Add a bandwidth estimator based on loss statistics and maximum likelihood modelling.
Bug: webrtc:12707
Change-Id: Ia221d0b7aee6edb5ae7b0f3b0ad08ac610b3340e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/224300
Commit-Queue: Christoffer Rodbro <crodbro@webrtc.org>
Reviewed-by: Christoffer Rodbro <crodbro@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34626}
diff --git a/modules/congestion_controller/goog_cc/BUILD.gn b/modules/congestion_controller/goog_cc/BUILD.gn
index ea20da8..9aafedb 100644
--- a/modules/congestion_controller/goog_cc/BUILD.gn
+++ b/modules/congestion_controller/goog_cc/BUILD.gn
@@ -27,9 +27,9 @@
":alr_detector",
":delay_based_bwe",
":estimators",
- ":loss_based_controller",
":probe_controller",
":pushback_controller",
+ ":send_side_bwe",
"../..:module_api",
"../../../api:network_state_predictor_api",
"../../../api/rtc_event_log",
@@ -146,15 +146,55 @@
]
}
-rtc_library("loss_based_controller") {
+rtc_library("loss_based_bwe_v2") {
+ sources = [
+ "loss_based_bwe_v2.cc",
+ "loss_based_bwe_v2.h",
+ ]
+ deps = [
+ "../../../api:array_view",
+ "../../../api/transport:network_control",
+ "../../../api/transport:webrtc_key_value_config",
+ "../../../api/units:data_rate",
+ "../../../api/units:data_size",
+ "../../../api/units:time_delta",
+ "../../../api/units:timestamp",
+ "../../../rtc_base:logging",
+ "../../../rtc_base/experiments:field_trial_parser",
+ ]
+ absl_deps = [
+ "//third_party/abseil-cpp/absl/algorithm:container",
+ "//third_party/abseil-cpp/absl/types:optional",
+ ]
+}
+
+rtc_library("loss_based_bwe_v1") {
configs += [ ":bwe_test_logging" ]
sources = [
"loss_based_bandwidth_estimation.cc",
"loss_based_bandwidth_estimation.h",
+ ]
+ deps = [
+ "../../../api/transport:network_control",
+ "../../../api/transport:webrtc_key_value_config",
+ "../../../api/units:data_rate",
+ "../../../api/units:time_delta",
+ "../../../api/units:timestamp",
+ "../../../rtc_base:checks",
+ "../../../rtc_base/experiments:field_trial_parser",
+ ]
+ absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
+}
+
+rtc_library("send_side_bwe") {
+ configs += [ ":bwe_test_logging" ]
+ sources = [
"send_side_bandwidth_estimation.cc",
"send_side_bandwidth_estimation.h",
]
deps = [
+ ":loss_based_bwe_v1",
+ ":loss_based_bwe_v2",
"../../../api/rtc_event_log",
"../../../api/transport:network_control",
"../../../api/transport:webrtc_key_value_config",
@@ -269,6 +309,7 @@
"delay_based_bwe_unittest_helper.cc",
"delay_based_bwe_unittest_helper.h",
"goog_cc_network_control_unittest.cc",
+ "loss_based_bwe_v2_test.cc",
"probe_bitrate_estimator_unittest.cc",
"probe_controller_unittest.cc",
"robust_throughput_estimator_unittest.cc",
@@ -280,9 +321,10 @@
":delay_based_bwe",
":estimators",
":goog_cc",
- ":loss_based_controller",
+ ":loss_based_bwe_v2",
":probe_controller",
":pushback_controller",
+ ":send_side_bwe",
"../../../api/rtc_event_log",
"../../../api/test/network_emulation",
"../../../api/test/network_emulation:create_cross_traffic",
@@ -291,12 +333,15 @@
"../../../api/transport:network_control",
"../../../api/transport:webrtc_key_value_config",
"../../../api/units:data_rate",
+ "../../../api/units:data_size",
+ "../../../api/units:time_delta",
"../../../api/units:timestamp",
"../../../logging:mocks",
"../../../logging:rtc_event_bwe",
"../../../rtc_base:checks",
"../../../rtc_base:rtc_base_approved",
"../../../rtc_base:rtc_base_tests_utils",
+ "../../../rtc_base:stringutils",
"../../../rtc_base/experiments:alr_experiment",
"../../../system_wrappers",
"../../../test:explicit_key_value_config",
diff --git a/modules/congestion_controller/goog_cc/loss_based_bwe_v2.cc b/modules/congestion_controller/goog_cc/loss_based_bwe_v2.cc
new file mode 100644
index 0000000..ae52b2d
--- /dev/null
+++ b/modules/congestion_controller/goog_cc/loss_based_bwe_v2.cc
@@ -0,0 +1,652 @@
+/*
+ * Copyright 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 "modules/congestion_controller/goog_cc/loss_based_bwe_v2.h"
+
+#include <algorithm>
+#include <cmath>
+#include <cstddef>
+#include <cstdlib>
+#include <limits>
+#include <utility>
+#include <vector>
+
+#include "absl/algorithm/container.h"
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "api/transport/network_types.h"
+#include "api/transport/webrtc_key_value_config.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 "rtc_base/experiments/field_trial_list.h"
+#include "rtc_base/experiments/field_trial_parser.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+
+namespace {
+
+bool IsValid(DataRate datarate) {
+ return datarate.IsFinite();
+}
+
+bool IsValid(Timestamp timestamp) {
+ return timestamp.IsFinite();
+}
+
+struct PacketResultsSummary {
+ int num_packets = 0;
+ int num_lost_packets = 0;
+ DataSize total_size = DataSize::Zero();
+ Timestamp first_send_time = Timestamp::PlusInfinity();
+ Timestamp last_send_time = Timestamp::MinusInfinity();
+};
+
+// Returns a `PacketResultsSummary` where `first_send_time` is `PlusInfinity,
+// and `last_send_time` is `MinusInfinity`, if `packet_results` is empty.
+PacketResultsSummary GetPacketResultsSummary(
+ rtc::ArrayView<const PacketResult> packet_results) {
+ PacketResultsSummary packet_results_summary;
+
+ packet_results_summary.num_packets = packet_results.size();
+ for (const PacketResult& packet : packet_results) {
+ if (!packet.IsReceived()) {
+ packet_results_summary.num_lost_packets++;
+ }
+ packet_results_summary.total_size += packet.sent_packet.size;
+ packet_results_summary.first_send_time = std::min(
+ packet_results_summary.first_send_time, packet.sent_packet.send_time);
+ packet_results_summary.last_send_time = std::max(
+ packet_results_summary.last_send_time, packet.sent_packet.send_time);
+ }
+
+ return packet_results_summary;
+}
+
+double GetLossProbability(double inherent_loss,
+ DataRate loss_limited_bandwidth,
+ DataRate sending_rate) {
+ if (inherent_loss < 0.0 || inherent_loss > 1.0) {
+ RTC_LOG(LS_WARNING) << "The inherent loss must be in [0,1]: "
+ << inherent_loss;
+ inherent_loss = std::min(std::max(inherent_loss, 0.0), 1.0);
+ }
+ if (!sending_rate.IsFinite()) {
+ RTC_LOG(LS_WARNING) << "The sending rate must be finite: "
+ << ToString(sending_rate);
+ }
+ if (!loss_limited_bandwidth.IsFinite()) {
+ RTC_LOG(LS_WARNING) << "The loss limited bandwidth must be finite: "
+ << ToString(loss_limited_bandwidth);
+ }
+
+ // We approximate the loss model
+ // loss_probability = inherent_loss + (1 - inherent_loss) *
+ // max(0, sending_rate - bandwidth) / sending_rate
+ // by
+ // loss_probability = inherent_loss +
+ // max(0, sending_rate - bandwidth) / sending_rate
+ // as it allows for simpler calculations and makes little difference in
+ // practice.
+ double loss_probability = inherent_loss;
+ if (IsValid(sending_rate) && IsValid(loss_limited_bandwidth) &&
+ (sending_rate > loss_limited_bandwidth)) {
+ loss_probability += (sending_rate - loss_limited_bandwidth) / sending_rate;
+ }
+ return std::min(std::max(loss_probability, 1.0e-6), 1.0 - 1.0e-6);
+}
+
+} // namespace
+
+LossBasedBweV2::LossBasedBweV2(const WebRtcKeyValueConfig* key_value_config)
+ : config_(CreateConfig(key_value_config)) {
+ if (!config_.has_value()) {
+ RTC_LOG(LS_VERBOSE) << "The configuration does not specify that the "
+ "estimator should be enabled, disabling it.";
+ return;
+ }
+ if (!IsConfigValid()) {
+ RTC_LOG(LS_WARNING)
+ << "The configuration is not valid, disabling the estimator.";
+ config_.reset();
+ return;
+ }
+
+ current_estimate_.inherent_loss = config_->initial_inherent_loss_estimate;
+ observations_.resize(config_->observation_window_size);
+ temporal_weights_.resize(config_->observation_window_size);
+ tcp_fairness_temporal_weights_.resize(config_->observation_window_size);
+ CalculateTemporalWeights();
+}
+
+bool LossBasedBweV2::IsEnabled() const {
+ return config_.has_value();
+}
+
+bool LossBasedBweV2::IsReady() const {
+ return IsEnabled() && IsValid(current_estimate_.loss_limited_bandwidth) &&
+ num_observations_ > 0;
+}
+
+DataRate LossBasedBweV2::GetBandwidthEstimate() const {
+ if (!IsReady()) {
+ if (!IsEnabled()) {
+ RTC_LOG(LS_WARNING)
+ << "The estimator must be enabled before it can be used.";
+ } else {
+ if (!IsValid(current_estimate_.loss_limited_bandwidth)) {
+ RTC_LOG(LS_WARNING)
+ << "The estimator must be initialized before it can be used.";
+ }
+ if (num_observations_ <= 0) {
+ RTC_LOG(LS_WARNING) << "The estimator must receive enough loss "
+ "statistics before it can be used.";
+ }
+ }
+ return DataRate::PlusInfinity();
+ }
+
+ return std::min(current_estimate_.loss_limited_bandwidth,
+ GetTcpFairnessBandwidthUpperBound());
+}
+
+void LossBasedBweV2::SetAcknowledgedBitrate(DataRate acknowledged_bitrate) {
+ if (IsValid(acknowledged_bitrate)) {
+ acknowledged_bitrate_ = acknowledged_bitrate;
+ } else {
+ RTC_LOG(LS_WARNING) << "The acknowledged bitrate must be finite: "
+ << ToString(acknowledged_bitrate);
+ }
+}
+
+void LossBasedBweV2::SetBandwidthEstimate(DataRate bandwidth_estimate) {
+ if (IsValid(bandwidth_estimate)) {
+ current_estimate_.loss_limited_bandwidth = bandwidth_estimate;
+ } else {
+ RTC_LOG(LS_WARNING) << "The bandwidth estimate must be finite: "
+ << ToString(bandwidth_estimate);
+ }
+}
+
+void LossBasedBweV2::UpdateBandwidthEstimate(
+ rtc::ArrayView<const PacketResult> packet_results) {
+ if (!IsEnabled()) {
+ RTC_LOG(LS_WARNING)
+ << "The estimator must be enabled before it can be used.";
+ return;
+ }
+ if (packet_results.empty()) {
+ RTC_LOG(LS_VERBOSE)
+ << "The estimate cannot be updated without any loss statistics.";
+ return;
+ }
+
+ if (!PushBackObservation(packet_results)) {
+ return;
+ }
+
+ if (!IsValid(current_estimate_.loss_limited_bandwidth)) {
+ RTC_LOG(LS_VERBOSE)
+ << "The estimator must be initialized before it can be used.";
+ return;
+ }
+
+ ChannelParameters best_candidate = current_estimate_;
+ double objective_max = std::numeric_limits<double>::lowest();
+ for (ChannelParameters candidate : GetCandidates()) {
+ NewtonsMethodUpdate(candidate);
+
+ const double candidate_objective = GetObjective(candidate);
+ if (candidate_objective > objective_max) {
+ objective_max = candidate_objective;
+ best_candidate = candidate;
+ }
+ }
+
+ current_estimate_ = best_candidate;
+}
+
+// Returns a `LossBasedBweV2::Config` iff the `key_value_config` specifies a
+// configuration for the `LossBasedBweV2` which is explicitly enabled.
+absl::optional<LossBasedBweV2::Config> LossBasedBweV2::CreateConfig(
+ const WebRtcKeyValueConfig* key_value_config) {
+ FieldTrialParameter<bool> enabled("Enabled", false);
+ FieldTrialParameter<double> bandwidth_rampup_upper_bound_factor(
+ "BwRampupUpperBoundFactor", 1.1);
+ FieldTrialList<double> candidate_factors("CandidateFactors",
+ {1.05, 1.0, 0.95});
+ FieldTrialParameter<double> higher_bandwidth_bias_factor("HigherBwBiasFactor",
+ 0.00001);
+ FieldTrialParameter<double> inherent_loss_lower_bound(
+ "InherentLossLowerBound", 1.0e-3);
+ FieldTrialParameter<DataRate> inherent_loss_upper_bound_bandwidth_balance(
+ "InherentLossUpperBoundBwBalance", DataRate::KilobitsPerSec(15.0));
+ FieldTrialParameter<double> inherent_loss_upper_bound_offset(
+ "InherentLossUpperBoundOffset", 0.05);
+ FieldTrialParameter<double> initial_inherent_loss_estimate(
+ "InitialInherentLossEstimate", 0.01);
+ FieldTrialParameter<int> newton_iterations("NewtonIterations", 1);
+ FieldTrialParameter<double> newton_step_size("NewtonStepSize", 0.5);
+ FieldTrialParameter<TimeDelta> observation_duration_lower_bound(
+ "ObservationDurationLowerBound", TimeDelta::Seconds(1));
+ FieldTrialParameter<int> observation_window_size("ObservationWindowSize", 20);
+ FieldTrialParameter<double> sending_rate_smoothing_factor(
+ "SendingRateSmoothingFactor", 0.0);
+ FieldTrialParameter<double> tcp_fairness_temporal_weight_factor(
+ "TcpFairnessTemporalWeightFactor", 0.99);
+ FieldTrialParameter<DataRate> tcp_fairness_upper_bound_bandwidth_balance(
+ "TcpFairnessUpperBoundBwBalance", DataRate::KilobitsPerSec(15.0));
+ FieldTrialParameter<double> tcp_fairness_upper_bound_loss_offset(
+ "TcpFairnessUpperBoundLossOffset", 0.05);
+ FieldTrialParameter<double> temporal_weight_factor("TemporalWeightFactor",
+ 0.99);
+
+ if (key_value_config) {
+ ParseFieldTrial(
+ {&enabled, &bandwidth_rampup_upper_bound_factor, &candidate_factors,
+ &higher_bandwidth_bias_factor, &inherent_loss_lower_bound,
+ &inherent_loss_upper_bound_bandwidth_balance,
+ &inherent_loss_upper_bound_offset, &initial_inherent_loss_estimate,
+ &newton_iterations, &newton_step_size,
+ &observation_duration_lower_bound, &observation_window_size,
+ &sending_rate_smoothing_factor, &tcp_fairness_temporal_weight_factor,
+ &tcp_fairness_upper_bound_bandwidth_balance,
+ &tcp_fairness_upper_bound_loss_offset, &temporal_weight_factor},
+ key_value_config->Lookup("WebRTC-Bwe-LossBasedBweV2"));
+ }
+
+ absl::optional<Config> config;
+ if (!enabled.Get()) {
+ return config;
+ }
+ config.emplace();
+ config->bandwidth_rampup_upper_bound_factor =
+ bandwidth_rampup_upper_bound_factor.Get();
+ config->candidate_factors = candidate_factors.Get();
+ config->higher_bandwidth_bias_factor = higher_bandwidth_bias_factor.Get();
+ config->inherent_loss_lower_bound = inherent_loss_lower_bound.Get();
+ config->inherent_loss_upper_bound_bandwidth_balance =
+ inherent_loss_upper_bound_bandwidth_balance.Get();
+ config->inherent_loss_upper_bound_offset =
+ inherent_loss_upper_bound_offset.Get();
+ config->initial_inherent_loss_estimate = initial_inherent_loss_estimate.Get();
+ config->newton_iterations = newton_iterations.Get();
+ config->newton_step_size = newton_step_size.Get();
+ config->observation_duration_lower_bound =
+ observation_duration_lower_bound.Get();
+ config->observation_window_size = observation_window_size.Get();
+ config->sending_rate_smoothing_factor = sending_rate_smoothing_factor.Get();
+ config->tcp_fairness_temporal_weight_factor =
+ tcp_fairness_temporal_weight_factor.Get();
+ config->tcp_fairness_upper_bound_bandwidth_balance =
+ tcp_fairness_upper_bound_bandwidth_balance.Get();
+ config->tcp_fairness_upper_bound_loss_offset =
+ tcp_fairness_upper_bound_loss_offset.Get();
+ config->temporal_weight_factor = temporal_weight_factor.Get();
+ return config;
+}
+
+bool LossBasedBweV2::IsConfigValid() const {
+ if (!config_.has_value()) {
+ return false;
+ }
+
+ bool valid = true;
+
+ if (config_->bandwidth_rampup_upper_bound_factor <= 1.0) {
+ RTC_LOG(LS_WARNING)
+ << "The bandwidth rampup upper bound factor must be greater than 1: "
+ << config_->bandwidth_rampup_upper_bound_factor;
+ valid = false;
+ }
+ if (config_->higher_bandwidth_bias_factor < 0.0) {
+ RTC_LOG(LS_WARNING)
+ << "The higher bandwidth bias factor must be non-negative: "
+ << config_->higher_bandwidth_bias_factor;
+ valid = false;
+ }
+ if (config_->inherent_loss_lower_bound < 0.0 ||
+ config_->inherent_loss_lower_bound >= 1.0) {
+ RTC_LOG(LS_WARNING) << "The inherent loss lower bound must be in [0, 1): "
+ << config_->inherent_loss_lower_bound;
+ valid = false;
+ }
+ if (config_->inherent_loss_upper_bound_bandwidth_balance <=
+ DataRate::Zero()) {
+ RTC_LOG(LS_WARNING)
+ << "The inherent loss upper bound bandwidth balance "
+ "must be positive: "
+ << ToString(config_->inherent_loss_upper_bound_bandwidth_balance);
+ valid = false;
+ }
+ if (config_->inherent_loss_upper_bound_offset <
+ config_->inherent_loss_lower_bound ||
+ config_->inherent_loss_upper_bound_offset >= 1.0) {
+ RTC_LOG(LS_WARNING) << "The inherent loss upper bound must be greater "
+ "than or equal to the inherent "
+ "loss lower bound, which is "
+ << config_->inherent_loss_lower_bound
+ << ", and less than 1: "
+ << config_->inherent_loss_upper_bound_offset;
+ valid = false;
+ }
+ if (config_->initial_inherent_loss_estimate < 0.0 ||
+ config_->initial_inherent_loss_estimate >= 1.0) {
+ RTC_LOG(LS_WARNING)
+ << "The initial inherent loss estimate must be in [0, 1): "
+ << config_->initial_inherent_loss_estimate;
+ valid = false;
+ }
+ if (config_->newton_iterations <= 0) {
+ RTC_LOG(LS_WARNING) << "The number of Newton iterations must be positive: "
+ << config_->newton_iterations;
+ valid = false;
+ }
+ if (config_->newton_step_size <= 0.0) {
+ RTC_LOG(LS_WARNING) << "The Newton step size must be positive: "
+ << config_->newton_step_size;
+ valid = false;
+ }
+ if (config_->observation_duration_lower_bound <= TimeDelta::Zero()) {
+ RTC_LOG(LS_WARNING)
+ << "The observation duration lower bound must be positive: "
+ << ToString(config_->observation_duration_lower_bound);
+ valid = false;
+ }
+ if (config_->observation_window_size < 2) {
+ RTC_LOG(LS_WARNING) << "The observation window size must be at least 2: "
+ << config_->observation_window_size;
+ valid = false;
+ }
+ if (config_->sending_rate_smoothing_factor < 0.0 ||
+ config_->sending_rate_smoothing_factor >= 1.0) {
+ RTC_LOG(LS_WARNING)
+ << "The sending rate smoothing factor must be in [0, 1): "
+ << config_->sending_rate_smoothing_factor;
+ valid = false;
+ }
+ if (config_->tcp_fairness_temporal_weight_factor <= 0.0 ||
+ config_->tcp_fairness_temporal_weight_factor > 1.0) {
+ RTC_LOG(LS_WARNING)
+ << "The TCP fairness temporal weight factor must be in (0, 1]"
+ << config_->tcp_fairness_temporal_weight_factor;
+ valid = false;
+ }
+ if (config_->tcp_fairness_upper_bound_bandwidth_balance <= DataRate::Zero()) {
+ RTC_LOG(LS_WARNING)
+ << "The TCP fairness upper bound bandwidth balance must be positive: "
+ << ToString(config_->tcp_fairness_upper_bound_bandwidth_balance);
+ valid = false;
+ }
+ if (config_->tcp_fairness_upper_bound_loss_offset < 0.0 ||
+ config_->tcp_fairness_upper_bound_loss_offset >= 1.0) {
+ RTC_LOG(LS_WARNING)
+ << "The TCP fairness upper bound loss offset must be in [0, 1): "
+ << config_->tcp_fairness_upper_bound_loss_offset;
+ valid = false;
+ }
+ if (config_->temporal_weight_factor <= 0.0 ||
+ config_->temporal_weight_factor > 1.0) {
+ RTC_LOG(LS_WARNING) << "The temporal weight factor must be in (0, 1]: "
+ << config_->temporal_weight_factor;
+ valid = false;
+ }
+
+ return valid;
+}
+
+double LossBasedBweV2::GetAverageReportedLossRatio() const {
+ if (num_observations_ <= 0) {
+ return 0.0;
+ }
+
+ int num_packets = 0;
+ int num_lost_packets = 0;
+ for (const Observation& observation : observations_) {
+ if (!observation.IsInitialized()) {
+ continue;
+ }
+
+ double tcp_fairness_temporal_weight =
+ tcp_fairness_temporal_weights_[(num_observations_ - 1) -
+ observation.id];
+ num_packets += tcp_fairness_temporal_weight * observation.num_packets;
+ num_lost_packets +=
+ tcp_fairness_temporal_weight * observation.num_lost_packets;
+ }
+
+ return static_cast<double>(num_lost_packets) / num_packets;
+}
+
+std::vector<LossBasedBweV2::ChannelParameters> LossBasedBweV2::GetCandidates()
+ const {
+ std::vector<DataRate> bandwidths;
+ for (double candidate_factor : config_->candidate_factors) {
+ bandwidths.emplace_back(candidate_factor *
+ current_estimate_.loss_limited_bandwidth);
+ }
+
+ if (acknowledged_bitrate_.has_value()) {
+ bandwidths.emplace_back(*acknowledged_bitrate_);
+ }
+
+ // TODO(crodbro): Consider adding the delay based estimate as a candidate.
+
+ const DataRate candidate_bandwidth_upper_bound =
+ acknowledged_bitrate_.has_value()
+ ? config_->bandwidth_rampup_upper_bound_factor *
+ (*acknowledged_bitrate_)
+ : DataRate::PlusInfinity();
+
+ std::vector<ChannelParameters> candidates;
+ candidates.resize(bandwidths.size());
+ for (size_t i = 0; i < bandwidths.size(); ++i) {
+ ChannelParameters candidate = current_estimate_;
+ candidate.loss_limited_bandwidth = std::min(
+ bandwidths[i], std::max(current_estimate_.loss_limited_bandwidth,
+ candidate_bandwidth_upper_bound));
+ candidate.inherent_loss = GetFeasibleInherentLoss(candidate);
+ candidates[i] = candidate;
+ }
+ return candidates;
+}
+
+LossBasedBweV2::Derivatives LossBasedBweV2::GetDerivatives(
+ const ChannelParameters& channel_parameters) const {
+ Derivatives derivatives;
+
+ for (const Observation& observation : observations_) {
+ if (!observation.IsInitialized()) {
+ continue;
+ }
+
+ double loss_probability = GetLossProbability(
+ channel_parameters.inherent_loss,
+ channel_parameters.loss_limited_bandwidth, observation.sending_rate);
+
+ double temporal_weight =
+ temporal_weights_[(num_observations_ - 1) - observation.id];
+
+ derivatives.first +=
+ temporal_weight *
+ ((observation.num_lost_packets / loss_probability) -
+ (observation.num_received_packets / (1.0 - loss_probability)));
+ derivatives.second -=
+ temporal_weight *
+ ((observation.num_lost_packets / std::pow(loss_probability, 2)) +
+ (observation.num_received_packets /
+ std::pow(1.0 - loss_probability, 2)));
+ }
+
+ if (derivatives.second >= 0.0) {
+ RTC_LOG(LS_ERROR) << "The second derivative is mathematically guaranteed "
+ "to be negative but is "
+ << derivatives.second << ".";
+ derivatives.second = -1.0e-6;
+ }
+
+ return derivatives;
+}
+
+double LossBasedBweV2::GetFeasibleInherentLoss(
+ const ChannelParameters& channel_parameters) const {
+ return std::min(
+ std::max(channel_parameters.inherent_loss,
+ config_->inherent_loss_lower_bound),
+ GetInherentLossUpperBound(channel_parameters.loss_limited_bandwidth));
+}
+
+double LossBasedBweV2::GetInherentLossUpperBound(DataRate bandwidth) const {
+ if (bandwidth.IsZero()) {
+ return 1.0;
+ }
+
+ double inherent_loss_upper_bound =
+ config_->inherent_loss_upper_bound_offset +
+ config_->inherent_loss_upper_bound_bandwidth_balance / bandwidth;
+ return std::min(inherent_loss_upper_bound, 1.0);
+}
+
+double LossBasedBweV2::GetObjective(
+ const ChannelParameters& channel_parameters) const {
+ double objective = 0.0;
+
+ for (const Observation& observation : observations_) {
+ if (!observation.IsInitialized()) {
+ continue;
+ }
+
+ double loss_probability = GetLossProbability(
+ channel_parameters.inherent_loss,
+ channel_parameters.loss_limited_bandwidth, observation.sending_rate);
+
+ double temporal_weight =
+ temporal_weights_[(num_observations_ - 1) - observation.id];
+
+ objective +=
+ temporal_weight *
+ ((observation.num_lost_packets * std::log(loss_probability)) +
+ (observation.num_received_packets * std::log(1.0 - loss_probability)));
+ objective +=
+ temporal_weight * (config_->higher_bandwidth_bias_factor *
+ channel_parameters.loss_limited_bandwidth.kbps() *
+ observation.num_packets);
+ }
+
+ return objective;
+}
+
+DataRate LossBasedBweV2::GetSendingRate(
+ DataRate instantaneous_sending_rate) const {
+ if (num_observations_ <= 0) {
+ return instantaneous_sending_rate;
+ }
+
+ const int most_recent_observation_idx =
+ (num_observations_ - 1) % config_->observation_window_size;
+ const Observation& most_recent_observation =
+ observations_[most_recent_observation_idx];
+ DataRate sending_rate_previous_observation =
+ most_recent_observation.sending_rate;
+
+ return config_->sending_rate_smoothing_factor *
+ sending_rate_previous_observation +
+ (1.0 - config_->sending_rate_smoothing_factor) *
+ instantaneous_sending_rate;
+}
+
+DataRate LossBasedBweV2::GetTcpFairnessBandwidthUpperBound() const {
+ if (num_observations_ <= 0) {
+ return DataRate::PlusInfinity();
+ }
+
+ const double average_reported_loss_ratio = GetAverageReportedLossRatio();
+ if (average_reported_loss_ratio <=
+ config_->tcp_fairness_upper_bound_loss_offset) {
+ return DataRate::PlusInfinity();
+ }
+ return config_->tcp_fairness_upper_bound_bandwidth_balance /
+ (average_reported_loss_ratio -
+ config_->tcp_fairness_upper_bound_loss_offset);
+}
+
+void LossBasedBweV2::CalculateTemporalWeights() {
+ for (int i = 0; i < config_->observation_window_size; ++i) {
+ temporal_weights_[i] = std::pow(config_->temporal_weight_factor, i);
+ tcp_fairness_temporal_weights_[i] =
+ std::pow(config_->tcp_fairness_temporal_weight_factor, i);
+ }
+}
+
+void LossBasedBweV2::NewtonsMethodUpdate(
+ ChannelParameters& channel_parameters) const {
+ if (num_observations_ <= 0) {
+ return;
+ }
+
+ for (int i = 0; i < config_->newton_iterations; ++i) {
+ const Derivatives derivatives = GetDerivatives(channel_parameters);
+ channel_parameters.inherent_loss -=
+ config_->newton_step_size * derivatives.first / derivatives.second;
+ channel_parameters.inherent_loss =
+ GetFeasibleInherentLoss(channel_parameters);
+ }
+}
+
+bool LossBasedBweV2::PushBackObservation(
+ rtc::ArrayView<const PacketResult> packet_results) {
+ if (packet_results.empty()) {
+ return false;
+ }
+
+ PacketResultsSummary packet_results_summary =
+ GetPacketResultsSummary(packet_results);
+
+ partial_observation_.num_packets += packet_results_summary.num_packets;
+ partial_observation_.num_lost_packets +=
+ packet_results_summary.num_lost_packets;
+ partial_observation_.size += packet_results_summary.total_size;
+
+ // This is the first packet report we have received.
+ if (!IsValid(last_send_time_most_recent_observation_)) {
+ last_send_time_most_recent_observation_ =
+ packet_results_summary.first_send_time;
+ }
+
+ const Timestamp last_send_time = packet_results_summary.last_send_time;
+ const TimeDelta observation_duration =
+ last_send_time - last_send_time_most_recent_observation_;
+
+ // Too small to be meaningful.
+ if (observation_duration < config_->observation_duration_lower_bound) {
+ return false;
+ }
+
+ last_send_time_most_recent_observation_ = last_send_time;
+
+ Observation observation;
+ observation.num_packets = partial_observation_.num_packets;
+ observation.num_lost_packets = partial_observation_.num_lost_packets;
+ observation.num_received_packets =
+ observation.num_packets - observation.num_lost_packets;
+ observation.sending_rate =
+ GetSendingRate(partial_observation_.size / observation_duration);
+ observation.id = num_observations_++;
+ observations_[observation.id % config_->observation_window_size] =
+ observation;
+
+ partial_observation_ = PartialObservation();
+
+ return true;
+}
+
+} // namespace webrtc
diff --git a/modules/congestion_controller/goog_cc/loss_based_bwe_v2.h b/modules/congestion_controller/goog_cc/loss_based_bwe_v2.h
new file mode 100644
index 0000000..83d6f33
--- /dev/null
+++ b/modules/congestion_controller/goog_cc/loss_based_bwe_v2.h
@@ -0,0 +1,135 @@
+/*
+ * Copyright 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_GOOG_CC_LOSS_BASED_BWE_V2_H_
+#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_LOSS_BASED_BWE_V2_H_
+
+#include <cstddef>
+#include <vector>
+
+#include "absl/types/optional.h"
+#include "api/array_view.h"
+#include "api/transport/network_types.h"
+#include "api/transport/webrtc_key_value_config.h"
+#include "api/units/data_rate.h"
+#include "api/units/data_size.h"
+#include "api/units/time_delta.h"
+#include "api/units/timestamp.h"
+
+namespace webrtc {
+
+class LossBasedBweV2 {
+ public:
+ // Creates a disabled `LossBasedBweV2` if the
+ // `key_value_config` is not valid.
+ explicit LossBasedBweV2(const WebRtcKeyValueConfig* key_value_config);
+
+ LossBasedBweV2(const LossBasedBweV2&) = delete;
+ LossBasedBweV2& operator=(const LossBasedBweV2&) = delete;
+
+ ~LossBasedBweV2() = default;
+
+ bool IsEnabled() const;
+ // Returns true iff a BWE can be calculated, i.e., the estimator has been
+ // initialized with a BWE and then has received enough `PacketResult`s.
+ bool IsReady() const;
+
+ // Returns `DataRate::PlusInfinity` if no BWE can be calculated.
+ DataRate GetBandwidthEstimate() const;
+
+ void SetAcknowledgedBitrate(DataRate acknowledged_bitrate);
+ void SetBandwidthEstimate(DataRate bandwidth_estimate);
+
+ void UpdateBandwidthEstimate(
+ rtc::ArrayView<const PacketResult> packet_results);
+
+ private:
+ struct ChannelParameters {
+ double inherent_loss = 0.0;
+ DataRate loss_limited_bandwidth = DataRate::MinusInfinity();
+ };
+
+ struct Config {
+ double bandwidth_rampup_upper_bound_factor = 0.0;
+ std::vector<double> candidate_factors;
+ double higher_bandwidth_bias_factor = 0.0;
+ double inherent_loss_lower_bound = 0.0;
+ DataRate inherent_loss_upper_bound_bandwidth_balance =
+ DataRate::MinusInfinity();
+ double inherent_loss_upper_bound_offset = 0.0;
+ double initial_inherent_loss_estimate = 0.0;
+ int newton_iterations = 0;
+ double newton_step_size = 0.0;
+ TimeDelta observation_duration_lower_bound = TimeDelta::Zero();
+ int observation_window_size = 0;
+ double sending_rate_smoothing_factor = 0.0;
+ double tcp_fairness_temporal_weight_factor = 0.0;
+ DataRate tcp_fairness_upper_bound_bandwidth_balance =
+ DataRate::MinusInfinity();
+ double tcp_fairness_upper_bound_loss_offset = 0.0;
+ double temporal_weight_factor = 0.0;
+ };
+
+ struct Derivatives {
+ double first = 0.0;
+ double second = 0.0;
+ };
+
+ struct Observation {
+ bool IsInitialized() const { return id != -1; }
+
+ int num_packets = 0;
+ int num_lost_packets = 0;
+ int num_received_packets = 0;
+ DataRate sending_rate = DataRate::MinusInfinity();
+ int id = -1;
+ };
+
+ struct PartialObservation {
+ int num_packets = 0;
+ int num_lost_packets = 0;
+ DataSize size = DataSize::Zero();
+ };
+
+ static absl::optional<Config> CreateConfig(
+ const WebRtcKeyValueConfig* key_value_config);
+ bool IsConfigValid() const;
+
+ // Returns `0.0` if not enough loss statistics have been received.
+ double GetAverageReportedLossRatio() const;
+ std::vector<ChannelParameters> GetCandidates() const;
+ Derivatives GetDerivatives(const ChannelParameters& channel_parameters) const;
+ double GetFeasibleInherentLoss(
+ const ChannelParameters& channel_parameters) const;
+ double GetInherentLossUpperBound(DataRate bandwidth) const;
+ double GetObjective(const ChannelParameters& channel_parameters) const;
+ DataRate GetSendingRate(DataRate instantaneous_sending_rate) const;
+ DataRate GetTcpFairnessBandwidthUpperBound() const;
+
+ void CalculateTemporalWeights();
+ void NewtonsMethodUpdate(ChannelParameters& channel_parameters) const;
+
+ // Returns false if no observation was created.
+ bool PushBackObservation(rtc::ArrayView<const PacketResult> packet_results);
+
+ absl::optional<DataRate> acknowledged_bitrate_;
+ absl::optional<Config> config_;
+ ChannelParameters current_estimate_;
+ int num_observations_ = 0;
+ std::vector<Observation> observations_;
+ PartialObservation partial_observation_;
+ Timestamp last_send_time_most_recent_observation_ = Timestamp::PlusInfinity();
+ std::vector<double> tcp_fairness_temporal_weights_;
+ std::vector<double> temporal_weights_;
+};
+
+} // namespace webrtc
+
+#endif // MODULES_CONGESTION_CONTROLLER_GOOG_CC_LOSS_BASED_BWE_V2_H_
diff --git a/modules/congestion_controller/goog_cc/loss_based_bwe_v2_test.cc b/modules/congestion_controller/goog_cc/loss_based_bwe_v2_test.cc
new file mode 100644
index 0000000..87ac31d
--- /dev/null
+++ b/modules/congestion_controller/goog_cc/loss_based_bwe_v2_test.cc
@@ -0,0 +1,299 @@
+/*
+ * Copyright 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 "modules/congestion_controller/goog_cc/loss_based_bwe_v2.h"
+
+#include <string>
+
+#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 "rtc_base/strings/string_builder.h"
+#include "test/explicit_key_value_config.h"
+#include "test/gtest.h"
+
+namespace webrtc {
+
+namespace {
+
+constexpr TimeDelta kObservationDurationLowerBound = TimeDelta::Millis(200);
+
+std::string Config(bool enabled, bool valid) {
+ char buffer[1024];
+ rtc::SimpleStringBuilder config_string(buffer);
+
+ config_string << "WebRTC-Bwe-LossBasedBweV2/";
+
+ if (enabled) {
+ config_string << "Enabled:true";
+ } else {
+ config_string << "Enabled:false";
+ }
+
+ if (valid) {
+ config_string << ",BwRampupUpperBoundFactor:1.2";
+ } else {
+ config_string << ",BwRampupUpperBoundFactor:0.0";
+ }
+
+ config_string
+ << ",CandidateFactors:0.9|1.1,HigherBwBiasFactor:0.01,"
+ "InherentLossLowerBound:0.001,InherentLossUpperBoundBwBalance:14kbps,"
+ "InherentLossUpperBoundOffset:0.9,InitialInherentLossEstimate:0.01,"
+ "NewtonIterations:2,NewtonStepSize:0.4,ObservationWindowSize:15,"
+ "SendingRateSmoothingFactor:0.01,TcpFairnessTemporalWeightFactor:0.97,"
+ "TcpFairnessUpperBoundBwBalance:90kbps,"
+ "TcpFairnessUpperBoundLossOffset:0.1,TemporalWeightFactor:0.98";
+
+ config_string.AppendFormat(
+ ",ObservationDurationLowerBound:%dms",
+ static_cast<int>(kObservationDurationLowerBound.ms()));
+
+ config_string << "/";
+
+ return config_string.str();
+}
+
+TEST(LossBasedBweV2Test, EnabledWhenGivenValidConfigurationValues) {
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/true, /*valid=*/true));
+ LossBasedBweV2 loss_based_bandwidth_estimator(&key_value_config);
+
+ EXPECT_TRUE(loss_based_bandwidth_estimator.IsEnabled());
+}
+
+TEST(LossBasedBweV2Test, DisabledWhenGivenDisabledConfiguration) {
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/false, /*valid=*/true));
+ LossBasedBweV2 loss_based_bandwidth_estimator(&key_value_config);
+
+ EXPECT_FALSE(loss_based_bandwidth_estimator.IsEnabled());
+}
+
+TEST(LossBasedBweV2Test, DisabledWhenGivenNonValidConfigurationValues) {
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/true, /*valid=*/false));
+ LossBasedBweV2 loss_based_bandwidth_estimator(&key_value_config);
+
+ EXPECT_FALSE(loss_based_bandwidth_estimator.IsEnabled());
+}
+
+TEST(LossBasedBweV2Test, BandwidthEstimateGivenInitializationAndThenFeedback) {
+ PacketResult enough_feedback[2];
+ enough_feedback[0].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback[1].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback[0].sent_packet.send_time = Timestamp::Zero();
+ enough_feedback[1].sent_packet.send_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback[0].receive_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback[1].receive_time =
+ Timestamp::Zero() + 2 * kObservationDurationLowerBound;
+
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/true, /*valid=*/true));
+ LossBasedBweV2 loss_based_bandwidth_estimator(&key_value_config);
+
+ loss_based_bandwidth_estimator.SetBandwidthEstimate(
+ DataRate::KilobitsPerSec(600));
+ loss_based_bandwidth_estimator.UpdateBandwidthEstimate(enough_feedback);
+
+ EXPECT_TRUE(loss_based_bandwidth_estimator.IsReady());
+ EXPECT_TRUE(loss_based_bandwidth_estimator.GetBandwidthEstimate().IsFinite());
+}
+
+TEST(LossBasedBweV2Test, NoBandwidthEstimateGivenNoInitialization) {
+ PacketResult enough_feedback[2];
+ enough_feedback[0].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback[1].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback[0].sent_packet.send_time = Timestamp::Zero();
+ enough_feedback[1].sent_packet.send_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback[0].receive_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback[1].receive_time =
+ Timestamp::Zero() + 2 * kObservationDurationLowerBound;
+
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/true, /*valid=*/true));
+ LossBasedBweV2 loss_based_bandwidth_estimator(&key_value_config);
+
+ loss_based_bandwidth_estimator.UpdateBandwidthEstimate(enough_feedback);
+
+ EXPECT_FALSE(loss_based_bandwidth_estimator.IsReady());
+ EXPECT_TRUE(
+ loss_based_bandwidth_estimator.GetBandwidthEstimate().IsPlusInfinity());
+}
+
+TEST(LossBasedBweV2Test, NoBandwidthEstimateGivenNotEnoughFeedback) {
+ // Create packet results where the observation duration is less than the lower
+ // bound.
+ PacketResult not_enough_feedback[2];
+ not_enough_feedback[0].sent_packet.size = DataSize::Bytes(15'000);
+ not_enough_feedback[1].sent_packet.size = DataSize::Bytes(15'000);
+ not_enough_feedback[0].sent_packet.send_time = Timestamp::Zero();
+ not_enough_feedback[1].sent_packet.send_time =
+ Timestamp::Zero() + kObservationDurationLowerBound / 2;
+ not_enough_feedback[0].receive_time =
+ Timestamp::Zero() + kObservationDurationLowerBound / 2;
+ not_enough_feedback[1].receive_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/true, /*valid=*/true));
+ LossBasedBweV2 loss_based_bandwidth_estimator(&key_value_config);
+
+ loss_based_bandwidth_estimator.SetBandwidthEstimate(
+ DataRate::KilobitsPerSec(600));
+
+ EXPECT_FALSE(loss_based_bandwidth_estimator.IsReady());
+ EXPECT_TRUE(
+ loss_based_bandwidth_estimator.GetBandwidthEstimate().IsPlusInfinity());
+
+ loss_based_bandwidth_estimator.UpdateBandwidthEstimate(not_enough_feedback);
+
+ EXPECT_FALSE(loss_based_bandwidth_estimator.IsReady());
+ EXPECT_TRUE(
+ loss_based_bandwidth_estimator.GetBandwidthEstimate().IsPlusInfinity());
+}
+
+TEST(LossBasedBweV2Test,
+ SetValueIsTheEstimateUntilAdditionalFeedbackHasBeenReceived) {
+ PacketResult enough_feedback_1[2];
+ PacketResult enough_feedback_2[2];
+ enough_feedback_1[0].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback_1[1].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback_2[0].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback_2[1].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback_1[0].sent_packet.send_time = Timestamp::Zero();
+ enough_feedback_1[1].sent_packet.send_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback_2[0].sent_packet.send_time =
+ Timestamp::Zero() + 2 * kObservationDurationLowerBound;
+ enough_feedback_2[1].sent_packet.send_time =
+ Timestamp::Zero() + 3 * kObservationDurationLowerBound;
+ enough_feedback_1[0].receive_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback_1[1].receive_time =
+ Timestamp::Zero() + 2 * kObservationDurationLowerBound;
+ enough_feedback_2[0].receive_time =
+ Timestamp::Zero() + 3 * kObservationDurationLowerBound;
+ enough_feedback_2[1].receive_time =
+ Timestamp::Zero() + 4 * kObservationDurationLowerBound;
+
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/true, /*valid=*/true));
+ LossBasedBweV2 loss_based_bandwidth_estimator(&key_value_config);
+
+ loss_based_bandwidth_estimator.SetBandwidthEstimate(
+ DataRate::KilobitsPerSec(600));
+ loss_based_bandwidth_estimator.UpdateBandwidthEstimate(enough_feedback_1);
+
+ EXPECT_NE(loss_based_bandwidth_estimator.GetBandwidthEstimate(),
+ DataRate::KilobitsPerSec(600));
+
+ loss_based_bandwidth_estimator.SetBandwidthEstimate(
+ DataRate::KilobitsPerSec(600));
+
+ EXPECT_EQ(loss_based_bandwidth_estimator.GetBandwidthEstimate(),
+ DataRate::KilobitsPerSec(600));
+
+ loss_based_bandwidth_estimator.UpdateBandwidthEstimate(enough_feedback_2);
+
+ EXPECT_NE(loss_based_bandwidth_estimator.GetBandwidthEstimate(),
+ DataRate::KilobitsPerSec(600));
+}
+
+TEST(LossBasedBweV2Test,
+ SetAcknowledgedBitrateOnlyAffectsTheBweWhenAdditionalFeedbackIsGiven) {
+ PacketResult enough_feedback_1[2];
+ PacketResult enough_feedback_2[2];
+ enough_feedback_1[0].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback_1[1].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback_2[0].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback_2[1].sent_packet.size = DataSize::Bytes(15'000);
+ enough_feedback_1[0].sent_packet.send_time = Timestamp::Zero();
+ enough_feedback_1[1].sent_packet.send_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback_2[0].sent_packet.send_time =
+ Timestamp::Zero() + 2 * kObservationDurationLowerBound;
+ enough_feedback_2[1].sent_packet.send_time =
+ Timestamp::Zero() + 3 * kObservationDurationLowerBound;
+ enough_feedback_1[0].receive_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback_1[1].receive_time =
+ Timestamp::Zero() + 2 * kObservationDurationLowerBound;
+ enough_feedback_2[0].receive_time =
+ Timestamp::Zero() + 3 * kObservationDurationLowerBound;
+ enough_feedback_2[1].receive_time =
+ Timestamp::Zero() + 4 * kObservationDurationLowerBound;
+
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/true, /*valid=*/true));
+ LossBasedBweV2 loss_based_bandwidth_estimator_1(&key_value_config);
+ LossBasedBweV2 loss_based_bandwidth_estimator_2(&key_value_config);
+
+ loss_based_bandwidth_estimator_1.SetBandwidthEstimate(
+ DataRate::KilobitsPerSec(600));
+ loss_based_bandwidth_estimator_2.SetBandwidthEstimate(
+ DataRate::KilobitsPerSec(600));
+ loss_based_bandwidth_estimator_1.UpdateBandwidthEstimate(enough_feedback_1);
+ loss_based_bandwidth_estimator_2.UpdateBandwidthEstimate(enough_feedback_1);
+
+ EXPECT_EQ(loss_based_bandwidth_estimator_1.GetBandwidthEstimate(),
+ DataRate::KilobitsPerSec(660));
+
+ loss_based_bandwidth_estimator_1.SetAcknowledgedBitrate(
+ DataRate::KilobitsPerSec(600));
+
+ EXPECT_EQ(loss_based_bandwidth_estimator_1.GetBandwidthEstimate(),
+ DataRate::KilobitsPerSec(660));
+
+ loss_based_bandwidth_estimator_1.UpdateBandwidthEstimate(enough_feedback_2);
+ loss_based_bandwidth_estimator_2.UpdateBandwidthEstimate(enough_feedback_2);
+
+ EXPECT_NE(loss_based_bandwidth_estimator_1.GetBandwidthEstimate(),
+ loss_based_bandwidth_estimator_2.GetBandwidthEstimate());
+}
+
+TEST(LossBasedBweV2Test,
+ BandwidthEstimateIsCappedToBeTcpFairGivenTooHighLossRate) {
+ PacketResult enough_feedback_no_received_packets[2];
+ enough_feedback_no_received_packets[0].sent_packet.size =
+ DataSize::Bytes(15'000);
+ enough_feedback_no_received_packets[1].sent_packet.size =
+ DataSize::Bytes(15'000);
+ enough_feedback_no_received_packets[0].sent_packet.send_time =
+ Timestamp::Zero();
+ enough_feedback_no_received_packets[1].sent_packet.send_time =
+ Timestamp::Zero() + kObservationDurationLowerBound;
+ enough_feedback_no_received_packets[0].receive_time =
+ Timestamp::PlusInfinity();
+ enough_feedback_no_received_packets[1].receive_time =
+ Timestamp::PlusInfinity();
+
+ test::ExplicitKeyValueConfig key_value_config(
+ Config(/*enabled=*/true, /*valid=*/true));
+ LossBasedBweV2 loss_based_bandwidth_estimator(&key_value_config);
+
+ loss_based_bandwidth_estimator.SetBandwidthEstimate(
+ DataRate::KilobitsPerSec(600));
+ loss_based_bandwidth_estimator.UpdateBandwidthEstimate(
+ enough_feedback_no_received_packets);
+
+ EXPECT_EQ(loss_based_bandwidth_estimator.GetBandwidthEstimate(),
+ DataRate::KilobitsPerSec(100));
+}
+
+} // namespace
+
+} // namespace webrtc
diff --git a/modules/congestion_controller/goog_cc/send_side_bandwidth_estimation.cc b/modules/congestion_controller/goog_cc/send_side_bandwidth_estimation.cc
index c5f51df..749b073 100644
--- a/modules/congestion_controller/goog_cc/send_side_bandwidth_estimation.cc
+++ b/modules/congestion_controller/goog_cc/send_side_bandwidth_estimation.cc
@@ -23,6 +23,7 @@
#include "api/units/data_rate.h"
#include "api/units/time_delta.h"
#include "logging/rtc_event_log/events/rtc_event_bwe_update_loss_based.h"
+#include "modules/congestion_controller/goog_cc/loss_based_bwe_v2.h"
#include "modules/remote_bitrate_estimator/include/bwe_defines.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
@@ -226,7 +227,8 @@
low_loss_threshold_(kDefaultLowLossThreshold),
high_loss_threshold_(kDefaultHighLossThreshold),
bitrate_threshold_(kDefaultBitrateThreshold),
- loss_based_bandwidth_estimation_(key_value_config),
+ loss_based_bandwidth_estimator_v1_(key_value_config),
+ loss_based_bandwidth_estimator_v2_(key_value_config),
receiver_limit_caps_only_("Enabled") {
RTC_DCHECK(event_log);
if (BweLossExperimentIsEnabled()) {
@@ -341,18 +343,29 @@
absl::optional<DataRate> acknowledged_rate,
Timestamp at_time) {
acknowledged_rate_ = acknowledged_rate;
- if (acknowledged_rate && loss_based_bandwidth_estimation_.Enabled()) {
- loss_based_bandwidth_estimation_.UpdateAcknowledgedBitrate(
+ if (!acknowledged_rate.has_value()) {
+ return;
+ }
+ if (LossBasedBandwidthEstimatorV1Enabled()) {
+ loss_based_bandwidth_estimator_v1_.UpdateAcknowledgedBitrate(
*acknowledged_rate, at_time);
}
+ if (LossBasedBandwidthEstimatorV2Enabled()) {
+ loss_based_bandwidth_estimator_v2_.SetAcknowledgedBitrate(
+ *acknowledged_rate);
+ }
}
void SendSideBandwidthEstimation::IncomingPacketFeedbackVector(
const TransportPacketsFeedback& report) {
- if (loss_based_bandwidth_estimation_.Enabled()) {
- loss_based_bandwidth_estimation_.UpdateLossStatistics(
+ if (LossBasedBandwidthEstimatorV1Enabled()) {
+ loss_based_bandwidth_estimator_v1_.UpdateLossStatistics(
report.packet_feedbacks, report.feedback_time);
}
+ if (LossBasedBandwidthEstimatorV2Enabled()) {
+ loss_based_bandwidth_estimator_v2_.UpdateBandwidthEstimate(
+ report.packet_feedbacks);
+ }
}
void SendSideBandwidthEstimation::UpdatePacketsLost(int64_t packets_lost,
@@ -459,13 +472,16 @@
new_bitrate = std::max(receiver_limit_, new_bitrate);
if (delay_based_limit_.IsFinite())
new_bitrate = std::max(delay_based_limit_, new_bitrate);
- if (loss_based_bandwidth_estimation_.Enabled()) {
- loss_based_bandwidth_estimation_.Initialize(new_bitrate);
+ if (LossBasedBandwidthEstimatorV1Enabled()) {
+ loss_based_bandwidth_estimator_v1_.Initialize(new_bitrate);
+ }
+ if (LossBasedBandwidthEstimatorV2Enabled()) {
+ loss_based_bandwidth_estimator_v2_.SetBandwidthEstimate(new_bitrate);
}
if (new_bitrate != current_target_) {
min_bitrate_history_.clear();
- if (loss_based_bandwidth_estimation_.Enabled()) {
+ if (LossBasedBandwidthEstimatorV1Enabled()) {
min_bitrate_history_.push_back(std::make_pair(at_time, new_bitrate));
} else {
min_bitrate_history_.push_back(
@@ -483,14 +499,22 @@
return;
}
- if (loss_based_bandwidth_estimation_.InUse()) {
- DataRate new_bitrate = loss_based_bandwidth_estimation_.Update(
+ if (LossBasedBandwidthEstimatorV1ReadyForUse()) {
+ DataRate new_bitrate = loss_based_bandwidth_estimator_v1_.Update(
at_time, min_bitrate_history_.front().second, delay_based_limit_,
last_round_trip_time_);
UpdateTargetBitrate(new_bitrate, at_time);
return;
}
+ if (LossBasedBandwidthEstimatorV2ReadyForUse()) {
+ DataRate new_bitrate =
+ loss_based_bandwidth_estimator_v2_.GetBandwidthEstimate();
+ new_bitrate = std::min(new_bitrate, delay_based_limit_);
+ UpdateTargetBitrate(new_bitrate, at_time);
+ return;
+ }
+
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.
@@ -628,4 +652,26 @@
void SendSideBandwidthEstimation::ApplyTargetLimits(Timestamp at_time) {
UpdateTargetBitrate(current_target_, at_time);
}
+
+bool SendSideBandwidthEstimation::LossBasedBandwidthEstimatorV1Enabled() const {
+ return loss_based_bandwidth_estimator_v1_.Enabled() &&
+ !LossBasedBandwidthEstimatorV2Enabled();
+}
+
+bool SendSideBandwidthEstimation::LossBasedBandwidthEstimatorV1ReadyForUse()
+ const {
+ return LossBasedBandwidthEstimatorV1Enabled() &&
+ loss_based_bandwidth_estimator_v1_.InUse();
+}
+
+bool SendSideBandwidthEstimation::LossBasedBandwidthEstimatorV2Enabled() const {
+ return loss_based_bandwidth_estimator_v2_.IsEnabled();
+}
+
+bool SendSideBandwidthEstimation::LossBasedBandwidthEstimatorV2ReadyForUse()
+ const {
+ return LossBasedBandwidthEstimatorV2Enabled() &&
+ loss_based_bandwidth_estimator_v2_.IsReady();
+}
+
} // namespace webrtc
diff --git a/modules/congestion_controller/goog_cc/send_side_bandwidth_estimation.h b/modules/congestion_controller/goog_cc/send_side_bandwidth_estimation.h
index 5917d9b..63be1f0 100644
--- a/modules/congestion_controller/goog_cc/send_side_bandwidth_estimation.h
+++ b/modules/congestion_controller/goog_cc/send_side_bandwidth_estimation.h
@@ -26,6 +26,7 @@
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "modules/congestion_controller/goog_cc/loss_based_bandwidth_estimation.h"
+#include "modules/congestion_controller/goog_cc/loss_based_bwe_v2.h"
#include "rtc_base/experiments/field_trial_parser.h"
namespace webrtc {
@@ -149,6 +150,12 @@
// should be cleaned up.
void ApplyTargetLimits(Timestamp at_time);
+ bool LossBasedBandwidthEstimatorV1Enabled() const;
+ bool LossBasedBandwidthEstimatorV2Enabled() const;
+
+ bool LossBasedBandwidthEstimatorV1ReadyForUse() const;
+ bool LossBasedBandwidthEstimatorV2ReadyForUse() const;
+
RttBasedBackoff rtt_backoff_;
LinkCapacityTracker link_capacity_;
@@ -189,7 +196,8 @@
float low_loss_threshold_;
float high_loss_threshold_;
DataRate bitrate_threshold_;
- LossBasedBandwidthEstimation loss_based_bandwidth_estimation_;
+ LossBasedBandwidthEstimation loss_based_bandwidth_estimator_v1_;
+ LossBasedBweV2 loss_based_bandwidth_estimator_v2_;
FieldTrialFlag receiver_limit_caps_only_;
};
} // namespace webrtc
diff --git a/modules/congestion_controller/goog_cc/test/goog_cc_printer.cc b/modules/congestion_controller/goog_cc/test/goog_cc_printer.cc
index 52baab0..6dadf8b 100644
--- a/modules/congestion_controller/goog_cc/test/goog_cc_printer.cc
+++ b/modules/congestion_controller/goog_cc/test/goog_cc_printer.cc
@@ -87,7 +87,7 @@
};
auto loss_cont = [&] {
return &controller_->bandwidth_estimation_
- ->loss_based_bandwidth_estimation_;
+ ->loss_based_bandwidth_estimator_v1_;
};
std::deque<FieldLogger*> loggers({
Log("time", [=] { return target_.at_time; }),
