bf8a2c94ce
Since the interval between the timestamps does not include the send/receive time of the last/first packet we correct the interval by adding the average of the interval between probing packets. BUG=webrtc:5859 R=mflodman@webrtc.org, stefan@webrtc.org Review URL: https://codereview.webrtc.org/2224173003 . Cr-Commit-Position: refs/heads/master@{#13719}
121 lines
4.6 KiB
C++
121 lines
4.6 KiB
C++
/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/modules/congestion_controller/probe_bitrate_estimator.h"
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#include <algorithm>
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#include "webrtc/base/logging.h"
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namespace {
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// Max number of saved clusters.
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constexpr size_t kMaxNumSavedClusters = 5;
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// The minumum number of probes we need for a valid cluster.
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constexpr int kMinNumProbesValidCluster = 4;
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// The maximum (receive rate)/(send rate) ratio for a valid estimate.
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constexpr float kValidRatio = 1.2f;
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}
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namespace webrtc {
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ProbingResult::ProbingResult() : bps(kNoEstimate), timestamp(0) {}
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ProbingResult::ProbingResult(int bps, int64_t timestamp)
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: bps(bps), timestamp(timestamp) {}
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bool ProbingResult::valid() const {
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return bps != kNoEstimate;
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}
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ProbeBitrateEstimator::ProbeBitrateEstimator() : last_valid_cluster_id_(0) {}
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ProbingResult ProbeBitrateEstimator::PacketFeedback(
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const PacketInfo& packet_info) {
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// If this is not a probing packet or if this probing packet
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// belongs to an old cluster, do nothing.
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if (packet_info.probe_cluster_id == PacketInfo::kNotAProbe ||
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packet_info.probe_cluster_id < last_valid_cluster_id_) {
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return ProbingResult();
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}
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AggregatedCluster* cluster = &clusters_[packet_info.probe_cluster_id];
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cluster->first_send_ms =
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std::min(cluster->first_send_ms, packet_info.send_time_ms);
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cluster->last_send_ms =
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std::max(cluster->last_send_ms, packet_info.send_time_ms);
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cluster->first_receive_ms =
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std::min(cluster->first_receive_ms, packet_info.arrival_time_ms);
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cluster->last_receive_ms =
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std::max(cluster->last_receive_ms, packet_info.arrival_time_ms);
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cluster->size += packet_info.payload_size * 8;
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cluster->num_probes += 1;
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// Clean up old clusters.
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while (clusters_.size() > kMaxNumSavedClusters)
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clusters_.erase(clusters_.begin());
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if (cluster->num_probes < kMinNumProbesValidCluster)
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return ProbingResult();
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float send_interval_ms = cluster->last_send_ms - cluster->first_send_ms;
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float receive_interval_ms =
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cluster->last_receive_ms - cluster->first_receive_ms;
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// Since the send/receive interval does not include the send/receive time of
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// the last/first packet we expand the interval by the average inverval
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// between the probing packets.
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float interval_correction =
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static_cast<float>(cluster->num_probes) / (cluster->num_probes - 1);
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send_interval_ms *= interval_correction;
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receive_interval_ms *= interval_correction;
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if (send_interval_ms == 0 || receive_interval_ms == 0) {
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LOG(LS_INFO) << "Probing unsuccessful, invalid send/receive interval"
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<< " [cluster id: " << packet_info.probe_cluster_id
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<< "] [send interval: " << send_interval_ms << " ms]"
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<< " [receive interval: " << receive_interval_ms << " ms]";
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return ProbingResult();
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}
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float send_bps = static_cast<float>(cluster->size) / send_interval_ms * 1000;
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float receive_bps =
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static_cast<float>(cluster->size) / receive_interval_ms * 1000;
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float ratio = receive_bps / send_bps;
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if (ratio > kValidRatio) {
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LOG(LS_INFO) << "Probing unsuccessful, receive/send ratio too high"
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<< " [cluster id: " << packet_info.probe_cluster_id
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<< "] [send: " << cluster->size << " bytes / "
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<< send_interval_ms << " ms = " << send_bps / 1000 << " kb/s]"
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<< " [receive: " << cluster->size << " bytes / "
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<< receive_interval_ms << " ms = " << receive_bps / 1000
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<< " kb/s]"
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<< " [ratio: " << receive_bps / 1000 << " / "
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<< send_bps / 1000 << " = " << ratio << " > kValidRatio ("
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<< kValidRatio << ")]";
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return ProbingResult();
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}
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// We have a valid estimate.
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int result_bps = std::min(send_bps, receive_bps);
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last_valid_cluster_id_ = packet_info.probe_cluster_id;
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LOG(LS_INFO) << "Probing successful"
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<< " [cluster id: " << packet_info.probe_cluster_id
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<< "] [send: " << cluster->size << " bytes / "
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<< send_interval_ms << " ms = " << send_bps / 1000 << " kb/s]"
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<< " [receive: " << cluster->size << " bytes / "
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<< receive_interval_ms << " ms = " << receive_bps / 1000
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<< " kb/s]";
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return ProbingResult(result_bps, packet_info.arrival_time_ms);
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}
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} // namespace webrtc
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