针对高效视频编码(high efficiency video coding,HEVC)在码率控制中采用平均绝对误差对图像复杂度估计不准确和比特分配偏差较大问题,提出一种基于内容复杂度的HEVC码率控制改进算法。该算法首先从帧层出发,估计出待编码帧的预测方差,...针对高效视频编码(high efficiency video coding,HEVC)在码率控制中采用平均绝对误差对图像复杂度估计不准确和比特分配偏差较大问题,提出一种基于内容复杂度的HEVC码率控制改进算法。该算法首先从帧层出发,估计出待编码帧的预测方差,并由此方差构建内容复杂度模型,然后通过复杂度模型对参数更新,实现对帧层码率的重新分配。以4种不同类型的测试序列为研究对象,实验结果表明,与R-λ模型标准算法及低复杂度的码率控制算法相比,提出的改进算法的输出码率更加接近目标码率,实际编码码率偏差平均减少了3.35‰和1.50‰,峰值信噪比的平均值分别提高0.27dB和0.09dB,视频视觉质量较好。所提算法可用于HEVC编码的码率控制中。展开更多
Paper study the MAC layer security mechanism and data frame structure in ZigBee protocol, improve the algorithm for random Fuzzing test technology, and test method of attack fusion boundary, structure of Fuzzing and t...Paper study the MAC layer security mechanism and data frame structure in ZigBee protocol, improve the algorithm for random Fuzzing test technology, and test method of attack fusion boundary, structure of Fuzzing and the node clone, proposed a ZigBee routing protocol for the MAC layer security comprehensive detection algorithm. Fuzzing test show that the testing algorithm can not only greatly improve the test efficiency in Fuzzing, more than the structure of Fuzzing is increased by 50% in path coverage.展开更多
In this paper,we aim at improving the video quality degradation due to high motions or scene changes. An improved frame-layer bit allocation scheme for H.264/AVC rate control is proposed.First,current frame is pre-enc...In this paper,we aim at improving the video quality degradation due to high motions or scene changes. An improved frame-layer bit allocation scheme for H.264/AVC rate control is proposed.First,current frame is pre-encoded in 16×16 modes with a fixed quantization parameter(QP).The frame coding complexity is then measured based on the resulting bits and peak signal-to-ratio(PSNR) in the pre-coding stage.Finally,a bit budget is calculated for current frame according to its coding complexity and inter-frame PSNR fluctuation,combined with the buffer status.Simulation results show that,in comparison with the H.264 adopted rate control scheme, our method is more efficient to suppress the sharp PSNR drops caused by high motions and scene changes.The visual quality variations in a sequence are also relieved.展开更多
文摘针对高效视频编码(high efficiency video coding,HEVC)在码率控制中采用平均绝对误差对图像复杂度估计不准确和比特分配偏差较大问题,提出一种基于内容复杂度的HEVC码率控制改进算法。该算法首先从帧层出发,估计出待编码帧的预测方差,并由此方差构建内容复杂度模型,然后通过复杂度模型对参数更新,实现对帧层码率的重新分配。以4种不同类型的测试序列为研究对象,实验结果表明,与R-λ模型标准算法及低复杂度的码率控制算法相比,提出的改进算法的输出码率更加接近目标码率,实际编码码率偏差平均减少了3.35‰和1.50‰,峰值信噪比的平均值分别提高0.27dB和0.09dB,视频视觉质量较好。所提算法可用于HEVC编码的码率控制中。
文摘Paper study the MAC layer security mechanism and data frame structure in ZigBee protocol, improve the algorithm for random Fuzzing test technology, and test method of attack fusion boundary, structure of Fuzzing and the node clone, proposed a ZigBee routing protocol for the MAC layer security comprehensive detection algorithm. Fuzzing test show that the testing algorithm can not only greatly improve the test efficiency in Fuzzing, more than the structure of Fuzzing is increased by 50% in path coverage.
基金the Grant from Shanghai Key Laboratory of Digital Media Processing and Transmissions
文摘In this paper,we aim at improving the video quality degradation due to high motions or scene changes. An improved frame-layer bit allocation scheme for H.264/AVC rate control is proposed.First,current frame is pre-encoded in 16×16 modes with a fixed quantization parameter(QP).The frame coding complexity is then measured based on the resulting bits and peak signal-to-ratio(PSNR) in the pre-coding stage.Finally,a bit budget is calculated for current frame according to its coding complexity and inter-frame PSNR fluctuation,combined with the buffer status.Simulation results show that,in comparison with the H.264 adopted rate control scheme, our method is more efficient to suppress the sharp PSNR drops caused by high motions and scene changes.The visual quality variations in a sequence are also relieved.
