The Research Of Fast Coding Unit Size Decision Algorithm For H.265/HEVC

As a new generation of highly efficient video coding standard,H.265/HEVC adopted the recursive partitioning based quadtree hybrid coding framework,which is more efficient than H.264/AVC while the computational complexity is also higher.To reduce the computational complexity of the HEVC intra coding algorithm,the two algorithms were proposed: one is the ESTA-TC algorithm,and another is the integration of ESTA-D algorithm and ESTA-TC algorithm.The ESTA-TC algorithm: the four directional texture complexity metrics was proposed,according to the texture complexity,the current coding block classified as three categories: High,Low and Mid ssssssdle.If the current coding block is High,skip the calculation of rate-distortion cost in the current depth;If the current coding block is Low,terminate in the current depth;If the current coding block is Middle,calculate the current coding block rate-distortion cost to determine the final coding unit size.Compared with the reference software HM10.0,the encoding time is reduced by 4 5.3% on average,with 1.27% BD-Bitrate increasing and 0.058 d B BD-PSNR decreasing.Compared with the literature [28] algorithm,the encoding time is reduced by 3.02% on average,with 0.54% BD-Bitrate increasing and 0.023 d B BD-PSNR decreasing.The ESTA-D and ESTA-TC combining algorithm: according to depth of neighboring coding unit,whether the current coding unit is further partitioned.If the best depth of the current coding unit is undetermined,the algorithm based on four directional texture complexities will be used to decide it.Compared with the reference software HM10.0,the encoding time is reduced by 49.4% on average,with 1.57 % BD-Bitrate increasing and 0.074 d B BD-PSNR decreasing.Compared with the literature [28] algorithm,the encoding time is reduced by 5.74% on average,with 0.76% BD-Bitrate increasing and 0.022 d B BD-PSNR decreasing.Experimental results show that the proposed algorithm is faster than the literature [28] algorithm while maintaining almost the same RD performance as the original H.265/HEVC encoder.