| /* |
| * Copyright (c) 2015 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_estimator_proxy.h" |
| |
| #include <limits> |
| #include <algorithm> |
| |
| #include "modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h" |
| #include "rtc_base/checks.h" |
| #include "rtc_base/logging.h" |
| #include "rtc_base/numerics/safe_minmax.h" |
| #include "system_wrappers/include/clock.h" |
| |
| namespace webrtc { |
| |
| // TODO(sprang): Tune these! |
| const int RemoteEstimatorProxy::kBackWindowMs = 500; |
| const int RemoteEstimatorProxy::kMinSendIntervalMs = 50; |
| const int RemoteEstimatorProxy::kMaxSendIntervalMs = 250; |
| const int RemoteEstimatorProxy::kDefaultSendIntervalMs = 100; |
| |
| // The maximum allowed value for a timestamp in milliseconds. This is lower |
| // than the numerical limit since we often convert to microseconds. |
| static constexpr int64_t kMaxTimeMs = |
| std::numeric_limits<int64_t>::max() / 1000; |
| |
| RemoteEstimatorProxy::RemoteEstimatorProxy( |
| const Clock* clock, |
| TransportFeedbackSenderInterface* feedback_sender) |
| : clock_(clock), |
| feedback_sender_(feedback_sender), |
| last_process_time_ms_(-1), |
| media_ssrc_(0), |
| feedback_sequence_(0), |
| window_start_seq_(-1), |
| send_interval_ms_(kDefaultSendIntervalMs) {} |
| |
| RemoteEstimatorProxy::~RemoteEstimatorProxy() {} |
| |
| void RemoteEstimatorProxy::IncomingPacket(int64_t arrival_time_ms, |
| size_t payload_size, |
| const RTPHeader& header) { |
| if (!header.extension.hasTransportSequenceNumber) { |
| RTC_LOG(LS_WARNING) |
| << "RemoteEstimatorProxy: Incoming packet " |
| "is missing the transport sequence number extension!"; |
| return; |
| } |
| rtc::CritScope cs(&lock_); |
| media_ssrc_ = header.ssrc; |
| |
| OnPacketArrival(header.extension.transportSequenceNumber, arrival_time_ms); |
| } |
| |
| bool RemoteEstimatorProxy::LatestEstimate(std::vector<unsigned int>* ssrcs, |
| unsigned int* bitrate_bps) const { |
| return false; |
| } |
| |
| int64_t RemoteEstimatorProxy::TimeUntilNextProcess() { |
| int64_t time_until_next = 0; |
| if (last_process_time_ms_ != -1) { |
| rtc::CritScope cs(&lock_); |
| int64_t now = clock_->TimeInMilliseconds(); |
| if (now - last_process_time_ms_ < send_interval_ms_) |
| time_until_next = (last_process_time_ms_ + send_interval_ms_ - now); |
| } |
| return time_until_next; |
| } |
| |
| void RemoteEstimatorProxy::Process() { |
| last_process_time_ms_ = clock_->TimeInMilliseconds(); |
| |
| bool more_to_build = true; |
| while (more_to_build) { |
| rtcp::TransportFeedback feedback_packet; |
| if (BuildFeedbackPacket(&feedback_packet)) { |
| RTC_DCHECK(feedback_sender_ != nullptr); |
| feedback_sender_->SendTransportFeedback(&feedback_packet); |
| } else { |
| more_to_build = false; |
| } |
| } |
| } |
| |
| void RemoteEstimatorProxy::OnBitrateChanged(int bitrate_bps) { |
| // TwccReportSize = Ipv4(20B) + UDP(8B) + SRTP(10B) + |
| // AverageTwccReport(30B) |
| // TwccReport size at 50ms interval is 24 byte. |
| // TwccReport size at 250ms interval is 36 byte. |
| // AverageTwccReport = (TwccReport(50ms) + TwccReport(250ms)) / 2 |
| constexpr int kTwccReportSize = 20 + 8 + 10 + 30; |
| constexpr double kMinTwccRate = |
| kTwccReportSize * 8.0 * 1000.0 / kMaxSendIntervalMs; |
| constexpr double kMaxTwccRate = |
| kTwccReportSize * 8.0 * 1000.0 / kMinSendIntervalMs; |
| |
| // Let TWCC reports occupy 5% of total bandwidth. |
| rtc::CritScope cs(&lock_); |
| send_interval_ms_ = static_cast<int>( |
| 0.5 + kTwccReportSize * 8.0 * 1000.0 / |
| rtc::SafeClamp(0.05 * bitrate_bps, kMinTwccRate, kMaxTwccRate)); |
| } |
| |
| void RemoteEstimatorProxy::OnPacketArrival(uint16_t sequence_number, |
| int64_t arrival_time) { |
| if (arrival_time < 0 || arrival_time > kMaxTimeMs) { |
| RTC_LOG(LS_WARNING) << "Arrival time out of bounds: " << arrival_time; |
| return; |
| } |
| |
| // TODO(holmer): We should handle a backwards wrap here if the first |
| // sequence number was small and the new sequence number is large. The |
| // SequenceNumberUnwrapper doesn't do this, so we should replace this with |
| // calls to IsNewerSequenceNumber instead. |
| int64_t seq = unwrapper_.Unwrap(sequence_number); |
| if (seq > window_start_seq_ + 0xFFFF / 2) { |
| RTC_LOG(LS_WARNING) << "Skipping this sequence number (" << sequence_number |
| << ") since it likely is reordered, but the unwrapper" |
| "failed to handle it. Feedback window starts at " |
| << window_start_seq_ << "."; |
| return; |
| } |
| |
| if (packet_arrival_times_.lower_bound(window_start_seq_) == |
| packet_arrival_times_.end()) { |
| // Start new feedback packet, cull old packets. |
| for (auto it = packet_arrival_times_.begin(); |
| it != packet_arrival_times_.end() && it->first < seq && |
| arrival_time - it->second >= kBackWindowMs;) { |
| auto delete_it = it; |
| ++it; |
| packet_arrival_times_.erase(delete_it); |
| } |
| } |
| |
| if (window_start_seq_ == -1) { |
| window_start_seq_ = sequence_number; |
| } else if (seq < window_start_seq_) { |
| window_start_seq_ = seq; |
| } |
| |
| // We are only interested in the first time a packet is received. |
| if (packet_arrival_times_.find(seq) != packet_arrival_times_.end()) |
| return; |
| |
| packet_arrival_times_[seq] = arrival_time; |
| } |
| |
| bool RemoteEstimatorProxy::BuildFeedbackPacket( |
| rtcp::TransportFeedback* feedback_packet) { |
| // window_start_seq_ is the first sequence number to include in the current |
| // feedback packet. Some older may still be in the map, in case a reordering |
| // happens and we need to retransmit them. |
| rtc::CritScope cs(&lock_); |
| auto it = packet_arrival_times_.lower_bound(window_start_seq_); |
| if (it == packet_arrival_times_.end()) { |
| // Feedback for all packets already sent. |
| return false; |
| } |
| |
| // TODO(sprang): Measure receive times in microseconds and remove the |
| // conversions below. |
| const int64_t first_sequence = it->first; |
| feedback_packet->SetMediaSsrc(media_ssrc_); |
| // Base sequence is the expected next (window_start_seq_). This is known, but |
| // we might not have actually received it, so the base time shall be the time |
| // of the first received packet in the feedback. |
| feedback_packet->SetBase(static_cast<uint16_t>(window_start_seq_ & 0xFFFF), |
| it->second * 1000); |
| feedback_packet->SetFeedbackSequenceNumber(feedback_sequence_++); |
| for (; it != packet_arrival_times_.end(); ++it) { |
| if (!feedback_packet->AddReceivedPacket( |
| static_cast<uint16_t>(it->first & 0xFFFF), it->second * 1000)) { |
| // If we can't even add the first seq to the feedback packet, we won't be |
| // able to build it at all. |
| RTC_CHECK_NE(first_sequence, it->first); |
| |
| // Could not add timestamp, feedback packet might be full. Return and |
| // try again with a fresh packet. |
| break; |
| } |
| |
| // Note: Don't erase items from packet_arrival_times_ after sending, in case |
| // they need to be re-sent after a reordering. Removal will be handled |
| // by OnPacketArrival once packets are too old. |
| window_start_seq_ = it->first + 1; |
| } |
| |
| return true; |
| } |
| |
| } // namespace webrtc |