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/*
* Copyright (c) 2012 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 "webrtc/modules/congestion_controller/include/congestion_controller.h"
#include <algorithm>
#include <memory>
#include <vector>
#include "webrtc/base/checks.h"
#include "webrtc/base/constructormagic.h"
#include "webrtc/base/logging.h"
#include "webrtc/base/rate_limiter.h"
#include "webrtc/base/socket.h"
#include "webrtc/base/thread_annotations.h"
#include "webrtc/modules/bitrate_controller/include/bitrate_controller.h"
#include "webrtc/modules/congestion_controller/probe_controller.h"
#include "webrtc/modules/remote_bitrate_estimator/include/send_time_history.h"
#include "webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.h"
#include "webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.h"
#include "webrtc/modules/utility/include/process_thread.h"
#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
#include "webrtc/video/payload_router.h"
namespace webrtc {
namespace {
static const uint32_t kTimeOffsetSwitchThreshold = 30;
static const int64_t kRetransmitWindowSizeMs = 500;
// Makes sure that the bitrate and the min, max values are in valid range.
static void ClampBitrates(int* bitrate_bps,
int* min_bitrate_bps,
int* max_bitrate_bps) {
// TODO(holmer): We should make sure the default bitrates are set to 10 kbps,
// and that we don't try to set the min bitrate to 0 from any applications.
// The congestion controller should allow a min bitrate of 0.
const int kMinBitrateBps = 10000;
if (*min_bitrate_bps < kMinBitrateBps)
*min_bitrate_bps = kMinBitrateBps;
if (*max_bitrate_bps > 0)
*max_bitrate_bps = std::max(*min_bitrate_bps, *max_bitrate_bps);
if (*bitrate_bps > 0)
*bitrate_bps = std::max(*min_bitrate_bps, *bitrate_bps);
}
class WrappingBitrateEstimator : public RemoteBitrateEstimator {
public:
WrappingBitrateEstimator(RemoteBitrateObserver* observer, Clock* clock)
: observer_(observer),
clock_(clock),
crit_sect_(CriticalSectionWrapper::CreateCriticalSection()),
rbe_(new RemoteBitrateEstimatorSingleStream(observer_, clock_)),
using_absolute_send_time_(false),
packets_since_absolute_send_time_(0),
min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps) {}
virtual ~WrappingBitrateEstimator() {}
void IncomingPacket(int64_t arrival_time_ms,
size_t payload_size,
const RTPHeader& header) override {
CriticalSectionScoped cs(crit_sect_.get());
PickEstimatorFromHeader(header);
rbe_->IncomingPacket(arrival_time_ms, payload_size, header);
}
void Process() override {
CriticalSectionScoped cs(crit_sect_.get());
rbe_->Process();
}
int64_t TimeUntilNextProcess() override {
CriticalSectionScoped cs(crit_sect_.get());
return rbe_->TimeUntilNextProcess();
}
void OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms) override {
CriticalSectionScoped cs(crit_sect_.get());
rbe_->OnRttUpdate(avg_rtt_ms, max_rtt_ms);
}
void RemoveStream(unsigned int ssrc) override {
CriticalSectionScoped cs(crit_sect_.get());
rbe_->RemoveStream(ssrc);
}
bool LatestEstimate(std::vector<unsigned int>* ssrcs,
unsigned int* bitrate_bps) const override {
CriticalSectionScoped cs(crit_sect_.get());
return rbe_->LatestEstimate(ssrcs, bitrate_bps);
}
void SetMinBitrate(int min_bitrate_bps) override {
CriticalSectionScoped cs(crit_sect_.get());
rbe_->SetMinBitrate(min_bitrate_bps);
min_bitrate_bps_ = min_bitrate_bps;
}
private:
void PickEstimatorFromHeader(const RTPHeader& header)
EXCLUSIVE_LOCKS_REQUIRED(crit_sect_.get()) {
if (header.extension.hasAbsoluteSendTime) {
// If we see AST in header, switch RBE strategy immediately.
if (!using_absolute_send_time_) {
LOG(LS_INFO) <<
"WrappingBitrateEstimator: Switching to absolute send time RBE.";
using_absolute_send_time_ = true;
PickEstimator();
}
packets_since_absolute_send_time_ = 0;
} else {
// When we don't see AST, wait for a few packets before going back to TOF.
if (using_absolute_send_time_) {
++packets_since_absolute_send_time_;
if (packets_since_absolute_send_time_ >= kTimeOffsetSwitchThreshold) {
LOG(LS_INFO) << "WrappingBitrateEstimator: Switching to transmission "
<< "time offset RBE.";
using_absolute_send_time_ = false;
PickEstimator();
}
}
}
}
// Instantiate RBE for Time Offset or Absolute Send Time extensions.
void PickEstimator() EXCLUSIVE_LOCKS_REQUIRED(crit_sect_.get()) {
if (using_absolute_send_time_) {
rbe_.reset(new RemoteBitrateEstimatorAbsSendTime(observer_, clock_));
} else {
rbe_.reset(new RemoteBitrateEstimatorSingleStream(observer_, clock_));
}
rbe_->SetMinBitrate(min_bitrate_bps_);
}
RemoteBitrateObserver* observer_;
Clock* const clock_;
std::unique_ptr<CriticalSectionWrapper> crit_sect_;
std::unique_ptr<RemoteBitrateEstimator> rbe_;
bool using_absolute_send_time_;
uint32_t packets_since_absolute_send_time_;
int min_bitrate_bps_;
RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(WrappingBitrateEstimator);
};
} // namespace
CongestionController::CongestionController(
Clock* clock,
Observer* observer,
RemoteBitrateObserver* remote_bitrate_observer,
RtcEventLog* event_log)
: clock_(clock),
observer_(observer),
packet_router_(new PacketRouter()),
pacer_(new PacedSender(clock_, packet_router_.get())),
remote_bitrate_estimator_(
new WrappingBitrateEstimator(remote_bitrate_observer, clock_)),
bitrate_controller_(
BitrateController::CreateBitrateController(clock_, event_log)),
probe_controller_(new ProbeController(pacer_.get(), clock_)),
retransmission_rate_limiter_(
new RateLimiter(clock, kRetransmitWindowSizeMs)),
remote_estimator_proxy_(clock_, packet_router_.get()),
transport_feedback_adapter_(clock_, bitrate_controller_.get()),
min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps),
max_bitrate_bps_(0),
last_reported_bitrate_bps_(0),
last_reported_fraction_loss_(0),
last_reported_rtt_(0),
network_state_(kNetworkUp) {
Init();
}
CongestionController::CongestionController(
Clock* clock,
Observer* observer,
RemoteBitrateObserver* remote_bitrate_observer,
RtcEventLog* event_log,
std::unique_ptr<PacketRouter> packet_router,
std::unique_ptr<PacedSender> pacer)
: clock_(clock),
observer_(observer),
packet_router_(std::move(packet_router)),
pacer_(std::move(pacer)),
remote_bitrate_estimator_(
new WrappingBitrateEstimator(remote_bitrate_observer, clock_)),
// Constructed last as this object calls the provided callback on
// construction.
bitrate_controller_(
BitrateController::CreateBitrateController(clock_, event_log)),
probe_controller_(new ProbeController(pacer_.get(), clock_)),
retransmission_rate_limiter_(
new RateLimiter(clock, kRetransmitWindowSizeMs)),
remote_estimator_proxy_(clock_, packet_router_.get()),
transport_feedback_adapter_(clock_, bitrate_controller_.get()),
min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps),
max_bitrate_bps_(0),
last_reported_bitrate_bps_(0),
last_reported_fraction_loss_(0),
last_reported_rtt_(0),
network_state_(kNetworkUp) {
Init();
}
CongestionController::~CongestionController() {}
void CongestionController::Init() {
transport_feedback_adapter_.InitBwe();
transport_feedback_adapter_.SetMinBitrate(min_bitrate_bps_);
}
void CongestionController::SetBweBitrates(int min_bitrate_bps,
int start_bitrate_bps,
int max_bitrate_bps) {
ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
bitrate_controller_->SetBitrates(start_bitrate_bps,
min_bitrate_bps,
max_bitrate_bps);
probe_controller_->SetBitrates(min_bitrate_bps, start_bitrate_bps,
max_bitrate_bps);
max_bitrate_bps_ = max_bitrate_bps;
if (remote_bitrate_estimator_)
remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
min_bitrate_bps_ = min_bitrate_bps;
transport_feedback_adapter_.SetMinBitrate(min_bitrate_bps_);
MaybeTriggerOnNetworkChanged();
}
void CongestionController::ResetBweAndBitrates(int bitrate_bps,
int min_bitrate_bps,
int max_bitrate_bps) {
ClampBitrates(&bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
// TODO(honghaiz): Recreate this object once the bitrate controller is
// no longer exposed outside CongestionController.
bitrate_controller_->ResetBitrates(bitrate_bps, min_bitrate_bps,
max_bitrate_bps);
min_bitrate_bps_ = min_bitrate_bps;
max_bitrate_bps_ = max_bitrate_bps;
// TODO(honghaiz): Recreate this object once the remote bitrate estimator is
// no longer exposed outside CongestionController.
if (remote_bitrate_estimator_)
remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
transport_feedback_adapter_.InitBwe();
transport_feedback_adapter_.SetMinBitrate(min_bitrate_bps);
// TODO(holmer): Trigger a new probe once mid-call probing is implemented.
MaybeTriggerOnNetworkChanged();
}
BitrateController* CongestionController::GetBitrateController() const {
return bitrate_controller_.get();
}
RemoteBitrateEstimator* CongestionController::GetRemoteBitrateEstimator(
bool send_side_bwe) {
if (send_side_bwe) {
return &remote_estimator_proxy_;
} else {
return remote_bitrate_estimator_.get();
}
}
TransportFeedbackObserver*
CongestionController::GetTransportFeedbackObserver() {
return &transport_feedback_adapter_;
}
RateLimiter* CongestionController::GetRetransmissionRateLimiter() {
return retransmission_rate_limiter_.get();
}
void CongestionController::SetAllocatedSendBitrateLimits(
int min_send_bitrate_bps,
int max_padding_bitrate_bps) {
pacer_->SetSendBitrateLimits(min_send_bitrate_bps, max_padding_bitrate_bps);
}
int64_t CongestionController::GetPacerQueuingDelayMs() const {
return IsNetworkDown() ? 0 : pacer_->QueueInMs();
}
void CongestionController::SignalNetworkState(NetworkState state) {
LOG(LS_INFO) << "SignalNetworkState "
<< (state == kNetworkUp ? "Up" : "Down");
if (state == kNetworkUp) {
pacer_->Resume();
} else {
pacer_->Pause();
}
{
rtc::CritScope cs(&critsect_);
network_state_ = state;
}
MaybeTriggerOnNetworkChanged();
}
void CongestionController::OnSentPacket(const rtc::SentPacket& sent_packet) {
transport_feedback_adapter_.OnSentPacket(sent_packet.packet_id,
sent_packet.send_time_ms);
}
void CongestionController::OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms) {
remote_bitrate_estimator_->OnRttUpdate(avg_rtt_ms, max_rtt_ms);
transport_feedback_adapter_.OnRttUpdate(avg_rtt_ms, max_rtt_ms);
}
int64_t CongestionController::TimeUntilNextProcess() {
return std::min(bitrate_controller_->TimeUntilNextProcess(),
remote_bitrate_estimator_->TimeUntilNextProcess());
}
void CongestionController::Process() {
bitrate_controller_->Process();
remote_bitrate_estimator_->Process();
MaybeTriggerOnNetworkChanged();
}
void CongestionController::MaybeTriggerOnNetworkChanged() {
// TODO(perkj): |observer_| can be nullptr if the ctor that accepts a
// BitrateObserver is used. Remove this check once the ctor is removed.
if (!observer_)
return;
uint32_t bitrate_bps;
uint8_t fraction_loss;
int64_t rtt;
bool estimate_changed = bitrate_controller_->GetNetworkParameters(
&bitrate_bps, &fraction_loss, &rtt);
if (estimate_changed) {
pacer_->SetEstimatedBitrate(bitrate_bps);
probe_controller_->SetEstimatedBitrate(bitrate_bps);
retransmission_rate_limiter_->SetMaxRate(bitrate_bps);
}
bitrate_bps = IsNetworkDown() || IsSendQueueFull() ? 0 : bitrate_bps;
if (HasNetworkParametersToReportChanged(bitrate_bps, fraction_loss, rtt)) {
observer_->OnNetworkChanged(bitrate_bps, fraction_loss, rtt);
}
}
bool CongestionController::HasNetworkParametersToReportChanged(
uint32_t bitrate_bps,
uint8_t fraction_loss,
int64_t rtt) {
rtc::CritScope cs(&critsect_);
bool changed =
last_reported_bitrate_bps_ != bitrate_bps ||
(bitrate_bps > 0 && (last_reported_fraction_loss_ != fraction_loss ||
last_reported_rtt_ != rtt));
if (changed && (last_reported_bitrate_bps_ == 0 || bitrate_bps == 0)) {
LOG(LS_INFO) << "Bitrate estimate state changed, BWE: " << bitrate_bps
<< " bps.";
}
last_reported_bitrate_bps_ = bitrate_bps;
last_reported_fraction_loss_ = fraction_loss;
last_reported_rtt_ = rtt;
return changed;
}
bool CongestionController::IsSendQueueFull() const {
return pacer_->ExpectedQueueTimeMs() > PacedSender::kMaxQueueLengthMs;
}
bool CongestionController::IsNetworkDown() const {
rtc::CritScope cs(&critsect_);
return network_state_ == kNetworkDown;
}
} // namespace webrtc