| /* |
| * 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_UTILITY_FRAME_DROPPER_H_ |
| #define WEBRTC_MODULES_VIDEO_CODING_UTILITY_FRAME_DROPPER_H_ |
| |
| #include <cstddef> |
| |
| #include "webrtc/base/exp_filter.h" |
| #include "webrtc/typedefs.h" |
| |
| namespace webrtc { |
| |
| // 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 FrameDropper { |
| public: |
| FrameDropper(); |
| explicit FrameDropper(float max_time_drops); |
| virtual ~FrameDropper() {} |
| |
| // Resets the FrameDropper to its initial state. |
| // This means that the frameRateWeight is set to its |
| // default value as well. |
| virtual void Reset(); |
| |
| virtual 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 |
| virtual 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. |
| virtual void Fill(size_t frameSizeBytes, bool deltaFrame); |
| |
| virtual void Leak(uint32_t inputFrameRate); |
| |
| void UpdateNack(uint32_t nackBytes); |
| |
| // Sets the target bit rate and the frame rate produced by |
| // the camera. |
| // |
| // Input: |
| // - bitRate : The target bit rate |
| virtual void SetRates(float bitRate, float incoming_frame_rate); |
| |
| // Return value : The current average frame rate produced |
| // if the DropFrame() function is used as |
| // instruction of when to drop frames. |
| virtual float ActualFrameRate(uint32_t inputFrameRate) const; |
| |
| private: |
| void FillBucket(float inKbits, float outKbits); |
| void UpdateRatio(); |
| void CapAccumulator(); |
| |
| rtc::ExpFilter _keyFrameSizeAvgKbits; |
| rtc::ExpFilter _keyFrameRatio; |
| float _keyFrameSpreadFrames; |
| int32_t _keyFrameCount; |
| float _accumulator; |
| float _accumulatorMax; |
| float _targetBitRate; |
| bool _dropNext; |
| rtc::ExpFilter _dropRatio; |
| int32_t _dropCount; |
| float _windowSize; |
| float _incoming_frame_rate; |
| bool _wasBelowMax; |
| bool _enabled; |
| bool _fastMode; |
| float _cap_buffer_size; |
| float _max_time_drops; |
| }; // end of VCMFrameDropper class |
| |
| } // namespace webrtc |
| |
| #endif // WEBRTC_MODULES_VIDEO_CODING_UTILITY_FRAME_DROPPER_H_ |