Probe bitrate estimator correction.

webrtc/modules/congestion_controller/probe_bitrate_estimator.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 14 matching lines @@
 constexpr float kValidRatio = 1.2f;
 }
 
 namespace webrtc {
 
 ProbingResult::ProbingResult() : bps(kNoEstimate), timestamp(0) {}
 
 ProbingResult::ProbingResult(int bps, int64_t timestamp)
     : bps(bps), timestamp(timestamp) {}
 
+bool ProbingResult::valid() const {
+  return bps != kNoEstimate;
+}
+
 ProbeBitrateEstimator::ProbeBitrateEstimator() : last_valid_cluster_id_(0) {}
 
 ProbingResult ProbeBitrateEstimator::PacketFeedback(
     const PacketInfo& packet_info) {
   // If this is not a probing packet or if this probing packet
   // belongs to an old cluster, do nothing.
   if (packet_info.probe_cluster_id == PacketInfo::kNotAProbe ||
       packet_info.probe_cluster_id < last_valid_cluster_id_) {
     return ProbingResult();
   }
 
   AggregatedCluster* cluster = &clusters_[packet_info.probe_cluster_id];
   cluster->first_send_ms =
       std::min(cluster->first_send_ms, packet_info.send_time_ms);
   cluster->last_send_ms =
       std::max(cluster->last_send_ms, packet_info.send_time_ms);
   cluster->first_receive_ms =
       std::min(cluster->first_receive_ms, packet_info.arrival_time_ms);
   cluster->last_receive_ms =
       std::max(cluster->last_receive_ms, packet_info.arrival_time_ms);
-  cluster->size += packet_info.payload_size;
+  cluster->size += packet_info.payload_size * 8;
   cluster->num_probes += 1;
 
   // Clean up old clusters.
   while (clusters_.size() > kMaxNumSavedClusters)
     clusters_.erase(clusters_.begin());
 
   if (cluster->num_probes < kMinNumProbesValidCluster)
     return ProbingResult();
 
-  int send_interval_ms = cluster->last_send_ms - cluster->first_send_ms;
-  int receive_interval_ms =
+  float send_interval_ms = cluster->last_send_ms - cluster->first_send_ms;
+  float receive_interval_ms =
       cluster->last_receive_ms - cluster->first_receive_ms;
 
+  // Since the send/receive interval does not include the send/receive time of
+  // the last/first packet we expand the interval by the average inverval
+  // between the probing packets.
+  float interval_correction =
+      static_cast<float>(cluster->num_probes) / (cluster->num_probes - 1);
+  send_interval_ms *= interval_correction;
+  receive_interval_ms *= interval_correction;
+
   if (send_interval_ms == 0 || receive_interval_ms == 0) {
     LOG(LS_INFO) << "Probing unsuccessful, invalid send/receive interval"
                  << " [cluster id: " << packet_info.probe_cluster_id
                  << "] [send interval: " << send_interval_ms << " ms]"
                  << " [receive interval: " << receive_interval_ms << " ms]";
 
     return ProbingResult();
   }
-
   float send_bps = static_cast<float>(cluster->size) / send_interval_ms * 1000;
   float receive_bps =
       static_cast<float>(cluster->size) / receive_interval_ms * 1000;
   float ratio = receive_bps / send_bps;
   if (ratio > kValidRatio) {
     LOG(LS_INFO) << "Probing unsuccessful, receive/send ratio too high"
                  << " [cluster id: " << packet_info.probe_cluster_id
                  << "] [send: " << cluster->size << " bytes / "
                  << send_interval_ms << " ms = " << send_bps / 1000 << " kb/s]"
                  << " [receive: " << cluster->size << " bytes / "
@@ skipping 12 matching lines @@
                << " [cluster id: " << packet_info.probe_cluster_id
                << "] [send: " << cluster->size << " bytes / "
                << send_interval_ms << " ms = " << send_bps / 1000 << " kb/s]"
                << " [receive: " << cluster->size << " bytes / "
                << receive_interval_ms << " ms = " << receive_bps / 1000
                << " kb/s]";
 
   return ProbingResult(result_bps, packet_info.arrival_time_ms);
 }
 }  // namespace webrtc