一种场景切换下的HEVC码率控制算法

摘要

The HEVC (High Efficiency Video Coding)encoder employs equal bit allocation in a G0P (Group of Picture) level,in the background of scene change,resulting in quality degradation in current and subsequent frame,so this paper presents a rate control algorithm based on scene change:According to the complexity of current scene,the target bits of current GOP will be reallocated and when a scene change was detected,the model parameters,the current frame and the reference pictures will be adjusted.Experimental results show that compared with the rate control in HEVC,the scheme can efficiently reduce the negative influence of scene change,improves the average PSNR (Peak Signal Noise Ratio) of sequence 1.4 dB at most and maintains the accuracy of output bitrate.%针对HEVC(High Efficiency Video Coding)编码器对图像组(Group of Picture,GOP)层采用平均分配的方式,在场景切换背景下,容易导致场景切换帧以及后续视频图像质量严重下降的问题,本文提出一种基于场景切换的码率控制算法:根据场景的复杂度,重新分配GOP层目标比特,并且当检测到场景切换时,对模型参数,当前帧以及参考帧等做出适当调整.实验结果表明:相比HEVC自带的码率控制算法,该策略能有效降低场景切换带来的负面影响,使序列的平均峰值信噪比(PSNR)最高提升1.4 dB,并保持精确的输出码率.