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* 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.
#include "exp_filter.h"
#include "typedefs.h"
namespace webrtc
/* VCMFrameDropper class */
// The Frame Dropper implements a variant of the leaky bucket algorithm
// for keeping track of when to drop frames to avoid bit rate
// over use when the encoder can't keep its bit rate.
class VCMFrameDropper
VCMFrameDropper(WebRtc_Word32 vcmId = 0);
// Resets the FrameDropper to its initial state.
// This means that the frameRateWeight is set to its
// default value as well.
void Reset();
void Enable(bool enable);
// Answers the question if it's time to drop a frame
// if we want to reach a given frame rate. Must be
// called for every frame.
// Return value : True if we should drop the current frame
bool DropFrame();
// Updates the FrameDropper with the size of the latest encoded
// frame. The FrameDropper calculates a new drop ratio (can be
// seen as the probability to drop a frame) and updates its
// internal statistics.
// Input:
// - frameSizeBytes : The size of the latest frame
// returned from the encoder.
// - deltaFrame : True if the encoder returned
// a key frame.
void Fill(WebRtc_UWord32 frameSizeBytes, bool deltaFrame);
void Leak(WebRtc_UWord32 inputFrameRate);
void UpdateNack(WebRtc_UWord32 nackBytes);
// Sets the target bit rate and the frame rate produced by
// the camera.
// Input:
// - bitRate : The target bit rate
void SetRates(float bitRate, float userFrameRate);
// Return value : The current average frame rate produced
// if the DropFrame() function is used as
// instruction of when to drop frames.
float ActualFrameRate(WebRtc_UWord32 inputFrameRate) const;
void FillBucket(float inKbits, float outKbits);
void UpdateRatio();
WebRtc_Word32 _vcmId;
VCMExpFilter _keyFrameSizeAvgKbits;
VCMExpFilter _keyFrameRatio;
float _keyFrameSpreadFrames;
WebRtc_Word32 _keyFrameCount;
float _accumulator;
float _accumulatorMax;
float _targetBitRate;
bool _dropNext;
VCMExpFilter _dropRatio;
WebRtc_Word32 _dropCount;
float _windowSize;
float _userFrameRate;
bool _wasBelowMax;
bool _enabled;
bool _fastMode;
}; // end of VCMFrameDropper class
} // namespace webrtc