Add a new overuse estimator for the delay based BWE behind experiment.
Parse the estimation parameters from the field trial string.
BUG=webrtc:6690
Review-Url: https://codereview.webrtc.org/2489323002
Cr-Commit-Position: refs/heads/master@{#15126}
diff --git a/webrtc/modules/congestion_controller/delay_based_bwe.cc b/webrtc/modules/congestion_controller/delay_based_bwe.cc
index af27505..78bc7f0 100644
--- a/webrtc/modules/congestion_controller/delay_based_bwe.cc
+++ b/webrtc/modules/congestion_controller/delay_based_bwe.cc
@@ -12,6 +12,7 @@
#include <algorithm>
#include <cmath>
+#include <string>
#include "webrtc/base/checks.h"
#include "webrtc/base/constructormagic.h"
@@ -38,15 +39,52 @@
constexpr int kInitialRateWindowMs = 500;
constexpr int kRateWindowMs = 150;
+constexpr size_t kDefaultTrendlineWindowSize = 15;
+constexpr double kDefaultTrendlineSmoothingCoeff = 0.9;
+constexpr double kDefaultTrendlineThresholdGain = 4.0;
+
const char kBitrateEstimateExperiment[] = "WebRTC-ImprovedBitrateEstimate";
+const char kBweTrendlineFilterExperiment[] = "WebRTC-BweTrendlineFilter";
bool BitrateEstimateExperimentIsEnabled() {
return webrtc::field_trial::FindFullName(kBitrateEstimateExperiment) ==
"Enabled";
}
+
+bool TrendlineFilterExperimentIsEnabled() {
+ std::string experiment_string =
+ webrtc::field_trial::FindFullName(kBweTrendlineFilterExperiment);
+ // The experiment is enabled iff the field trial string begins with "Enabled".
+ return experiment_string.find("Enabled") == 0;
+}
+
+bool ReadTrendlineFilterExperimentParameters(size_t* window_points,
+ double* smoothing_coef,
+ double* threshold_gain) {
+ RTC_DCHECK(TrendlineFilterExperimentIsEnabled());
+ std::string experiment_string =
+ webrtc::field_trial::FindFullName(kBweTrendlineFilterExperiment);
+ int parsed_values = sscanf(experiment_string.c_str(), "Enabled-%zu,%lf,%lf",
+ window_points, smoothing_coef, threshold_gain);
+ if (parsed_values == 3) {
+ RTC_CHECK_GT(*window_points, 1) << "Need at least 2 points to fit a line.";
+ RTC_CHECK(0 <= *smoothing_coef && *smoothing_coef <= 1)
+ << "Coefficient needs to be between 0 and 1 for weighted average.";
+ RTC_CHECK_GT(*threshold_gain, 0) << "Threshold gain needs to be positive.";
+ return true;
+ }
+ LOG(LS_WARNING) << "Failed to parse parameters for BweTrendlineFilter "
+ "experiment from field trial string. Using default.";
+ *window_points = kDefaultTrendlineWindowSize;
+ *smoothing_coef = kDefaultTrendlineSmoothingCoeff;
+ *threshold_gain = kDefaultTrendlineThresholdGain;
+ return false;
+}
+
} // namespace
namespace webrtc {
+
DelayBasedBwe::BitrateEstimator::BitrateEstimator()
: sum_(0),
current_win_ms_(0),
@@ -132,12 +170,22 @@
DelayBasedBwe::DelayBasedBwe(Clock* clock)
: clock_(clock),
inter_arrival_(),
- estimator_(),
+ kalman_estimator_(),
+ trendline_estimator_(),
detector_(OverUseDetectorOptions()),
receiver_incoming_bitrate_(),
last_update_ms_(-1),
last_seen_packet_ms_(-1),
- uma_recorded_(false) {
+ uma_recorded_(false),
+ trendline_window_size_(kDefaultTrendlineWindowSize),
+ trendline_smoothing_coeff_(kDefaultTrendlineSmoothingCoeff),
+ trendline_threshold_gain_(kDefaultTrendlineThresholdGain),
+ in_trendline_experiment_(TrendlineFilterExperimentIsEnabled()) {
+ if (in_trendline_experiment_) {
+ ReadTrendlineFilterExperimentParameters(&trendline_window_size_,
+ &trendline_smoothing_coeff_,
+ &trendline_threshold_gain_);
+ }
network_thread_.DetachFromThread();
}
@@ -171,7 +219,10 @@
inter_arrival_.reset(
new InterArrival((kTimestampGroupLengthMs << kInterArrivalShift) / 1000,
kTimestampToMs, true));
- estimator_.reset(new OveruseEstimator(OverUseDetectorOptions()));
+ kalman_estimator_.reset(new OveruseEstimator(OverUseDetectorOptions()));
+ trendline_estimator_.reset(new TrendlineEstimator(
+ trendline_window_size_, trendline_smoothing_coeff_,
+ trendline_threshold_gain_));
}
last_seen_packet_ms_ = now_ms;
@@ -192,10 +243,19 @@
info.payload_size, &ts_delta, &t_delta,
&size_delta)) {
double ts_delta_ms = (1000.0 * ts_delta) / (1 << kInterArrivalShift);
- estimator_->Update(t_delta, ts_delta_ms, size_delta, detector_.State(),
+ if (in_trendline_experiment_) {
+ trendline_estimator_->Update(t_delta, ts_delta_ms, info.arrival_time_ms);
+ detector_.Detect(trendline_estimator_->trendline_slope(), ts_delta_ms,
+ trendline_estimator_->num_of_deltas(),
info.arrival_time_ms);
- detector_.Detect(estimator_->offset(), ts_delta_ms,
- estimator_->num_of_deltas(), info.arrival_time_ms);
+
+ } else {
+ kalman_estimator_->Update(t_delta, ts_delta_ms, size_delta,
+ detector_.State(), info.arrival_time_ms);
+ detector_.Detect(kalman_estimator_->offset(), ts_delta_ms,
+ kalman_estimator_->num_of_deltas(),
+ info.arrival_time_ms);
+ }
}
int probing_bps = 0;
@@ -237,8 +297,9 @@
int64_t now_ms,
rtc::Optional<uint32_t> acked_bitrate_bps,
uint32_t* target_bitrate_bps) {
- const RateControlInput input(detector_.State(), acked_bitrate_bps,
- estimator_->var_noise());
+ // TODO(terelius): RateControlInput::noise_var is deprecated and will be
+ // removed. In the meantime, we set it to zero.
+ const RateControlInput input(detector_.State(), acked_bitrate_bps, 0);
rate_control_.Update(&input, now_ms);
*target_bitrate_bps = rate_control_.UpdateBandwidthEstimate(now_ms);
return rate_control_.ValidEstimate();