利用纹理和空间相关性的HEVC帧内预测模式选择

HEVC intra-prediction mode selection by using texture and spatial correlation

目的提出一种结合图像纹理方向和空间相关性的高效视频编码(HEVC)帧内模式选择快速算法,减少粗模式选择过程的候选模式数目,加快帧内模式选择速度。方法首先,使用Sobel算子获得当前预测单元(PU)的纹理方向,利用此纹理方向选取相应的角度预测模式组成粗模式选择的候选模式列表;另外,利用图像的空间相关性,将相邻预测单元的最优帧内预测模式添加到候选模式列表中。结果本文算法将粗模式选择过程的候选模式数目从35种减少到不超过10种,比特率升高0.41%,峰值信噪比下降0.031 4 dB,编码时间缩短了34.9%。结论实验结果显示,在保持编码质量基本不变的情况下,此算法明显减少了粗模式选择过程的预测模式数量,提高了HEVC的编码效率。

Objective This study proposes a fast mode decision algorithm combined with image texture direction and spatial correlation in high-efficiency video coding （HEVC） to reduce the number of candidate patterns in the rough mode decision （RMD） and to speed up the frame of mode selection.Method In the HEVC algorithm,the Sobel operator is used to obtain the texture direction of the current block Prediction Union （PU）,in order to select the corresponding angle prediction model to comprise the RMD candidate list,and the spatial correlation of images is adopted to add the optimal mode of the neighboring PU to the candidate list.Result The proposed algorithm will reduce the number of candidate patterns from 35 to less than 10 in the RMD.Thus,this method significantly shortens the encoding time by 34.9％,with the bit-rate increasing to 0.41％ and the PSNR decreasing to 0.031 4 dB.Conclusion Resultsshow that this method significantly reduces the complexity of RMD algorithm and improves the efficiency of HEVC coding when the encoding quality is invariant.