39ae69690e
The intention of this change is to separate the Kalman filter state (that prior to this change lived in JitterEstimator) from the other filter's state, making it easier to see how the different filters interact. This move does not include any interface, functional, or documentation changes. Those will follow in later changes. A very basic unit test is added, which will also be expanded later on. Bug: webrtc:14151 Change-Id: Ifb9b8ce2d9418ea52ccf64a77fd46d1ebba30779 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/264984 Commit-Queue: Rasmus Brandt <brandtr@webrtc.org> Reviewed-by: Philip Eliasson <philipel@webrtc.org> Cr-Commit-Position: refs/heads/main@{#37721}
131 lines
4.4 KiB
C++
131 lines
4.4 KiB
C++
/*
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* Copyright (c) 2011 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_VIDEO_CODING_TIMING_JITTER_ESTIMATOR_H_
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#define MODULES_VIDEO_CODING_TIMING_JITTER_ESTIMATOR_H_
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#include "absl/types/optional.h"
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#include "api/field_trials_view.h"
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#include "api/units/data_size.h"
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#include "api/units/frequency.h"
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#include "api/units/time_delta.h"
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#include "api/units/timestamp.h"
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#include "modules/video_coding/timing/frame_delay_delta_kalman_filter.h"
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#include "modules/video_coding/timing/rtt_filter.h"
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#include "rtc_base/rolling_accumulator.h"
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namespace webrtc {
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class Clock;
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class JitterEstimator {
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public:
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explicit JitterEstimator(Clock* clock, const FieldTrialsView& field_trials);
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virtual ~JitterEstimator();
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JitterEstimator(const JitterEstimator&) = delete;
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JitterEstimator& operator=(const JitterEstimator&) = delete;
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// Resets the estimate to the initial state.
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void Reset();
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// Updates the jitter estimate with the new data.
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//
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// Input:
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// - frame_delay : Delay-delta calculated by UTILDelayEstimate.
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// - frame_size : Frame size of the current frame.
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void UpdateEstimate(TimeDelta frame_delay, DataSize frame_size);
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// Returns the current jitter estimate and adds an RTT dependent term in cases
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// of retransmission.
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// Input:
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// - rtt_multiplier : RTT param multiplier (when applicable).
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// - rtt_mult_add_cap : Multiplier cap from the RTTMultExperiment.
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//
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// Return value : Jitter estimate.
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virtual TimeDelta GetJitterEstimate(
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double rtt_multiplier,
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absl::optional<TimeDelta> rtt_mult_add_cap);
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// Updates the nack counter.
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void FrameNacked();
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// Updates the RTT filter.
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//
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// Input:
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// - rtt : Round trip time.
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void UpdateRtt(TimeDelta rtt);
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// A constant describing the delay from the jitter buffer to the delay on the
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// receiving side which is not accounted for by the jitter buffer nor the
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// decoding delay estimate.
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static constexpr TimeDelta OPERATING_SYSTEM_JITTER = TimeDelta::Millis(10);
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private:
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double var_noise_; // Variance of the time-deviation from the line
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// Updates the random jitter estimate, i.e. the variance of the time
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// deviations from the line given by the Kalman filter.
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//
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// Input:
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// - d_dT : The deviation from the kalman estimate.
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void EstimateRandomJitter(double d_dT);
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double NoiseThreshold() const;
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// Calculates the current jitter estimate.
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//
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// Return value : The current jitter estimate.
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TimeDelta CalculateEstimate();
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// Post process the calculated estimate.
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void PostProcessEstimate();
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Frequency GetFrameRate() const;
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// Filters the {frame_delay_delta, frame_size_delta} measurements through
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// a linear Kalman filter.
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FrameDelayDeltaKalmanFilter kalman_filter_;
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static constexpr DataSize kDefaultAvgAndMaxFrameSize = DataSize::Bytes(500);
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DataSize avg_frame_size_ = kDefaultAvgAndMaxFrameSize; // Average frame size
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double var_frame_size_; // Frame size variance. Unit is bytes^2.
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// Largest frame size received (descending with a factor kPsi)
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DataSize max_frame_size_ = kDefaultAvgAndMaxFrameSize;
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DataSize frame_size_sum_ = DataSize::Zero();
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uint32_t frame_size_count_;
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absl::optional<Timestamp> last_update_time_;
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// The previously returned jitter estimate
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absl::optional<TimeDelta> prev_estimate_;
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// Frame size of the previous frame
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absl::optional<DataSize> prev_frame_size_;
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// Average of the random jitter
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double avg_noise_;
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uint32_t alpha_count_;
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// The filtered sum of jitter estimates
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TimeDelta filter_jitter_estimate_ = TimeDelta::Zero();
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uint32_t startup_count_;
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// Time when the latest nack was seen
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Timestamp latest_nack_ = Timestamp::Zero();
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// Keeps track of the number of nacks received, but never goes above
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// kNackLimit.
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uint32_t nack_count_;
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RttFilter rtt_filter_;
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// Tracks frame rates in microseconds.
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rtc::RollingAccumulator<uint64_t> fps_counter_;
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Clock* clock_;
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};
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} // namespace webrtc
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#endif // MODULES_VIDEO_CODING_TIMING_JITTER_ESTIMATOR_H_
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