基于内容预分析的环路滤波算法

In-loop filter algorithm based on content pre-analysis

传统基于块的视频编码系统,在较低码率情形下进行编码时总会遇到块效应现象。针对H.264中去块滤波中边缘强度判断的高计算复杂度问题,提出了一种基于内容预分析的快速环路滤波算法。该算法在光流方程的基础之上,充分利用帧间的相关性,采用STGS(spatial-temporal gradient scale)图进行不同区域特征的划分,将块效应强度的划分由以像素为单位转化为以块为单位。实验结果表明,该算法大大降低了滤波算法的复杂度,且主观效果与H.264环路滤波系统的结果相当。

Traditional block-based video coders suffered from annoying blocking artifacts in low bit-rate coding. Aiming to high complexity for determining the block edge strength of deblocking filter, a fast indoop deblocking filter based on content pre-analysis was proposed, which utilized STGS-image to partition character of different regions and measured the block effect intension in blockwise based on optical flow equation and relativity of interframe. Experimental results show that the proposed greatly reduces the complexity of filter algorithm, and then the subjective image quality of the proposed is approximate to that of the H.264 in-loop filter.