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Diffstat (limited to 'webrtc/modules/video_coding/jitter_estimator.h')
| -rw-r--r-- | webrtc/modules/video_coding/jitter_estimator.h | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/webrtc/modules/video_coding/jitter_estimator.h b/webrtc/modules/video_coding/jitter_estimator.h new file mode 100644 index 0000000000..a7b4b3e3df --- /dev/null +++ b/webrtc/modules/video_coding/jitter_estimator.h @@ -0,0 +1,170 @@ +/* + * Copyright (c) 2011 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 WEBRTC_MODULES_VIDEO_CODING_JITTER_ESTIMATOR_H_ +#define WEBRTC_MODULES_VIDEO_CODING_JITTER_ESTIMATOR_H_ + +#include "webrtc/base/rollingaccumulator.h" +#include "webrtc/modules/video_coding/rtt_filter.h" +#include "webrtc/typedefs.h" + +namespace webrtc { + +class Clock; + +class VCMJitterEstimator { + public: + VCMJitterEstimator(const Clock* clock, + int32_t vcmId = 0, + int32_t receiverId = 0); + virtual ~VCMJitterEstimator(); + VCMJitterEstimator& operator=(const VCMJitterEstimator& rhs); + + // Resets the estimate to the initial state + void Reset(); + void ResetNackCount(); + + // Updates the jitter estimate with the new data. + // + // Input: + // - frameDelay : Delay-delta calculated by UTILDelayEstimate in + // milliseconds + // - frameSize : Frame size of the current frame. + // - incompleteFrame : Flags if the frame is used to update the + // estimate before it + // was complete. Default is false. + void UpdateEstimate(int64_t frameDelayMS, + uint32_t frameSizeBytes, + bool incompleteFrame = false); + + // Returns the current jitter estimate in milliseconds and adds + // also adds an RTT dependent term in cases of retransmission. + // Input: + // - rttMultiplier : RTT param multiplier (when applicable). + // + // Return value : Jitter estimate in milliseconds + int GetJitterEstimate(double rttMultiplier); + + // Updates the nack counter. + void FrameNacked(); + + // Updates the RTT filter. + // + // Input: + // - rttMs : RTT in ms + void UpdateRtt(int64_t rttMs); + + void UpdateMaxFrameSize(uint32_t frameSizeBytes); + + // A constant describing the delay from the jitter buffer + // to the delay on the receiving side which is not accounted + // for by the jitter buffer nor the decoding delay estimate. + static const uint32_t OPERATING_SYSTEM_JITTER = 10; + + protected: + // These are protected for better testing possibilities + double _theta[2]; // Estimated line parameters (slope, offset) + double _varNoise; // Variance of the time-deviation from the line + + virtual bool LowRateExperimentEnabled(); + + private: + // Updates the Kalman filter for the line describing + // the frame size dependent jitter. + // + // Input: + // - frameDelayMS : Delay-delta calculated by UTILDelayEstimate in + // milliseconds + // - deltaFSBytes : Frame size delta, i.e. + // : frame size at time T minus frame size at time + // T-1 + void KalmanEstimateChannel(int64_t frameDelayMS, int32_t deltaFSBytes); + + // Updates the random jitter estimate, i.e. the variance + // of the time deviations from the line given by the Kalman filter. + // + // Input: + // - d_dT : The deviation from the kalman estimate + // - incompleteFrame : True if the frame used to update the + // estimate + // with was incomplete + void EstimateRandomJitter(double d_dT, bool incompleteFrame); + + double NoiseThreshold() const; + + // Calculates the current jitter estimate. + // + // Return value : The current jitter estimate in milliseconds + double CalculateEstimate(); + + // Post process the calculated estimate + void PostProcessEstimate(); + + // Calculates the difference in delay between a sample and the + // expected delay estimated by the Kalman filter. + // + // Input: + // - frameDelayMS : Delay-delta calculated by UTILDelayEstimate in + // milliseconds + // - deltaFS : Frame size delta, i.e. frame size at time + // T minus frame size at time T-1 + // + // Return value : The difference in milliseconds + double DeviationFromExpectedDelay(int64_t frameDelayMS, + int32_t deltaFSBytes) const; + + double GetFrameRate() const; + + // Constants, filter parameters + int32_t _vcmId; + int32_t _receiverId; + const double _phi; + const double _psi; + const uint32_t _alphaCountMax; + const double _thetaLow; + const uint32_t _nackLimit; + const int32_t _numStdDevDelayOutlier; + const int32_t _numStdDevFrameSizeOutlier; + const double _noiseStdDevs; + const double _noiseStdDevOffset; + + double _thetaCov[2][2]; // Estimate covariance + double _Qcov[2][2]; // Process noise covariance + double _avgFrameSize; // Average frame size + double _varFrameSize; // Frame size variance + double _maxFrameSize; // Largest frame size received (descending + // with a factor _psi) + uint32_t _fsSum; + uint32_t _fsCount; + + int64_t _lastUpdateT; + double _prevEstimate; // The previously returned jitter estimate + uint32_t _prevFrameSize; // Frame size of the previous frame + double _avgNoise; // Average of the random jitter + uint32_t _alphaCount; + double _filterJitterEstimate; // The filtered sum of jitter estimates + + uint32_t _startupCount; + + int64_t + _latestNackTimestamp; // Timestamp in ms when the latest nack was seen + uint32_t _nackCount; // Keeps track of the number of nacks received, + // but never goes above _nackLimit + VCMRttFilter _rttFilter; + + rtc::RollingAccumulator<uint64_t> fps_counter_; + enum ExperimentFlag { kInit, kEnabled, kDisabled }; + ExperimentFlag low_rate_experiment_; + const Clock* clock_; +}; + +} // namespace webrtc + +#endif // WEBRTC_MODULES_VIDEO_CODING_JITTER_ESTIMATOR_H_ |