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/*
* Copyright (c) 2017 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.
*/
#ifndef MODULES_CONGESTION_CONTROLLER_GOOG_CC_BITRATE_ESTIMATOR_H_
#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_BITRATE_ESTIMATOR_H_
#include <stdint.h>
#include <optional>
#include "api/field_trials_view.h"
#include "api/units/data_rate.h"
#include "api/units/data_size.h"
#include "api/units/timestamp.h"
#include "rtc_base/experiments/field_trial_parser.h"
namespace webrtc {
// Computes a bayesian estimate of the throughput given acks containing
// the arrival time and payload size. Samples which are far from the current
// estimate or are based on few packets are given a smaller weight, as they
// are considered to be more likely to have been caused by, e.g., delay spikes
// unrelated to congestion.
class BitrateEstimator {
public:
explicit BitrateEstimator(const FieldTrialsView* key_value_config);
virtual ~BitrateEstimator();
virtual void Update(Timestamp at_time, DataSize amount, bool in_alr);
virtual std::optional<DataRate> bitrate() const;
std::optional<DataRate> PeekRate() const;
virtual void ExpectFastRateChange();
private:
float UpdateWindow(int64_t now_ms,
int bytes,
int rate_window_ms,
bool* is_small_sample);
int sum_;
FieldTrialConstrained<int> initial_window_ms_;
FieldTrialConstrained<int> noninitial_window_ms_;
FieldTrialParameter<double> uncertainty_scale_;
FieldTrialParameter<double> uncertainty_scale_in_alr_;
FieldTrialParameter<double> small_sample_uncertainty_scale_;
FieldTrialParameter<DataSize> small_sample_threshold_;
FieldTrialParameter<DataRate> uncertainty_symmetry_cap_;
FieldTrialParameter<DataRate> estimate_floor_;
int64_t current_window_ms_;
int64_t prev_time_ms_;
float bitrate_estimate_kbps_;
float bitrate_estimate_var_;
};
} // namespace webrtc
#endif // MODULES_CONGESTION_CONTROLLER_GOOG_CC_BITRATE_ESTIMATOR_H_
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