| /* |
| * Copyright (c) 2013 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/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.h" |
| |
| #include <math.h> |
| |
| #include <algorithm> |
| #include <memory> |
| #include <utility> |
| |
| #include "api/transport/field_trial_based_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 "modules/remote_bitrate_estimator/include/bwe_defines.h" |
| #include "modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h" |
| #include "rtc_base/checks.h" |
| #include "rtc_base/logging.h" |
| #include "rtc_base/thread_annotations.h" |
| #include "system_wrappers/include/metrics.h" |
| |
| namespace webrtc { |
| namespace { |
| |
| constexpr TimeDelta kMinClusterDelta = TimeDelta::Millis(1); |
| constexpr TimeDelta kInitialProbingInterval = TimeDelta::Seconds(2); |
| constexpr int kTimestampGroupLengthMs = 5; |
| constexpr int kAbsSendTimeInterArrivalUpshift = 8; |
| constexpr int kInterArrivalShift = |
| RTPHeaderExtension::kAbsSendTimeFraction + kAbsSendTimeInterArrivalUpshift; |
| constexpr int kMinClusterSize = 4; |
| constexpr int kMaxProbePackets = 15; |
| constexpr int kExpectedNumberOfProbes = 3; |
| constexpr double kTimestampToMs = |
| 1000.0 / static_cast<double>(1 << kInterArrivalShift); |
| |
| absl::optional<DataRate> OptionalRateFromOptionalBps( |
| absl::optional<int> bitrate_bps) { |
| if (bitrate_bps) { |
| return DataRate::BitsPerSec(*bitrate_bps); |
| } else { |
| return absl::nullopt; |
| } |
| } |
| |
| template <typename K, typename V> |
| std::vector<K> Keys(const std::map<K, V>& map) { |
| std::vector<K> keys; |
| keys.reserve(map.size()); |
| for (const auto& kv_pair : map) { |
| keys.push_back(kv_pair.first); |
| } |
| return keys; |
| } |
| |
| } // namespace |
| |
| RemoteBitrateEstimatorAbsSendTime::~RemoteBitrateEstimatorAbsSendTime() = |
| default; |
| |
| bool RemoteBitrateEstimatorAbsSendTime::IsWithinClusterBounds( |
| TimeDelta send_delta, |
| const Cluster& cluster_aggregate) { |
| if (cluster_aggregate.count == 0) |
| return true; |
| TimeDelta cluster_mean = |
| cluster_aggregate.send_mean / cluster_aggregate.count; |
| return (send_delta - cluster_mean).Abs() < TimeDelta::Micros(2'500); |
| } |
| |
| void RemoteBitrateEstimatorAbsSendTime::MaybeAddCluster( |
| const Cluster& cluster_aggregate, |
| std::list<Cluster>& clusters) { |
| if (cluster_aggregate.count < kMinClusterSize || |
| cluster_aggregate.send_mean <= TimeDelta::Zero() || |
| cluster_aggregate.recv_mean <= TimeDelta::Zero()) { |
| return; |
| } |
| |
| Cluster cluster; |
| cluster.send_mean = cluster_aggregate.send_mean / cluster_aggregate.count; |
| cluster.recv_mean = cluster_aggregate.recv_mean / cluster_aggregate.count; |
| cluster.mean_size = cluster_aggregate.mean_size / cluster_aggregate.count; |
| cluster.count = cluster_aggregate.count; |
| cluster.num_above_min_delta = cluster_aggregate.num_above_min_delta; |
| clusters.push_back(cluster); |
| } |
| |
| RemoteBitrateEstimatorAbsSendTime::RemoteBitrateEstimatorAbsSendTime( |
| RemoteBitrateObserver* observer, |
| Clock* clock) |
| : clock_(clock), |
| observer_(observer), |
| detector_(&field_trials_), |
| remote_rate_(&field_trials_) { |
| RTC_DCHECK(clock_); |
| RTC_DCHECK(observer_); |
| RTC_LOG(LS_INFO) << "RemoteBitrateEstimatorAbsSendTime: Instantiating."; |
| } |
| |
| std::list<RemoteBitrateEstimatorAbsSendTime::Cluster> |
| RemoteBitrateEstimatorAbsSendTime::ComputeClusters() const { |
| std::list<Cluster> clusters; |
| Cluster cluster_aggregate; |
| Timestamp prev_send_time = Timestamp::MinusInfinity(); |
| Timestamp prev_recv_time = Timestamp::MinusInfinity(); |
| for (const Probe& probe : probes_) { |
| if (prev_send_time.IsFinite()) { |
| TimeDelta send_delta = probe.send_time - prev_send_time; |
| TimeDelta recv_delta = probe.recv_time - prev_recv_time; |
| if (send_delta >= kMinClusterDelta && recv_delta >= kMinClusterDelta) { |
| ++cluster_aggregate.num_above_min_delta; |
| } |
| if (!IsWithinClusterBounds(send_delta, cluster_aggregate)) { |
| MaybeAddCluster(cluster_aggregate, clusters); |
| cluster_aggregate = Cluster(); |
| } |
| cluster_aggregate.send_mean += send_delta; |
| cluster_aggregate.recv_mean += recv_delta; |
| cluster_aggregate.mean_size += probe.payload_size; |
| ++cluster_aggregate.count; |
| } |
| prev_send_time = probe.send_time; |
| prev_recv_time = probe.recv_time; |
| } |
| MaybeAddCluster(cluster_aggregate, clusters); |
| return clusters; |
| } |
| |
| const RemoteBitrateEstimatorAbsSendTime::Cluster* |
| RemoteBitrateEstimatorAbsSendTime::FindBestProbe( |
| const std::list<Cluster>& clusters) const { |
| DataRate highest_probe_bitrate = DataRate::Zero(); |
| const Cluster* best = nullptr; |
| for (const auto& cluster : clusters) { |
| if (cluster.send_mean == TimeDelta::Zero() || |
| cluster.recv_mean == TimeDelta::Zero()) { |
| continue; |
| } |
| if (cluster.num_above_min_delta > cluster.count / 2 && |
| (cluster.recv_mean - cluster.send_mean <= TimeDelta::Millis(2) && |
| cluster.send_mean - cluster.recv_mean <= TimeDelta::Millis(5))) { |
| DataRate probe_bitrate = |
| std::min(cluster.SendBitrate(), cluster.RecvBitrate()); |
| if (probe_bitrate > highest_probe_bitrate) { |
| highest_probe_bitrate = probe_bitrate; |
| best = &cluster; |
| } |
| } else { |
| RTC_LOG(LS_INFO) << "Probe failed, sent at " |
| << cluster.SendBitrate().bps() << " bps, received at " |
| << cluster.RecvBitrate().bps() |
| << " bps. Mean send delta: " << cluster.send_mean.ms() |
| << " ms, mean recv delta: " << cluster.recv_mean.ms() |
| << " ms, num probes: " << cluster.count; |
| break; |
| } |
| } |
| return best; |
| } |
| |
| RemoteBitrateEstimatorAbsSendTime::ProbeResult |
| RemoteBitrateEstimatorAbsSendTime::ProcessClusters(Timestamp now) { |
| std::list<Cluster> clusters = ComputeClusters(); |
| if (clusters.empty()) { |
| // If we reach the max number of probe packets and still have no clusters, |
| // we will remove the oldest one. |
| if (probes_.size() >= kMaxProbePackets) |
| probes_.pop_front(); |
| return ProbeResult::kNoUpdate; |
| } |
| |
| if (const Cluster* best = FindBestProbe(clusters)) { |
| DataRate probe_bitrate = std::min(best->SendBitrate(), best->RecvBitrate()); |
| // Make sure that a probe sent on a lower bitrate than our estimate can't |
| // reduce the estimate. |
| if (IsBitrateImproving(probe_bitrate)) { |
| RTC_LOG(LS_INFO) << "Probe successful, sent at " |
| << best->SendBitrate().bps() << " bps, received at " |
| << best->RecvBitrate().bps() |
| << " bps. Mean send delta: " << best->send_mean.ms() |
| << " ms, mean recv delta: " << best->recv_mean.ms() |
| << " ms, num probes: " << best->count; |
| remote_rate_.SetEstimate(probe_bitrate, now); |
| return ProbeResult::kBitrateUpdated; |
| } |
| } |
| |
| // Not probing and received non-probe packet, or finished with current set |
| // of probes. |
| if (clusters.size() >= kExpectedNumberOfProbes) |
| probes_.clear(); |
| return ProbeResult::kNoUpdate; |
| } |
| |
| bool RemoteBitrateEstimatorAbsSendTime::IsBitrateImproving( |
| DataRate probe_bitrate) const { |
| bool initial_probe = |
| !remote_rate_.ValidEstimate() && probe_bitrate > DataRate::Zero(); |
| bool bitrate_above_estimate = remote_rate_.ValidEstimate() && |
| probe_bitrate > remote_rate_.LatestEstimate(); |
| return initial_probe || bitrate_above_estimate; |
| } |
| |
| void RemoteBitrateEstimatorAbsSendTime::IncomingPacket( |
| int64_t arrival_time_ms, |
| size_t payload_size, |
| const RTPHeader& header) { |
| RTC_DCHECK_RUNS_SERIALIZED(&network_race_); |
| if (!header.extension.hasAbsoluteSendTime) { |
| RTC_LOG(LS_WARNING) |
| << "RemoteBitrateEstimatorAbsSendTimeImpl: Incoming packet " |
| "is missing absolute send time extension!"; |
| return; |
| } |
| IncomingPacketInfo(Timestamp::Millis(arrival_time_ms), |
| header.extension.absoluteSendTime, |
| DataSize::Bytes(payload_size), header.ssrc); |
| } |
| |
| void RemoteBitrateEstimatorAbsSendTime::IncomingPacketInfo( |
| Timestamp arrival_time, |
| uint32_t send_time_24bits, |
| DataSize payload_size, |
| uint32_t ssrc) { |
| RTC_CHECK(send_time_24bits < (1ul << 24)); |
| if (!uma_recorded_) { |
| RTC_HISTOGRAM_ENUMERATION(kBweTypeHistogram, BweNames::kReceiverAbsSendTime, |
| BweNames::kBweNamesMax); |
| uma_recorded_ = true; |
| } |
| // 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; |
| Timestamp send_time = |
| Timestamp::Millis(static_cast<int64_t>(timestamp) * kTimestampToMs); |
| |
| Timestamp now = clock_->CurrentTime(); |
| // TODO(holmer): SSRCs are only needed for REMB, should be broken out from |
| // here. |
| |
| // Check if incoming bitrate estimate is valid, and if it needs to be reset. |
| absl::optional<uint32_t> incoming_bitrate = |
| incoming_bitrate_.Rate(arrival_time.ms()); |
| if (incoming_bitrate) { |
| incoming_bitrate_initialized_ = true; |
| } else if (incoming_bitrate_initialized_) { |
| // Incoming bitrate had a previous valid value, but now not enough data |
| // point are left within the current window. Reset incoming bitrate |
| // estimator so that the window size will only contain new data points. |
| incoming_bitrate_.Reset(); |
| incoming_bitrate_initialized_ = false; |
| } |
| incoming_bitrate_.Update(payload_size.bytes(), arrival_time.ms()); |
| |
| if (first_packet_time_.IsInfinite()) { |
| first_packet_time_ = now; |
| } |
| |
| uint32_t ts_delta = 0; |
| int64_t t_delta = 0; |
| int size_delta = 0; |
| bool update_estimate = false; |
| DataRate target_bitrate = DataRate::Zero(); |
| std::vector<uint32_t> ssrcs; |
| { |
| MutexLock lock(&mutex_); |
| |
| TimeoutStreams(now); |
| RTC_DCHECK(inter_arrival_); |
| RTC_DCHECK(estimator_); |
| ssrcs_.insert_or_assign(ssrc, now); |
| |
| // For now only try to detect probes while we don't have a valid estimate. |
| // We currently assume that only packets larger than 200 bytes are paced by |
| // the sender. |
| static constexpr DataSize kMinProbePacketSize = DataSize::Bytes(200); |
| if (payload_size > kMinProbePacketSize && |
| (!remote_rate_.ValidEstimate() || |
| now - first_packet_time_ < kInitialProbingInterval)) { |
| // TODO(holmer): Use a map instead to get correct order? |
| if (total_probes_received_ < kMaxProbePackets) { |
| TimeDelta send_delta = TimeDelta::Millis(-1); |
| TimeDelta recv_delta = TimeDelta::Millis(-1); |
| if (!probes_.empty()) { |
| send_delta = send_time - probes_.back().send_time; |
| recv_delta = arrival_time - probes_.back().recv_time; |
| } |
| RTC_LOG(LS_INFO) << "Probe packet received: send time=" |
| << send_time.ms() |
| << " ms, recv time=" << arrival_time.ms() |
| << " ms, send delta=" << send_delta.ms() |
| << " ms, recv delta=" << recv_delta.ms() << " ms."; |
| } |
| probes_.emplace_back(send_time, arrival_time, payload_size); |
| ++total_probes_received_; |
| // Make sure that a probe which updated the bitrate immediately has an |
| // effect by calling the OnReceiveBitrateChanged callback. |
| if (ProcessClusters(now) == ProbeResult::kBitrateUpdated) |
| update_estimate = true; |
| } |
| if (inter_arrival_->ComputeDeltas(timestamp, arrival_time.ms(), now.ms(), |
| payload_size.bytes(), &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(), |
| arrival_time.ms()); |
| detector_.Detect(estimator_->offset(), ts_delta_ms, |
| estimator_->num_of_deltas(), arrival_time.ms()); |
| } |
| |
| if (!update_estimate) { |
| // Check if it's time for a periodic update or if we should update because |
| // of an over-use. |
| if (last_update_.IsInfinite() || |
| now.ms() - last_update_.ms() > |
| remote_rate_.GetFeedbackInterval().ms()) { |
| update_estimate = true; |
| } else if (detector_.State() == BandwidthUsage::kBwOverusing) { |
| absl::optional<uint32_t> incoming_rate = |
| incoming_bitrate_.Rate(arrival_time.ms()); |
| if (incoming_rate && remote_rate_.TimeToReduceFurther( |
| now, DataRate::BitsPerSec(*incoming_rate))) { |
| update_estimate = true; |
| } |
| } |
| } |
| |
| if (update_estimate) { |
| // The first overuse should immediately trigger a new estimate. |
| // We also have to update the estimate immediately if we are overusing |
| // and the target bitrate is too high compared to what we are receiving. |
| const RateControlInput input( |
| detector_.State(), OptionalRateFromOptionalBps( |
| incoming_bitrate_.Rate(arrival_time.ms()))); |
| target_bitrate = remote_rate_.Update(&input, now); |
| update_estimate = remote_rate_.ValidEstimate(); |
| ssrcs = Keys(ssrcs_); |
| } |
| } |
| if (update_estimate) { |
| last_update_ = now; |
| observer_->OnReceiveBitrateChanged(ssrcs, target_bitrate.bps<uint32_t>()); |
| } |
| } |
| |
| TimeDelta RemoteBitrateEstimatorAbsSendTime::Process() { |
| return TimeDelta::PlusInfinity(); |
| } |
| |
| void RemoteBitrateEstimatorAbsSendTime::TimeoutStreams(Timestamp now) { |
| for (auto it = ssrcs_.begin(); it != ssrcs_.end();) { |
| if (now - it->second > TimeDelta::Millis(kStreamTimeOutMs)) { |
| ssrcs_.erase(it++); |
| } else { |
| ++it; |
| } |
| } |
| if (ssrcs_.empty()) { |
| // We can't update the estimate if we don't have any active streams. |
| inter_arrival_ = std::make_unique<InterArrival>( |
| (kTimestampGroupLengthMs << kInterArrivalShift) / 1000, kTimestampToMs, |
| true); |
| estimator_ = std::make_unique<OveruseEstimator>(OverUseDetectorOptions()); |
| // We deliberately don't reset the first_packet_time_ms_ here for now since |
| // we only probe for bandwidth in the beginning of a call right now. |
| } |
| } |
| |
| void RemoteBitrateEstimatorAbsSendTime::OnRttUpdate(int64_t avg_rtt_ms, |
| int64_t /*max_rtt_ms*/) { |
| MutexLock lock(&mutex_); |
| remote_rate_.SetRtt(TimeDelta::Millis(avg_rtt_ms)); |
| } |
| |
| void RemoteBitrateEstimatorAbsSendTime::RemoveStream(uint32_t ssrc) { |
| MutexLock lock(&mutex_); |
| ssrcs_.erase(ssrc); |
| } |
| |
| DataRate RemoteBitrateEstimatorAbsSendTime::LatestEstimate() const { |
| // Currently accessed only from the worker thread (see Call::GetStats()). |
| MutexLock lock(&mutex_); |
| if (!remote_rate_.ValidEstimate() || ssrcs_.empty()) { |
| return DataRate::Zero(); |
| } |
| return remote_rate_.LatestEstimate(); |
| } |
| |
| } // namespace webrtc |
