基于纹理主方向强度的HEVC帧内快速分层算法

Fast Intraframe Hierarchical Algorithm for HEVC Based on Intensity of Texture Dominant Orientation

为降低高效视频编码帧内预测过程的计算复杂度,提出一种基于纹理主方向强度的快速帧内预测算法。根据每一深度层编码单元(CU)分布特点,并结合每块CU纹理主方向强度判断CU是否需要进行分割处理。在深度层为0和1的CU块上统计4×4块的纹理方向,确定当前CU的纹理主方向强度,判断其纹理复杂度。在深度为2和3的CU上结合像素方差,以像素点为单位计算相应CU的纹理主方向强度。通过实验训练序列获得恰当的阈值,自适应提前终止编码单元的划分,减少帧内预测的编码复杂度。实验结果表明,在保证信噪比和比特率基本不变的条件下,与平台HM15.0相比,该算法编码时间平均节省51.1%。

In order to reduce the computational complexity of the intra prediction process of High Efficiency Video Coding （ HEVC）, a fast intraframe prediction algorithm based on the dominant direction intensity of texture is proposed. According to the Coding Unit（CU） distribution feature of each depth layer and it the main direction strength of each CU texture determine whether the CU needs to be divided. The texture directions of 4 ×4 blocks are counted on CU blocks with depth levels of 0 and 1 to determine the texture main direction strength of the current CU and judge its texture complexity. Pixel variance is combined on CU with depths of 2 and 3, and the main direction intensity of the corresponding CU is calculated in pixel units. Through experiment training sequence, the algorithm obtains the appropriate threshold, adaptively terminate the coding unit ahead of time, and reduces the complexity of intraframe prediction coding. Experimental results show that,compared with the platform HM15.0,the average encoding time of this algorithm can be saved by 51.1% while ensuring the same signal-to-noise ratio and bit rate.