c592257953
This class measures the allocated cumulative byte budget (as specified by one or more rate updates) and the actual cumulative number of bytes produced over a sliding window. A utilization factor (produced bytes / budgeted bytes) is calculated seen from the first data point timestamp until the last data point timestamp plus the amount time needed to send that last data point given no further updates to the rate. Wireup to EncoderBitrateAdjuster will happen in a follow-up CL. Bug: b/349561566 Change-Id: Id0dc183b07a96366531007be9ff1c1ec6574e9ff Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/356200 Commit-Queue: Erik Språng <sprang@webrtc.org> Reviewed-by: Philip Eliasson <philipel@webrtc.org> Auto-Submit: Erik Språng <sprang@webrtc.org> Cr-Commit-Position: refs/heads/main@{#42591}
69 lines
2.5 KiB
C++
69 lines
2.5 KiB
C++
/*
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* Copyright (c) 2024 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 VIDEO_RATE_UTILIZATION_TRACKER_H_
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#define VIDEO_RATE_UTILIZATION_TRACKER_H_
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#include <deque>
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#include "absl/types/optional.h"
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#include "api/units/data_rate.h"
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#include "api/units/data_size.h"
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#include "api/units/time_delta.h"
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#include "api/units/timestamp.h"
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namespace webrtc {
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// Helper class that tracks the rate of utilization over a sliding window.
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// tl;dr: if an encoder has a target rate of 1000kbps but in practice
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// produces 500kbps it would have a utilization factor of 0.5.
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// The tracker looks only at discrete events, and keeps only a fixed amount
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// of data points (e.g. encoded frames) or points newer than a given time
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// limit, whichever is lower.
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// More precisely This class measures the allocated cumulative byte budget (as
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// specified by one or more rate updates) and the actual cumulative number of
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// bytes produced over a sliding window. A utilization factor (produced bytes /
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// budgeted bytes) is calculated seen from the first data point timestamp until
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// the last data point timestamp plus the amount time needed to send that last
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// data point given no further updates to the rate. The implication of this is a
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// smoother value, and e.g. setting a rate and adding a data point, then
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// immediately querying the utilization reports 1.0 utilization instead of some
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// undefined state.
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class RateUtilizationTracker {
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public:
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RateUtilizationTracker(size_t max_num_encoded_data_points,
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TimeDelta max_duration);
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// The timestamps used should never decrease relative the last one.
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void OnDataRateChanged(DataRate rate, Timestamp time);
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void OnDataProduced(DataSize size, Timestamp time);
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absl::optional<double> GetRateUtilizationFactor(Timestamp time) const;
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private:
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struct RateUsageUpdate {
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Timestamp time;
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DataRate target_rate;
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DataSize produced_data;
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};
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void CullOldData(Timestamp time);
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const size_t max_data_points_;
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const TimeDelta max_duration_;
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DataRate current_rate_;
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std::deque<RateUsageUpdate> data_points_;
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};
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} // namespace webrtc
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#endif // VIDEO_RATE_UTILIZATION_TRACKER_H_
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