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/*
* 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/rtp_rtcp/source/receive_statistics_impl.h"
#include <math.h>
#include <cstdlib>
#include <vector>
#include "modules/remote_bitrate_estimator/test/bwe_test_logging.h"
#include "modules/rtp_rtcp/source/rtp_packet_received.h"
#include "modules/rtp_rtcp/source/rtp_rtcp_config.h"
#include "modules/rtp_rtcp/source/time_util.h"
#include "rtc_base/logging.h"
#include "system_wrappers/include/clock.h"
namespace webrtc {
const int64_t kStatisticsTimeoutMs = 8000;
const int64_t kStatisticsProcessIntervalMs = 1000;
StreamStatistician::~StreamStatistician() {}
StreamStatisticianImpl::StreamStatisticianImpl(
uint32_t ssrc,
Clock* clock,
bool enable_retransmit_detection,
RtcpStatisticsCallback* rtcp_callback,
StreamDataCountersCallback* rtp_callback)
: ssrc_(ssrc),
clock_(clock),
incoming_bitrate_(kStatisticsProcessIntervalMs,
RateStatistics::kBpsScale),
max_reordering_threshold_(kDefaultMaxReorderingThreshold),
enable_retransmit_detection_(enable_retransmit_detection),
jitter_q4_(0),
cumulative_loss_(0),
last_receive_time_ms_(0),
last_received_timestamp_(0),
received_seq_first_(0),
received_seq_max_(0),
received_seq_wraps_(0),
received_packet_overhead_(12),
last_report_inorder_packets_(0),
last_report_old_packets_(0),
last_report_seq_max_(0),
rtcp_callback_(rtcp_callback),
rtp_callback_(rtp_callback) {}
StreamStatisticianImpl::~StreamStatisticianImpl() = default;
void StreamStatisticianImpl::IncomingPacket(const RTPHeader& header,
size_t packet_length) {
StreamDataCounters counters;
{
rtc::CritScope cs(&stream_lock_);
bool retransmitted =
enable_retransmit_detection_ && IsRetransmitOfOldPacket(header);
counters = UpdateCounters(header, packet_length, retransmitted);
}
rtp_callback_->DataCountersUpdated(counters, ssrc_);
}
StreamDataCounters StreamStatisticianImpl::UpdateCounters(
const RTPHeader& header,
size_t packet_length,
bool retransmitted) {
bool in_order = InOrderPacketInternal(header.sequenceNumber);
RTC_DCHECK_EQ(ssrc_, header.ssrc);
incoming_bitrate_.Update(packet_length, clock_->TimeInMilliseconds());
receive_counters_.transmitted.AddPacket(packet_length, header);
if (!in_order && retransmitted) {
receive_counters_.retransmitted.AddPacket(packet_length, header);
}
if (receive_counters_.transmitted.packets == 1) {
received_seq_first_ = header.sequenceNumber;
receive_counters_.first_packet_time_ms = clock_->TimeInMilliseconds();
}
// Count only the new packets received. That is, if packets 1, 2, 3, 5, 4, 6
// are received, 4 will be ignored.
if (in_order) {
// Current time in samples.
NtpTime receive_time = clock_->CurrentNtpTime();
// Wrong if we use RetransmitOfOldPacket.
if (receive_counters_.transmitted.packets > 1 &&
received_seq_max_ > header.sequenceNumber) {
// Wrap around detected.
received_seq_wraps_++;
}
// New max.
received_seq_max_ = header.sequenceNumber;
// If new time stamp and more than one in-order packet received, calculate
// new jitter statistics.
if (header.timestamp != last_received_timestamp_ &&
(receive_counters_.transmitted.packets -
receive_counters_.retransmitted.packets) > 1) {
UpdateJitter(header, receive_time);
}
last_received_timestamp_ = header.timestamp;
last_receive_time_ntp_ = receive_time;
last_receive_time_ms_ = clock_->TimeInMilliseconds();
}
size_t packet_oh = header.headerLength + header.paddingLength;
// Our measured overhead. Filter from RFC 5104 4.2.1.2:
// avg_OH (new) = 15/16*avg_OH (old) + 1/16*pckt_OH,
received_packet_overhead_ = (15 * received_packet_overhead_ + packet_oh) >> 4;
return receive_counters_;
}
void StreamStatisticianImpl::UpdateJitter(const RTPHeader& header,
NtpTime receive_time) {
uint32_t receive_time_rtp =
NtpToRtp(receive_time, header.payload_type_frequency);
uint32_t last_receive_time_rtp =
NtpToRtp(last_receive_time_ntp_, header.payload_type_frequency);
int32_t time_diff_samples = (receive_time_rtp - last_receive_time_rtp) -
(header.timestamp - last_received_timestamp_);
time_diff_samples = std::abs(time_diff_samples);
// lib_jingle sometimes deliver crazy jumps in TS for the same stream.
// If this happens, don't update jitter value. Use 5 secs video frequency
// as the threshold.
if (time_diff_samples < 450000) {
// Note we calculate in Q4 to avoid using float.
int32_t jitter_diff_q4 = (time_diff_samples << 4) - jitter_q4_;
jitter_q4_ += ((jitter_diff_q4 + 8) >> 4);
}
}
void StreamStatisticianImpl::FecPacketReceived(const RTPHeader& header,
size_t packet_length) {
StreamDataCounters counters;
{
rtc::CritScope cs(&stream_lock_);
receive_counters_.fec.AddPacket(packet_length, header);
counters = receive_counters_;
}
rtp_callback_->DataCountersUpdated(counters, ssrc_);
}
void StreamStatisticianImpl::SetMaxReorderingThreshold(
int max_reordering_threshold) {
rtc::CritScope cs(&stream_lock_);
max_reordering_threshold_ = max_reordering_threshold;
}
void StreamStatisticianImpl::EnableRetransmitDetection(bool enable) {
rtc::CritScope cs(&stream_lock_);
enable_retransmit_detection_ = enable;
}
bool StreamStatisticianImpl::GetStatistics(RtcpStatistics* statistics,
bool reset) {
{
rtc::CritScope cs(&stream_lock_);
if (received_seq_first_ == 0 &&
receive_counters_.transmitted.payload_bytes == 0) {
// We have not received anything.
return false;
}
if (!reset) {
if (last_report_inorder_packets_ == 0) {
// No report.
return false;
}
// Just get last report.
*statistics = last_reported_statistics_;
return true;
}
*statistics = CalculateRtcpStatistics();
}
rtcp_callback_->StatisticsUpdated(*statistics, ssrc_);
return true;
}
bool StreamStatisticianImpl::GetActiveStatisticsAndReset(
RtcpStatistics* statistics) {
{
rtc::CritScope cs(&stream_lock_);
if (clock_->CurrentNtpInMilliseconds() - last_receive_time_ntp_.ToMs() >=
kStatisticsTimeoutMs) {
// Not active.
return false;
}
if (received_seq_first_ == 0 &&
receive_counters_.transmitted.payload_bytes == 0) {
// We have not received anything.
return false;
}
*statistics = CalculateRtcpStatistics();
}
rtcp_callback_->StatisticsUpdated(*statistics, ssrc_);
return true;
}
RtcpStatistics StreamStatisticianImpl::CalculateRtcpStatistics() {
RtcpStatistics stats;
if (last_report_inorder_packets_ == 0) {
// First time we send a report.
last_report_seq_max_ = received_seq_first_ - 1;
}
// Calculate fraction lost.
uint16_t exp_since_last = (received_seq_max_ - last_report_seq_max_);
if (last_report_seq_max_ > received_seq_max_) {
// Can we assume that the seq_num can't go decrease over a full RTCP period?
exp_since_last = 0;
}
// Number of received RTP packets since last report, counts all packets but
// not re-transmissions.
uint32_t rec_since_last = (receive_counters_.transmitted.packets -
receive_counters_.retransmitted.packets) -
last_report_inorder_packets_;
// With NACK we don't know the expected retransmissions during the last
// second. We know how many "old" packets we have received. We just count
// the number of old received to estimate the loss, but it still does not
// guarantee an exact number since we run this based on time triggered by
// sending of an RTP packet. This should have a minimum effect.
// With NACK we don't count old packets as received since they are
// re-transmitted. We use RTT to decide if a packet is re-ordered or
// re-transmitted.
uint32_t retransmitted_packets =
receive_counters_.retransmitted.packets - last_report_old_packets_;
rec_since_last += retransmitted_packets;
int32_t missing = 0;
if (exp_since_last > rec_since_last) {
missing = (exp_since_last - rec_since_last);
}
uint8_t local_fraction_lost = 0;
if (exp_since_last) {
// Scale 0 to 255, where 255 is 100% loss.
local_fraction_lost = static_cast<uint8_t>(255 * missing / exp_since_last);
}
stats.fraction_lost = local_fraction_lost;
// We need a counter for cumulative loss too.
// TODO(danilchap): Ensure cumulative loss is below maximum value of 2^24.
cumulative_loss_ += missing;
stats.packets_lost = cumulative_loss_;
stats.extended_highest_sequence_number =
(received_seq_wraps_ << 16) + received_seq_max_;
// Note: internal jitter value is in Q4 and needs to be scaled by 1/16.
stats.jitter = jitter_q4_ >> 4;
// Store this report.
last_reported_statistics_ = stats;
// Only for report blocks in RTCP SR and RR.
last_report_inorder_packets_ = receive_counters_.transmitted.packets -
receive_counters_.retransmitted.packets;
last_report_old_packets_ = receive_counters_.retransmitted.packets;
last_report_seq_max_ = received_seq_max_;
BWE_TEST_LOGGING_PLOT_WITH_SSRC(1, "cumulative_loss_pkts",
clock_->TimeInMilliseconds(),
cumulative_loss_, ssrc_);
BWE_TEST_LOGGING_PLOT_WITH_SSRC(
1, "received_seq_max_pkts", clock_->TimeInMilliseconds(),
(received_seq_max_ - received_seq_first_), ssrc_);
return stats;
}
void StreamStatisticianImpl::GetDataCounters(size_t* bytes_received,
uint32_t* packets_received) const {
rtc::CritScope cs(&stream_lock_);
if (bytes_received) {
*bytes_received = receive_counters_.transmitted.payload_bytes +
receive_counters_.transmitted.header_bytes +
receive_counters_.transmitted.padding_bytes;
}
if (packets_received) {
*packets_received = receive_counters_.transmitted.packets;
}
}
void StreamStatisticianImpl::GetReceiveStreamDataCounters(
StreamDataCounters* data_counters) const {
rtc::CritScope cs(&stream_lock_);
*data_counters = receive_counters_;
}
uint32_t StreamStatisticianImpl::BitrateReceived() const {
rtc::CritScope cs(&stream_lock_);
return incoming_bitrate_.Rate(clock_->TimeInMilliseconds()).value_or(0);
}
bool StreamStatisticianImpl::IsRetransmitOfOldPacket(
const RTPHeader& header) const {
if (InOrderPacketInternal(header.sequenceNumber)) {
return false;
}
uint32_t frequency_khz = header.payload_type_frequency / 1000;
assert(frequency_khz > 0);
int64_t time_diff_ms = clock_->TimeInMilliseconds() - last_receive_time_ms_;
// Diff in time stamp since last received in order.
uint32_t timestamp_diff = header.timestamp - last_received_timestamp_;
uint32_t rtp_time_stamp_diff_ms = timestamp_diff / frequency_khz;
int64_t max_delay_ms = 0;
// Jitter standard deviation in samples.
float jitter_std = sqrt(static_cast<float>(jitter_q4_ >> 4));
// 2 times the standard deviation => 95% confidence.
// And transform to milliseconds by dividing by the frequency in kHz.
max_delay_ms = static_cast<int64_t>((2 * jitter_std) / frequency_khz);
// Min max_delay_ms is 1.
if (max_delay_ms == 0) {
max_delay_ms = 1;
}
return time_diff_ms > rtp_time_stamp_diff_ms + max_delay_ms;
}
bool StreamStatisticianImpl::InOrderPacketInternal(
uint16_t sequence_number) const {
// First packet is always in order.
if (last_receive_time_ms_ == 0)
return true;
if (IsNewerSequenceNumber(sequence_number, received_seq_max_)) {
return true;
} else {
// If we have a restart of the remote side this packet is still in order.
return !IsNewerSequenceNumber(
sequence_number, received_seq_max_ - max_reordering_threshold_);
}
}
ReceiveStatistics* ReceiveStatistics::Create(Clock* clock) {
return new ReceiveStatisticsImpl(clock);
}
ReceiveStatisticsImpl::ReceiveStatisticsImpl(Clock* clock)
: clock_(clock),
last_returned_ssrc_(0),
rtcp_stats_callback_(NULL),
rtp_stats_callback_(NULL) {}
ReceiveStatisticsImpl::~ReceiveStatisticsImpl() {
while (!statisticians_.empty()) {
delete statisticians_.begin()->second;
statisticians_.erase(statisticians_.begin());
}
}
void ReceiveStatisticsImpl::OnRtpPacket(const RtpPacketReceived& packet) {
RTPHeader header;
packet.GetHeader(&header);
IncomingPacket(header, packet.size());
}
void ReceiveStatisticsImpl::IncomingPacket(const RTPHeader& header,
size_t packet_length) {
StreamStatisticianImpl* impl;
{
rtc::CritScope cs(&receive_statistics_lock_);
auto it = statisticians_.find(header.ssrc);
if (it != statisticians_.end()) {
impl = it->second;
} else {
impl = new StreamStatisticianImpl(
header.ssrc, clock_, /* enable_retransmit_detection = */ false, this,
this);
statisticians_[header.ssrc] = impl;
}
}
// StreamStatisticianImpl instance is created once and only destroyed when
// this whole ReceiveStatisticsImpl is destroyed. StreamStatisticianImpl has
// it's own locking so don't hold receive_statistics_lock_ (potential
// deadlock).
impl->IncomingPacket(header, packet_length);
}
void ReceiveStatisticsImpl::FecPacketReceived(const RtpPacketReceived& packet) {
StreamStatisticianImpl* impl;
{
rtc::CritScope cs(&receive_statistics_lock_);
auto it = statisticians_.find(packet.Ssrc());
// Ignore FEC if it is the first packet.
if (it == statisticians_.end())
return;
impl = it->second;
}
RTPHeader header;
packet.GetHeader(&header);
impl->FecPacketReceived(header, packet.size());
}
StreamStatistician* ReceiveStatisticsImpl::GetStatistician(
uint32_t ssrc) const {
rtc::CritScope cs(&receive_statistics_lock_);
auto it = statisticians_.find(ssrc);
if (it == statisticians_.end())
return NULL;
return it->second;
}
void ReceiveStatisticsImpl::SetMaxReorderingThreshold(
int max_reordering_threshold) {
rtc::CritScope cs(&receive_statistics_lock_);
for (auto& statistician : statisticians_) {
statistician.second->SetMaxReorderingThreshold(max_reordering_threshold);
}
}
void ReceiveStatisticsImpl::EnableRetransmitDetection(uint32_t ssrc,
bool enable) {
StreamStatisticianImpl* impl;
{
rtc::CritScope cs(&receive_statistics_lock_);
StreamStatisticianImpl*& impl_ref = statisticians_[ssrc];
if (impl_ref == nullptr) { // new element
impl_ref = new StreamStatisticianImpl(ssrc, clock_, enable, this, this);
return;
}
impl = impl_ref;
}
impl->EnableRetransmitDetection(enable);
}
void ReceiveStatisticsImpl::RegisterRtcpStatisticsCallback(
RtcpStatisticsCallback* callback) {
rtc::CritScope cs(&receive_statistics_lock_);
if (callback != NULL)
assert(rtcp_stats_callback_ == NULL);
rtcp_stats_callback_ = callback;
}
void ReceiveStatisticsImpl::StatisticsUpdated(const RtcpStatistics& statistics,
uint32_t ssrc) {
rtc::CritScope cs(&receive_statistics_lock_);
if (rtcp_stats_callback_)
rtcp_stats_callback_->StatisticsUpdated(statistics, ssrc);
}
void ReceiveStatisticsImpl::CNameChanged(const char* cname, uint32_t ssrc) {
rtc::CritScope cs(&receive_statistics_lock_);
if (rtcp_stats_callback_)
rtcp_stats_callback_->CNameChanged(cname, ssrc);
}
void ReceiveStatisticsImpl::RegisterRtpStatisticsCallback(
StreamDataCountersCallback* callback) {
rtc::CritScope cs(&receive_statistics_lock_);
if (callback != NULL)
assert(rtp_stats_callback_ == NULL);
rtp_stats_callback_ = callback;
}
void ReceiveStatisticsImpl::DataCountersUpdated(const StreamDataCounters& stats,
uint32_t ssrc) {
rtc::CritScope cs(&receive_statistics_lock_);
if (rtp_stats_callback_) {
rtp_stats_callback_->DataCountersUpdated(stats, ssrc);
}
}
std::vector<rtcp::ReportBlock> ReceiveStatisticsImpl::RtcpReportBlocks(
size_t max_blocks) {
std::map<uint32_t, StreamStatisticianImpl*> statisticians;
{
rtc::CritScope cs(&receive_statistics_lock_);
statisticians = statisticians_;
}
std::vector<rtcp::ReportBlock> result;
result.reserve(std::min(max_blocks, statisticians.size()));
auto add_report_block = [&result](uint32_t media_ssrc,
StreamStatisticianImpl* statistician) {
// Do we have receive statistics to send?
RtcpStatistics stats;
if (!statistician->GetActiveStatisticsAndReset(&stats))
return;
result.emplace_back();
rtcp::ReportBlock& block = result.back();
block.SetMediaSsrc(media_ssrc);
block.SetFractionLost(stats.fraction_lost);
if (!block.SetCumulativeLost(stats.packets_lost)) {
RTC_LOG(LS_WARNING) << "Cumulative lost is oversized.";
result.pop_back();
return;
}
block.SetExtHighestSeqNum(stats.extended_highest_sequence_number);
block.SetJitter(stats.jitter);
};
const auto start_it = statisticians.upper_bound(last_returned_ssrc_);
for (auto it = start_it;
result.size() < max_blocks && it != statisticians.end(); ++it)
add_report_block(it->first, it->second);
for (auto it = statisticians.begin();
result.size() < max_blocks && it != start_it; ++it)
add_report_block(it->first, it->second);
if (!result.empty())
last_returned_ssrc_ = result.back().source_ssrc();
return result;
}
} // namespace webrtc