HEVC去方块滤波的优化算法

Optimization of HEVC deblocking filter algorithm

高效视频编码(HEVC)的编码效率极高,但编解码复杂度也急剧增加,且在解码时间里用了较多时间进行去方块滤波。本文提出一种去方块滤波(DF)的优化算法。先计算滤波基本单元中首末两行的像素梯度之和,再决策滤波开关。若开关打开,则计算首末两行的边界差值并与其梯度值共同判断滤波强度,若为强滤波则不用限幅函数,弱滤波则算法不变;否则,进行下一基本单元的操作。仿真结果表明,与HM16.0相比,本文算法在低时延P帧模式下,编码性能没有很大变化,解码时间平均减少2.39%,DF的时间平均减少14.56%。本文算法在保证编码性能和视频质量基本不变的情况下,有效降低了DF的计算复杂度。

High efficiency video coding （HEVC） ha s extremely high coding efficiency,but the codec complexity is also increased dr amatically,and in the decoding time,more time is needed to deal with the deblocking filter.Therefore,an optimization algorithm is proposed in this paper so as to solve the deblocking filter.First,calculate the sum of the pixel gradie nts in the first and second rows of the filter base unit,and then make the filter switch.If the switc h is turned on,the boundary difference between the first and second lines is calculated and the fil ter strength is determined by the gradient value.If the filter is strong,we don′t have to limi t the function,and the algorithm is also the same for the normal filtering.Otherwise,the operation of the next basic unit will be performed.The simulation results show that the coding performance is not changed greatly in the low delay P frame mode compared with HM16.0,the decoding time is reduced by 2.39% on average,and the time of the block filtering is reduced by 14.56%.In thi s paper,the algorithm can effectively reduce the computational complexity of deblocking filt er when the coding performance and video quality are basically the same.