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d0e0ec959f
This is useful for debugging and has minimal effect on production code. Bug: webrtc:9510 Change-Id: I3a71f484a0d4e54999e376b7924b73230d86cd96 Reviewed-on: https://webrtc-review.googlesource.com/97607 Commit-Queue: Sebastian Jansson <srte@webrtc.org> Reviewed-by: Björn Terelius <terelius@webrtc.org> Cr-Commit-Position: refs/heads/master@{#24557}
104 lines
4.5 KiB
C++
104 lines
4.5 KiB
C++
/*
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* Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_
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#define MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_
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#include "modules/remote_bitrate_estimator/include/bwe_defines.h"
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#include "rtc_base/constructormagic.h"
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namespace webrtc {
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// A rate control implementation based on additive increases of
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// bitrate when no over-use is detected and multiplicative decreases when
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// over-uses are detected. When we think the available bandwidth has changes or
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// is unknown, we will switch to a "slow-start mode" where we increase
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// multiplicatively.
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class AimdRateControl {
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public:
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AimdRateControl();
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~AimdRateControl();
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// Returns true if the target bitrate has been initialized. This happens
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// either if it has been explicitly set via SetStartBitrate/SetEstimate, or if
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// we have measured a throughput.
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bool ValidEstimate() const;
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void SetStartBitrate(int start_bitrate_bps);
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void SetMinBitrate(int min_bitrate_bps);
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int64_t GetFeedbackInterval() const;
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// Returns true if the bitrate estimate hasn't been changed for more than
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// an RTT, or if the estimated_throughput is less than half of the current
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// estimate. Should be used to decide if we should reduce the rate further
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// when over-using.
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bool TimeToReduceFurther(int64_t now_ms,
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uint32_t estimated_throughput_bps) const;
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// As above. To be used if overusing before we have measured a throughput.
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bool InitialTimeToReduceFurther(int64_t now_ms) const;
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uint32_t LatestEstimate() const;
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void SetRtt(int64_t rtt);
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uint32_t Update(const RateControlInput* input, int64_t now_ms);
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void SetEstimate(int bitrate_bps, int64_t now_ms);
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// Returns the increase rate when used bandwidth is near the link capacity.
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int GetNearMaxIncreaseRateBps() const;
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// Returns the expected time between overuse signals (assuming steady state).
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int GetExpectedBandwidthPeriodMs() const;
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private:
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friend class GoogCcStatePrinter;
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// Update the target bitrate based on, among other things, the current rate
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// control state, the current target bitrate and the estimated throughput.
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// When in the "increase" state the bitrate will be increased either
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// additively or multiplicatively depending on the rate control region. When
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// in the "decrease" state the bitrate will be decreased to slightly below the
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// current throughput. When in the "hold" state the bitrate will be kept
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// constant to allow built up queues to drain.
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uint32_t ChangeBitrate(uint32_t current_bitrate,
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const RateControlInput& input,
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int64_t now_ms);
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// Clamps new_bitrate_bps to within the configured min bitrate and a linear
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// function of the throughput, so that the new bitrate can't grow too
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// large compared to the bitrate actually being received by the other end.
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uint32_t ClampBitrate(uint32_t new_bitrate_bps,
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uint32_t estimated_throughput_bps) const;
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uint32_t MultiplicativeRateIncrease(int64_t now_ms,
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int64_t last_ms,
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uint32_t current_bitrate_bps) const;
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uint32_t AdditiveRateIncrease(int64_t now_ms, int64_t last_ms) const;
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void UpdateChangePeriod(int64_t now_ms);
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void UpdateMaxThroughputEstimate(float estimated_throughput_kbps);
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void ChangeState(const RateControlInput& input, int64_t now_ms);
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void ChangeRegion(RateControlRegion region);
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uint32_t min_configured_bitrate_bps_;
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uint32_t max_configured_bitrate_bps_;
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uint32_t current_bitrate_bps_;
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uint32_t latest_estimated_throughput_bps_;
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float avg_max_bitrate_kbps_;
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float var_max_bitrate_kbps_;
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RateControlState rate_control_state_;
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RateControlRegion rate_control_region_;
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int64_t time_last_bitrate_change_;
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int64_t time_last_bitrate_decrease_;
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int64_t time_first_throughput_estimate_;
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bool bitrate_is_initialized_;
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float beta_;
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int64_t rtt_;
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const bool in_experiment_;
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const bool smoothing_experiment_;
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const bool in_initial_backoff_interval_experiment_;
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int64_t initial_backoff_interval_ms_;
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absl::optional<int> last_decrease_;
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};
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} // namespace webrtc
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#endif // MODULES_REMOTE_BITRATE_ESTIMATOR_AIMD_RATE_CONTROL_H_
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