth. Network
+// controllers does not guarantee thread safety, the interface must be used in a
+// non-concurrent fashion.
+class NetworkControllerInterface {
+ public:
+  virtual ~NetworkControllerInterface() = default;
+
+  // Called when network availabilty changes.
+  virtual NetworkControlUpdate OnNetworkAvailability(NetworkAvailability) = 0;
+  // Called when the receiving or sending endpoint changes address.
+  virtual NetworkControlUpdate OnNetworkRouteChange(NetworkRouteChange) = 0;
+  // Called periodically with a periodicy as specified by
+  // NetworkControllerFactoryInterface::GetProcessInterval.
+  virtual NetworkControlUpdate OnProcessInterval(ProcessInterval) = 0;
+  // Called when remotely calculated bitrate is received.
+  virtual NetworkControlUpdate OnRemoteBitrateReport(RemoteBitrateReport) = 0;
+  // Called round trip time has been calculated by protocol specific mechanisms.
+  virtual NetworkControlUpdate OnRoundTripTimeUpdate(RoundTripTimeUpdate) = 0;
+  // Called when a packet is sent on the network.
+  virtual NetworkControlUpdate OnSentPacket(SentPacket) = 0;
+  // Called when a packet is received from the remote client.
+  virtual NetworkControlUpdate OnReceivedPacket(ReceivedPacket) = 0;
+  // Called when the stream specific configuration has been updated.
+  virtual NetworkControlUpdate OnStreamsConfig(StreamsConfig) = 0;
+  // Called when target transfer rate constraints has been changed.
+  virtual NetworkControlUpdate OnTargetRateConstraints(
+      TargetRateConstraints) = 0;
+  // Called when a protocol specific calculation of packet loss has been made.
+  virtual NetworkControlUpdate OnTransportLossReport(TransportLossReport) = 0;
+  // Called with per packet feedback regarding receive time.
+  virtual NetworkControlUpdate OnTransportPacketsFeedback(
+      TransportPacketsFeedback) = 0;
+  // Called with network state estimate updates.
+  virtual NetworkControlUpdate OnNetworkStateEstimate(NetworkStateEstimate) = 0;
+};
+
+// NetworkControllerFactoryInterface is an interface for creating a network
+// controller.
+class NetworkControllerFactoryInterface {
+ public:
+  virtual ~NetworkControllerFactoryInterface() = default;
+
+  // Used to create a new network controller, requires an observer to be
+  // provided to handle callbacks.
+  virtual std::unique_ptr<NetworkControllerInterface> Create(
+      NetworkControllerConfig config) = 0;
+  // Returns the interval by which the network controller expects
+  // OnProcessInterval calls.
+  virtual TimeDelta GetProcessInterval() const = 0;
+};
+
+// Under development, subject to change without notice.
+class NetworkStateEstimator {
+ public:
+  // Gets the current best estimate according to the estimator.
+  virtual std::optional<NetworkStateEstimate> GetCurrentEstimate() = 0;
+  // Called with per packet feedback regarding receive time.
+  // Used when the NetworkStateEstimator runs in the sending endpoint.
+  virtual void OnTransportPacketsFeedback(const TransportPacketsFeedback&) = 0;
+  // Called with per packet feedback regarding receive time.
+  // Used when the NetworkStateEstimator runs in the receiving endpoint.
+  virtual void OnReceivedPacket(const PacketResult&) {}
+  // Called when the receiving or sending endpoint changes address.
+  virtual void OnRouteChange(const NetworkRouteChange&) = 0;
+  virtual ~NetworkStateEstimator() = default;
+};
+class NetworkStateEstimatorFactory {
+ public:
+  virtual std::unique_ptr<NetworkStateEstimator> Create() = 0;
+  virtual ~NetworkStateEstimatorFactory() = default;
+};
+}  // namespace webrtc
+
+#endif  // API_TRANSPORT_NETWORK_CONTROL_H_

src/common/rtc_base/bitrate_tracker.cc

@@ -0,0 +1,39 @@
+/*
+ *  Copyright (c) 2023 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.
+ */
+
+#include "rtc_base/bitrate_tracker.h"
+
+#include <optional>
+
+#include "api/units/data_rate.h"
+#include "api/units/timestamp.h"
+#include "rtc_base/rate_statistics.h"
+
+namespace webrtc {
+
+BitrateTracker::BitrateTracker(TimeDelta max_window_size)
+    : impl_(max_window_size.ms(), RateStatistics::kBpsScale) {}
+
+std::optional<DataRate> BitrateTracker::Rate(Timestamp now) const {
+  if (std::optional<int64_t> rate = impl_.Rate(now.ms())) {
+    return DataRate::BitsPerSec(*rate);
+  }
+  return std::nullopt;
+}
+
+bool BitrateTracker::SetWindowSize(TimeDelta window_size, Timestamp now) {
+  return impl_.SetWindowSize(window_size.ms(), now.ms());
+}
+
+void BitrateTracker::Update(int64_t bytes, Timestamp now) {
+  impl_.Update(bytes, now.ms());
+}
+
+}  // namespace webrtc

src/common/rtc_base/bitrate_tracker.h

@@ -0,0 +1,64 @@
+/*
+ *  Copyright (c) 2023 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 RTC_BASE_BITRATE_TRACKER_H_
+#define RTC_BASE_BITRATE_TRACKER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <optional>
+
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "rtc_base/rate_statistics.h"
+
+namespace webrtc {
+// Class to estimate bitrates over running window.
+// Timestamps used in Update(), Rate() and SetWindowSize() must never
+// decrease for two consecutive calls.
+// This class is thread unsafe.
+class BitrateTracker {
+ public:
+  // max_window_sizes = Maximum window size for the rate estimation.
+  //                    Initial window size is set to this, but may be changed
+  //                    to something lower by calling SetWindowSize().
+  explicit BitrateTracker(TimeDelta max_window_size);
+
+  BitrateTracker(const BitrateTracker&) = default;
+  BitrateTracker(BitrateTracker&&) = default;
+  BitrateTracker& operator=(const BitrateTracker&) = delete;
+  BitrateTracker& operator=(BitrateTracker&&) = delete;
+
+  ~BitrateTracker() = default;
+
+  // Resets instance to original state.
+  void Reset() { impl_.Reset(); }
+
+  // Updates bitrate with a new data point, moving averaging window as needed.
+  void Update(int64_t bytes, Timestamp now);
+  void Update(DataSize size, Timestamp now) { Update(size.bytes(), now); }
+
+  // Returns bitrate, moving averaging window as needed.
+  // Returns nullopt when bitrate can't be measured.
+  std::optional<DataRate> Rate(Timestamp now) const;
+
+  // Update the size of the averaging window. The maximum allowed value for
+  // `window_size` is `max_window_size` as supplied in the constructor.
+  bool SetWindowSize(TimeDelta window_size, Timestamp now);
+
+ private:
+  RateStatistics impl_;
+};
+}  // namespace webrtc
+
+#endif  // RTC_BASE_BITRATE_TRACKER_H_

src/common/rtc_base/rate_statistics.cc

@@ -0,0 +1,160 @@
+/*
+ *  Copyright (c) 2013 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.
+ */
+
+#include "rtc_base/rate_statistics.h"
+
+#include <algorithm>
+#include <limits>
+#include <memory>
+
+#include "log.h"
+#include "rtc_base/numerics/safe_conversions.h"
+
+namespace webrtc {
+
+RateStatistics::Bucket::Bucket(int64_t timestamp)
+    : sum(0), num_samples(0), timestamp(timestamp) {}
+
+RateStatistics::RateStatistics(int64_t window_size_ms, float scale)
+    : accumulated_count_(0),
+      first_timestamp_(-1),
+      num_samples_(0),
+      scale_(scale),
+      max_window_size_ms_(window_size_ms),
+      current_window_size_ms_(max_window_size_ms_) {}
+
+RateStatistics::RateStatistics(const RateStatistics& other)
+    : buckets_(other.buckets_),
+      accumulated_count_(other.accumulated_count_),
+      first_timestamp_(other.first_timestamp_),
+      overflow_(other.overflow_),
+      num_samples_(other.num_samples_),
+      scale_(other.scale_),
+      max_window_size_ms_(other.max_window_size_ms_),
+      current_window_size_ms_(other.current_window_size_ms_) {}
+
+RateStatistics::RateStatistics(RateStatistics&& other) = default;
+
+RateStatistics::~RateStatistics() {}
+
+void RateStatistics::Reset() {
+  accumulated_count_ = 0;
+  overflow_ = false;
+  num_samples_ = 0;
+  first_timestamp_ = -1;
+  current_window_size_ms_ = max_window_size_ms_;
+  buckets_.clear();
+}
+
+void RateStatistics::Update(int64_t count, int64_t now_ms) {
+  // Don't reset `first_timestamp_` if the last sample removed by EraseOld() was
+  // recent. This ensures that the window maintains its intended duration even
+  // when samples are received near the boundary. Use a margin of 50% of the
+  // current window size.
+  const int64_t recent_sample_time_margin = 1.5 * current_window_size_ms_;
+  bool last_sample_is_recent =
+      !buckets_.empty() &&
+      buckets_.back().timestamp > now_ms - recent_sample_time_margin;
+
+  EraseOld(now_ms);
+  if (first_timestamp_ == -1 || (num_samples_ == 0 && !last_sample_is_recent)) {
+    first_timestamp_ = now_ms;
+  }
+
+  if (buckets_.empty() || now_ms != buckets_.back().timestamp) {
+    if (!buckets_.empty() && now_ms < buckets_.back().timestamp) {
+      LOG_WARN(
+          "Timestamp {} is before the last added timestamp in the rate window: "
+          "{}, aligning to that.",
+          now_ms, buckets_.back().timestamp);
+      now_ms = buckets_.back().timestamp;
+    }
+    buckets_.emplace_back(now_ms);
+  }
+  Bucket& last_bucket = buckets_.back();
+  last_bucket.sum += count;
+  ++last_bucket.num_samples;
+
+  if (std::numeric_limits<int64_t>::max() - accumulated_count_ > count) {
+    accumulated_count_ += count;
+  } else {
+    overflow_ = true;
+  }
+  ++num_samples_;
+}
+
+std::optional<int64_t> RateStatistics::Rate(int64_t now_ms) const {
+  // Yeah, this const_cast ain't pretty, but the alternative is to declare most
+  // of the members as mutable...
+  const_cast<RateStatistics*>(this)->EraseOld(now_ms);
+
+  int active_window_size = 0;
+  if (first_timestamp_ != -1) {
+    if (first_timestamp_ <= now_ms - current_window_size_ms_) {
+      // Count window as full even if no data points currently in view, if the
+      // data stream started before the window.
+      active_window_size = current_window_size_ms_;
+    } else {
+      // Size of a single bucket is 1ms, so even if now_ms == first_timestmap_
+      // the window size should be 1.
+      active_window_size = now_ms - first_timestamp_ + 1;
+    }
+  }
+
+  // If window is a single bucket or there is only one sample in a data set that
+  // has not grown to the full window size, or if the accumulator has
+  // overflowed, treat this as rate unavailable.
+  if (num_samples_ == 0 || active_window_size <= 1 ||
+      (num_samples_ <= 1 &&
+       rtc::SafeLt(active_window_size, current_window_size_ms_)) ||
+      overflow_) {
+    return std::nullopt;
+  }
+
+  float scale = static_cast<float>(scale_) / active_window_size;
+  float result = accumulated_count_ * scale + 0.5f;
+
+  // Better return unavailable rate than garbage value (undefined behavior).
+  if (result > static_cast<float>(std::numeric_limits<int64_t>::max())) {
+    return std::nullopt;
+  }
+  return rtc::dchecked_cast<int64_t>(result);
+}
+
+void RateStatistics::EraseOld(int64_t now_ms) {
+  // New oldest time that is included in data set.
+  const int64_t new_oldest_time = now_ms - current_window_size_ms_ + 1;
+
+  // Loop over buckets and remove too old data points.
+  while (!buckets_.empty() && buckets_.front().timestamp < new_oldest_time) {
+    const Bucket& oldest_bucket = buckets_.front();
+    accumulated_count_ -= oldest_bucket.sum;
+    num_samples_ -= oldest_bucket.num_samples;
+    buckets_.pop_front();
+    // This does not clear overflow_ even when counter is empty.
+    // TODO(https://bugs.webrtc.org/11247): Consider if overflow_ can be reset.
+  }
+}
+
+bool RateStatistics::SetWindowSize(int64_t window_size_ms, int64_t now_ms) {
+  if (window_size_ms <= 0 || window_size_ms > max_window_size_ms_) return false;
+  if (first_timestamp_ != -1) {
+    // If the window changes (e.g. decreases - removing data point, then
+    // increases again) we need to update the first timestamp mark as
+    // otherwise it indicates the window coveres a region of zeros, suddenly
+    // under-estimating the rate.
+    first_timestamp_ = std::max(first_timestamp_, now_ms - window_size_ms + 1);
+  }
+  current_window_size_ms_ = window_size_ms;
+  EraseOld(now_ms);
+  return true;
+}
+
+}  // namespace webrtc

src/common/rtc_base/rate_statistics.h

@@ -0,0 +1,103 @@
+/*
+ *  Copyright (c) 2013 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 RTC_BASE_RATE_STATISTICS_H_
+#define RTC_BASE_RATE_STATISTICS_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <deque>
+#include <memory>
+#include <optional>
+
+namespace webrtc {
+
+// Class to estimate rates based on counts in a sequence of 1-millisecond
+// intervals.
+
+// This class uses int64 for all its numbers because some rates can be very
+// high; for instance, a 20 Mbit/sec video stream can wrap a 32-bit byte
+// counter in 14 minutes.
+
+// Note that timestamps used in Update(), Rate() and SetWindowSize() must never
+// decrease for two consecutive calls.
+// TODO(bugs.webrtc.org/11600): Migrate from int64_t to Timestamp.
+
+class RateStatistics {
+ public:
+  static constexpr float kBpsScale = 8000.0f;
+
+  // max_window_size_ms = Maximum window size in ms for the rate estimation.
+  //                      Initial window size is set to this, but may be changed
+  //                      to something lower by calling SetWindowSize().
+  // scale = coefficient to convert counts/ms to desired unit
+  //         ex: kBpsScale (8000) for bits/s if count represents bytes.
+  RateStatistics(int64_t max_window_size_ms, float scale);
+
+  RateStatistics(const RateStatistics& other);
+
+  RateStatistics(RateStatistics&& other);
+
+  ~RateStatistics();
+
+  // Reset instance to original state.
+  void Reset();
+
+  // Update rate with a new data point, moving averaging window as needed.
+  void Update(int64_t count, int64_t now_ms);
+
+  // Note that despite this being a const method, it still updates the internal
+  // state (moves averaging window), but it doesn't make any alterations that
+  // are observable from the other methods, as long as supplied timestamps are
+  // from a monotonic clock. Ie, it doesn't matter if this call moves the
+  // window, since any subsequent call to Update or Rate would still have moved
+  // the window as much or more.
+  std::optional<int64_t> Rate(int64_t now_ms) const;
+
+  // Update the size of the averaging window. The maximum allowed value for
+  // window_size_ms is max_window_size_ms as supplied in the constructor.
+  bool SetWindowSize(int64_t window_size_ms, int64_t now_ms);
+
+ private:
+  void EraseOld(int64_t now_ms);
+
+  struct Bucket {
+    explicit Bucket(int64_t timestamp);
+    int64_t sum;              // Sum of all samples in this bucket.
+    int num_samples;          // Number of samples in this bucket.
+    const int64_t timestamp;  // Timestamp this bucket corresponds to.
+  };
+  // All buckets within the time window, ordered by time.
+  std::deque<Bucket> buckets_;
+
+  // Total count recorded in all buckets.
+  int64_t accumulated_count_;
+
+  // Timestamp of the first data point seen, or -1 of none seen.
+  int64_t first_timestamp_;
+
+  // True if accumulated_count_ has ever grown too large to be
+  // contained in its integer type.
+  bool overflow_ = false;
+
+  // The total number of samples in the buckets.
+  int num_samples_;
+
+  // To convert counts/ms to desired units
+  const float scale_;
+
+  // The window sizes, in ms, over which the rate is calculated.
+  const int64_t max_window_size_ms_;
+  int64_t current_window_size_ms_;
+};
+}  // namespace webrtc
+
+#endif  // RTC_BASE_RATE_STATISTICS_H_

src/common/rtc_base/thread_annotations.h

@@ -0,0 +1,98 @@
+//
+// Copyright (c) 2013 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.
+//
+// Borrowed from
+// https://code.google.com/p/gperftools/source/browse/src/base/thread_annotations.h
+// but adapted for clang attributes instead of the gcc.
+//
+// This header file contains the macro definitions for thread safety
+// annotations that allow the developers to document the locking policies
+// of their multi-threaded code. The annotations can also help program
+// analysis tools to identify potential thread safety issues.
+
+#ifndef RTC_BASE_THREAD_ANNOTATIONS_H_
+#define RTC_BASE_THREAD_ANNOTATIONS_H_
+
+#if defined(__clang__) && (!defined(SWIG))
+#define RTC_THREAD_ANNOTATION_ATTRIBUTE__(x) __attribute__((x))
+#else
+#define RTC_THREAD_ANNOTATION_ATTRIBUTE__(x)  // no-op
+#endif
+
+// Document if a shared variable/field needs to be protected by a lock.
+// GUARDED_BY allows the user to specify a particular lock that should be
+// held when accessing the annotated variable.
+#define RTC_GUARDED_BY(x) RTC_THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))
+
+// Document if the memory location pointed to by a pointer should be guarded
+// by a lock when dereferencing the pointer. Note that a pointer variable to a
+// shared memory location could itself be a shared variable. For example, if a
+// shared global pointer q, which is guarded by mu1, points to a shared memory
+// location that is guarded by mu2, q should be annotated as follows:
+//     int *q GUARDED_BY(mu1) PT_GUARDED_BY(mu2);
+#define RTC_PT_GUARDED_BY(x) RTC_THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_by(x))
+
+// Document the acquisition order between locks that can be held
+// simultaneously by a thread. For any two locks that need to be annotated
+// to establish an acquisition order, only one of them needs the annotation.
+// (i.e. You don't have to annotate both locks with both ACQUIRED_AFTER
+// and ACQUIRED_BEFORE.)
+#define RTC_ACQUIRED_AFTER(x) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(x))
+#define RTC_ACQUIRED_BEFORE(x) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(x))
+
+// The following three annotations document the lock requirements for
+// functions/methods.
+
+// Document if a function expects certain locks to be held before it is called
+#define RTC_EXCLUSIVE_LOCKS_REQUIRED(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(exclusive_locks_required(__VA_ARGS__))
+#define RTC_SHARED_LOCKS_REQUIRED(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(shared_locks_required(__VA_ARGS__))
+
+// Document the locks acquired in the body of the function. These locks
+// cannot be held when calling this function (as google3's Mutex locks are
+// non-reentrant).
+#define RTC_LOCKS_EXCLUDED(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(__VA_ARGS__))
+
+// Document the lock the annotated function returns without acquiring it.
+#define RTC_LOCK_RETURNED(x) RTC_THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))
+
+// Document if a class/type is a lockable type (such as the Mutex class).
+#define RTC_LOCKABLE RTC_THREAD_ANNOTATION_ATTRIBUTE__(lockable)
+
+// Document if a class is a scoped lockable type (such as the MutexLock class).
+#define RTC_SCOPED_LOCKABLE RTC_THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)
+
+// The following annotations specify lock and unlock primitives.
+#define RTC_EXCLUSIVE_LOCK_FUNCTION(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(exclusive_lock_function(__VA_ARGS__))
+
+#define RTC_SHARED_LOCK_FUNCTION(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(shared_lock_function(__VA_ARGS__))
+
+#define RTC_EXCLUSIVE_TRYLOCK_FUNCTION(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(exclusive_trylock_function(__VA_ARGS__))
+
+#define RTC_SHARED_TRYLOCK_FUNCTION(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(shared_trylock_function(__VA_ARGS__))
+
+#define RTC_UNLOCK_FUNCTION(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(unlock_function(__VA_ARGS__))
+
+#define RTC_ASSERT_EXCLUSIVE_LOCK(...) \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(assert_exclusive_lock(__VA_ARGS__))
+
+// An escape hatch for thread safety analysis to ignore the annotated function.
+#define RTC_NO_THREAD_SAFETY_ANALYSIS \
+  RTC_THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)
+
+#endif  // RTC_BASE_THREAD_ANNOTATIONS_H_

src/qos/acknowledged_bitrate_estimator.cc

@@ -16,10 +16,10 @@
 #include <utility>
 #include <vector>
 
+#include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "api/units/data_size.h"
 #include "api/units/timestamp.h"
-#include "network_types.h"
 
 namespace webrtc {
 

src/qos/acknowledged_bitrate_estimator.h

@@ -15,10 +15,10 @@
 #include <optional>
 #include <vector>
 
+#include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "api/units/timestamp.h"
 #include "bitrate_estimator.h"
-#include "network_types.h"
 
 namespace webrtc {
 

src/qos/acknowledged_bitrate_estimator_interface.h

@@ -0,0 +1,78 @@
+/*
+ *  Copyright (c) 2019 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_CONGESTION_CONTROLLER_GOOG_CC_ACKNOWLEDGED_BITRATE_ESTIMATOR_INTERFACE_H_
+#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_ACKNOWLEDGED_BITRATE_ESTIMATOR_INTERFACE_H_
+
+#include <memory>
+#include <optional>
+#include <vector>
+
+#include "api/transport/network_types.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+
+namespace webrtc {
+
+struct RobustThroughputEstimatorSettings {
+  static constexpr char kKey[] = "WebRTC-Bwe-RobustThroughputEstimatorSettings";
+
+  RobustThroughputEstimatorSettings();
+
+  // Set `enabled` to true to use the RobustThroughputEstimator, false to use
+  // the AcknowledgedBitrateEstimator.
+  bool enabled = true;
+
+  // The estimator keeps the smallest window containing at least
+  // `window_packets` and at least the packets received during the last
+  // `min_window_duration` milliseconds.
+  // (This means that it may store more than `window_packets` at high bitrates,
+  // and a longer duration than `min_window_duration` at low bitrates.)
+  // However, if will never store more than kMaxPackets (for performance
+  // reasons), and never longer than max_window_duration (to avoid very old
+  // packets influencing the estimate for example when sending is paused).
+  unsigned window_packets = 20;
+  unsigned max_window_packets = 500;
+  TimeDelta min_window_duration = TimeDelta::Seconds(1);
+  TimeDelta max_window_duration = TimeDelta::Seconds(5);
+
+  // The estimator window requires at least `required_packets` packets
+  // to produce an estimate.
+  unsigned required_packets = 10;
+
+  // If audio packets aren't included in allocation (i.e. the
+  // estimated available bandwidth is divided only among the video
+  // streams), then `unacked_weight` should be set to 0.
+  // If audio packets are included in allocation, but not in bandwidth
+  // estimation (i.e. they don't have transport-wide sequence numbers,
+  // but we nevertheless divide the estimated available bandwidth among
+  // both audio and video streams), then `unacked_weight` should be set to 1.
+  // If all packets have transport-wide sequence numbers, then the value
+  // of `unacked_weight` doesn't matter.
+  double unacked_weight = 1.0;
+};
+
+class AcknowledgedBitrateEstimatorInterface {
+ public:
+  static std::unique_ptr<AcknowledgedBitrateEstimatorInterface> Create();
+  virtual ~AcknowledgedBitrateEstimatorInterface();
+
+  virtual void IncomingPacketFeedbackVector(
+      const std::vector<PacketResult>& packet_feedback_vector) = 0;
+  virtual std::optional<DataRate> bitrate() const = 0;
+  virtual std::optional<DataRate> PeekRate() const = 0;
+  virtual void SetAlr(bool in_alr) = 0;
+  virtual void SetAlrEndedTime(Timestamp alr_ended_time) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_CONGESTION_CONTROLLER_GOOG_CC_ACKNOWLEDGED_BITRATE_ESTIMATOR_INTERFACE_H_

src/qos/aimd_rate_control.cc

@@ -17,9 +17,9 @@
 #include <cstdio>
 #include <string>
 
+#include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "log.h"
-#include "network_types.h"
 #include "overuse_detector.h"
 #include "rtc_base/numerics/safe_minmax.h"
 

src/qos/aimd_rate_control.h

@@ -15,11 +15,11 @@
 
 #include <optional>
 
+#include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "api/units/timestamp.h"
 #include "bwe_defines.h"
 #include "link_capacity_estimator.h"
-#include "network_types.h"
 
 namespace webrtc {
 // A rate control implementation based on additive increases of
@@ -98,7 +98,7 @@ class AimdRateControl {
   const bool send_side_;
   // Allow the delay based estimate to only increase as long as application
   // limited region (alr) is not detected.
-  const bool no_bitrate_increase_in_alr_;
+  const bool no_bitrate_increase_in_alr_ = true;
   // If "Disabled",  estimated link capacity is not used as upper bound.
   bool disable_estimate_bounded_increase_ = true;
   bool use_current_estimate_as_min_upper_bound_ = true;

src/qos/bwe_defines.h

@@ -15,9 +15,9 @@
 
 #include <optional>
 
+#include "api/transport/bandwidth_usage.h"
 #include "api/units/data_rate.h"
 #include "api/units/time_delta.h"
-#include "bandwidth_usage.h"
 
 namespace webrtc {
 

src/qos/clock.cc

@@ -0,0 +1,101 @@
+/*
+ *  Copyright (c) 2013 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.
+ */
+
+#include "clock.h"
+
+#include "rtc_base/time_utils.h"
+
+namespace webrtc {
+namespace {
+
+int64_t NtpOffsetUsCalledOnce() {
+  constexpr int64_t kNtpJan1970Sec = 2208988800;
+  int64_t clock_time = rtc::TimeMicros();
+  int64_t utc_time = rtc::TimeUTCMicros();
+  return utc_time - clock_time + kNtpJan1970Sec * rtc::kNumMicrosecsPerSec;
+}
+
+NtpTime TimeMicrosToNtp(int64_t time_us) {
+  static int64_t ntp_offset_us = NtpOffsetUsCalledOnce();
+
+  int64_t time_ntp_us = time_us + ntp_offset_us;
+
+  // Convert seconds to uint32 through uint64 for a well-defined cast.
+  // A wrap around, which will happen in 2036, is expected for NTP time.
+  uint32_t ntp_seconds =
+      static_cast<uint64_t>(time_ntp_us / rtc::kNumMicrosecsPerSec);
+
+  // Scale fractions of the second to NTP resolution.
+  constexpr int64_t kNtpFractionsInSecond = 1LL << 32;
+  int64_t us_fractions = time_ntp_us % rtc::kNumMicrosecsPerSec;
+  uint32_t ntp_fractions =
+      us_fractions * kNtpFractionsInSecond / rtc::kNumMicrosecsPerSec;
+
+  return NtpTime(ntp_seconds, ntp_fractions);
+}
+
+}  // namespace
+
+class RealTimeClock : public Clock {
+ public:
+  RealTimeClock() = default;
+
+  Timestamp CurrentTime() override {
+    return Timestamp::Micros(rtc::TimeMicros());
+  }
+
+  NtpTime ConvertTimestampToNtpTime(Timestamp timestamp) override {
+    return TimeMicrosToNtp(timestamp.us());
+  }
+};
+
+Clock* Clock::GetRealTimeClock() {
+  static Clock* const clock = new RealTimeClock();
+  return clock;
+}
+
+SimulatedClock::SimulatedClock(int64_t initial_time_us)
+    : time_us_(initial_time_us) {}
+
+SimulatedClock::SimulatedClock(Timestamp initial_time)
+    : SimulatedClock(initial_time.us()) {}
+
+SimulatedClock::~SimulatedClock() {}
+
+Timestamp SimulatedClock::CurrentTime() {
+  return Timestamp::Micros(time_us_.load(std::memory_order_relaxed));
+}
+
+NtpTime SimulatedClock::ConvertTimestampToNtpTime(Timestamp timestamp) {
+  int64_t now_us = timestamp.us();
+  uint32_t seconds = (now_us / 1'000'000) + kNtpJan1970;
+  uint32_t fractions = static_cast<uint32_t>(
+      (now_us % 1'000'000) * kMagicNtpFractionalUnit / 1'000'000);
+  return NtpTime(seconds, fractions);
+}
+
+void SimulatedClock::AdvanceTimeMilliseconds(int64_t milliseconds) {
+  AdvanceTime(TimeDelta::Millis(milliseconds));
+}
+
+void SimulatedClock::AdvanceTimeMicroseconds(int64_t microseconds) {
+  AdvanceTime(TimeDelta::Micros(microseconds));
+}
+
+// TODO(bugs.webrtc.org(12102): It's desirable to let a single thread own
+// advancement of the clock. We could then replace this read-modify-write
+// operation with just a thread checker. But currently, that breaks a couple of
+// tests, in particular, RepeatingTaskTest.ClockIntegration and
+// CallStatsTest.LastProcessedRtt.
+void SimulatedClock::AdvanceTime(TimeDelta delta) {
+  time_us_.fetch_add(delta.us(), std::memory_order_relaxed);
+}
+
+}  // namespace webrtc

src/qos/clock.h

@@ -0,0 +1,100 @@
+/*
+ *  Copyright (c) 2013 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 SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_
+#define SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_
+
+#include <stdint.h>
+
+#include <atomic>
+#include <memory>
+
+#include "api/units/timestamp.h"
+#include "ntp_time.h"
+
+namespace webrtc {
+
+// January 1970, in NTP seconds.
+const uint32_t kNtpJan1970 = 2208988800UL;
+
+// Magic NTP fractional unit.
+const double kMagicNtpFractionalUnit = 4.294967296E+9;
+
+// A clock interface that allows reading of absolute and relative timestamps.
+class Clock {
+ public:
+  virtual ~Clock() {}
+
+  // Return a timestamp relative to an unspecified epoch.
+  virtual Timestamp CurrentTime() = 0;
+  int64_t TimeInMilliseconds() { return CurrentTime().ms(); }
+  int64_t TimeInMicroseconds() { return CurrentTime().us(); }
+
+  // Retrieve an NTP absolute timestamp (with an epoch of Jan 1, 1900).
+  NtpTime CurrentNtpTime() { return ConvertTimestampToNtpTime(CurrentTime()); }
+  int64_t CurrentNtpInMilliseconds() { return CurrentNtpTime().ToMs(); }
+
+  // Converts between a relative timestamp returned by this clock, to NTP time.
+  virtual NtpTime ConvertTimestampToNtpTime(Timestamp timestamp) = 0;
+  int64_t ConvertTimestampToNtpTimeInMilliseconds(int64_t timestamp_ms) {
+    return ConvertTimestampToNtpTime(Timestamp::Millis(timestamp_ms)).ToMs();
+  }
+
+  // Converts NtpTime to a Timestamp with UTC epoch.
+  // A `Minus Infinity` Timestamp is returned if the NtpTime is invalid.
+  static Timestamp NtpToUtc(NtpTime ntp_time) {
+    if (!ntp_time.Valid()) {
+      return Timestamp::MinusInfinity();
+    }
+    // Seconds since UTC epoch.
+    int64_t time = ntp_time.seconds() - kNtpJan1970;
+    // Microseconds since UTC epoch (not including NTP fraction)
+    time = time * 1'000'000;
+    // Fractions part of the NTP time, in microseconds.
+    int64_t time_fraction =
+        DivideRoundToNearest(int64_t{ntp_time.fractions()} * 1'000'000,
+                             NtpTime::kFractionsPerSecond);
+    return Timestamp::Micros(time + time_fraction);
+  }
+
+  // Returns an instance of the real-time system clock implementation.
+  static Clock* GetRealTimeClock();
+};
+
+class SimulatedClock : public Clock {
+ public:
+  // The constructors assume an epoch of Jan 1, 1970.
+  explicit SimulatedClock(int64_t initial_time_us);
+  explicit SimulatedClock(Timestamp initial_time);
+  ~SimulatedClock() override;
+
+  // Return a timestamp with an epoch of Jan 1, 1970.
+  Timestamp CurrentTime() override;
+
+  NtpTime ConvertTimestampToNtpTime(Timestamp timestamp) override;
+
+  // Advance the simulated clock with a given number of milliseconds or
+  // microseconds.
+  void AdvanceTimeMilliseconds(int64_t milliseconds);
+  void AdvanceTimeMicroseconds(int64_t microseconds);
+  void AdvanceTime(TimeDelta delta);
+
+ private:
+  // The time is read and incremented with relaxed order. Each thread will see
+  // monotonically increasing time, and when threads post tasks or messages to
+  // one another, the synchronization done as part of the message passing should
+  // ensure that any causual chain of events on multiple threads also
+  // corresponds to monotonically increasing time.
+  std::atomic<int64_t> time_us_;
+};
+
+}  // namespace webrtc
+
+#endif  // SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_

src/qos/congestion_control.cpp

@@ -21,7 +21,34 @@ constexpr float kDefaultPaceMultiplier = 2.5f;
 // below the current throughput estimate to drain the network queues.
 constexpr double kProbeDropThroughputFraction = 0.85;
 
-CongestionControl::CongestionControl() {}
+CongestionControl::CongestionControl()
+    : use_min_allocatable_as_lower_bound_(false),
+      ignore_probes_lower_than_network_estimate_(false),
+      limit_probes_lower_than_throughput_estimate_(false),
+      pace_at_max_of_bwe_and_lower_link_capacity_(false),
+      limit_pacingfactor_by_upper_link_capacity_estimate_(false),
+      probe_controller_(new ProbeController()),
+      bandwidth_estimation_(new SendSideBandwidthEstimation()),
+      alr_detector_(new AlrDetector()),
+      probe_bitrate_estimator_(new ProbeBitrateEstimator()),
+      network_estimator_(new NetworkStateEstimator()),
+      network_state_predictor_(new NetworkStatePredictor()),
+      delay_based_bwe_(new DelayBasedBwe()),
+      acknowledged_bitrate_estimator_(new AcknowledgedBitrateEstimator()),
+      initial_config_(std::nullopt),
+      last_loss_based_target_rate_(*config.constraints.starting_rate),
+      last_pushback_target_rate_(last_loss_based_target_rate_),
+      last_stable_target_rate_(last_loss_based_target_rate_),
+      last_loss_base_state_(LossBasedState::kDelayBasedEstimate),
+      pacing_factor_(config.stream_based_config.pacing_factor.value_or(
+          kDefaultPaceMultiplier)),
+      min_total_allocated_bitrate_(
+          config.stream_based_config.min_total_allocated_bitrate.value_or(
+              DataRate::Zero())),
+      max_padding_rate_(config.stream_based_config.max_padding_rate.value_or(
+          DataRate::Zero()))
+
+{}
 
 CongestionControl::~CongestionControl() {}
 
@@ -35,28 +62,27 @@ NetworkControlUpdate CongestionControl::OnTransportPacketsFeedback(
 
   if (congestion_window_pushback_controller_) {
     congestion_window_pushback_controller_->UpdateOutstandingData(
-        report.data_in_flight);
+        report.data_in_flight.bytes());
   }
-  int64_t max_feedback_rtt = std::numeric_limits<int64_t>::min();
-  int64_t min_propagation_rtt = std::numeric_limits<int64_t>::max();
-  int64_t max_recv_time = std::numeric_limits<int64_t>::min();
+  TimeDelta max_feedback_rtt = TimeDelta::MinusInfinity();
+  TimeDelta min_propagation_rtt = TimeDelta::PlusInfinity();
+  Timestamp max_recv_time = Timestamp::MinusInfinity();
 
   std::vector<PacketResult> feedbacks = report.ReceivedWithSendInfo();
   for (const auto& feedback : feedbacks)
     max_recv_time = std::max(max_recv_time, feedback.receive_time);
 
   for (const auto& feedback : feedbacks) {
-    int64_t feedback_rtt =
+    TimeDelta feedback_rtt =
         report.feedback_time - feedback.sent_packet.send_time;
-    int64_t min_pending_time = max_recv_time - feedback.receive_time;
-    int64_t propagation_rtt = feedback_rtt - min_pending_time;
+    TimeDelta min_pending_time = max_recv_time - feedback.receive_time;
+    TimeDelta propagation_rtt = feedback_rtt - min_pending_time;
     max_feedback_rtt = std::max(max_feedback_rtt, feedback_rtt);
     min_propagation_rtt = std::min(min_propagation_rtt, propagation_rtt);
   }
 
-  if (max_feedback_rtt != std::numeric_limits<int64_t>::min() &&
-      min_propagation_rtt != std::numeric_limits<int64_t>::max()) {
-    feedback_max_rtts_.push_back(max_feedback_rtt);
+  if (max_feedback_rtt.IsFinite()) {
+    feedback_max_rtts_.push_back(max_feedback_rtt.ms());
     const size_t kMaxFeedbackRttWindow = 32;
     if (feedback_max_rtts_.size() > kMaxFeedbackRttWindow)
       feedback_max_rtts_.pop_front();
@@ -70,19 +96,19 @@ NetworkControlUpdate CongestionControl::OnTransportPacketsFeedback(
           std::accumulate(feedback_max_rtts_.begin(), feedback_max_rtts_.end(),
                           static_cast<int64_t>(0));
       int64_t mean_rtt_ms = sum_rtt_ms / feedback_max_rtts_.size();
-      if (delay_based_bwe_) delay_based_bwe_->OnRttUpdate(mean_rtt_ms);
+      if (delay_based_bwe_)
+        delay_based_bwe_->OnRttUpdate(TimeDelta::Millis(mean_rtt_ms));
     }
 
-    int64_t feedback_min_rtt = std::numeric_limits<int64_t>::max();
+    TimeDelta feedback_min_rtt = TimeDelta::PlusInfinity();
     for (const auto& packet_feedback : feedbacks) {
-      int64_t pending_time = max_recv_time - packet_feedback.receive_time;
-      int64_t rtt = report.feedback_time -
-                    packet_feedback.sent_packet.send_time - pending_time;
+      TimeDelta pending_time = max_recv_time - packet_feedback.receive_time;
+      TimeDelta rtt = report.feedback_time -
+                      packet_feedback.sent_packet.send_time - pending_time;
       // Value used for predicting NACK round trip time in FEC controller.
       feedback_min_rtt = std::min(rtt, feedback_min_rtt);
     }
-    if (feedback_min_rtt != std::numeric_limits<int64_t>::max() &&
-        feedback_min_rtt != std::numeric_limits<int64_t>::min()) {
+    if (feedback_min_rtt.IsFinite()) {
       bandwidth_estimation_->UpdateRtt(feedback_min_rtt, report.feedback_time);
     }
 
@@ -105,7 +131,7 @@ NetworkControlUpdate CongestionControl::OnTransportPacketsFeedback(
       alr_detector_->GetApplicationLimitedRegionStartTime();
 
   if (previously_in_alr_ && !alr_start_time.has_value()) {
-    int64_t now_ms = report.feedback_time;
+    int64_t now_ms = report.feedback_time.ms();
     acknowledged_bitrate_estimator_->SetAlrEndedTime(report.feedback_time);
     probe_controller_->SetAlrEndedTimeMs(now_ms);
   }
@@ -122,7 +148,11 @@ NetworkControlUpdate CongestionControl::OnTransportPacketsFeedback(
     }
   }
 
-  std::optional<int64_t> probe_bitrate =
+  if (network_estimator_) {
+    network_estimator_->OnTransportPacketsFeedback(report);
+    SetNetworkStateEstimate(network_estimator_->GetCurrentEstimate());
+  }
+  std::optional<DataRate> probe_bitrate =
       probe_bitrate_estimator_->FetchAndResetLastEstimatedBitrate();
   if (ignore_probes_lower_than_network_estimate_ && probe_bitrate &&
       estimate_ && *probe_bitrate < delay_based_bwe_->last_estimate() &&
@@ -138,7 +168,7 @@ NetworkControlUpdate CongestionControl::OnTransportPacketsFeedback(
     // based estimate, but it could happen e.g. due to packet bursts or
     // encoder overshoot. We use std::min to ensure that a probe result
     // below the current BWE never causes an increase.
-    int64_t limit =
+    DataRate limit =
         std::min(delay_based_bwe_->last_estimate(),
                  *acknowledged_bitrate * kProbeDropThroughputFraction);
     probe_bitrate = std::max(*probe_bitrate, limit);

src/qos/congestion_control.h

@@ -5,12 +5,18 @@
 #include <memory>
 
 #include "acknowledged_bitrate_estimator.h"
+#include "acknowledged_bitrate_estimator_interface.h"
 #include "alr_detector.h"
+#include "api/network_state_predictor.h"
+#include "api/transport/network_control.h"
+#include "api/transport/network_types.h"
 #include "congestion_window_pushback_controller.h"
 #include "delay_based_bwe.h"
-#include "network_types.h"
+#include "probe_controller.h"
 #include "send_side_bandwidth_estimation.h"
 
+using namespace webrtc;
+
 class CongestionControl {
  public:
   CongestionControl();
@@ -21,24 +27,54 @@ class CongestionControl {
       TransportPacketsFeedback report);
 
  private:
-  const std::unique_ptr<CongestionWindowPushbackController>
-      congestion_window_pushback_controller_;
+  const bool use_min_allocatable_as_lower_bound_;
+  const bool ignore_probes_lower_than_network_estimate_;
+  const bool limit_probes_lower_than_throughput_estimate_;
+  const bool pace_at_max_of_bwe_and_lower_link_capacity_;
+  const bool limit_pacingfactor_by_upper_link_capacity_estimate_;
 
- private:
-  std::deque<int64_t> feedback_max_rtts_;
-  int expected_packets_since_last_loss_update_ = 0;
-  int lost_packets_since_last_loss_update_ = 0;
-  int64_t next_loss_update_ = std::numeric_limits<int64_t>::min();
-  const bool packet_feedback_only_ = false;
-  bool previously_in_alr_ = false;
-  const bool limit_probes_lower_than_throughput_estimate_ = false;
-  std::optional<int64_t> current_data_window_;
+  const std::unique_ptr<ProbeController> probe_controller_;
 
- private:
   std::unique_ptr<SendSideBandwidthEstimation> bandwidth_estimation_;
   std::unique_ptr<AlrDetector> alr_detector_;
-  std::unique_ptr<AcknowledgedBitrateEstimator> acknowledged_bitrate_estimator_;
+  std::unique_ptr<ProbeBitrateEstimator> probe_bitrate_estimator_;
+  std::unique_ptr<NetworkStateEstimator> network_estimator_;
+  std::unique_ptr<NetworkStatePredictor> network_state_predictor_;
   std::unique_ptr<DelayBasedBwe> delay_based_bwe_;
+  std::unique_ptr<AcknowledgedBitrateEstimatorInterface>
+      acknowledged_bitrate_estimator_;
+
+  std::optional<NetworkControllerConfig> initial_config_;
+
+  DataRate min_target_rate_ = DataRate::Zero();
+  DataRate min_data_rate_ = DataRate::Zero();
+  DataRate max_data_rate_ = DataRate::PlusInfinity();
+  std::optional<DataRate> starting_rate_;
+
+  bool first_packet_sent_ = false;
+
+  std::optional<NetworkStateEstimate> estimate_;
+
+  Timestamp next_loss_update_ = Timestamp::MinusInfinity();
+  int lost_packets_since_last_loss_update_ = 0;
+  int expected_packets_since_last_loss_update_ = 0;
+
+  std::deque<int64_t> feedback_max_rtts_;
+
+  DataRate last_loss_based_target_rate_;
+  DataRate last_pushback_target_rate_;
+  DataRate last_stable_target_rate_;
+
+  std::optional<uint8_t> last_estimated_fraction_loss_ = 0;
+  TimeDelta last_estimated_round_trip_time_ = TimeDelta::PlusInfinity();
+
+  double pacing_factor_;
+  DataRate min_total_allocated_bitrate_;
+  DataRate max_padding_rate_;
+
+  bool previously_in_alr_ = false;
+
+  std::optional<DataSize> current_data_window_;
 };
 
 #endif

src/qos/congestion_control_feedback_generator.cc

@@ -0,0 +1,125 @@
+/*
+ *  Copyright (c) 2024 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.
+ */
+#include "congestion_control_feedback_generator.h"
+
+#include <algorithm>
+#include <chrono>
+#include <cstdint>
+#include <memory>
+#include <optional>
+#include <utility>
+#include <vector>
+
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "clock.h"
+#include "congestion_control_feedback.h"
+#include "ntp_time_util.h"
+#include "rtcp_packet.h"
+#include "rtp_packet_received.h"
+
+namespace webrtc {
+
+CongestionControlFeedbackGenerator::CongestionControlFeedbackGenerator(
+    std::shared_ptr<SimulatedClock> clock, RtcpSender rtcp_sender)
+    : clock_(clock),
+      rtcp_sender_(std::move(rtcp_sender)),
+      min_time_between_feedback_(TimeDelta::Millis(25)),
+      max_time_to_wait_for_packet_with_marker_(TimeDelta::Millis(25)),
+      max_time_between_feedback_(TimeDelta::Millis(250)) {}
+
+void CongestionControlFeedbackGenerator::OnReceivedPacket(
+    const RtpPacketReceived& packet) {
+  marker_bit_seen_ |= packet.Marker();
+  if (!first_arrival_time_since_feedback_) {
+    first_arrival_time_since_feedback_ = packet.arrival_time();
+  }
+  feedback_trackers_[packet.Ssrc()].ReceivedPacket(packet);
+  if (NextFeedbackTime() < packet.arrival_time()) {
+    SendFeedback(Timestamp::Micros(
+        std::chrono::duration_cast<std::chrono::microseconds>(
+            std::chrono::system_clock::now().time_since_epoch())
+            .count()));
+  }
+}
+
+Timestamp CongestionControlFeedbackGenerator::NextFeedbackTime() const {
+  if (!first_arrival_time_since_feedback_) {
+    return std::max(Timestamp::Micros(
+                        std::chrono::duration_cast<std::chrono::microseconds>(
+                            std::chrono::system_clock::now().time_since_epoch())
+                            .count()) +
+                        min_time_between_feedback_,
+                    next_possible_feedback_send_time_);
+  }
+
+  if (!marker_bit_seen_) {
+    return std::max(next_possible_feedback_send_time_,
+                    *first_arrival_time_since_feedback_ +
+                        max_time_to_wait_for_packet_with_marker_);
+  }
+  return next_possible_feedback_send_time_;
+}
+
+TimeDelta CongestionControlFeedbackGenerator::Process(Timestamp now) {
+  if (NextFeedbackTime() <= now) {
+    SendFeedback(now);
+  }
+  return NextFeedbackTime() - now;
+}
+
+void CongestionControlFeedbackGenerator::OnSendBandwidthEstimateChanged(
+    DataRate estimate) {
+  // Feedback reports should max occupy 5% of total bandwidth.
+  max_feedback_rate_ = estimate * 0.05;
+}
+
+void CongestionControlFeedbackGenerator::SetTransportOverhead(
+    DataSize overhead_per_packet) {
+  packet_overhead_ = overhead_per_packet;
+}
+
+void CongestionControlFeedbackGenerator::SendFeedback(Timestamp now) {
+  SimulatedClock clock(now);
+  uint32_t compact_ntp = CompactNtp(clock.ConvertTimestampToNtpTime(now));
+  std::vector<rtcp::CongestionControlFeedback::PacketInfo> rtcp_packet_info;
+  for (auto& [unused, tracker] : feedback_trackers_) {
+    tracker.AddPacketsToFeedback(now, rtcp_packet_info);
+  }
+  marker_bit_seen_ = false;
+  first_arrival_time_since_feedback_ = std::nullopt;
+
+  auto feedback = std::make_unique<rtcp::CongestionControlFeedback>(
+      std::move(rtcp_packet_info), compact_ntp);
+  CalculateNextPossibleSendTime(DataSize::Bytes(feedback->BlockLength()), now);
+
+  std::vector<std::unique_ptr<RtcpPacket>> rtcp_packets;
+  rtcp_packets.push_back(std::move(feedback));
+  rtcp_sender_(std::move(rtcp_packets));
+}
+
+void CongestionControlFeedbackGenerator::CalculateNextPossibleSendTime(
+    DataSize feedback_size, Timestamp now) {
+  TimeDelta time_since_last_sent = now - last_feedback_sent_time_;
+  DataSize debt_payed = time_since_last_sent * max_feedback_rate_;
+  send_rate_debt_ = debt_payed > send_rate_debt_ ? DataSize::Zero()
+                                                 : send_rate_debt_ - debt_payed;
+  send_rate_debt_ += feedback_size + packet_overhead_;
+  last_feedback_sent_time_ = now;
+  next_possible_feedback_send_time_ =
+      now + std::clamp(max_feedback_rate_.IsZero()
+                           ? TimeDelta::PlusInfinity()
+                           : send_rate_debt_ / max_feedback_rate_,
+                       min_time_between_feedback_, max_time_between_feedback_);
+}
+
+}  // namespace webrtc

src/qos/congestion_control_feedback_generator.cpp

@@ -1,108 +0,0 @@
-#include "congestion_control_feedback_generator.h"
-
-#include <algorithm>
-#include <cstdint>
-#include <memory>
-#include <optional>
-#include <utility>
-#include <vector>
-
-uint32_t ConvertToCompactNtp(int64_t now_ms) {
-  int64_t seconds = now_ms / 1000;
-  int64_t milliseconds = now_ms % 1000;
-  uint16_t ntp_seconds = static_cast<uint16_t>(seconds & 0xFFFF);
-  uint16_t ntp_fraction = static_cast<uint16_t>((milliseconds * 65536) / 1000);
-  uint32_t compact_ntp = (ntp_seconds << 16) | ntp_fraction;
-  return compact_ntp;
-}
-
-CongestionControlFeedbackGenerator::CongestionControlFeedbackGenerator(
-    RtcpSender rtcp_sender)
-    : rtcp_sender_(std::move(rtcp_sender)) {}
-
-void CongestionControlFeedbackGenerator::OnReceivedPacket(
-    RtpPacketReceived& packet) {
-  marker_bit_seen_ |= packet.Marker();
-  if (!first_arrival_time_since_feedback_) {
-    first_arrival_time_since_feedback_ = packet.arrival_time();
-  }
-  feedback_trackers_[packet.Ssrc()].ReceivedPacket(packet);
-  if (NextFeedbackTime() < packet.arrival_time()) {
-    auto now = std::chrono::system_clock::now();
-    auto now_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
-                      now.time_since_epoch())
-                      .count();
-    SendFeedback(now_ms);
-  }
-}
-
-int64_t CongestionControlFeedbackGenerator::NextFeedbackTime() const {
-  auto now = std::chrono::system_clock::now();
-  auto now_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
-                    now.time_since_epoch())
-                    .count();
-
-  if (!first_arrival_time_since_feedback_) {
-    return std::max(now_ms + min_time_between_feedback_,
-                    next_possible_feedback_send_time_);
-  }
-
-  if (!marker_bit_seen_) {
-    return std::max(next_possible_feedback_send_time_,
-                    *first_arrival_time_since_feedback_ +
-                        max_time_to_wait_for_packet_with_marker_);
-  }
-  return next_possible_feedback_send_time_;
-}
-
-int64_t CongestionControlFeedbackGenerator::Process(int64_t now_ms) {
-  if (NextFeedbackTime() <= now_ms) {
-    SendFeedback(now_ms);
-  }
-  return NextFeedbackTime() - now_ms;
-}
-
-void CongestionControlFeedbackGenerator::OnSendBandwidthEstimateChanged(
-    int64_t estimate) {
-  // Feedback reports should max occupy 5% of total bandwidth.
-  max_feedback_rate_ = estimate * 0.05;
-}
-
-void CongestionControlFeedbackGenerator::SetTransportOverhead(
-    int64_t overhead_per_packet) {
-  packet_overhead_ = overhead_per_packet;
-}
-
-void CongestionControlFeedbackGenerator::SendFeedback(int64_t now_ms) {
-  uint32_t compact_ntp = ConvertToCompactNtp(now_ms);
-  std::vector<CongestionControlFeedback::PacketInfo> rtcp_packet_info;
-  for (auto& [unused, tracker] : feedback_trackers_) {
-    tracker.AddPacketsToFeedback(now_ms, rtcp_packet_info);
-  }
-
-  marker_bit_seen_ = false;
-  first_arrival_time_since_feedback_ = std::nullopt;
-
-  auto feedback = std::make_unique<CongestionControlFeedback>(
-      std::move(rtcp_packet_info), compact_ntp);
-  CalculateNextPossibleSendTime(feedback->BlockLength(), now_ms);
-
-  std::vector<std::unique_ptr<RtcpPacket>> rtcp_packets;
-  rtcp_packets.push_back(std::move(feedback));
-  rtcp_sender_(std::move(rtcp_packets));
-}
-
-void CongestionControlFeedbackGenerator::CalculateNextPossibleSendTime(
-    int64_t feedback_size, int64_t now_ms) {
-  int64_t time_since_last_sent = now_ms - last_feedback_sent_time_;
-  size_t debt_payed = time_since_last_sent * max_feedback_rate_;
-  send_rate_debt_ =
-      debt_payed > send_rate_debt_ ? 0 : send_rate_debt_ - debt_payed;
-  send_rate_debt_ += feedback_size + packet_overhead_;
-  last_feedback_sent_time_ = now_ms;
-  next_possible_feedback_send_time_ =
-      now_ms +
-      std::clamp(max_feedback_rate_ == 0 ? std::numeric_limits<int64_t>::max()
-                                         : send_rate_debt_ / max_feedback_rate_,
-                 min_time_between_feedback_, max_time_between_feedback_);
-}

src/qos/congestion_control_feedback_generator.h

@@ -1,67 +1,88 @@
 /*
- * @Author: DI JUNKUN
- * @Date: 2024-12-18
- * Copyright (c) 2024 by DI JUNKUN, All Rights Reserved.
+ *  Copyright (c) 2024 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_REMOTE_BITRATE_ESTIMATOR_CONGESTION_CONTROL_FEEDBACK_GENERATOR_H_
+#define MODULES_REMOTE_BITRATE_ESTIMATOR_CONGESTION_CONTROL_FEEDBACK_GENERATOR_H_
 
-#ifndef _CONGESTION_CONTROL_FEEDBACK_GENERATOR_H_
-#define _CONGESTION_CONTROL_FEEDBACK_GENERATOR_H_
-
+#include <cstdint>
+#include <map>
+#include <memory>
 #include <optional>
-#include <vector>
 
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "clock.h"
 #include "congestion_control_feedback_tracker.h"
-#include "rtcp_packet.h"
 #include "rtp_packet_received.h"
+#include "rtp_transport_feedback_generator.h"
 
-class CongestionControlFeedbackGenerator {
+namespace webrtc {
+
+// The class is responsible for generating RTCP feedback packets based on
+// incoming media packets. Feedback format will comply with RFC 8888.
+// https://datatracker.ietf.org/doc/rfc8888/
+
+// Feedback should not use more than 5% of the configured send bandwidth
+// estimate. Min and max duration between feedback is configurable using field
+// trials, but per default, min is 25ms and max is 250ms.
+// If possible, given the other constraints, feedback will be sent when a packet
+// with marker bit is received in order to provide feedback as soon as possible
+// after receiving a complete video frame. If no packet with marker bit is
+// received, feedback can be delayed up to 25ms after the first packet since the
+// last sent feedback. On good networks, this means that a sender may receive
+// feedback for every sent frame.
+class CongestionControlFeedbackGenerator
+    : public RtpTransportFeedbackGenerator {
  public:
-  CongestionControlFeedbackGenerator(RtcpSender feedback_sender);
+  CongestionControlFeedbackGenerator(
+      std::shared_ptr<SimulatedClock> clock,
+      RtpTransportFeedbackGenerator::RtcpSender feedback_sender);
   ~CongestionControlFeedbackGenerator() = default;
 
-  void OnReceivedPacket(RtpPacketReceived& packet);
+  void OnReceivedPacket(const RtpPacketReceived& packet) override;
 
-  void OnSendBandwidthEstimateChanged(int64_t estimate);
+  void OnSendBandwidthEstimateChanged(DataRate estimate) override;
 
-  int64_t Process(int64_t now_ms);
+  TimeDelta Process(Timestamp now) override;
 
-  void SetTransportOverhead(int64_t overhead_per_packet);
+  void SetTransportOverhead(DataSize overhead_per_packet) override;
 
  private:
-  int64_t NextFeedbackTime() const;
+  Timestamp NextFeedbackTime() const;
 
-  void SendFeedback(int64_t now_ms);
+  void SendFeedback(Timestamp now);
 
-  void CalculateNextPossibleSendTime(int64_t feedback_size, int64_t now_ms);
+  void CalculateNextPossibleSendTime(DataSize feedback_size, Timestamp now);
 
+  std::shared_ptr<SimulatedClock> clock_;
   const RtcpSender rtcp_sender_;
 
- private:
-  // Feedback should not use more than 5% of the configured send bandwidth
-  // estimate. Min and max duration between feedback is configurable using field
-  // trials, but per default, min is 25ms and max is 250ms.
-  // If possible, given the other constraints, feedback will be sent when a
-  // packet with marker bit is received in order to provide feedback as soon as
-  // possible after receiving a complete video frame. If no packet with marker
-  // bit is received, feedback can be delayed up to 25ms after the first packet
-  // since the last sent feedback. On good networks, this means that a sender
-  // may receive feedback for every sent frame.
-  int64_t min_time_between_feedback_ = 25;
-  int64_t max_time_between_feedback_ = 250;
-  int64_t max_time_to_wait_for_packet_with_marker_ = 25;
+  TimeDelta min_time_between_feedback_;
+  TimeDelta max_time_to_wait_for_packet_with_marker_;
+  TimeDelta max_time_between_feedback_;
 
-  int64_t max_feedback_rate_ = 1000;  // kbps
-  int64_t packet_overhead_ = 0;
-  int64_t send_rate_debt_ = 0;
+  DataRate max_feedback_rate_ = DataRate::KilobitsPerSec(1000);
+  DataSize packet_overhead_ = DataSize::Zero();
+  DataSize send_rate_debt_ = DataSize::Zero();
 
   std::map</*ssrc=*/uint32_t, CongestionControlFeedbackTracker>
       feedback_trackers_;
 
-  std::optional<int64_t> first_arrival_time_since_feedback_;
-  int64_t next_possible_feedback_send_time_ = 0;
-  int64_t last_feedback_sent_time_ = 0;
-
+  // std::vector<PacketInfo> packets_;
+  Timestamp last_feedback_sent_time_ = Timestamp::Zero();
+  std::optional<Timestamp> first_arrival_time_since_feedback_;
   bool marker_bit_seen_ = false;
+  Timestamp next_possible_feedback_send_time_ = Timestamp::Zero();
 };
 
-#endif
+}  // namespace webrtc
+
+#endif  // MODULES_REMOTE_BITRATE_ESTIMATOR_CONGESTION_CONTROL_FEEDBACK_GENERATOR_H_

src/qos/congestion_control_feedback_tracker.cc

@@ -41,8 +41,8 @@ void CongestionControlFeedbackTracker::ReceivedPacket(
     // received.
     last_sequence_number_in_feedback_ = unwrapped_sequence_number - 1;
   }
-  packets_.emplace_back(packet.Ssrc(), unwrapped_sequence_number,
-                        packet.arrival_time(), packet.ecn());
+  packets_.push_back({packet.Ssrc(), unwrapped_sequence_number,
+                      packet.arrival_time(), packet.ecn()});
 }
 
 void CongestionControlFeedbackTracker::AddPacketsToFeedback(
@@ -89,8 +89,8 @@ void CongestionControlFeedbackTracker::AddPacketsToFeedback(
         ++packet_it;
       }
     }  // else - the packet has not been received yet.
-    packet_feedback.emplace_back(ssrc, static_cast<uint16_t>(sequence_number),
-                                 arrival_time_offset, ecn);
+    packet_feedback.push_back({ssrc, static_cast<uint16_t>(sequence_number),
+                               arrival_time_offset, ecn});
   }
   last_sequence_number_in_feedback_ = packets_.back().unwrapped_sequence_number;
   packets_.clear();

src/qos/congestion_window_pushback_controller.cc

@@ -13,7 +13,17 @@
 #include <algorithm>
 #include <cstdint>
 
-CongestionWindowPushbackController::CongestionWindowPushbackController() {}
+#include "api/units/data_size.h"
+
+namespace webrtc {
+
+const int kDefaultMinPushbackTargetBitrateBps = 30000;
+
+CongestionWindowPushbackController::CongestionWindowPushbackController()
+    : add_pacing_(false),
+      min_pushback_target_bitrate_bps_(kDefaultMinPushbackTargetBitrateBps),
+      current_data_window_(
+          DataSize::Bytes(kDefaultMinPushbackTargetBitrateBps)) {}
 
 void CongestionWindowPushbackController::UpdateOutstandingData(
     int64_t outstanding_bytes) {
@@ -24,17 +34,18 @@ void CongestionWindowPushbackController::UpdatePacingQueue(
   pacing_bytes_ = pacing_bytes;
 }
 
-void CongestionWindowPushbackController::SetDataWindow(int64_t data_window) {
+void CongestionWindowPushbackController::SetDataWindow(DataSize data_window) {
   current_data_window_ = data_window;
 }
 
 uint32_t CongestionWindowPushbackController::UpdateTargetBitrate(
     uint32_t bitrate_bps) {
-  if (!current_data_window_ || current_data_window_ == 0) return bitrate_bps;
+  if (!current_data_window_ || current_data_window_->IsZero())
+    return bitrate_bps;
   int64_t total_bytes = outstanding_bytes_;
   if (add_pacing_) total_bytes += pacing_bytes_;
   double fill_ratio =
-      total_bytes / static_cast<double>(current_data_window_.value());
+      total_bytes / static_cast<double>(current_data_window_->bytes());
   if (fill_ratio > 1.5) {
     encoding_rate_ratio_ *= 0.9;
   } else if (fill_ratio > 1) {
@@ -55,3 +66,5 @@ uint32_t CongestionWindowPushbackController::UpdateTargetBitrate(
                     : adjusted_target_bitrate_bps;
   return bitrate_bps;
 }
+
+}  // namespace webrtc

src/qos/congestion_window_pushback_controller.h

@@ -1,16 +1,24 @@
 /*
- * @Author: DI JUNKUN
- * @Date: 2025-01-13
- * Copyright (c) 2025 by DI JUNKUN, All Rights Reserved.
+ *  Copyright (c) 2018 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 _CONGESTION_WINDOW_PUSHBACK_CONTROLLER_H_
-#define _CONGESTION_WINDOW_PUSHBACK_CONTROLLER_H_
+#ifndef MODULES_CONGESTION_CONTROLLER_GOOG_CC_CONGESTION_WINDOW_PUSHBACK_CONTROLLER_H_
+#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_CONGESTION_WINDOW_PUSHBACK_CONTROLLER_H_
 
 #include <stdint.h>
 
 #include <optional>
 
+#include "api/units/data_size.h"
+
+namespace webrtc {
+
 // This class enables pushback from congestion window directly to video encoder.
 // When the congestion window is filling up, the video encoder target bitrate
 // will be reduced accordingly to accommodate the network changes. To avoid
@@ -22,15 +30,17 @@ class CongestionWindowPushbackController {
   void UpdateOutstandingData(int64_t outstanding_bytes);
   void UpdatePacingQueue(int64_t pacing_bytes);
   uint32_t UpdateTargetBitrate(uint32_t bitrate_bps);
-  void SetDataWindow(int64_t data_window);
+  void SetDataWindow(DataSize data_window);
 
  private:
-  const bool add_pacing_ = true;
-  const uint32_t min_pushback_target_bitrate_bps_ = 10000;
-  std::optional<int64_t> current_data_window_ = std::nullopt;
+  const bool add_pacing_;
+  const uint32_t min_pushback_target_bitrate_bps_;
+  std::optional<DataSize> current_data_window_;
   int64_t outstanding_bytes_ = 0;
   int64_t pacing_bytes_ = 0;
   double encoding_rate_ratio_ = 1.0;
 };
 
-#endif
+}  // namespace webrtc
+
+#endif  // MODULES_CONGESTION_CONTROLLER_GOOG_CC_CONGESTION_WINDOW_PUSHBACK_CONTROLLER_H_

src/qos/delay_based_bwe.cc

@@ -17,6 +17,7 @@
 #include <utility>
 #include <vector>
 
+#include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "api/units/data_size.h"
 #include "api/units/time_delta.h"
@@ -24,7 +25,6 @@
 #include "bwe_defines.h"
 #include "inter_arrival_delta.h"
 #include "log.h"
-#include "network_types.h"
 #include "trendline_estimator.h"
 
 namespace webrtc {

src/qos/delay_based_bwe.h

@@ -18,15 +18,15 @@
 #include <vector>
 
 #include "aimd_rate_control.h"
+#include "api/transport/bandwidth_usage.h"
+#include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "api/units/time_delta.h"
 #include "api/units/timestamp.h"
-#include "bandwidth_usage.h"
 #include "delay_increase_detector_interface.h"
 #include "inter_arrival.h"
 #include "inter_arrival_delta.h"
 #include "link_capacity_estimator.h"
-#include "network_types.h"
 #include "probe_bitrate_estimator.h"
 
 namespace webrtc {

src/qos/delay_increase_detector_interface.h

@@ -14,7 +14,7 @@
 
 #include <cstddef>
 
-#include "bandwidth_usage.h"
+#include "api/transport/bandwidth_usage.h"
 
 namespace webrtc {
 

src/qos/module_common_types.h

@@ -0,0 +1,66 @@
+/*
+ *  Copyright (c) 2012 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_INCLUDE_MODULE_COMMON_TYPES_H_
+#define MODULES_INCLUDE_MODULE_COMMON_TYPES_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+namespace webrtc {
+
+// Interface used by the CallStats class to distribute call statistics.
+// Callbacks will be triggered as soon as the class has been registered to a
+// CallStats object using RegisterStatsObserver.
+class CallStatsObserver {
+ public:
+  virtual void OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms) = 0;
+
+  virtual ~CallStatsObserver() {}
+};
+
+// Interface used by NackModule and JitterBuffer.
+class NackSender {
+ public:
+  // If `buffering_allowed`, other feedback messages (e.g. key frame requests)
+  // may be added to the same outgoing feedback message. In that case, it's up
+  // to the user of the interface to ensure that when all buffer-able messages
+  // have been added, the feedback message is triggered.
+  virtual void SendNack(const std::vector<uint16_t>& sequence_numbers,
+                        bool buffering_allowed) = 0;
+
+ protected:
+  virtual ~NackSender() {}
+};
+
+// Interface used by NackModule and JitterBuffer.
+class KeyFrameRequestSender {
+ public:
+  virtual void RequestKeyFrame() = 0;
+
+ protected:
+  virtual ~KeyFrameRequestSender() {}
+};
+
+// Interface used by LossNotificationController to communicate to RtpRtcp.
+class LossNotificationSender {
+ public:
+  virtual ~LossNotificationSender() {}
+
+  virtual void SendLossNotification(uint16_t last_decoded_seq_num,
+                                    uint16_t last_received_seq_num,
+                                    bool decodability_flag,
+                                    bool buffering_allowed) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_INCLUDE_MODULE_COMMON_TYPES_H_

src/qos/ntp_time.h

@@ -0,0 +1,136 @@
+/*
+ *  Copyright (c) 2015 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 SYSTEM_WRAPPERS_INCLUDE_NTP_TIME_H_
+#define SYSTEM_WRAPPERS_INCLUDE_NTP_TIME_H_
+
+#include <cmath>
+#include <cstdint>
+#include <limits>
+
+#include "rtc_base/numerics/safe_conversions.h"
+
+namespace webrtc {
+
+class NtpTime {
+ public:
+  static constexpr uint64_t kFractionsPerSecond = 0x100000000;
+  NtpTime() : value_(0) {}
+  explicit NtpTime(uint64_t value) : value_(value) {}
+  NtpTime(uint32_t seconds, uint32_t fractions)
+      : value_(seconds * kFractionsPerSecond + fractions) {}
+
+  NtpTime(const NtpTime&) = default;
+  NtpTime& operator=(const NtpTime&) = default;
+  explicit operator uint64_t() const { return value_; }
+
+  void Set(uint32_t seconds, uint32_t fractions) {
+    value_ = seconds * kFractionsPerSecond + fractions;
+  }
+  void Reset() { value_ = 0; }
+
+  int64_t ToMs() const {
+    static constexpr double kNtpFracPerMs = 4.294967296E6;  // 2^32 / 1000.
+    const double frac_ms = static_cast<double>(fractions()) / kNtpFracPerMs;
+    return 1000 * static_cast<int64_t>(seconds()) +
+           static_cast<int64_t>(frac_ms + 0.5);
+  }
+  // NTP standard (RFC1305, section 3.1) explicitly state value 0 is invalid.
+  bool Valid() const { return value_ != 0; }
+
+  uint32_t seconds() const {
+    return rtc::dchecked_cast<uint32_t>(value_ / kFractionsPerSecond);
+  }
+  uint32_t fractions() const {
+    return rtc::dchecked_cast<uint32_t>(value_ % kFractionsPerSecond);
+  }
+
+ private:
+  uint64_t value_;
+};
+
+inline bool operator==(const NtpTime& n1, const NtpTime& n2) {
+  return static_cast<uint64_t>(n1) == static_cast<uint64_t>(n2);
+}
+inline bool operator!=(const NtpTime& n1, const NtpTime& n2) {
+  return !(n1 == n2);
+}
+
+// Converts `int64_t` milliseconds to Q32.32-formatted fixed-point seconds.
+// Performs clamping if the result overflows or underflows.
+inline int64_t Int64MsToQ32x32(int64_t milliseconds) {
+  // TODO(bugs.webrtc.org/10893): Change to use `rtc::saturated_cast` once the
+  // bug has been fixed.
+  double result =
+      std::round(milliseconds * (NtpTime::kFractionsPerSecond / 1000.0));
+
+  // Explicitly cast values to double to avoid implicit conversion warnings
+  // The conversion of the std::numeric_limits<int64_t>::max() triggers
+  // -Wimplicit-int-float-conversion warning in clang 10.0.0 without explicit
+  // cast
+  if (result <= static_cast<double>(std::numeric_limits<int64_t>::min())) {
+    return std::numeric_limits<int64_t>::min();
+  }
+
+  if (result >= static_cast<double>(std::numeric_limits<int64_t>::max())) {
+    return std::numeric_limits<int64_t>::max();
+  }
+
+  return rtc::dchecked_cast<int64_t>(result);
+}
+
+// Converts `int64_t` milliseconds to UQ32.32-formatted fixed-point seconds.
+// Performs clamping if the result overflows or underflows.
+inline uint64_t Int64MsToUQ32x32(int64_t milliseconds) {
+  // TODO(bugs.webrtc.org/10893): Change to use `rtc::saturated_cast` once the
+  // bug has been fixed.
+  double result =
+      std::round(milliseconds * (NtpTime::kFractionsPerSecond / 1000.0));
+
+  // Explicitly cast values to double to avoid implicit conversion warnings
+  // The conversion of the std::numeric_limits<int64_t>::max() triggers
+  // -Wimplicit-int-float-conversion warning in clang 10.0.0 without explicit
+  // cast
+  if (result <= static_cast<double>(std::numeric_limits<uint64_t>::min())) {
+    return std::numeric_limits<uint64_t>::min();
+  }
+
+  if (result >= static_cast<double>(std::numeric_limits<uint64_t>::max())) {
+    return std::numeric_limits<uint64_t>::max();
+  }
+
+  return rtc::dchecked_cast<uint64_t>(result);
+}
+
+// Converts Q32.32-formatted fixed-point seconds to `int64_t` milliseconds.
+inline int64_t Q32x32ToInt64Ms(int64_t q32x32) {
+  return rtc::dchecked_cast<int64_t>(
+      std::round(q32x32 * (1000.0 / NtpTime::kFractionsPerSecond)));
+}
+
+// Converts UQ32.32-formatted fixed-point seconds to `int64_t` milliseconds.
+inline int64_t UQ32x32ToInt64Ms(uint64_t q32x32) {
+  return rtc::dchecked_cast<int64_t>(
+      std::round(q32x32 * (1000.0 / NtpTime::kFractionsPerSecond)));
+}
+
+// Converts UQ32.32-formatted fixed-point seconds to `int64_t` microseconds.
+inline int64_t UQ32x32ToInt64Us(uint64_t q32x32) {
+  return rtc::dchecked_cast<int64_t>(
+      std::round(q32x32 * (1'000'000.0 / NtpTime::kFractionsPerSecond)));
+}
+
+// Converts Q32.32-formatted fixed-point seconds to `int64_t` microseconds.
+inline int64_t Q32x32ToInt64Us(int64_t q32x32) {
+  return rtc::dchecked_cast<int64_t>(
+      std::round(q32x32 * (1'000'000.0 / NtpTime::kFractionsPerSecond)));
+}
+
+}  // namespace webrtc
+#endif  // SYSTEM_WRAPPERS_INCLUDE_NTP_TIME_H_

src/qos/ntp_time_util.h

@@ -0,0 +1,61 @@
+/*
+ *  Copyright (c) 2015 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_RTP_RTCP_SOURCE_NTP_TIME_UTIL_H_
+#define MODULES_RTP_RTCP_SOURCE_NTP_TIME_UTIL_H_
+
+#include <stdint.h>
+
+#include "api/units/time_delta.h"
+#include "ntp_time.h"
+#include "rtc_base/numerics/safe_conversions.h"
+
+namespace webrtc {
+
+// Helper function for compact ntp representation:
+// RFC 3550, Section 4. Time Format.
+// Wallclock time is represented using the timestamp format of
+// the Network Time Protocol (NTP).
+// ...
+// In some fields where a more compact representation is
+// appropriate, only the middle 32 bits are used; that is, the low 16
+// bits of the integer part and the high 16 bits of the fractional part.
+inline uint32_t CompactNtp(NtpTime ntp) {
+  return (ntp.seconds() << 16) | (ntp.fractions() >> 16);
+}
+
+// Converts interval to compact ntp (1/2^16 seconds) resolution.
+// Negative values converted to 0, Overlarge values converted to max uint32_t.
+uint32_t SaturatedToCompactNtp(TimeDelta delta);
+
+// Convert interval to the NTP time resolution (1/2^32 seconds ~= 0.2 ns).
+// For deltas with absolute value larger than 35 minutes result is unspecified.
+inline constexpr int64_t ToNtpUnits(TimeDelta delta) {
+  // For better precision `delta` is taken with best TimeDelta precision (us),
+  // then multiplaction and conversion to seconds are swapped to avoid float
+  // arithmetic.
+  // 2^31 us ~= 35.8 minutes.
+  return (rtc::saturated_cast<int32_t>(delta.us()) * (int64_t{1} << 32)) /
+         1'000'000;
+}
+
+// Converts interval from compact ntp (1/2^16 seconds) resolution to TimeDelta.
+// This interval can be up to ~9.1 hours (2^15 seconds).
+// Values close to 2^16 seconds are considered negative.
+TimeDelta CompactNtpIntervalToTimeDelta(uint32_t compact_ntp_interval);
+
+// Converts interval from compact ntp (1/2^16 seconds) resolution to TimeDelta.
+// This interval can be up to ~9.1 hours (2^15 seconds).
+// Values close to 2^16 seconds are considered negative and are converted to
+// minimum value of 1ms.
+TimeDelta CompactNtpRttToTimeDelta(uint32_t compact_ntp_interval);
+
+}  // namespace webrtc
+#endif  // MODULES_RTP_RTCP_SOURCE_NTP_TIME_UTIL_H_

src/qos/overuse_detector.h

@@ -12,7 +12,7 @@
 
 #include <stdint.h>
 
-#include "bandwidth_usage.h"
+#include "api/transport/bandwidth_usage.h"
 
 namespace webrtc {
 

src/qos/overuse_estimator.cc

@@ -0,0 +1,136 @@
+/*
+ *  Copyright (c) 2013 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.
+ */
+
+#include "overuse_estimator.h"
+
+#include <math.h>
+#include <string.h>
+
+#include <algorithm>
+
+#include "api/transport/bandwidth_usage.h"
+#include "log.h"
+
+namespace webrtc {
+namespace {
+
+constexpr int kMinFramePeriodHistoryLength = 60;
+constexpr int kDeltaCounterMax = 1000;
+
+}  // namespace
+
+OveruseEstimator::OveruseEstimator() = default;
+
+void OveruseEstimator::Update(int64_t t_delta, double ts_delta, int size_delta,
+                              BandwidthUsage current_hypothesis,
+                              int64_t /* now_ms */) {
+  const double min_frame_period = UpdateMinFramePeriod(ts_delta);
+  const double t_ts_delta = t_delta - ts_delta;
+  double fs_delta = size_delta;
+
+  ++num_of_deltas_;
+  if (num_of_deltas_ > kDeltaCounterMax) {
+    num_of_deltas_ = kDeltaCounterMax;
+  }
+
+  // Update the Kalman filter.
+  E_[0][0] += process_noise_[0];
+  E_[1][1] += process_noise_[1];
+
+  if ((current_hypothesis == BandwidthUsage::kBwOverusing &&
+       offset_ < prev_offset_) ||
+      (current_hypothesis == BandwidthUsage::kBwUnderusing &&
+       offset_ > prev_offset_)) {
+    E_[1][1] += 10 * process_noise_[1];
+  }
+
+  const double h[2] = {fs_delta, 1.0};
+  const double Eh[2] = {E_[0][0] * h[0] + E_[0][1] * h[1],
+                        E_[1][0] * h[0] + E_[1][1] * h[1]};
+
+  const double residual = t_ts_delta - slope_ * h[0] - offset_;
+
+  const bool in_stable_state =
+      (current_hypothesis == BandwidthUsage::kBwNormal);
+  const double max_residual = 3.0 * sqrt(var_noise_);
+  // We try to filter out very late frames. For instance periodic key
+  // frames doesn't fit the Gaussian model well.
+  if (fabs(residual) < max_residual) {
+    UpdateNoiseEstimate(residual, min_frame_period, in_stable_state);
+  } else {
+    UpdateNoiseEstimate(residual < 0 ? -max_residual : max_residual,
+                        min_frame_period, in_stable_state);
+  }
+
+  const double denom = var_noise_ + h[0] * Eh[0] + h[1] * Eh[1];
+
+  const double K[2] = {Eh[0] / denom, Eh[1] / denom};
+
+  const double IKh[2][2] = {{1.0 - K[0] * h[0], -K[0] * h[1]},
+                            {-K[1] * h[0], 1.0 - K[1] * h[1]}};
+  const double e00 = E_[0][0];
+  const double e01 = E_[0][1];
+
+  // Update state.
+  E_[0][0] = e00 * IKh[0][0] + E_[1][0] * IKh[0][1];
+  E_[0][1] = e01 * IKh[0][0] + E_[1][1] * IKh[0][1];
+  E_[1][0] = e00 * IKh[1][0] + E_[1][0] * IKh[1][1];
+  E_[1][1] = e01 * IKh[1][0] + E_[1][1] * IKh[1][1];
+
+  // The covariance matrix must be positive semi-definite.
+  bool positive_semi_definite =
+      E_[0][0] + E_[1][1] >= 0 &&
+      E_[0][0] * E_[1][1] - E_[0][1] * E_[1][0] >= 0 && E_[0][0] >= 0;
+  if (!positive_semi_definite) {
+    LOG_ERROR(
+        "The over-use estimator's covariance matrix is no longer "
+        "semi-definite.");
+  }
+
+  slope_ = slope_ + K[0] * residual;
+  prev_offset_ = offset_;
+  offset_ = offset_ + K[1] * residual;
+}
+
+double OveruseEstimator::UpdateMinFramePeriod(double ts_delta) {
+  double min_frame_period = ts_delta;
+  if (ts_delta_hist_.size() >= kMinFramePeriodHistoryLength) {
+    ts_delta_hist_.pop_front();
+  }
+  for (const double old_ts_delta : ts_delta_hist_) {
+    min_frame_period = std::min(old_ts_delta, min_frame_period);
+  }
+  ts_delta_hist_.push_back(ts_delta);
+  return min_frame_period;
+}
+
+void OveruseEstimator::UpdateNoiseEstimate(double residual, double ts_delta,
+                                           bool stable_state) {
+  if (!stable_state) {
+    return;
+  }
+  // Faster filter during startup to faster adapt to the jitter level
+  // of the network. `alpha` is tuned for 30 frames per second, but is scaled
+  // according to `ts_delta`.
+  double alpha = 0.01;
+  if (num_of_deltas_ > 10 * 30) {
+    alpha = 0.002;
+  }
+  // Only update the noise estimate if we're not over-using. `beta` is a
+  // function of alpha and the time delta since the previous update.
+  const double beta = pow(1 - alpha, ts_delta * 30.0 / 1000.0);
+  avg_noise_ = beta * avg_noise_ + (1 - beta) * residual;
+  var_noise_ = beta * var_noise_ +
+               (1 - beta) * (avg_noise_ - residual) * (avg_noise_ - residual);
+  if (var_noise_ < 1) {
+    var_noise_ = 1;
+  }
+}
+}  // namespace webrtc

src/qos/overuse_estimator.h

@@ -0,0 +1,66 @@
+/*
+ *  Copyright (c) 2013 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_REMOTE_BITRATE_ESTIMATOR_OVERUSE_ESTIMATOR_H_
+#define MODULES_REMOTE_BITRATE_ESTIMATOR_OVERUSE_ESTIMATOR_H_
+
+#include <stdint.h>
+
+#include <deque>
+
+#include "api/transport/bandwidth_usage.h"
+
+namespace webrtc {
+
+class OveruseEstimator {
+ public:
+  OveruseEstimator();
+
+  OveruseEstimator(const OveruseEstimator&) = delete;
+  OveruseEstimator& operator=(const OveruseEstimator&) = delete;
+
+  ~OveruseEstimator() = default;
+
+  // Update the estimator with a new sample. The deltas should represent deltas
+  // between timestamp groups as defined by the InterArrival class.
+  // `current_hypothesis` should be the hypothesis of the over-use detector at
+  // this time.
+  void Update(int64_t t_delta,
+              double ts_delta,
+              int size_delta,
+              BandwidthUsage current_hypothesis,
+              int64_t now_ms);
+
+  // Returns the estimated noise/jitter variance in ms^2.
+  double var_noise() const { return var_noise_; }
+
+  // Returns the estimated inter-arrival time delta offset in ms.
+  double offset() const { return offset_; }
+
+  // Returns the number of deltas which the current over-use estimator state is
+  // based on.
+  int num_of_deltas() const { return num_of_deltas_; }
+
+ private:
+  double UpdateMinFramePeriod(double ts_delta);
+  void UpdateNoiseEstimate(double residual, double ts_delta, bool stable_state);
+
+  int num_of_deltas_ = 0;
+  double slope_ = 8.0 / 512.0;
+  double offset_ = 0;
+  double prev_offset_ = 0;
+  double E_[2][2] = {{100.0, 0.0}, {0.0, 1e-1}};
+  double process_noise_[2] = {1e-13, 1e-3};
+  double avg_noise_ = 0.0;
+  double var_noise_ = 50.0;
+  std::deque<double> ts_delta_hist_;
+};
+}  // namespace webrtc
+
+#endif  // MODULES_REMOTE_BITRATE_ESTIMATOR_OVERUSE_ESTIMATOR_H_

src/qos/probe_bitrate_estimator.cc

@@ -14,12 +14,12 @@
 #include <memory>
 #include <optional>
 
+#include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "api/units/data_size.h"
 #include "api/units/time_delta.h"
 #include "api/units/timestamp.h"
 #include "log.h"
-#include "network_types.h"
 
 namespace webrtc {
 namespace {

src/qos/probe_bitrate_estimator.h

@@ -14,10 +14,10 @@
 #include <map>
 #include <optional>
 
+#include "api/transport/network_types.h"
 #include "api/units/data_rate.h"
 #include "api/units/data_size.h"
 #include "api/units/timestamp.h"
-#include "network_types.h"
 
 namespace webrtc {
 class RtcEventLog;

src/qos/probe_controller.cc

@@ -0,0 +1,536 @@
+/*
+ *  Copyright (c) 2016 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.
+ */
+
+#include "probe_controller.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <initializer_list>
+#include <memory>
+#include <optional>
+#include <vector>
+
+#include "api/transport/network_types.h"
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "log.h"
+
+namespace webrtc {
+
+namespace {
+// Maximum waiting time from the time of initiating probing to getting
+// the measured results back.
+constexpr TimeDelta kMaxWaitingTimeForProbingResult = TimeDelta::Seconds(1);
+
+// Default probing bitrate limit. Applied only when the application didn't
+// specify max bitrate.
+constexpr DataRate kDefaultMaxProbingBitrate = DataRate::KilobitsPerSec(5000);
+
+// If the bitrate drops to a factor `kBitrateDropThreshold` or lower
+// and we recover within `kBitrateDropTimeoutMs`, then we'll send
+// a probe at a fraction `kProbeFractionAfterDrop` of the original bitrate.
+constexpr double kBitrateDropThreshold = 0.66;
+constexpr TimeDelta kBitrateDropTimeout = TimeDelta::Seconds(5);
+constexpr double kProbeFractionAfterDrop = 0.85;
+
+// Timeout for probing after leaving ALR. If the bitrate drops significantly,
+// (as determined by the delay based estimator) and we leave ALR, then we will
+// send a probe if we recover within `kLeftAlrTimeoutMs` ms.
+constexpr TimeDelta kAlrEndedTimeout = TimeDelta::Seconds(3);
+
+// The expected uncertainty of probe result (as a fraction of the target probe
+// This is a limit on how often probing can be done when there is a BW
+// drop detected in ALR.
+constexpr TimeDelta kMinTimeBetweenAlrProbes = TimeDelta::Seconds(5);
+
+// bitrate). Used to avoid probing if the probe bitrate is close to our current
+// estimate.
+constexpr double kProbeUncertainty = 0.05;
+
+// Use probing to recover faster after large bitrate estimate drops.
+constexpr char kBweRapidRecoveryExperiment[] =
+    "WebRTC-BweRapidRecoveryExperiment";
+
+}  // namespace
+
+ProbeControllerConfig::ProbeControllerConfig()
+    : first_exponential_probe_scale(3.0),
+      second_exponential_probe_scale(6.0),
+      further_exponential_probe_scale(2),
+      further_probe_threshold(0.7),
+      abort_further_probe_if_max_lower_than_current(false),
+      repeated_initial_probing_time_period(TimeDelta::Seconds(5)),
+      initial_probe_duration(TimeDelta::Millis(100)),
+      initial_min_probe_delta(TimeDelta::Millis(20)),
+      alr_probing_interval(TimeDelta::Seconds(5)),
+      alr_probe_scale(2),
+      network_state_estimate_probing_interval(TimeDelta::PlusInfinity()),
+      probe_if_estimate_lower_than_network_state_estimate_ratio(0),
+      estimate_lower_than_network_state_estimate_probing_interval(
+          TimeDelta::Seconds(3)),
+      network_state_probe_scale(1.0),
+      network_state_probe_duration(TimeDelta::Millis(15)),
+      network_state_min_probe_delta(TimeDelta::Millis(20)),
+      probe_on_max_allocated_bitrate_change(true),
+      first_allocation_probe_scale(1),
+      second_allocation_probe_scale(2),
+      allocation_probe_limit_by_current_scale(2),
+      min_probe_packets_sent(5),
+      min_probe_duration(TimeDelta::Millis(15)),
+      min_probe_delta(TimeDelta::Millis(2)),
+      loss_limited_probe_scale(1.5),
+      skip_if_estimate_larger_than_fraction_of_max(0.0),
+      skip_probe_max_allocated_scale(1.0) {}
+
+ProbeControllerConfig::ProbeControllerConfig(const ProbeControllerConfig&) =
+    default;
+ProbeControllerConfig::~ProbeControllerConfig() = default;
+
+ProbeController::ProbeController()
+    : network_available_(false), enable_periodic_alr_probing_(false) {
+  Reset(Timestamp::Zero());
+}
+
+ProbeController::~ProbeController() {}
+
+std::vector<ProbeClusterConfig> ProbeController::SetBitrates(
+    DataRate min_bitrate, DataRate start_bitrate, DataRate max_bitrate,
+    Timestamp at_time) {
+  if (start_bitrate > DataRate::Zero()) {
+    start_bitrate_ = start_bitrate;
+    estimated_bitrate_ = start_bitrate;
+  } else if (start_bitrate_.IsZero()) {
+    start_bitrate_ = min_bitrate;
+  }
+
+  // The reason we use the variable `old_max_bitrate_pbs` is because we
+  // need to set `max_bitrate_` before we call InitiateProbing.
+  DataRate old_max_bitrate = max_bitrate_;
+  max_bitrate_ =
+      max_bitrate.IsFinite() ? max_bitrate : kDefaultMaxProbingBitrate;
+
+  switch (state_) {
+    case State::kInit:
+      if (network_available_) return InitiateExponentialProbing(at_time);
+      break;
+
+    case State::kWaitingForProbingResult:
+      break;
+
+    case State::kProbingComplete:
+      // If the new max bitrate is higher than both the old max bitrate and the
+      // estimate then initiate probing.
+      if (!estimated_bitrate_.IsZero() && old_max_bitrate < max_bitrate_ &&
+          estimated_bitrate_ < max_bitrate_) {
+        return InitiateProbing(at_time, {max_bitrate_}, false);
+      }
+      break;
+  }
+  return std::vector<ProbeClusterConfig>();
+}
+
+std::vector<ProbeClusterConfig> ProbeController::OnMaxTotalAllocatedBitrate(
+    DataRate max_total_allocated_bitrate, Timestamp at_time) {
+  const bool in_alr = alr_start_time_.has_value();
+  const bool allow_allocation_probe = in_alr;
+  if (config_.probe_on_max_allocated_bitrate_change &&
+      state_ == State::kProbingComplete &&
+      max_total_allocated_bitrate != max_total_allocated_bitrate_ &&
+      estimated_bitrate_ < max_bitrate_ &&
+      estimated_bitrate_ < max_total_allocated_bitrate &&
+      allow_allocation_probe) {
+    max_total_allocated_bitrate_ = max_total_allocated_bitrate;
+
+    if (!config_.first_allocation_probe_scale)
+      return std::vector<ProbeClusterConfig>();
+
+    DataRate first_probe_rate =
+        max_total_allocated_bitrate * config_.first_allocation_probe_scale;
+    const DataRate current_bwe_limit =
+        config_.allocation_probe_limit_by_current_scale * estimated_bitrate_;
+    bool limited_by_current_bwe = current_bwe_limit < first_probe_rate;
+    if (limited_by_current_bwe) {
+      first_probe_rate = current_bwe_limit;
+    }
+
+    std::vector<DataRate> probes = {first_probe_rate};
+    if (!limited_by_current_bwe && config_.second_allocation_probe_scale) {
+      DataRate second_probe_rate =
+          max_total_allocated_bitrate * config_.second_allocation_probe_scale;
+      limited_by_current_bwe = current_bwe_limit < second_probe_rate;
+      if (limited_by_current_bwe) {
+        second_probe_rate = current_bwe_limit;
+      }
+      if (second_probe_rate > first_probe_rate)
+        probes.push_back(second_probe_rate);
+    }
+    bool allow_further_probing = limited_by_current_bwe;
+
+    return InitiateProbing(at_time, probes, allow_further_probing);
+  }
+  if (!max_total_allocated_bitrate.IsZero()) {
+    last_allowed_repeated_initial_probe_ = at_time;
+  }
+
+  max_total_allocated_bitrate_ = max_total_allocated_bitrate;
+  return std::vector<ProbeClusterConfig>();
+}
+
+std::vector<ProbeClusterConfig> ProbeController::OnNetworkAvailability(
+    NetworkAvailability msg) {
+  network_available_ = msg.network_available;
+
+  if (!network_available_ && state_ == State::kWaitingForProbingResult) {
+    state_ = State::kProbingComplete;
+    min_bitrate_to_probe_further_ = DataRate::PlusInfinity();
+  }
+
+  if (network_available_ && state_ == State::kInit && !start_bitrate_.IsZero())
+    return InitiateExponentialProbing(msg.at_time);
+  return std::vector<ProbeClusterConfig>();
+}
+
+void ProbeController::UpdateState(State new_state) {
+  switch (new_state) {
+    case State::kInit:
+      state_ = State::kInit;
+      break;
+    case State::kWaitingForProbingResult:
+      state_ = State::kWaitingForProbingResult;
+      break;
+    case State::kProbingComplete:
+      state_ = State::kProbingComplete;
+      min_bitrate_to_probe_further_ = DataRate::PlusInfinity();
+      break;
+  }
+}
+
+std::vector<ProbeClusterConfig> ProbeController::InitiateExponentialProbing(
+    Timestamp at_time) {
+  // When probing at 1.8 Mbps ( 6x 300), this represents a threshold of
+  // 1.2 Mbps to continue probing.
+  std::vector<DataRate> probes = {config_.first_exponential_probe_scale *
+                                  start_bitrate_};
+  if (config_.second_exponential_probe_scale &&
+      config_.second_exponential_probe_scale > 0) {
+    probes.push_back(config_.second_exponential_probe_scale * start_bitrate_);
+  }
+  if (repeated_initial_probing_enabled_ &&
+      max_total_allocated_bitrate_.IsZero()) {
+    last_allowed_repeated_initial_probe_ =
+        at_time + config_.repeated_initial_probing_time_period;
+    LOG_INFO("Repeated initial probing enabled, last allowed probe: {} now: {}",
+             last_allowed_repeated_initial_probe_, at_time);
+  }
+
+  return InitiateProbing(at_time, probes, true);
+}
+
+std::vector<ProbeClusterConfig> ProbeController::SetEstimatedBitrate(
+    DataRate bitrate, BandwidthLimitedCause bandwidth_limited_cause,
+    Timestamp at_time) {
+  bandwidth_limited_cause_ = bandwidth_limited_cause;
+  if (bitrate < kBitrateDropThreshold * estimated_bitrate_) {
+    time_of_last_large_drop_ = at_time;
+    bitrate_before_last_large_drop_ = estimated_bitrate_;
+  }
+  estimated_bitrate_ = bitrate;
+
+  if (state_ == State::kWaitingForProbingResult) {
+    // Continue probing if probing results indicate channel has greater
+    // capacity unless we already reached the needed bitrate.
+    if (config_.abort_further_probe_if_max_lower_than_current &&
+        (bitrate > max_bitrate_ ||
+         (!max_total_allocated_bitrate_.IsZero() &&
+          bitrate > 2 * max_total_allocated_bitrate_))) {
+      // No need to continue probing.
+      min_bitrate_to_probe_further_ = DataRate::PlusInfinity();
+    }
+    DataRate network_state_estimate_probe_further_limit =
+        config_.network_state_estimate_probing_interval.IsFinite() &&
+                network_estimate_ &&
+                network_estimate_->link_capacity_upper.IsFinite()
+            ? network_estimate_->link_capacity_upper *
+                  config_.further_probe_threshold
+            : DataRate::PlusInfinity();
+    LOG_INFO(
+        "Measured bitrate: {} Minimum to probe further: {} upper limit: {}",
+        bitrate, min_bitrate_to_probe_further_,
+        network_state_estimate_probe_further_limit);
+
+    if (bitrate > min_bitrate_to_probe_further_ &&
+        bitrate <= network_state_estimate_probe_further_limit) {
+      return InitiateProbing(
+          at_time, {config_.further_exponential_probe_scale * bitrate}, true);
+    }
+  }
+  return {};
+}
+
+void ProbeController::EnablePeriodicAlrProbing(bool enable) {
+  enable_periodic_alr_probing_ = enable;
+}
+
+void ProbeController::EnableRepeatedInitialProbing(bool enable) {
+  repeated_initial_probing_enabled_ = enable;
+}
+
+void ProbeController::SetAlrStartTimeMs(
+    std::optional<int64_t> alr_start_time_ms) {
+  if (alr_start_time_ms) {
+    alr_start_time_ = Timestamp::Millis(*alr_start_time_ms);
+  } else {
+    alr_start_time_ = std::nullopt;
+  }
+}
+void ProbeController::SetAlrEndedTimeMs(int64_t alr_end_time_ms) {
+  alr_end_time_.emplace(Timestamp::Millis(alr_end_time_ms));
+}
+
+std::vector<ProbeClusterConfig> ProbeController::RequestProbe(
+    Timestamp at_time) {
+  // Called once we have returned to normal state after a large drop in
+  // estimated bandwidth. The current response is to initiate a single probe
+  // session (if not already probing) at the previous bitrate.
+  //
+  // If the probe session fails, the assumption is that this drop was a
+  // real one from a competing flow or a network change.
+  bool in_alr = alr_start_time_.has_value();
+  bool alr_ended_recently =
+      (alr_end_time_.has_value() &&
+       at_time - alr_end_time_.value() < kAlrEndedTimeout);
+  if (in_alr || alr_ended_recently) {
+    if (state_ == State::kProbingComplete) {
+      DataRate suggested_probe =
+          kProbeFractionAfterDrop * bitrate_before_last_large_drop_;
+      DataRate min_expected_probe_result =
+          (1 - kProbeUncertainty) * suggested_probe;
+      TimeDelta time_since_drop = at_time - time_of_last_large_drop_;
+      TimeDelta time_since_probe = at_time - last_bwe_drop_probing_time_;
+      if (min_expected_probe_result > estimated_bitrate_ &&
+          time_since_drop < kBitrateDropTimeout &&
+          time_since_probe > kMinTimeBetweenAlrProbes) {
+        LOG_INFO("Detected big bandwidth drop, start probing");
+        last_bwe_drop_probing_time_ = at_time;
+        return InitiateProbing(at_time, {suggested_probe}, false);
+      }
+    }
+  }
+  return std::vector<ProbeClusterConfig>();
+}
+
+void ProbeController::SetNetworkStateEstimate(
+    webrtc::NetworkStateEstimate estimate) {
+  network_estimate_ = estimate;
+}
+
+void ProbeController::Reset(Timestamp at_time) {
+  bandwidth_limited_cause_ = BandwidthLimitedCause::kDelayBasedLimited;
+  state_ = State::kInit;
+  min_bitrate_to_probe_further_ = DataRate::PlusInfinity();
+  time_last_probing_initiated_ = Timestamp::Zero();
+  estimated_bitrate_ = DataRate::Zero();
+  network_estimate_ = std::nullopt;
+  start_bitrate_ = DataRate::Zero();
+  max_bitrate_ = kDefaultMaxProbingBitrate;
+  Timestamp now = at_time;
+  last_bwe_drop_probing_time_ = now;
+  alr_end_time_.reset();
+  time_of_last_large_drop_ = now;
+  bitrate_before_last_large_drop_ = DataRate::Zero();
+}
+
+bool ProbeController::TimeForAlrProbe(Timestamp at_time) const {
+  if (enable_periodic_alr_probing_ && alr_start_time_) {
+    Timestamp next_probe_time =
+        std::max(*alr_start_time_, time_last_probing_initiated_) +
+        config_.alr_probing_interval;
+    return at_time >= next_probe_time;
+  }
+  return false;
+}
+
+bool ProbeController::TimeForNetworkStateProbe(Timestamp at_time) const {
+  if (!network_estimate_ ||
+      network_estimate_->link_capacity_upper.IsInfinite()) {
+    return false;
+  }
+
+  bool probe_due_to_low_estimate =
+      bandwidth_limited_cause_ == BandwidthLimitedCause::kDelayBasedLimited &&
+      estimated_bitrate_ <
+          config_.probe_if_estimate_lower_than_network_state_estimate_ratio *
+              network_estimate_->link_capacity_upper;
+  if (probe_due_to_low_estimate &&
+      config_.estimate_lower_than_network_state_estimate_probing_interval
+          .IsFinite()) {
+    Timestamp next_probe_time =
+        time_last_probing_initiated_ +
+        config_.estimate_lower_than_network_state_estimate_probing_interval;
+    return at_time >= next_probe_time;
+  }
+
+  bool periodic_probe =
+      estimated_bitrate_ < network_estimate_->link_capacity_upper;
+  if (periodic_probe &&
+      config_.network_state_estimate_probing_interval.IsFinite()) {
+    Timestamp next_probe_time = time_last_probing_initiated_ +
+                                config_.network_state_estimate_probing_interval;
+    return at_time >= next_probe_time;
+  }
+
+  return false;
+}
+
+bool ProbeController::TimeForNextRepeatedInitialProbe(Timestamp at_time) const {
+  if (state_ != State::kWaitingForProbingResult &&
+      last_allowed_repeated_initial_probe_ > at_time) {
+    Timestamp next_probe_time =
+        time_last_probing_initiated_ + kMaxWaitingTimeForProbingResult;
+    if (at_time >= next_probe_time) {
+      return true;
+    }
+  }
+  return false;
+}
+
+std::vector<ProbeClusterConfig> ProbeController::Process(Timestamp at_time) {
+  if (at_time - time_last_probing_initiated_ >
+      kMaxWaitingTimeForProbingResult) {
+    if (state_ == State::kWaitingForProbingResult) {
+      LOG_INFO("kWaitingForProbingResult: timeout");
+      UpdateState(State::kProbingComplete);
+    }
+  }
+  if (estimated_bitrate_.IsZero() || state_ != State::kProbingComplete) {
+    return {};
+  }
+  if (TimeForNextRepeatedInitialProbe(at_time)) {
+    return InitiateProbing(
+        at_time, {estimated_bitrate_ * config_.first_exponential_probe_scale},
+        true);
+  }
+  if (TimeForAlrProbe(at_time) || TimeForNetworkStateProbe(at_time)) {
+    return InitiateProbing(
+        at_time, {estimated_bitrate_ * config_.alr_probe_scale}, true);
+  }
+  return std::vector<ProbeClusterConfig>();
+}
+
+ProbeClusterConfig ProbeController::CreateProbeClusterConfig(Timestamp at_time,
+                                                             DataRate bitrate) {
+  ProbeClusterConfig config;
+  config.at_time = at_time;
+  config.target_data_rate = bitrate;
+  if (network_estimate_ &&
+      config_.network_state_estimate_probing_interval.IsFinite() &&
+      network_estimate_->link_capacity_upper.IsFinite() &&
+      network_estimate_->link_capacity_upper >= bitrate) {
+    config.target_duration = config_.network_state_probe_duration;
+    config.min_probe_delta = config_.network_state_min_probe_delta;
+  } else if (at_time < last_allowed_repeated_initial_probe_) {
+    config.target_duration = config_.initial_probe_duration;
+    config.min_probe_delta = config_.initial_min_probe_delta;
+  } else {
+    config.target_duration = config_.min_probe_duration;
+    config.min_probe_delta = config_.min_probe_delta;
+  }
+  config.target_probe_count = config_.min_probe_packets_sent;
+  config.id = next_probe_cluster_id_;
+  next_probe_cluster_id_++;
+  return config;
+}
+
+std::vector<ProbeClusterConfig> ProbeController::InitiateProbing(
+    Timestamp now, std::vector<DataRate> bitrates_to_probe,
+    bool probe_further) {
+  if (config_.skip_if_estimate_larger_than_fraction_of_max > 0) {
+    DataRate network_estimate = network_estimate_
+                                    ? network_estimate_->link_capacity_upper
+                                    : DataRate::PlusInfinity();
+    DataRate max_probe_rate =
+        max_total_allocated_bitrate_.IsZero()
+            ? max_bitrate_
+            : std::min(config_.skip_probe_max_allocated_scale *
+                           max_total_allocated_bitrate_,
+                       max_bitrate_);
+    if (std::min(network_estimate, estimated_bitrate_) >
+        config_.skip_if_estimate_larger_than_fraction_of_max * max_probe_rate) {
+      UpdateState(State::kProbingComplete);
+      return {};
+    }
+  }
+
+  DataRate max_probe_bitrate = max_bitrate_;
+  if (max_total_allocated_bitrate_ > DataRate::Zero()) {
+    // If a max allocated bitrate has been configured, allow probing up to 2x
+    // that rate. This allows some overhead to account for bursty streams,
+    // which otherwise would have to ramp up when the overshoot is already in
+    // progress.
+    // It also avoids minor quality reduction caused by probes often being
+    // received at slightly less than the target probe bitrate.
+    max_probe_bitrate =
+        std::min(max_probe_bitrate, max_total_allocated_bitrate_ * 2);
+  }
+
+  switch (bandwidth_limited_cause_) {
+    case BandwidthLimitedCause::kRttBasedBackOffHighRtt:
+    case BandwidthLimitedCause::kDelayBasedLimitedDelayIncreased:
+    case BandwidthLimitedCause::kLossLimitedBwe:
+      LOG_INFO("Not sending probe in bandwidth limited state {}",
+               static_cast<int>(bandwidth_limited_cause_));
+      return {};
+    case BandwidthLimitedCause::kLossLimitedBweIncreasing:
+      max_probe_bitrate =
+          std::min(max_probe_bitrate,
+                   estimated_bitrate_ * config_.loss_limited_probe_scale);
+      break;
+    case BandwidthLimitedCause::kDelayBasedLimited:
+      break;
+    default:
+      break;
+  }
+
+  if (config_.network_state_estimate_probing_interval.IsFinite() &&
+      network_estimate_ && network_estimate_->link_capacity_upper.IsFinite()) {
+    if (network_estimate_->link_capacity_upper.IsZero()) {
+      LOG_INFO("Not sending probe, Network state estimate is zero");
+      return {};
+    }
+    max_probe_bitrate = std::min(
+        {max_probe_bitrate,
+         std::max(estimated_bitrate_, network_estimate_->link_capacity_upper *
+                                          config_.network_state_probe_scale)});
+  }
+
+  std::vector<ProbeClusterConfig> pending_probes;
+  for (DataRate bitrate : bitrates_to_probe) {
+    if (bitrate >= max_probe_bitrate) {
+      bitrate = max_probe_bitrate;
+      probe_further = false;
+    }
+    pending_probes.push_back(CreateProbeClusterConfig(now, bitrate));
+  }
+  time_last_probing_initiated_ = now;
+  if (probe_further) {
+    UpdateState(State::kWaitingForProbingResult);
+    // Dont expect probe results to be larger than a fraction of the actual
+    // probe rate.
+    min_bitrate_to_probe_further_ = pending_probes.back().target_data_rate *
+                                    config_.further_probe_threshold;
+  } else {
+    UpdateState(State::kProbingComplete);
+  }
+  return pending_probes;
+}
+
+}  // namespace webrtc

src/qos/probe_controller.h

@@ -0,0 +1,202 @@
+/*
+ *  Copyright (c) 2016 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_CONGESTION_CONTROLLER_GOOG_CC_PROBE_CONTROLLER_H_
+#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_PROBE_CONTROLLER_H_
+
+#include <stdint.h>
+
+#include <optional>
+#include <vector>
+
+#include "api/transport/network_types.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+
+namespace webrtc {
+
+struct ProbeControllerConfig {
+  ProbeControllerConfig();
+  ProbeControllerConfig(const ProbeControllerConfig&);
+  ProbeControllerConfig& operator=(const ProbeControllerConfig&) = default;
+  ~ProbeControllerConfig();
+
+  // These parameters configure the initial probes. First we send one or two
+  // probes of sizes p1 * start_bitrate_ and p2 * start_bitrate_.
+  // Then whenever we get a bitrate estimate of at least further_probe_threshold
+  // times the size of the last sent probe we'll send another one of size
+  // step_size times the new estimate.
+  double first_exponential_probe_scale;
+  double second_exponential_probe_scale;
+  double further_exponential_probe_scale;
+  double further_probe_threshold;
+  bool abort_further_probe_if_max_lower_than_current;
+  // Duration of time from the first initial probe where repeated initial probes
+  // are sent if repeated initial probing is enabled.
+  TimeDelta repeated_initial_probing_time_period;
+  // The minimum probing duration of an individual probe during
+  // the repeated_initial_probing_time_period.
+  TimeDelta initial_probe_duration;
+  // Delta time between sent bursts of packets in a probe during
+  // the repeated_initial_probing_time_period.
+  TimeDelta initial_min_probe_delta;
+  // Configures how often we send ALR probes and how big they are.
+  TimeDelta alr_probing_interval;
+  double alr_probe_scale;
+  // Configures how often we send probes if NetworkStateEstimate is available.
+  TimeDelta network_state_estimate_probing_interval;
+  // Periodically probe as long as the ratio between current estimate and
+  // NetworkStateEstimate is lower then this.
+  double probe_if_estimate_lower_than_network_state_estimate_ratio;
+  TimeDelta estimate_lower_than_network_state_estimate_probing_interval;
+  double network_state_probe_scale;
+  // Overrides min_probe_duration if network_state_estimate_probing_interval
+  // is set and a network state estimate is known and equal or higher than the
+  // probe target.
+  TimeDelta network_state_probe_duration;
+  // Overrides min_probe_delta if network_state_estimate_probing_interval
+  // is set and a network state estimate is known and equal or higher than the
+  // probe target.
+  TimeDelta network_state_min_probe_delta;
+
+  // Configures the probes emitted by changed to the allocated bitrate.
+  bool probe_on_max_allocated_bitrate_change;
+  double first_allocation_probe_scale;
+  double second_allocation_probe_scale;
+  double allocation_probe_limit_by_current_scale;
+
+  // The minimum number probing packets used.
+  int min_probe_packets_sent;
+  // The minimum probing duration.
+  TimeDelta min_probe_duration;
+  // Delta time between sent bursts of packets in a probe.
+  TimeDelta min_probe_delta;
+  double loss_limited_probe_scale;
+  // Don't send a probe if min(estimate, network state estimate) is larger than
+  // this fraction of the set max or max allocated bitrate.
+  double skip_if_estimate_larger_than_fraction_of_max;
+  // Scale factor of the max allocated bitrate. Used when deciding if a probe
+  // can be skiped due to that the estimate is already high enough.
+  double skip_probe_max_allocated_scale;
+};
+
+// Reason that bandwidth estimate is limited. Bandwidth estimate can be limited
+// by either delay based bwe, or loss based bwe when it increases/decreases the
+// estimate.
+enum class BandwidthLimitedCause : int {
+  kLossLimitedBweIncreasing = 0,
+  kLossLimitedBwe = 1,
+  kDelayBasedLimited = 2,
+  kDelayBasedLimitedDelayIncreased = 3,
+  kRttBasedBackOffHighRtt = 4
+};
+
+// This class controls initiation of probing to estimate initial channel
+// capacity. There is also support for probing during a session when max
+// bitrate is adjusted by an application.
+class ProbeController {
+ public:
+  ProbeController();
+  ~ProbeController();
+
+  ProbeController(const ProbeController&) = delete;
+  ProbeController& operator=(const ProbeController&) = delete;
+
+  std::vector<ProbeClusterConfig> SetBitrates(DataRate min_bitrate,
+                                              DataRate start_bitrate,
+                                              DataRate max_bitrate,
+                                              Timestamp at_time);
+
+  // The total bitrate, as opposed to the max bitrate, is the sum of the
+  // configured bitrates for all active streams.
+  std::vector<ProbeClusterConfig> OnMaxTotalAllocatedBitrate(
+      DataRate max_total_allocated_bitrate, Timestamp at_time);
+
+  std::vector<ProbeClusterConfig> OnNetworkAvailability(
+      NetworkAvailability msg);
+
+  std::vector<ProbeClusterConfig> SetEstimatedBitrate(
+      DataRate bitrate, BandwidthLimitedCause bandwidth_limited_cause,
+      Timestamp at_time);
+
+  void EnablePeriodicAlrProbing(bool enable);
+
+  // Probes are sent periodically every 1s during the first 5s after the network
+  // becomes available or until OnMaxTotalAllocatedBitrate is invoked with a
+  // none zero max_total_allocated_bitrate (there are active streams being
+  // sent.) Probe rate is up to max configured bitrate configured via
+  // SetBitrates.
+  void EnableRepeatedInitialProbing(bool enable);
+
+  void SetAlrStartTimeMs(std::optional<int64_t> alr_start_time);
+  void SetAlrEndedTimeMs(int64_t alr_end_time);
+
+  std::vector<ProbeClusterConfig> RequestProbe(Timestamp at_time);
+
+  void SetNetworkStateEstimate(webrtc::NetworkStateEstimate estimate);
+
+  // Resets the ProbeController to a state equivalent to as if it was just
+  // created EXCEPT for configuration settings like
+  // `enable_periodic_alr_probing_` `network_available_` and
+  // `max_total_allocated_bitrate_`.
+  void Reset(Timestamp at_time);
+
+  std::vector<ProbeClusterConfig> Process(Timestamp at_time);
+
+ private:
+  enum class State {
+    // Initial state where no probing has been triggered yet.
+    kInit,
+    // Waiting for probing results to continue further probing.
+    kWaitingForProbingResult,
+    // Probing is complete.
+    kProbingComplete,
+  };
+
+  void UpdateState(State new_state);
+  std::vector<ProbeClusterConfig> InitiateExponentialProbing(Timestamp at_time);
+  std::vector<ProbeClusterConfig> InitiateProbing(
+      Timestamp now, std::vector<DataRate> bitrates_to_probe,
+      bool probe_further);
+  bool TimeForAlrProbe(Timestamp at_time) const;
+  bool TimeForNetworkStateProbe(Timestamp at_time) const;
+  bool TimeForNextRepeatedInitialProbe(Timestamp at_time) const;
+  ProbeClusterConfig CreateProbeClusterConfig(Timestamp at_time,
+                                              DataRate bitrate);
+
+  bool network_available_;
+  bool repeated_initial_probing_enabled_ = false;
+  Timestamp last_allowed_repeated_initial_probe_ = Timestamp::MinusInfinity();
+  BandwidthLimitedCause bandwidth_limited_cause_ =
+      BandwidthLimitedCause::kDelayBasedLimited;
+  State state_;
+  DataRate min_bitrate_to_probe_further_ = DataRate::PlusInfinity();
+  Timestamp time_last_probing_initiated_ = Timestamp::MinusInfinity();
+  DataRate estimated_bitrate_ = DataRate::Zero();
+  std::optional<webrtc::NetworkStateEstimate> network_estimate_;
+  DataRate start_bitrate_ = DataRate::Zero();
+  DataRate max_bitrate_ = DataRate::PlusInfinity();
+  Timestamp last_bwe_drop_probing_time_ = Timestamp::Zero();
+  std::optional<Timestamp> alr_start_time_;
+  std::optional<Timestamp> alr_end_time_;
+  bool enable_periodic_alr_probing_;
+  Timestamp time_of_last_large_drop_ = Timestamp::MinusInfinity();
+  DataRate bitrate_before_last_large_drop_ = DataRate::Zero();
+  DataRate max_total_allocated_bitrate_ = DataRate::Zero();
+
+  int32_t next_probe_cluster_id_ = 1;
+
+  ProbeControllerConfig config_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_CONGESTION_CONTROLLER_GOOG_CC_PROBE_CONTROLLER_H_

src/qos/receive_side_congestion_controller.cc

@@ -0,0 +1,107 @@
+/*
+ *  Copyright (c) 2017 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.
+ */
+
+#include "receive_side_congestion_controller.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <memory>
+#include <utility>
+
+#include "api/media_types.h"
+#include "api/transport/network_control.h"
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "log.h"
+#include "remote_bitrate_estimator_single_stream.h"
+#include "rtp_packet_received.h"
+
+namespace webrtc {
+
+namespace {
+static const uint32_t kTimeOffsetSwitchThreshold = 30;
+}  // namespace
+
+void ReceiveSideCongestionController::OnRttUpdate(int64_t avg_rtt_ms,
+                                                  int64_t max_rtt_ms) {
+  std::lock_guard<std::mutex> lock(mutex_);
+  rbe_->OnRttUpdate(avg_rtt_ms, max_rtt_ms);
+}
+
+void ReceiveSideCongestionController::RemoveStream(uint32_t ssrc) {
+  std::lock_guard<std::mutex> lock(mutex_);
+  rbe_->RemoveStream(ssrc);
+}
+
+DataRate ReceiveSideCongestionController::LatestReceiveSideEstimate() const {
+  std::lock_guard<std::mutex> lock(mutex_);
+  return rbe_->LatestEstimate();
+}
+
+void ReceiveSideCongestionController::PickEstimator() {
+  // When we don't see AST, wait for a few packets before going back to TOF.
+  if (using_absolute_send_time_) {
+    ++packets_since_absolute_send_time_;
+    if (packets_since_absolute_send_time_ >= kTimeOffsetSwitchThreshold) {
+      LOG_INFO(
+          "WrappingBitrateEstimator: Switching to transmission "
+          "time offset RBE.");
+      using_absolute_send_time_ = false;
+      rbe_ = std::make_unique<RemoteBitrateEstimatorSingleStream>(
+          clock_, &remb_throttler_);
+    }
+  }
+}
+
+ReceiveSideCongestionController::ReceiveSideCongestionController(
+    std::shared_ptr<SimulatedClock> clock,
+    RtpTransportFeedbackGenerator::RtcpSender feedback_sender,
+    RembThrottler::RembSender remb_sender,
+    std::shared_ptr<NetworkStateEstimator> network_state_estimator)
+    : clock_(clock),
+      remb_throttler_(std::move(remb_sender), clock.get()),
+      congestion_control_feedback_generator_(clock, feedback_sender),
+      rbe_(std::make_unique<RemoteBitrateEstimatorSingleStream>(
+          clock, &remb_throttler_)),
+      using_absolute_send_time_(false),
+      packets_since_absolute_send_time_(0) {}
+
+void ReceiveSideCongestionController::OnReceivedPacket(
+    const RtpPacketReceived& packet, MediaType media_type) {
+  congestion_control_feedback_generator_.OnReceivedPacket(packet);
+  return;
+}
+
+void ReceiveSideCongestionController::OnBitrateChanged(int bitrate_bps) {
+  DataRate send_bandwidth_estimate = DataRate::BitsPerSec(bitrate_bps);
+  congestion_control_feedback_generator_.OnSendBandwidthEstimateChanged(
+      send_bandwidth_estimate);
+}
+
+TimeDelta ReceiveSideCongestionController::MaybeProcess() {
+  Timestamp now = clock_->CurrentTime();
+  TimeDelta time_until = congestion_control_feedback_generator_.Process(now);
+  return std::max(time_until, TimeDelta::Zero());
+}
+
+void ReceiveSideCongestionController::SetMaxDesiredReceiveBitrate(
+    DataRate bitrate) {
+  remb_throttler_.SetMaxDesiredReceiveBitrate(bitrate);
+}
+
+void ReceiveSideCongestionController::SetTransportOverhead(
+    DataSize overhead_per_packet) {
+  congestion_control_feedback_generator_.SetTransportOverhead(
+      overhead_per_packet);
+}
+
+}  // namespace webrtc

src/qos/receive_side_congestion_controller.cpp

@@ -1,61 +0,0 @@
-/*
- *  Copyright (c) 2017 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.
- */
-
-#include "receive_side_congestion_controller.h"
-
-#include <algorithm>
-#include <chrono>
-#include <memory>
-#include <utility>
-
-namespace {
-static const uint32_t kTimeOffsetSwitchThreshold = 30;
-}  // namespace
-
-ReceiveSideCongestionController::ReceiveSideCongestionController(
-    RtcpSender feedback_sender)
-    : congestion_control_feedback_generator_(feedback_sender),
-      using_absolute_send_time_(false),
-      packets_since_absolute_send_time_(0) {}
-
-void ReceiveSideCongestionController::OnReceivedPacket(
-    RtpPacketReceived& packet, MediaType media_type) {
-  // RTC_DCHECK_RUN_ON(&sequence_checker_);
-  congestion_control_feedback_generator_.OnReceivedPacket(packet);
-  return;
-}
-
-void ReceiveSideCongestionController::OnBitrateChanged(int bitrate_bps) {
-  // RTC_DCHECK_RUN_ON(&sequence_checker_);
-  int64_t send_bandwidth_estimate = bitrate_bps;
-  congestion_control_feedback_generator_.OnSendBandwidthEstimateChanged(
-      send_bandwidth_estimate);
-}
-
-int64_t ReceiveSideCongestionController::MaybeProcess() {
-  auto now = std::chrono::system_clock::now();
-  int64_t now_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
-                       now.time_since_epoch())
-                       .count();
-  // RTC_DCHECK_RUN_ON(&sequence_checker_);
-  return congestion_control_feedback_generator_.Process(now_ms);
-}
-
-void ReceiveSideCongestionController::SetMaxDesiredReceiveBitrate(
-    int64_t bitrate) {
-  // remb_throttler_.SetMaxDesiredReceiveBitrate(bitrate);
-}
-
-void ReceiveSideCongestionController::SetTransportOverhead(
-    int64_t overhead_per_packet) {
-  // RTC_DCHECK_RUN_ON(&sequence_checker_);
-  congestion_control_feedback_generator_.SetTransportOverhead(
-      overhead_per_packet);
-}

src/qos/receive_side_congestion_controller.h

@@ -1,55 +1,89 @@
 /*
- * @Author: DI JUNKUN
- * @Date: 2024-12-12
- * Copyright (c) 2024 by DI JUNKUN, All Rights Reserved.
+ *  Copyright (c) 2017 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 _RECEIVE_SIDE_CONGESTION_CONTROLLER_H_
-#define _RECEIVE_SIDE_CONGESTION_CONTROLLER_H_
+#ifndef MODULES_CONGESTION_CONTROLLER_INCLUDE_RECEIVE_SIDE_CONGESTION_CONTROLLER_H_
+#define MODULES_CONGESTION_CONTROLLER_INCLUDE_RECEIVE_SIDE_CONGESTION_CONTROLLER_H_
 
+#include <cstdint>
+#include <memory>
 #include <mutex>
 
+#include "api/media_types.h"
+#include "api/transport/network_control.h"
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
 #include "congestion_control_feedback_generator.h"
+#include "module_common_types.h"
+#include "remb_throttler.h"
+#include "rtc_base/thread_annotations.h"
 #include "rtp_packet_received.h"
 
-class ReceiveSideCongestionController {
- public:
-  enum MediaType { VIDEO, AUDIO, DATA };
+namespace webrtc {
+class RemoteBitrateEstimator;
 
+// This class represents the congestion control state for receive
+// streams. For send side bandwidth estimation, this is simply
+// relaying for each received RTP packet back to the sender. While for
+// receive side bandwidth estimation, we do the estimation locally and
+// send our results back to the sender.
+class ReceiveSideCongestionController : public CallStatsObserver {
  public:
-  ReceiveSideCongestionController(RtcpSender feedback_sender);
-  ~ReceiveSideCongestionController() = default;
+  ReceiveSideCongestionController(
+      std::shared_ptr<SimulatedClock> clock,
+      RtpTransportFeedbackGenerator::RtcpSender feedback_sender,
+      RembThrottler::RembSender remb_sender,
+      std::shared_ptr<NetworkStateEstimator> network_state_estimator);
 
- public:
-  void OnReceivedPacket(RtpPacketReceived& packet, MediaType media_type);
+  ~ReceiveSideCongestionController() override = default;
+
+  void OnReceivedPacket(const RtpPacketReceived& packet, MediaType media_type);
+
+  // Implements CallStatsObserver.
+  void OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms) override;
 
   // This is send bitrate, used to control the rate of feedback messages.
   void OnBitrateChanged(int bitrate_bps);
 
   // Ensures the remote party is notified of the receive bitrate no larger than
   // `bitrate` using RTCP REMB.
-  void SetMaxDesiredReceiveBitrate(int64_t bitrate);
+  void SetMaxDesiredReceiveBitrate(DataRate bitrate);
 
-  void SetTransportOverhead(int64_t overhead_per_packet);
+  void SetTransportOverhead(DataSize overhead_per_packet);
+
+  // Returns latest receive side bandwidth estimation.
+  // Returns zero if receive side bandwidth estimation is unavailable.
+  DataRate LatestReceiveSideEstimate() const;
+
+  // Removes stream from receive side bandwidth estimation.
+  // Noop if receive side bwe is not used or stream doesn't participate in it.
+  void RemoveStream(uint32_t ssrc);
 
   // Runs periodic tasks if it is time to run them, returns time until next
   // call to `MaybeProcess` should be non idle.
-  int64_t MaybeProcess();
+  TimeDelta MaybeProcess();
 
  private:
-  //   RembThrottler remb_throttler_;
+  void PickEstimator();
 
-  // TODO: bugs.webrtc.org/42224904 - Use sequence checker for all usage of
-  // ReceiveSideCongestionController. At the time of
-  // writing OnReceivedPacket and MaybeProcess can unfortunately be called on an
-  // arbitrary thread by external projects.
-  //   SequenceChecker sequence_checker_;
+  std::shared_ptr<SimulatedClock> clock_;
+  RembThrottler remb_throttler_;
 
   CongestionControlFeedbackGenerator congestion_control_feedback_generator_;
 
-  std::mutex mutex_;
+  mutable std::mutex mutex_;
+  std::unique_ptr<RemoteBitrateEstimator> rbe_;
   bool using_absolute_send_time_;
   uint32_t packets_since_absolute_send_time_;
 };
 
-#endif
+}  // namespace webrtc
+
+#endif  // MODULES_CONGESTION_CONTROLLER_INCLUDE_RECEIVE_SIDE_CONGESTION_CONTROLLER_H_

src/qos/remb_throttler.cc

@@ -0,0 +1,64 @@
+/*
+ *  Copyright (c) 2021 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.
+ */
+
+#include "remb_throttler.h"
+
+#include <algorithm>
+#include <mutex>  // Include the mutex header
+#include <utility>
+
+namespace webrtc {
+
+namespace {
+constexpr TimeDelta kRembSendInterval = TimeDelta::Millis(200);
+}  // namespace
+
+RembThrottler::RembThrottler(RembSender remb_sender, Clock* clock)
+    : remb_sender_(std::move(remb_sender)),
+      clock_(clock),
+      last_remb_time_(Timestamp::MinusInfinity()),
+      last_send_remb_bitrate_(DataRate::PlusInfinity()),
+      max_remb_bitrate_(DataRate::PlusInfinity()) {}
+
+void RembThrottler::OnReceiveBitrateChanged(const std::vector<uint32_t>& ssrcs,
+                                            uint32_t bitrate_bps) {
+  DataRate receive_bitrate = DataRate::BitsPerSec(bitrate_bps);
+  Timestamp now = clock_->CurrentTime();
+  {
+    std::lock_guard<std::mutex> lock(mutex_);  // Use std::lock_guard
+    // % threshold for if we should send a new REMB asap.
+    const int64_t kSendThresholdPercent = 103;
+    if (receive_bitrate * kSendThresholdPercent / 100 >
+            last_send_remb_bitrate_ &&
+        now < last_remb_time_ + kRembSendInterval) {
+      return;
+    }
+    last_remb_time_ = now;
+    last_send_remb_bitrate_ = receive_bitrate;
+    receive_bitrate = std::min(last_send_remb_bitrate_, max_remb_bitrate_);
+  }
+  remb_sender_(receive_bitrate.bps(), ssrcs);
+}
+
+void RembThrottler::SetMaxDesiredReceiveBitrate(DataRate bitrate) {
+  Timestamp now = clock_->CurrentTime();
+  {
+    std::lock_guard<std::mutex> lock(mutex_);  // Use std::lock_guard
+    max_remb_bitrate_ = bitrate;
+    if (now - last_remb_time_ < kRembSendInterval &&
+        !last_send_remb_bitrate_.IsZero() &&
+        last_send_remb_bitrate_ <= max_remb_bitrate_) {
+      return;
+    }
+  }
+  remb_sender_(bitrate.bps(), /*ssrcs=*/{});
+}
+
+}  // namespace webrtc

src/qos/remb_throttler.h

@@ -0,0 +1,54 @@
+/*
+ *  Copyright (c) 2021 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_CONGESTION_CONTROLLER_REMB_THROTTLER_H_
+#define MODULES_CONGESTION_CONTROLLER_REMB_THROTTLER_H_
+
+#include <functional>
+#include <mutex>
+#include <vector>
+
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "remote_bitrate_estimator.h"
+
+namespace webrtc {
+
+// RembThrottler is a helper class used for throttling RTCP REMB messages.
+// Throttles small changes to the received BWE within 200ms.
+class RembThrottler : public RemoteBitrateObserver {
+ public:
+  using RembSender =
+      std::function<void(int64_t bitrate_bps, std::vector<uint32_t> ssrcs)>;
+  RembThrottler(RembSender remb_sender, Clock* clock);
+
+  // Ensures the remote party is notified of the receive bitrate no larger than
+  // `bitrate` using RTCP REMB.
+  void SetMaxDesiredReceiveBitrate(DataRate bitrate);
+
+  // Implements RemoteBitrateObserver;
+  // Called every time there is a new bitrate estimate for a receive channel
+  // group. This call will trigger a new RTCP REMB packet if the bitrate
+  // estimate has decreased or if no RTCP REMB packet has been sent for
+  // a certain time interval.
+  void OnReceiveBitrateChanged(const std::vector<uint32_t>& ssrcs,
+                               uint32_t bitrate_bps) override;
+
+ private:
+  const RembSender remb_sender_;
+  Clock* const clock_;
+  std::mutex mutex_;
+  Timestamp last_remb_time_;
+  DataRate last_send_remb_bitrate_;
+  DataRate max_remb_bitrate_;
+};
+
+}  // namespace webrtc
+#endif  // MODULES_CONGESTION_CONTROLLER_REMB_THROTTLER_H_

src/qos/remote_bitrate_estimator.h

@@ -0,0 +1,65 @@
+/*
+ *  Copyright (c) 2012 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.
+ */
+
+// This class estimates the incoming available bandwidth.
+
+#ifndef MODULES_REMOTE_BITRATE_ESTIMATOR_INCLUDE_REMOTE_BITRATE_ESTIMATOR_H_
+#define MODULES_REMOTE_BITRATE_ESTIMATOR_INCLUDE_REMOTE_BITRATE_ESTIMATOR_H_
+
+#include <cstdint>
+#include <vector>
+
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "clock.h"
+#include "module_common_types.h"
+#include "rtp_packet_received.h"
+
+namespace webrtc {
+
+class Clock;
+
+// RemoteBitrateObserver is used to signal changes in bitrate estimates for
+// the incoming streams.
+class RemoteBitrateObserver {
+ public:
+  // Called when a receive channel group has a new bitrate estimate for the
+  // incoming streams.
+  virtual void OnReceiveBitrateChanged(const std::vector<uint32_t>& ssrcs,
+                                       uint32_t bitrate) = 0;
+
+  virtual ~RemoteBitrateObserver() {}
+};
+
+class RemoteBitrateEstimator : public CallStatsObserver {
+ public:
+  ~RemoteBitrateEstimator() override {}
+
+  // Called for each incoming packet. Updates the incoming payload bitrate
+  // estimate and the over-use detector. If an over-use is detected the
+  // remote bitrate estimate will be updated.
+  virtual void IncomingPacket(const RtpPacketReceived& rtp_packet) = 0;
+
+  // Removes all data for `ssrc`.
+  virtual void RemoveStream(uint32_t ssrc) = 0;
+
+  // Returns latest estimate or DataRate::Zero() if estimation is unavailable.
+  virtual DataRate LatestEstimate() const = 0;
+
+  virtual TimeDelta Process() = 0;
+
+ protected:
+  static constexpr TimeDelta kProcessInterval = TimeDelta::Millis(500);
+  static constexpr TimeDelta kStreamTimeOut = TimeDelta::Seconds(2);
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_REMOTE_BITRATE_ESTIMATOR_INCLUDE_REMOTE_BITRATE_ESTIMATOR_H_

src/qos/remote_bitrate_estimator_single_stream.cc

@@ -0,0 +1,181 @@
+/*
+ *  Copyright (c) 2012 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.
+ */
+
+#include "remote_bitrate_estimator_single_stream.h"
+
+#include <cstdint>
+#include <optional>
+#include <utility>
+
+#include "aimd_rate_control.h"
+#include "bwe_defines.h"
+#include "clock.h"
+#include "inter_arrival.h"
+#include "log.h"
+#include "overuse_detector.h"
+#include "overuse_estimator.h"
+#include "rtp_packet_received.h"
+
+namespace webrtc {
+namespace {
+
+constexpr int kTimestampGroupLengthMs = 5;
+constexpr double kTimestampToMs = 1.0 / 90.0;
+
+}  // namespace
+
+RemoteBitrateEstimatorSingleStream::Detector::Detector()
+    : last_packet_time(Timestamp::Zero()),
+      inter_arrival(90 * kTimestampGroupLengthMs, kTimestampToMs) {}
+
+RemoteBitrateEstimatorSingleStream::RemoteBitrateEstimatorSingleStream(
+    std::shared_ptr<SimulatedClock> clock, RemoteBitrateObserver* observer)
+    : clock_(clock),
+      observer_(observer),
+      incoming_bitrate_(kBitrateWindow),
+      last_valid_incoming_bitrate_(DataRate::Zero()),
+      process_interval_(kProcessInterval),
+      uma_recorded_(false) {
+  LOG_INFO("RemoteBitrateEstimatorSingleStream: Instantiating");
+}
+
+RemoteBitrateEstimatorSingleStream::~RemoteBitrateEstimatorSingleStream() =
+    default;
+
+void RemoteBitrateEstimatorSingleStream::IncomingPacket(
+    const RtpPacketReceived& rtp_packet) {
+  std::optional<int32_t> transmission_time_offset = rtp_packet.Timestamp();
+  if (!uma_recorded_) {
+    BweNames type = transmission_time_offset.has_value()
+                        ? BweNames::kReceiverTOffset
+                        : BweNames::kReceiverNoExtension;
+    uma_recorded_ = true;
+  }
+  uint32_t ssrc = rtp_packet.Ssrc();
+  uint32_t rtp_timestamp =
+      rtp_packet.Timestamp() + transmission_time_offset.value_or(0);
+  Timestamp now = clock_->CurrentTime();
+  Detector& estimator = overuse_detectors_[ssrc];
+  estimator.last_packet_time = now;
+
+  // Check if incoming bitrate estimate is valid, and if it needs to be reset.
+  std::optional<DataRate> incoming_bitrate = incoming_bitrate_.Rate(now);
+  if (incoming_bitrate) {
+    last_valid_incoming_bitrate_ = *incoming_bitrate;
+  } else if (last_valid_incoming_bitrate_ > DataRate::Zero()) {
+    // Incoming bitrate had a previous valid value, but now not enough data
+    // point are left within the current window. Reset incoming bitrate
+    // estimator so that the window size will only contain new data points.
+    incoming_bitrate_.Reset();
+    last_valid_incoming_bitrate_ = DataRate::Zero();
+  }
+  size_t payload_size = rtp_packet.payload_size() + rtp_packet.padding_size();
+  incoming_bitrate_.Update(payload_size, now);
+
+  const BandwidthUsage prior_state = estimator.detector.State();
+  uint32_t timestamp_delta = 0;
+  int64_t time_delta = 0;
+  int size_delta = 0;
+  int64_t now_ms = now.ms();
+  if (estimator.inter_arrival.ComputeDeltas(
+          rtp_timestamp, rtp_packet.arrival_time().ms(), now_ms, payload_size,
+          &timestamp_delta, &time_delta, &size_delta)) {
+    double timestamp_delta_ms = timestamp_delta * kTimestampToMs;
+    estimator.estimator.Update(time_delta, timestamp_delta_ms, size_delta,
+                               estimator.detector.State(), now_ms);
+    estimator.detector.Detect(estimator.estimator.offset(), timestamp_delta_ms,
+                              estimator.estimator.num_of_deltas(), now_ms);
+  }
+  if (estimator.detector.State() == BandwidthUsage::kBwOverusing) {
+    std::optional<DataRate> incoming_bitrate = incoming_bitrate_.Rate(now);
+    if (incoming_bitrate.has_value() &&
+        (prior_state != BandwidthUsage::kBwOverusing ||
+         remote_rate_.TimeToReduceFurther(now, *incoming_bitrate))) {
+      // The first overuse should immediately trigger a new estimate.
+      // We also have to update the estimate immediately if we are overusing
+      // and the target bitrate is too high compared to what we are receiving.
+      UpdateEstimate(now);
+    }
+  }
+}
+
+TimeDelta RemoteBitrateEstimatorSingleStream::Process() {
+  Timestamp now = clock_->CurrentTime();
+  Timestamp next_process_time = last_process_time_.has_value()
+                                    ? *last_process_time_ + process_interval_
+                                    : now;
+  // TODO(bugs.webrtc.org/13756): Removing rounding to milliseconds after
+  // investigating why tests fails without that rounding.
+  if (now.ms() >= next_process_time.ms()) {
+    UpdateEstimate(now);
+    last_process_time_ = now;
+    return process_interval_;
+  }
+
+  return next_process_time - now;
+}
+
+void RemoteBitrateEstimatorSingleStream::UpdateEstimate(Timestamp now) {
+  BandwidthUsage bw_state = BandwidthUsage::kBwNormal;
+  auto it = overuse_detectors_.begin();
+  while (it != overuse_detectors_.end()) {
+    if (now - it->second.last_packet_time > kStreamTimeOut) {
+      // This over-use detector hasn't received packets for `kStreamTimeOut`
+      // and is considered stale.
+      overuse_detectors_.erase(it++);
+    } else {
+      // Make sure that we trigger an over-use if any of the over-use detectors
+      // is detecting over-use.
+      if (it->second.detector.State() > bw_state) {
+        bw_state = it->second.detector.State();
+      }
+      ++it;
+    }
+  }
+  // We can't update the estimate if we don't have any active streams.
+  if (overuse_detectors_.empty()) {
+    return;
+  }
+
+  const RateControlInput input(bw_state, incoming_bitrate_.Rate(now));
+  uint32_t target_bitrate = remote_rate_.Update(input, now).bps<uint32_t>();
+  if (remote_rate_.ValidEstimate()) {
+    process_interval_ = remote_rate_.GetFeedbackInterval();
+    if (observer_)
+      observer_->OnReceiveBitrateChanged(GetSsrcs(), target_bitrate);
+  }
+}
+
+void RemoteBitrateEstimatorSingleStream::OnRttUpdate(int64_t avg_rtt_ms,
+                                                     int64_t /* max_rtt_ms */) {
+  remote_rate_.SetRtt(TimeDelta::Millis(avg_rtt_ms));
+}
+
+void RemoteBitrateEstimatorSingleStream::RemoveStream(uint32_t ssrc) {
+  overuse_detectors_.erase(ssrc);
+}
+
+DataRate RemoteBitrateEstimatorSingleStream::LatestEstimate() const {
+  if (!remote_rate_.ValidEstimate() || overuse_detectors_.empty()) {
+    return DataRate::Zero();
+  }
+  return remote_rate_.LatestEstimate();
+}
+
+std::vector<uint32_t> RemoteBitrateEstimatorSingleStream::GetSsrcs() const {
+  std::vector<uint32_t> ssrcs;
+  ssrcs.reserve(overuse_detectors_.size());
+  for (const auto& [ssrc, unused] : overuse_detectors_) {
+    ssrcs.push_back(ssrc);
+  }
+  return ssrcs;
+}
+
+}  // namespace webrtc

src/qos/remote_bitrate_estimator_single_stream.h

@@ -0,0 +1,80 @@
+/*
+ *  Copyright (c) 2015 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_REMOTE_BITRATE_ESTIMATOR_REMOTE_BITRATE_ESTIMATOR_SINGLE_STREAM_H_
+#define MODULES_REMOTE_BITRATE_ESTIMATOR_REMOTE_BITRATE_ESTIMATOR_SINGLE_STREAM_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <map>
+#include <optional>
+#include <vector>
+
+#include "aimd_rate_control.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "inter_arrival.h"
+#include "overuse_detector.h"
+#include "overuse_estimator.h"
+#include "remote_bitrate_estimator.h"
+#include "rtc_base/bitrate_tracker.h"
+
+namespace webrtc {
+
+class RemoteBitrateEstimatorSingleStream : public RemoteBitrateEstimator {
+ public:
+  RemoteBitrateEstimatorSingleStream(std::shared_ptr<SimulatedClock> clock,
+                                     RemoteBitrateObserver* observer);
+
+  RemoteBitrateEstimatorSingleStream() = delete;
+  RemoteBitrateEstimatorSingleStream(
+      const RemoteBitrateEstimatorSingleStream&) = delete;
+  RemoteBitrateEstimatorSingleStream& operator=(
+      const RemoteBitrateEstimatorSingleStream&) = delete;
+
+  ~RemoteBitrateEstimatorSingleStream() override;
+
+  void IncomingPacket(const RtpPacketReceived& rtp_packet) override;
+  TimeDelta Process() override;
+  void OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms) override;
+  void RemoveStream(uint32_t ssrc) override;
+  DataRate LatestEstimate() const override;
+
+ private:
+  struct Detector {
+    Detector();
+
+    Timestamp last_packet_time;
+    InterArrival inter_arrival;
+    OveruseEstimator estimator;
+    OveruseDetector detector;
+  };
+
+  // Triggers a new estimate calculation.
+  void UpdateEstimate(Timestamp now);
+
+  std::vector<uint32_t> GetSsrcs() const;
+
+  std::shared_ptr<SimulatedClock> clock_;
+  RemoteBitrateObserver* observer_;
+  std::map<uint32_t, Detector> overuse_detectors_;
+  BitrateTracker incoming_bitrate_;
+  DataRate last_valid_incoming_bitrate_;
+  AimdRateControl remote_rate_;
+  std::optional<Timestamp> last_process_time_;
+  TimeDelta process_interval_;
+  bool uma_recorded_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_REMOTE_BITRATE_ESTIMATOR_REMOTE_BITRATE_ESTIMATOR_SINGLE_STREAM_H_

src/qos/rtp_transport_feedback_generator.h

@@ -0,0 +1,47 @@
+/*
+ *  Copyright (c) 2024 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_REMOTE_BITRATE_ESTIMATOR_RTP_TRANSPORT_FEEDBACK_GENERATOR_H_
+#define MODULES_REMOTE_BITRATE_ESTIMATOR_RTP_TRANSPORT_FEEDBACK_GENERATOR_H_
+
+#include <memory>
+#include <vector>
+
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "rtp_packet_received.h"
+
+namespace webrtc {
+
+class RtpTransportFeedbackGenerator {
+ public:
+  // Function intented to be used for sending RTCP messages generated by an
+  // implementation of this class.
+  using RtcpSender =
+      std::function<void(std::vector<std::unique_ptr<RtcpPacket>> packets)>;
+  virtual ~RtpTransportFeedbackGenerator() = default;
+
+  virtual void OnReceivedPacket(const RtpPacketReceived& packet) = 0;
+
+  // Sends periodic feedback if it is time to send it.
+  // Returns time until next call to Process should be made.
+  virtual TimeDelta Process(Timestamp now) = 0;
+
+  virtual void OnSendBandwidthEstimateChanged(DataRate estimate) = 0;
+
+  // Overhead from transport layers below RTP. Ie, IP, SRTP.
+  virtual void SetTransportOverhead(DataSize overhead_per_packet) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_REMOTE_BITRATE_ESTIMATOR_RTP_TRANSPORT_FEEDBACK_GENERATOR_H_

src/qos/send_side_bandwidth_estimation.cc

@@ -20,25 +20,30 @@
 #include <string>
 #include <utility>
 
+#include "api/transport/bandwidth_usage.h"
+#include "api/transport/network_types.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+#include "bwe_defines.h"
 #include "log.h"
 
+namespace webrtc {
 namespace {
-constexpr int64_t kBweIncreaseInterval = 1000;
-constexpr int64_t kBweDecreaseInterval = 300;
-constexpr int64_t kStartPhase = 2000;
-constexpr int64_t kBweConverganceTime = 20000;
+constexpr TimeDelta kBweIncreaseInterval = TimeDelta::Millis(1000);
+constexpr TimeDelta kBweDecreaseInterval = TimeDelta::Millis(300);
+constexpr TimeDelta kStartPhase = TimeDelta::Millis(2000);
+constexpr TimeDelta kBweConverganceTime = TimeDelta::Millis(20000);
 constexpr int kLimitNumPackets = 20;
-constexpr int64_t kDefaultMaxBitrate = 1000000000;
-constexpr int64_t kLowBitrateLogPeriod = 10000;
-constexpr int64_t kRtcEventLogPeriod = 5000;
+constexpr DataRate kDefaultMaxBitrate = DataRate::BitsPerSec(1000000000);
+constexpr TimeDelta kLowBitrateLogPeriod = TimeDelta::Millis(10000);
+constexpr TimeDelta kRtcEventLogPeriod = TimeDelta::Millis(5000);
 // Expecting that RTCP feedback is sent uniformly within [0.5, 1.5]s intervals.
-constexpr int64_t kMaxRtcpFeedbackInterval = 5000;
+constexpr TimeDelta kMaxRtcpFeedbackInterval = TimeDelta::Millis(5000);
 
 constexpr float kDefaultLowLossThreshold = 0.02f;
 constexpr float kDefaultHighLossThreshold = 0.1f;
-constexpr int64_t kDefaultBitrateThreshold = 0;
-
-constexpr int64_t kCongestionControllerMinBitrate = 5000;
+constexpr DataRate kDefaultBitrateThreshold = DataRate::Zero();
 
 struct UmaRampUpMetric {
   const char* metric_name;
@@ -51,64 +56,70 @@ const UmaRampUpMetric kUmaRampupMetrics[] = {
     {"WebRTC.BWE.RampUpTimeTo2000kbpsInMs", 2000}};
 const size_t kNumUmaRampupMetrics =
     sizeof(kUmaRampupMetrics) / sizeof(kUmaRampupMetrics[0]);
+
+const char kBweLosExperiment[] = "WebRTC-BweLossExperiment";
+
 }  // namespace
 
 void LinkCapacityTracker::UpdateDelayBasedEstimate(
-    int64_t at_time, int64_t delay_based_bitrate) {
+    Timestamp at_time, DataRate delay_based_bitrate) {
   if (delay_based_bitrate < last_delay_based_estimate_) {
-    capacity_estimate_bps_ = std::min(capacity_estimate_bps_,
-                                      static_cast<double>(delay_based_bitrate));
+    capacity_estimate_bps_ =
+        std::min(capacity_estimate_bps_, delay_based_bitrate.bps<double>());
     last_link_capacity_update_ = at_time;
   }
   last_delay_based_estimate_ = delay_based_bitrate;
 }
 
-void LinkCapacityTracker::OnStartingRate(int64_t start_rate) {
-  if (IsInfinite(last_link_capacity_update_)) {
-    capacity_estimate_bps_ = start_rate;
-  }
+void LinkCapacityTracker::OnStartingRate(DataRate start_rate) {
+  if (last_link_capacity_update_.IsInfinite())
+    capacity_estimate_bps_ = start_rate.bps<double>();
 }
 
-void LinkCapacityTracker::OnRateUpdate(std::optional<int64_t> acknowledged,
-                                       int64_t target, int64_t at_time) {
+void LinkCapacityTracker::OnRateUpdate(std::optional<DataRate> acknowledged,
+                                       DataRate target, Timestamp at_time) {
   if (!acknowledged) return;
-  int64_t acknowledged_target = std::min(*acknowledged, target);
-  if (acknowledged_target > capacity_estimate_bps_) {
-    int64_t delta = at_time - last_link_capacity_update_;
-    double alpha = IsFinite(delta) ? exp(-(delta / 10)) : 0;
-    capacity_estimate_bps_ =
-        alpha * capacity_estimate_bps_ + (1 - alpha) * acknowledged_target;
+  DataRate acknowledged_target = std::min(*acknowledged, target);
+  if (acknowledged_target.bps() > capacity_estimate_bps_) {
+    TimeDelta delta = at_time - last_link_capacity_update_;
+    double alpha =
+        delta.IsFinite() ? exp(-(delta / TimeDelta::Seconds(10))) : 0;
+    capacity_estimate_bps_ = alpha * capacity_estimate_bps_ +
+                             (1 - alpha) * acknowledged_target.bps<double>();
   }
   last_link_capacity_update_ = at_time;
 }
 
-void LinkCapacityTracker::OnRttBackoff(int64_t backoff_rate, int64_t at_time) {
+void LinkCapacityTracker::OnRttBackoff(DataRate backoff_rate,
+                                       Timestamp at_time) {
   capacity_estimate_bps_ =
-      std::min(capacity_estimate_bps_, static_cast<double>(backoff_rate));
+      std::min(capacity_estimate_bps_, backoff_rate.bps<double>());
   last_link_capacity_update_ = at_time;
 }
 
-int64_t LinkCapacityTracker::estimate() const { return capacity_estimate_bps_; }
+DataRate LinkCapacityTracker::estimate() const {
+  return DataRate::BitsPerSec(capacity_estimate_bps_);
+}
 
 RttBasedBackoff::RttBasedBackoff()
     : disabled_(true),
-      configured_limit_(3),
+      configured_limit_(TimeDelta::Seconds(3)),
       drop_fraction_(0.8),
-      drop_interval_(1),
-      bandwidth_floor_(5),
-      rtt_limit_(INT64_T_MAX),
+      drop_interval_(TimeDelta::Seconds(1)),
+      bandwidth_floor_(DataRate::KilobitsPerSec(5)),
+      rtt_limit_(TimeDelta::PlusInfinity()),
       // By initializing this to plus infinity, we make sure that we never
       // trigger rtt backoff unless packet feedback is enabled.
-      last_propagation_rtt_update_(INT64_T_MAX),
-      last_propagation_rtt_(0),
-      last_packet_sent_(INT64_T_MIN) {
+      last_propagation_rtt_update_(Timestamp::PlusInfinity()),
+      last_propagation_rtt_(TimeDelta::Zero()),
+      last_packet_sent_(Timestamp::MinusInfinity()) {
   if (!disabled_) {
     rtt_limit_ = configured_limit_;
   }
 }
 
-void RttBasedBackoff::UpdatePropagationRtt(int64_t at_time,
-                                           int64_t propagation_rtt) {
+void RttBasedBackoff::UpdatePropagationRtt(Timestamp at_time,
+                                           TimeDelta propagation_rtt) {
   last_propagation_rtt_update_ = at_time;
   last_propagation_rtt_ = propagation_rtt;
 }
@@ -117,11 +128,10 @@ bool RttBasedBackoff::IsRttAboveLimit() const {
   return CorrectedRtt() > rtt_limit_;
 }
 
-int64_t RttBasedBackoff::CorrectedRtt() const {
+TimeDelta RttBasedBackoff::CorrectedRtt() const {
   // Avoid timeout when no packets are being sent.
-  int64_t timeout_correction =
-      std::max(last_packet_sent_ - last_propagation_rtt_update_,
-               static_cast<int64_t>(0));
+  TimeDelta timeout_correction = std::max(
+      last_packet_sent_ - last_propagation_rtt_update_, TimeDelta::Zero());
   return timeout_correction + last_propagation_rtt_;
 }
 
@@ -130,61 +140,61 @@ RttBasedBackoff::~RttBasedBackoff() = default;
 SendSideBandwidthEstimation::SendSideBandwidthEstimation()
     : lost_packets_since_last_loss_update_(0),
       expected_packets_since_last_loss_update_(0),
-      current_target_(0),
-      last_logged_target_(0),
+      current_target_(DataRate::Zero()),
+      last_logged_target_(DataRate::Zero()),
       min_bitrate_configured_(kCongestionControllerMinBitrate),
       max_bitrate_configured_(kDefaultMaxBitrate),
-      last_low_bitrate_log_(INT64_T_MIN),
+      last_low_bitrate_log_(Timestamp::MinusInfinity()),
       has_decreased_since_last_fraction_loss_(false),
-      last_loss_feedback_(INT64_T_MIN),
-      last_loss_packet_report_(INT64_T_MIN),
+      last_loss_feedback_(Timestamp::MinusInfinity()),
+      last_loss_packet_report_(Timestamp::MinusInfinity()),
       last_fraction_loss_(0),
       last_logged_fraction_loss_(0),
-      last_round_trip_time_(0),
-      receiver_limit_(INT64_T_MAX),
-      delay_based_limit_(INT64_T_MAX),
-      time_last_decrease_(INT64_T_MIN),
-      first_report_time_(INT64_T_MIN),
+      last_round_trip_time_(TimeDelta::Zero()),
+      receiver_limit_(DataRate::PlusInfinity()),
+      delay_based_limit_(DataRate::PlusInfinity()),
+      time_last_decrease_(Timestamp::MinusInfinity()),
+      first_report_time_(Timestamp::MinusInfinity()),
       initially_lost_packets_(0),
-      bitrate_at_2_seconds_(0),
+      bitrate_at_2_seconds_(DataRate::Zero()),
       uma_update_state_(kNoUpdate),
       uma_rtt_state_(kNoUpdate),
       rampup_uma_stats_updated_(kNumUmaRampupMetrics, false),
-      last_rtc_event_log_(INT64_T_MIN),
       low_loss_threshold_(kDefaultLowLossThreshold),
       high_loss_threshold_(kDefaultHighLossThreshold),
       bitrate_threshold_(kDefaultBitrateThreshold),
-      disable_receiver_limit_caps_only_(true) {}
+      disable_receiver_limit_caps_only_("Disabled") {
+  // rtt_backoff_ =
+}
 
 SendSideBandwidthEstimation::~SendSideBandwidthEstimation() {}
 
 void SendSideBandwidthEstimation::OnRouteChange() {
   lost_packets_since_last_loss_update_ = 0;
   expected_packets_since_last_loss_update_ = 0;
-  current_target_ = 0;
+  current_target_ = DataRate::Zero();
   min_bitrate_configured_ = kCongestionControllerMinBitrate;
   max_bitrate_configured_ = kDefaultMaxBitrate;
-  last_low_bitrate_log_ = INT64_T_MIN;
+  last_low_bitrate_log_ = Timestamp::MinusInfinity();
   has_decreased_since_last_fraction_loss_ = false;
-  last_loss_feedback_ = INT64_T_MIN;
-  last_loss_packet_report_ = INT64_T_MIN;
+  last_loss_feedback_ = Timestamp::MinusInfinity();
+  last_loss_packet_report_ = Timestamp::MinusInfinity();
   last_fraction_loss_ = 0;
   last_logged_fraction_loss_ = 0;
-  last_round_trip_time_ = 0;
-  receiver_limit_ = INT64_T_MAX;
-  delay_based_limit_ = INT64_T_MAX;
-  time_last_decrease_ = INT64_T_MIN;
-  first_report_time_ = INT64_T_MIN;
+  last_round_trip_time_ = TimeDelta::Zero();
+  receiver_limit_ = DataRate::PlusInfinity();
+  delay_based_limit_ = DataRate::PlusInfinity();
+  time_last_decrease_ = Timestamp::MinusInfinity();
+  first_report_time_ = Timestamp::MinusInfinity();
   initially_lost_packets_ = 0;
-  bitrate_at_2_seconds_ = 0;
+  bitrate_at_2_seconds_ = DataRate::Zero();
   uma_update_state_ = kNoUpdate;
   uma_rtt_state_ = kNoUpdate;
-  last_rtc_event_log_ = INT64_T_MIN;
 }
 
 void SendSideBandwidthEstimation::SetBitrates(
-    std::optional<int64_t> send_bitrate, int64_t min_bitrate,
-    int64_t max_bitrate, int64_t at_time) {
+    std::optional<DataRate> send_bitrate, DataRate min_bitrate,
+    DataRate max_bitrate, Timestamp at_time) {
   SetMinMaxBitrate(min_bitrate, max_bitrate);
   if (send_bitrate) {
     link_capacity_.OnStartingRate(*send_bitrate);
@@ -192,21 +202,21 @@ void SendSideBandwidthEstimation::SetBitrates(
   }
 }
 
-void SendSideBandwidthEstimation::SetSendBitrate(int64_t bitrate,
-                                                 int64_t at_time) {
+void SendSideBandwidthEstimation::SetSendBitrate(DataRate bitrate,
+                                                 Timestamp at_time) {
   // Reset to avoid being capped by the estimate.
-  delay_based_limit_ = INT64_T_MAX;
+  delay_based_limit_ = DataRate::PlusInfinity();
   UpdateTargetBitrate(bitrate, at_time);
   // Clear last sent bitrate history so the new value can be used directly
   // and not capped.
   min_bitrate_history_.clear();
 }
 
-void SendSideBandwidthEstimation::SetMinMaxBitrate(int64_t min_bitrate,
-                                                   int64_t max_bitrate) {
+void SendSideBandwidthEstimation::SetMinMaxBitrate(DataRate min_bitrate,
+                                                   DataRate max_bitrate) {
   min_bitrate_configured_ =
       std::max(min_bitrate, kCongestionControllerMinBitrate);
-  if (max_bitrate > 0 && IsFinite(max_bitrate)) {
+  if (max_bitrate > DataRate::Zero() && max_bitrate.IsFinite()) {
     max_bitrate_configured_ = std::max(min_bitrate_configured_, max_bitrate);
   } else {
     max_bitrate_configured_ = kDefaultMaxBitrate;
@@ -214,11 +224,11 @@ void SendSideBandwidthEstimation::SetMinMaxBitrate(int64_t min_bitrate,
 }
 
 int SendSideBandwidthEstimation::GetMinBitrate() const {
-  return min_bitrate_configured_;
+  return min_bitrate_configured_.bps<int>();
 }
 
-int64_t SendSideBandwidthEstimation::target_rate() const {
-  int64_t target = current_target_;
+DataRate SendSideBandwidthEstimation::target_rate() const {
+  DataRate target = current_target_;
   if (!disable_receiver_limit_caps_only_)
     target = std::min(target, receiver_limit_);
   return std::max(min_bitrate_configured_, target);
@@ -228,29 +238,29 @@ bool SendSideBandwidthEstimation::IsRttAboveLimit() const {
   return rtt_backoff_.IsRttAboveLimit();
 }
 
-int64_t SendSideBandwidthEstimation::GetEstimatedLinkCapacity() const {
+DataRate SendSideBandwidthEstimation::GetEstimatedLinkCapacity() const {
   return link_capacity_.estimate();
 }
 
-void SendSideBandwidthEstimation::UpdateReceiverEstimate(int64_t at_time,
-                                                         int64_t bandwidth) {
+void SendSideBandwidthEstimation::UpdateReceiverEstimate(Timestamp at_time,
+                                                         DataRate bandwidth) {
   // TODO(srte): Ensure caller passes PlusInfinity, not zero, to represent no
   // limitation.
-  receiver_limit_ = !bandwidth ? INT64_T_MAX : bandwidth;
+  receiver_limit_ = bandwidth.IsZero() ? DataRate::PlusInfinity() : bandwidth;
   ApplyTargetLimits(at_time);
 }
 
-void SendSideBandwidthEstimation::UpdateDelayBasedEstimate(int64_t at_time,
-                                                           int64_t bitrate) {
+void SendSideBandwidthEstimation::UpdateDelayBasedEstimate(Timestamp at_time,
+                                                           DataRate bitrate) {
   link_capacity_.UpdateDelayBasedEstimate(at_time, bitrate);
   // TODO(srte): Ensure caller passes PlusInfinity, not zero, to represent no
   // limitation.
-  delay_based_limit_ = !bitrate ? INT64_T_MAX : bitrate;
+  delay_based_limit_ = bitrate.IsZero() ? DataRate::PlusInfinity() : bitrate;
   ApplyTargetLimits(at_time);
 }
 
 void SendSideBandwidthEstimation::SetAcknowledgedRate(
-    std::optional<int64_t> acknowledged_rate, int64_t at_time) {
+    std::optional<DataRate> acknowledged_rate, Timestamp at_time) {
   acknowledged_rate_ = acknowledged_rate;
   if (!acknowledged_rate.has_value()) {
     return;
@@ -259,11 +269,9 @@ void SendSideBandwidthEstimation::SetAcknowledgedRate(
 
 void SendSideBandwidthEstimation::UpdatePacketsLost(int64_t packets_lost,
                                                     int64_t number_of_packets,
-                                                    int64_t at_time) {
+                                                    Timestamp at_time) {
   last_loss_feedback_ = at_time;
-  if (IsInfinite(first_report_time_)) {
-    first_report_time_ = at_time;
-  }
+  if (first_report_time_.IsInfinite()) first_report_time_ = at_time;
 
   // Check sequence number diff and weight loss report
   if (number_of_packets > 0) {
@@ -281,7 +289,7 @@ void SendSideBandwidthEstimation::UpdatePacketsLost(int64_t packets_lost,
     has_decreased_since_last_fraction_loss_ = false;
     int64_t lost_q8 =
         std::max<int64_t>(lost_packets_since_last_loss_update_ + packets_lost,
-                          static_cast<int64_t>(0))
+                          0)
         << 8;
     last_fraction_loss_ = std::min<int>(lost_q8 / expected, 255);
 
@@ -295,12 +303,13 @@ void SendSideBandwidthEstimation::UpdatePacketsLost(int64_t packets_lost,
   UpdateUmaStatsPacketsLost(at_time, packets_lost);
 }
 
-void SendSideBandwidthEstimation::UpdateUmaStatsPacketsLost(int64_t at_time,
+void SendSideBandwidthEstimation::UpdateUmaStatsPacketsLost(Timestamp at_time,
                                                             int packets_lost) {
-  int64_t bitrate_kbps = (current_target_ + 500) / 1000;
+  DataRate bitrate_kbps =
+      DataRate::KilobitsPerSec((current_target_.bps() + 500) / 1000);
   for (size_t i = 0; i < kNumUmaRampupMetrics; ++i) {
     if (!rampup_uma_stats_updated_[i] &&
-        bitrate_kbps >= kUmaRampupMetrics[i].bitrate_kbps) {
+        bitrate_kbps.kbps() >= kUmaRampupMetrics[i].bitrate_kbps) {
       rampup_uma_stats_updated_[i] = true;
     }
   }
@@ -312,29 +321,29 @@ void SendSideBandwidthEstimation::UpdateUmaStatsPacketsLost(int64_t at_time,
   } else if (uma_update_state_ == kFirstDone &&
              at_time - first_report_time_ >= kBweConverganceTime) {
     uma_update_state_ = kDone;
-    int bitrate_diff_kbps =
-        std::max(bitrate_at_2_seconds_ - bitrate_kbps, static_cast<int64_t>(0));
+    int bitrate_diff_kbps = std::max(
+        bitrate_at_2_seconds_.kbps<int>() - bitrate_kbps.kbps<int>(), 0);
   }
 }
 
-void SendSideBandwidthEstimation::UpdateRtt(int64_t rtt, int64_t at_time) {
+void SendSideBandwidthEstimation::UpdateRtt(TimeDelta rtt, Timestamp at_time) {
   // Update RTT if we were able to compute an RTT based on this RTCP.
   // FlexFEC doesn't send RTCP SR, which means we won't be able to compute RTT.
-  if (rtt > 0) last_round_trip_time_ = rtt;
+  if (rtt > TimeDelta::Zero()) last_round_trip_time_ = rtt;
 
   if (!IsInStartPhase(at_time) && uma_rtt_state_ == kNoUpdate) {
     uma_rtt_state_ = kDone;
   }
 }
 
-void SendSideBandwidthEstimation::UpdateEstimate(int64_t at_time) {
+void SendSideBandwidthEstimation::UpdateEstimate(Timestamp at_time) {
   if (rtt_backoff_.IsRttAboveLimit()) {
     if (at_time - time_last_decrease_ >= rtt_backoff_.drop_interval_ &&
         current_target_ > rtt_backoff_.bandwidth_floor_) {
       time_last_decrease_ = at_time;
-      int64_t new_bitrate =
+      DataRate new_bitrate =
           std::max(current_target_ * rtt_backoff_.drop_fraction_,
-                   static_cast<double>(rtt_backoff_.bandwidth_floor_));
+                   rtt_backoff_.bandwidth_floor_);
       link_capacity_.OnRttBackoff(new_bitrate, at_time);
       UpdateTargetBitrate(new_bitrate, at_time);
       return;
@@ -347,15 +356,14 @@ void SendSideBandwidthEstimation::UpdateEstimate(int64_t at_time) {
   // We trust the REMB and/or delay-based estimate during the first 2 seconds if
   // we haven't had any packet loss reported, to allow startup bitrate probing.
   if (last_fraction_loss_ == 0 && IsInStartPhase(at_time)) {
-    int64_t new_bitrate = current_target_;
+    DataRate new_bitrate = current_target_;
     // TODO(srte): We should not allow the new_bitrate to be larger than the
     // receiver limit here.
-    if (IsFinite(receiver_limit_)) {
+    if (receiver_limit_.IsFinite())
       new_bitrate = std::max(receiver_limit_, new_bitrate);
-    }
-    if (IsFinite(delay_based_limit_)) {
+    if (delay_based_limit_.IsFinite())
       new_bitrate = std::max(delay_based_limit_, new_bitrate);
-    }
+
     if (new_bitrate != current_target_) {
       min_bitrate_history_.clear();
       min_bitrate_history_.push_back(std::make_pair(at_time, current_target_));
@@ -364,14 +372,14 @@ void SendSideBandwidthEstimation::UpdateEstimate(int64_t at_time) {
     }
   }
   UpdateMinHistory(at_time);
-  if (IsInfinite(last_loss_packet_report_)) {
+  if (last_loss_packet_report_.IsInfinite()) {
     // No feedback received.
     // TODO(srte): This is likely redundant in most cases.
     ApplyTargetLimits(at_time);
     return;
   }
 
-  int64_t time_since_loss_packet_report = at_time - last_loss_packet_report_;
+  TimeDelta time_since_loss_packet_report = at_time - last_loss_packet_report_;
   if (time_since_loss_packet_report < 1.2 * kMaxRtcpFeedbackInterval) {
     // We only care about loss above a given bitrate threshold.
     float loss = last_fraction_loss_ / 256.0f;
@@ -389,12 +397,13 @@ void SendSideBandwidthEstimation::UpdateEstimate(int64_t at_time) {
       //   If instead one would do: current_bitrate_ *= 1.08^(delta time),
       //   it would take over one second since the lower packet loss to achieve
       //   108kbps.
-      int64_t new_bitrate = min_bitrate_history_.front().second * 1.08 + 0.5;
+      DataRate new_bitrate = DataRate::BitsPerSec(
+          min_bitrate_history_.front().second.bps() * 1.08 + 0.5);
 
       // Add 1 kbps extra, just to make sure that we do not get stuck
       // (gives a little extra increase at low rates, negligible at higher
       // rates).
-      new_bitrate += 1000;
+      new_bitrate += DataRate::BitsPerSec(1000);
       UpdateTargetBitrate(new_bitrate, at_time);
       return;
     } else if (current_target_ > bitrate_threshold_) {
@@ -411,10 +420,10 @@ void SendSideBandwidthEstimation::UpdateEstimate(int64_t at_time) {
           // Reduce rate:
           //   newRate = rate * (1 - 0.5*lossRate);
           //   where packetLoss = 256*lossRate;
-          int64_t new_bitrate =
-              (current_target_ *
+          DataRate new_bitrate = DataRate::BitsPerSec(
+              (current_target_.bps() *
                static_cast<double>(512 - last_fraction_loss_)) /
-              512.0;
+              512.0);
           has_decreased_since_last_fraction_loss_ = true;
           UpdateTargetBitrate(new_bitrate, at_time);
           return;
@@ -427,7 +436,7 @@ void SendSideBandwidthEstimation::UpdateEstimate(int64_t at_time) {
 }
 
 void SendSideBandwidthEstimation::UpdatePropagationRtt(
-    int64_t at_time, int64_t propagation_rtt) {
+    Timestamp at_time, TimeDelta propagation_rtt) {
   rtt_backoff_.UpdatePropagationRtt(at_time, propagation_rtt);
 }
 
@@ -436,17 +445,17 @@ void SendSideBandwidthEstimation::OnSentPacket(const SentPacket& sent_packet) {
   rtt_backoff_.last_packet_sent_ = sent_packet.send_time;
 }
 
-bool SendSideBandwidthEstimation::IsInStartPhase(int64_t at_time) const {
-  return (IsInfinite(first_report_time_)) ||
+bool SendSideBandwidthEstimation::IsInStartPhase(Timestamp at_time) const {
+  return first_report_time_.IsInfinite() ||
          at_time - first_report_time_ < kStartPhase;
 }
 
-void SendSideBandwidthEstimation::UpdateMinHistory(int64_t at_time) {
+void SendSideBandwidthEstimation::UpdateMinHistory(Timestamp at_time) {
   // Remove old data points from history.
   // Since history precision is in ms, add one so it is able to increase
   // bitrate if it is off by as little as 0.5ms.
   while (!min_bitrate_history_.empty() &&
-         at_time - min_bitrate_history_.front().first + 1 >
+         at_time - min_bitrate_history_.front().first + TimeDelta::Millis(1) >
              kBweIncreaseInterval) {
     min_bitrate_history_.pop_front();
   }
@@ -461,45 +470,36 @@ void SendSideBandwidthEstimation::UpdateMinHistory(int64_t at_time) {
   min_bitrate_history_.push_back(std::make_pair(at_time, current_target_));
 }
 
-int64_t SendSideBandwidthEstimation::GetUpperLimit() const {
-  int64_t upper_limit = delay_based_limit_;
+DataRate SendSideBandwidthEstimation::GetUpperLimit() const {
+  DataRate upper_limit = delay_based_limit_;
   if (disable_receiver_limit_caps_only_)
     upper_limit = std::min(upper_limit, receiver_limit_);
   return std::min(upper_limit, max_bitrate_configured_);
 }
 
-void SendSideBandwidthEstimation::MaybeLogLowBitrateWarning(int64_t bitrate,
-                                                            int64_t at_time) {
+void SendSideBandwidthEstimation::MaybeLogLowBitrateWarning(DataRate bitrate,
+                                                            Timestamp at_time) {
   if (at_time - last_low_bitrate_log_ > kLowBitrateLogPeriod) {
     LOG_WARN(
         "Estimated available bandwidth {} is below configured min bitrate {}",
-        bitrate, min_bitrate_configured_);
+        ToString(bitrate), ToString(min_bitrate_configured_));
     last_low_bitrate_log_ = at_time;
   }
 }
 
-void SendSideBandwidthEstimation::MaybeLogLossBasedEvent(int64_t at_time) {
-  if (current_target_ != last_logged_target_ ||
-      last_fraction_loss_ != last_logged_fraction_loss_ ||
-      at_time - last_rtc_event_log_ > kRtcEventLogPeriod) {
-    last_logged_fraction_loss_ = last_fraction_loss_;
-    last_logged_target_ = current_target_;
-    last_rtc_event_log_ = at_time;
-  }
-}
-
-void SendSideBandwidthEstimation::UpdateTargetBitrate(int64_t new_bitrate,
-                                                      int64_t at_time) {
+void SendSideBandwidthEstimation::UpdateTargetBitrate(DataRate new_bitrate,
+                                                      Timestamp at_time) {
   new_bitrate = std::min(new_bitrate, GetUpperLimit());
   if (new_bitrate < min_bitrate_configured_) {
     MaybeLogLowBitrateWarning(new_bitrate, at_time);
     new_bitrate = min_bitrate_configured_;
   }
   current_target_ = new_bitrate;
-  MaybeLogLossBasedEvent(at_time);
   link_capacity_.OnRateUpdate(acknowledged_rate_, current_target_, at_time);
 }
 
-void SendSideBandwidthEstimation::ApplyTargetLimits(int64_t at_time) {
+void SendSideBandwidthEstimation::ApplyTargetLimits(Timestamp at_time) {
   UpdateTargetBitrate(current_target_, at_time);
 }
+
+}  // namespace webrtc

src/qos/send_side_bandwidth_estimation.h

@@ -1,63 +1,74 @@
 /*
- * @Author: DI JUNKUN
- * @Date: 2025-01-13
- * Copyright (c) 2025 by DI JUNKUN, All Rights Reserved.
+ *  Copyright (c) 2012 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.
+ *
+ *  FEC and NACK added bitrate is handled outside class
  */
 
-#ifndef _SEND_SIDE_BANDWIDTH_ESTIMATION_H_
-#define _SEND_SIDE_BANDWIDTH_ESTIMATION_H_
+#ifndef MODULES_CONGESTION_CONTROLLER_GOOG_CC_SEND_SIDE_BANDWIDTH_ESTIMATION_H_
+#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_SEND_SIDE_BANDWIDTH_ESTIMATION_H_
+
+#include <stdint.h>
 
-#include <cstddef>
-#include <cstdint>
 #include <deque>
-#include <limits>
 #include <memory>
 #include <optional>
 #include <utility>
 #include <vector>
 
-#include "limits_base.h"
-#include "network_types.h"
+#include "api/transport/bandwidth_usage.h"
+#include "api/transport/network_types.h"
+#include "api/units/data_rate.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+
+namespace webrtc {
 
 class LinkCapacityTracker {
  public:
   LinkCapacityTracker() = default;
   ~LinkCapacityTracker() = default;
   // Call when a new delay-based estimate is available.
-  void UpdateDelayBasedEstimate(int64_t at_time, int64_t delay_based_bitrate);
-  void OnStartingRate(int64_t start_rate);
-  void OnRateUpdate(std::optional<int64_t> acknowledged, int64_t target,
-                    int64_t at_time);
-  void OnRttBackoff(int64_t backoff_rate, int64_t at_time);
-  int64_t estimate() const;
+  void UpdateDelayBasedEstimate(Timestamp at_time,
+                                DataRate delay_based_bitrate);
+  void OnStartingRate(DataRate start_rate);
+  void OnRateUpdate(std::optional<DataRate> acknowledged, DataRate target,
+                    Timestamp at_time);
+  void OnRttBackoff(DataRate backoff_rate, Timestamp at_time);
+  DataRate estimate() const;
 
  private:
   double capacity_estimate_bps_ = 0;
-  int64_t last_link_capacity_update_ = INT64_T_MIN;
-  int64_t last_delay_based_estimate_ = INT64_T_MAX;
+  Timestamp last_link_capacity_update_ = Timestamp::MinusInfinity();
+  DataRate last_delay_based_estimate_ = DataRate::PlusInfinity();
 };
 
 class RttBasedBackoff {
  public:
   explicit RttBasedBackoff();
   ~RttBasedBackoff();
-  void UpdatePropagationRtt(int64_t at_time, int64_t propagation_rtt);
+  void UpdatePropagationRtt(Timestamp at_time, TimeDelta propagation_rtt);
   bool IsRttAboveLimit() const;
 
   bool disabled_;
-  int64_t configured_limit_;
+  TimeDelta configured_limit_;
   double drop_fraction_;
-  int64_t drop_interval_;
-  int64_t bandwidth_floor_;
+  TimeDelta drop_interval_;
+  DataRate bandwidth_floor_;
 
  public:
-  int64_t rtt_limit_;
-  int64_t last_propagation_rtt_update_;
-  int64_t last_propagation_rtt_;
-  int64_t last_packet_sent_;
+  TimeDelta rtt_limit_;
+  Timestamp last_propagation_rtt_update_;
+  TimeDelta last_propagation_rtt_;
+  Timestamp last_packet_sent_;
 
  private:
-  int64_t CorrectedRtt() const;
+  TimeDelta CorrectedRtt() const;
 };
 
 class SendSideBandwidthEstimation {
@@ -67,112 +78,108 @@ class SendSideBandwidthEstimation {
 
   void OnRouteChange();
 
-  int64_t target_rate() const;
+  DataRate target_rate() const;
   // Return whether the current rtt is higher than the rtt limited configured in
   // RttBasedBackoff.
   bool IsRttAboveLimit() const;
   uint8_t fraction_loss() const { return last_fraction_loss_; }
-  int64_t round_trip_time() const { return last_round_trip_time_; }
+  TimeDelta round_trip_time() const { return last_round_trip_time_; }
 
-  int64_t GetEstimatedLinkCapacity() const;
+  DataRate GetEstimatedLinkCapacity() const;
   // Call periodically to update estimate.
-  void UpdateEstimate(int64_t at_time);
+  void UpdateEstimate(Timestamp at_time);
   void OnSentPacket(const SentPacket& sent_packet);
-  void UpdatePropagationRtt(int64_t at_time, int64_t propagation_rtt);
+  void UpdatePropagationRtt(Timestamp at_time, TimeDelta propagation_rtt);
 
   // Call when we receive a RTCP message with TMMBR or REMB.
-  void UpdateReceiverEstimate(int64_t at_time, int64_t bandwidth);
+  void UpdateReceiverEstimate(Timestamp at_time, DataRate bandwidth);
 
   // Call when a new delay-based estimate is available.
-  void UpdateDelayBasedEstimate(int64_t at_time, int64_t bitrate);
+  void UpdateDelayBasedEstimate(Timestamp at_time, DataRate bitrate);
 
   // Call when we receive a RTCP message with a ReceiveBlock.
   void UpdatePacketsLost(int64_t packets_lost, int64_t number_of_packets,
-                         int64_t at_time);
+                         Timestamp at_time);
 
   // Call when we receive a RTCP message with a ReceiveBlock.
-  void UpdateRtt(int64_t rtt, int64_t at_time);
+  void UpdateRtt(TimeDelta rtt, Timestamp at_time);
 
-  void SetBitrates(std::optional<int64_t> send_bitrate, int64_t min_bitrate,
-                   int64_t max_bitrate, int64_t at_time);
-  void SetSendBitrate(int64_t bitrate, int64_t at_time);
-  void SetMinMaxBitrate(int64_t min_bitrate, int64_t max_bitrate);
+  void SetBitrates(std::optional<DataRate> send_bitrate, DataRate min_bitrate,
+                   DataRate max_bitrate, Timestamp at_time);
+  void SetSendBitrate(DataRate bitrate, Timestamp at_time);
+  void SetMinMaxBitrate(DataRate min_bitrate, DataRate max_bitrate);
   int GetMinBitrate() const;
-  void SetAcknowledgedRate(std::optional<int64_t> acknowledged_rate,
-                           int64_t at_time);
+  void SetAcknowledgedRate(std::optional<DataRate> acknowledged_rate,
+                           Timestamp at_time);
 
  private:
   friend class GoogCcStatePrinter;
 
   enum UmaState { kNoUpdate, kFirstDone, kDone };
 
-  bool IsInStartPhase(int64_t at_time) const;
+  bool IsInStartPhase(Timestamp at_time) const;
 
-  void UpdateUmaStatsPacketsLost(int64_t at_time, int packets_lost);
+  void UpdateUmaStatsPacketsLost(Timestamp at_time, int packets_lost);
 
   // Updates history of min bitrates.
   // After this method returns min_bitrate_history_.front().second contains the
   // min bitrate used during last kBweIncreaseIntervalMs.
-  void UpdateMinHistory(int64_t at_time);
+  void UpdateMinHistory(Timestamp at_time);
 
   // Gets the upper limit for the target bitrate. This is the minimum of the
   // delay based limit, the receiver limit and the loss based controller limit.
-  int64_t GetUpperLimit() const;
+  DataRate GetUpperLimit() const;
   // Prints a warning if `bitrate` if sufficiently long time has past since last
   // warning.
-  void MaybeLogLowBitrateWarning(int64_t bitrate, int64_t at_time);
-  // Stores an update to the event log if the loss rate has changed, the target
-  // has changed, or sufficient time has passed since last stored event.
-  void MaybeLogLossBasedEvent(int64_t at_time);
+  void MaybeLogLowBitrateWarning(DataRate bitrate, Timestamp at_time);
 
   // Cap `bitrate` to [min_bitrate_configured_, max_bitrate_configured_] and
   // set `current_bitrate_` to the capped value and updates the event log.
-  void UpdateTargetBitrate(int64_t bitrate, int64_t at_time);
+  void UpdateTargetBitrate(DataRate bitrate, Timestamp at_time);
   // Applies lower and upper bounds to the current target rate.
   // TODO(srte): This seems to be called even when limits haven't changed, that
   // should be cleaned up.
-  void ApplyTargetLimits(int64_t at_time);
+  void ApplyTargetLimits(Timestamp at_time);
 
   RttBasedBackoff rtt_backoff_;
   LinkCapacityTracker link_capacity_;
 
-  std::deque<std::pair<int64_t, int64_t> > min_bitrate_history_;
+  std::deque<std::pair<Timestamp, DataRate> > min_bitrate_history_;
 
   // incoming filters
   int lost_packets_since_last_loss_update_;
   int expected_packets_since_last_loss_update_;
 
-  std::optional<int64_t> acknowledged_rate_;
-  int64_t current_target_;
-  int64_t last_logged_target_;
-  int64_t min_bitrate_configured_;
-  int64_t max_bitrate_configured_;
-  int64_t last_low_bitrate_log_;
+  std::optional<DataRate> acknowledged_rate_;
+  DataRate current_target_;
+  DataRate last_logged_target_;
+  DataRate min_bitrate_configured_;
+  DataRate max_bitrate_configured_;
+  Timestamp last_low_bitrate_log_;
 
   bool has_decreased_since_last_fraction_loss_;
-  int64_t last_loss_feedback_;
-  int64_t last_loss_packet_report_;
+  Timestamp last_loss_feedback_;
+  Timestamp last_loss_packet_report_;
   uint8_t last_fraction_loss_;
   uint8_t last_logged_fraction_loss_;
-  int64_t last_round_trip_time_;
+  TimeDelta last_round_trip_time_;
 
   // The max bitrate as set by the receiver in the call. This is typically
   // signalled using the REMB RTCP message and is used when we don't have any
   // send side delay based estimate.
-  int64_t receiver_limit_;
-  int64_t delay_based_limit_;
-  int64_t time_last_decrease_;
-  int64_t first_report_time_;
+  DataRate receiver_limit_;
+  DataRate delay_based_limit_;
+  Timestamp time_last_decrease_;
+  Timestamp first_report_time_;
   int initially_lost_packets_;
-  int64_t bitrate_at_2_seconds_;
+  DataRate bitrate_at_2_seconds_;
   UmaState uma_update_state_;
   UmaState uma_rtt_state_;
   std::vector<bool> rampup_uma_stats_updated_;
-  int64_t last_rtc_event_log_;
   float low_loss_threshold_;
   float high_loss_threshold_;
-  int64_t bitrate_threshold_;
+  DataRate bitrate_threshold_;
   bool disable_receiver_limit_caps_only_;
 };
-
-#endif
+}  // namespace webrtc
+#endif  // MODULES_CONGESTION_CONTROLLER_GOOG_CC_SEND_SIDE_BANDWIDTH_ESTIMATION_H_

src/qos/transport_feedback_adapter.h

@@ -14,9 +14,9 @@
 #include <tuple>
 #include <vector>
 
+#include "api/transport/network_types.h"
 #include "congestion_control_feedback.h"
 #include "network_route.h"
-#include "network_types.h"
 #include "rtc_base/numerics/sequence_number_unwrapper.h"
 
 struct PacketFeedback {

src/qos/trendline_estimator.h

@@ -16,7 +16,8 @@
 #include <deque>
 #include <memory>
 
-#include "bandwidth_usage.h"
+#include "api/transport/bandwidth_usage.h"
+#include "delay_increase_detector_interface.h"
 
 namespace webrtc {
 

src/rtp/rtp_packet/rtp_header.h

@@ -14,6 +14,8 @@
 
 #include "api/units/timestamp.h"
 
+static constexpr int kAbsSendTimeFraction = 18;
+
 enum { kRtpCsrcSize = 15 };  // RFC 3550 page 13
 
 struct RTPHeader {