Reland of Enable trendline experiment and bayesian bitrate estimator experiment by default.

webrtc/modules/congestion_controller/delay_based_bwe.cc

 /*
  *  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.
  */
 
@@ skipping 24 matching lines @@
     kAbsSendTimeFraction + kAbsSendTimeInterArrivalUpshift;
 constexpr double kTimestampToMs =
     1000.0 / static_cast<double>(1 << kInterArrivalShift);
 // This ssrc is used to fulfill the current API but will be removed
 // after the API has been changed.
 constexpr uint32_t kFixedSsrc = 0;
 constexpr int kInitialRateWindowMs = 500;
 constexpr int kRateWindowMs = 150;
 
 // Parameters for linear least squares fit of regression line to noisy data.
-constexpr size_t kDefaultTrendlineWindowSize = 15;
+constexpr size_t kDefaultTrendlineWindowSize = 20;
 constexpr double kDefaultTrendlineSmoothingCoeff = 0.9;
 constexpr double kDefaultTrendlineThresholdGain = 4.0;
 
-// Parameters for Theil-Sen robust fitting of line to noisy data.
-constexpr size_t kDefaultMedianSlopeWindowSize = 20;
-constexpr double kDefaultMedianSlopeThresholdGain = 4.0;
-
 constexpr int kMaxConsecutiveFailedLookups = 5;
 
-const char kBitrateEstimateExperiment[] = "WebRTC-ImprovedBitrateEstimate";
-const char kBweTrendlineFilterExperiment[] = "WebRTC-BweTrendlineFilter";
-const char kBweMedianSlopeFilterExperiment[] = "WebRTC-BweMedianSlopeFilter";
-
-bool BitrateEstimateExperimentIsEnabled() {
-  return webrtc::field_trial::IsEnabled(kBitrateEstimateExperiment);
-}
-
-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 MedianSlopeFilterExperimentIsEnabled() {
-  std::string experiment_string =
-      webrtc::field_trial::FindFullName(kBweMedianSlopeFilterExperiment);
-  // The experiment is enabled iff the field trial string begins with "Enabled".
-  return experiment_string.find("Enabled") == 0;
-}
-
-bool ReadTrendlineFilterExperimentParameters(size_t* window_size,
-                                             double* smoothing_coef,
-                                             double* threshold_gain) {
-  RTC_DCHECK(TrendlineFilterExperimentIsEnabled());
-  RTC_DCHECK(!MedianSlopeFilterExperimentIsEnabled());
-  RTC_DCHECK(window_size != nullptr);
-  RTC_DCHECK(smoothing_coef != nullptr);
-  RTC_DCHECK(threshold_gain != nullptr);
-  std::string experiment_string =
-      webrtc::field_trial::FindFullName(kBweTrendlineFilterExperiment);
-  int parsed_values = sscanf(experiment_string.c_str(), "Enabled-%zu,%lf,%lf",
-                             window_size, smoothing_coef, threshold_gain);
-  if (parsed_values == 3) {
-    RTC_CHECK_GT(*window_size, 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_size = kDefaultTrendlineWindowSize;
-  *smoothing_coef = kDefaultTrendlineSmoothingCoeff;
-  *threshold_gain = kDefaultTrendlineThresholdGain;
-  return false;
-}
-
-bool ReadMedianSlopeFilterExperimentParameters(size_t* window_size,
-                                               double* threshold_gain) {
-  RTC_DCHECK(!TrendlineFilterExperimentIsEnabled());
-  RTC_DCHECK(MedianSlopeFilterExperimentIsEnabled());
-  RTC_DCHECK(window_size != nullptr);
-  RTC_DCHECK(threshold_gain != nullptr);
-  std::string experiment_string =
-      webrtc::field_trial::FindFullName(kBweMedianSlopeFilterExperiment);
-  int parsed_values = sscanf(experiment_string.c_str(), "Enabled-%zu,%lf",
-                             window_size, threshold_gain);
-  if (parsed_values == 2) {
-    RTC_CHECK_GT(*window_size, 1) << "Need at least 2 points to fit a line.";
-    RTC_CHECK_GT(*threshold_gain, 0) << "Threshold gain needs to be positive.";
-    return true;
-  }
-  LOG(LS_WARNING) << "Failed to parse parameters for BweMedianSlopeFilter "
-                     "experiment from field trial string. Using default.";
-  *window_size = kDefaultMedianSlopeWindowSize;
-  *threshold_gain = kDefaultMedianSlopeThresholdGain;
-  return false;
-}
 
 class PacketFeedbackComparator {
  public:
   inline bool operator()(const webrtc::PacketFeedback& lhs,
                          const webrtc::PacketFeedback& rhs) {
     if (lhs.arrival_time_ms != rhs.arrival_time_ms)
       return lhs.arrival_time_ms < rhs.arrival_time_ms;
     if (lhs.send_time_ms != rhs.send_time_ms)
       return lhs.send_time_ms < rhs.send_time_ms;
     return lhs.sequence_number < rhs.sequence_number;
@@ skipping 11 matching lines @@
 }
 }  // namespace
 
 namespace webrtc {
 
 DelayBasedBwe::BitrateEstimator::BitrateEstimator()
     : sum_(0),
       current_win_ms_(0),
       prev_time_ms_(-1),
       bitrate_estimate_(-1.0f),
-      bitrate_estimate_var_(50.0f),
-      old_estimator_(kBitrateWindowMs, 8000),
-      in_experiment_(BitrateEstimateExperimentIsEnabled()) {}
+      bitrate_estimate_var_(50.0f) {}
 
 void DelayBasedBwe::BitrateEstimator::Update(int64_t now_ms, int bytes) {
-  if (!in_experiment_) {
-    old_estimator_.Update(bytes, now_ms);
-    rtc::Optional<uint32_t> rate = old_estimator_.Rate(now_ms);
-    bitrate_estimate_ = -1.0f;
-    if (rate)
-      bitrate_estimate_ = *rate / 1000.0f;
-    return;
-  }
   int rate_window_ms = kRateWindowMs;
   // We use a larger window at the beginning to get a more stable sample that
   // we can use to initialize the estimate.
   if (bitrate_estimate_ < 0.f)
     rate_window_ms = kInitialRateWindowMs;
   float bitrate_sample = UpdateWindow(now_ms, bytes, rate_window_ms);
   if (bitrate_sample < 0.0f)
     return;
   if (bitrate_estimate_ < 0.0f) {
     // This is the very first sample we get. Use it to initialize the estimate.
@@ skipping 45 matching lines @@
   return bitrate_sample;
 }
 
 rtc::Optional<uint32_t> DelayBasedBwe::BitrateEstimator::bitrate_bps() const {
   if (bitrate_estimate_ < 0.f)
     return rtc::Optional<uint32_t>();
   return rtc::Optional<uint32_t>(bitrate_estimate_ * 1000);
 }
 
 DelayBasedBwe::DelayBasedBwe(RtcEventLog* event_log, const Clock* clock)
-    : in_trendline_experiment_(TrendlineFilterExperimentIsEnabled()),
-      in_median_slope_experiment_(MedianSlopeFilterExperimentIsEnabled()),
-      event_log_(event_log),
+    : event_log_(event_log),
       clock_(clock),
       inter_arrival_(),
-      kalman_estimator_(),
       trendline_estimator_(),
       detector_(),
       receiver_incoming_bitrate_(),
       last_update_ms_(-1),
       last_seen_packet_ms_(-1),
       uma_recorded_(false),
       probe_bitrate_estimator_(event_log),
       trendline_window_size_(kDefaultTrendlineWindowSize),
       trendline_smoothing_coeff_(kDefaultTrendlineSmoothingCoeff),
       trendline_threshold_gain_(kDefaultTrendlineThresholdGain),
       probing_interval_estimator_(&rate_control_),
-      median_slope_window_size_(kDefaultMedianSlopeWindowSize),
-      median_slope_threshold_gain_(kDefaultMedianSlopeThresholdGain),
       consecutive_delayed_feedbacks_(0),
       last_logged_bitrate_(0),
       last_logged_state_(kBwNormal) {
-  if (in_trendline_experiment_) {
-    ReadTrendlineFilterExperimentParameters(&trendline_window_size_,
-                                            &trendline_smoothing_coeff_,
-                                            &trendline_threshold_gain_);
-    LOG(LS_INFO) << "Trendline filter experiment enabled with parameters "
-                 << trendline_window_size_ << ',' << trendline_smoothing_coeff_
-                 << ',' << trendline_threshold_gain_;
-  }
-  if (in_median_slope_experiment_) {
-    ReadMedianSlopeFilterExperimentParameters(&median_slope_window_size_,
-                                              &median_slope_threshold_gain_);
-    LOG(LS_INFO) << "Median-slope filter experiment enabled with parameters "
-                 << median_slope_window_size_ << ','
-                 << median_slope_threshold_gain_;
-  }
-  if (!in_trendline_experiment_ && !in_median_slope_experiment_) {
-    LOG(LS_INFO) << "No overuse experiment enabled. Using Kalman filter.";
-  }
+  LOG(LS_INFO) << "Using Trendline filter for delay change estimation.";
 
   network_thread_.DetachFromThread();
 }
 
 DelayBasedBwe::Result DelayBasedBwe::IncomingPacketFeedbackVector(
     const std::vector<PacketFeedback>& packet_feedback_vector) {
   RTC_DCHECK(network_thread_.CalledOnValidThread());
   RTC_DCHECK(!packet_feedback_vector.empty());
 
   std::vector<PacketFeedback> sorted_packet_feedback_vector;
@@ skipping 52 matching lines @@
 
   receiver_incoming_bitrate_.Update(packet_feedback.arrival_time_ms,
                                     packet_feedback.payload_size);
   Result result;
   // Reset if the stream has timed out.
   if (last_seen_packet_ms_ == -1 ||
       now_ms - last_seen_packet_ms_ > kStreamTimeOutMs) {
     inter_arrival_.reset(
         new InterArrival((kTimestampGroupLengthMs << kInterArrivalShift) / 1000,
                          kTimestampToMs, true));
-    kalman_estimator_.reset(new OveruseEstimator(OverUseDetectorOptions()));
     trendline_estimator_.reset(new TrendlineEstimator(
         trendline_window_size_, trendline_smoothing_coeff_,
         trendline_threshold_gain_));
-    median_slope_estimator_.reset(new MedianSlopeEstimator(
-        median_slope_window_size_, median_slope_threshold_gain_));
   }
   last_seen_packet_ms_ = now_ms;
 
   uint32_t send_time_24bits =
       static_cast<uint32_t>(
           ((static_cast<uint64_t>(packet_feedback.send_time_ms)
             << kAbsSendTimeFraction) +
            500) /
           1000) &
       0x00FFFFFF;
   // Shift up send time to use the full 32 bits that inter_arrival works with,
   // so wrapping works properly.
   uint32_t timestamp = send_time_24bits << kAbsSendTimeInterArrivalUpshift;
 
   uint32_t ts_delta = 0;
   int64_t t_delta = 0;
   int size_delta = 0;
   if (inter_arrival_->ComputeDeltas(timestamp, packet_feedback.arrival_time_ms,
                                     now_ms, packet_feedback.payload_size,
                                     &ts_delta, &t_delta, &size_delta)) {
     double ts_delta_ms = (1000.0 * ts_delta) / (1 << kInterArrivalShift);
-    if (in_trendline_experiment_) {
-      trendline_estimator_->Update(t_delta, ts_delta_ms,
-                                   packet_feedback.arrival_time_ms);
-      detector_.Detect(trendline_estimator_->trendline_slope(), ts_delta_ms,
-                       trendline_estimator_->num_of_deltas(),
-                       packet_feedback.arrival_time_ms);
-    } else if (in_median_slope_experiment_) {
-      median_slope_estimator_->Update(t_delta, ts_delta_ms,
-                                      packet_feedback.arrival_time_ms);
-      detector_.Detect(median_slope_estimator_->trendline_slope(), ts_delta_ms,
-                       median_slope_estimator_->num_of_deltas(),
-                       packet_feedback.arrival_time_ms);
-    } else {
-      kalman_estimator_->Update(t_delta, ts_delta_ms, size_delta,
-                                detector_.State(),
-                                packet_feedback.arrival_time_ms);
-      detector_.Detect(kalman_estimator_->offset(), ts_delta_ms,
-                       kalman_estimator_->num_of_deltas(),
-                       packet_feedback.arrival_time_ms);
-    }
+    trendline_estimator_->Update(t_delta, ts_delta_ms,
+                                 packet_feedback.arrival_time_ms);
+    detector_.Detect(trendline_estimator_->trendline_slope(), ts_delta_ms,
+                     trendline_estimator_->num_of_deltas(),
+                     packet_feedback.arrival_time_ms);
   }
 
   int probing_bps = 0;
   if (packet_feedback.pacing_info.probe_cluster_id !=
       PacedPacketInfo::kNotAProbe) {
     probing_bps =
         probe_bitrate_estimator_.HandleProbeAndEstimateBitrate(packet_feedback);
   }
   rtc::Optional<uint32_t> acked_bitrate_bps =
       receiver_incoming_bitrate_.bitrate_bps();
@@ skipping 76 matching lines @@
 void DelayBasedBwe::SetMinBitrate(int min_bitrate_bps) {
   // Called from both the configuration thread and the network thread. Shouldn't
   // be called from the network thread in the future.
   rate_control_.SetMinBitrate(min_bitrate_bps);
 }
 
 int64_t DelayBasedBwe::GetProbingIntervalMs() const {
   return probing_interval_estimator_.GetIntervalMs();
 }
 }  // namespace webrtc