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/*
* Copyright (c) 2021 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/congestion_controller/remb_throttler.h"
#include <algorithm>
#include <cstdint>
#include <utility>
#include <vector>
#include "api/units/data_rate.h"
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "rtc_base/synchronization/mutex.h"
#include "system_wrappers/include/clock.h"
namespace webrtc {
namespace {
constexpr TimeDelta kRembSendInterval = TimeDelta::Millis(200);
} // namespace
RembThrottler::RembThrottler(RembSender remb_sender, Clock* clock)
: remb_sender_(std::move(remb_sender)),
clock_(clock),
last_remb_time_(Timestamp::MinusInfinity()),
last_send_remb_bitrate_(DataRate::PlusInfinity()),
max_remb_bitrate_(DataRate::PlusInfinity()) {}
void RembThrottler::OnReceiveBitrateChanged(const std::vector<uint32_t>& ssrcs,
uint32_t bitrate_bps) {
DataRate receive_bitrate = DataRate::BitsPerSec(bitrate_bps);
Timestamp now = clock_->CurrentTime();
{
MutexLock lock(&mutex_);
// % threshold for if we should send a new REMB asap.
const int64_t kSendThresholdPercent = 103;
if (receive_bitrate * kSendThresholdPercent / 100 >
last_send_remb_bitrate_ &&
now < last_remb_time_ + kRembSendInterval) {
return;
}
last_remb_time_ = now;
last_send_remb_bitrate_ = receive_bitrate;
receive_bitrate = std::min(last_send_remb_bitrate_, max_remb_bitrate_);
}
remb_sender_(receive_bitrate.bps(), ssrcs);
}
void RembThrottler::SetMaxDesiredReceiveBitrate(DataRate bitrate) {
Timestamp now = clock_->CurrentTime();
{
MutexLock lock(&mutex_);
max_remb_bitrate_ = bitrate;
if (now - last_remb_time_ < kRembSendInterval &&
!last_send_remb_bitrate_.IsZero() &&
last_send_remb_bitrate_ <= max_remb_bitrate_) {
return;
}
}
remb_sender_(bitrate.bps(), /*ssrcs=*/{});
}
} // namespace webrtc
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