基于H．264／AVC的快速帧内预测模式决策方法

Fast Intra Mode Decision Algorithm Based on H.264/AVC

为了降低编解码复杂度,本文在对不同方向纹理块变换域系数特性分析的基础上,提出了一种简单有效的快速帧内预测模式决策算法。根据二维正交变换系数特性确定的决策准则,将可能性较小的部分预测模式在进行率失真优化(RDO,Rate distortion optimization)计算前排除,仅挑选可能性较大的几种模式作为候选模式进行RDO计算,并采用周期插入穷尽搜索和自适应门限的方法来防止误差扩散。仿真结果表明,该算法在保证必要的图像保真度和低码率的条件下,帧内编码速度平均提高5倍。

To reduce the calculation amount in the intra prediction, a simple and fast intra mode decision algorithm is proposed based on the analysis of the coefficient characteristics in transform domain. According to the decision-making rule determined by 2-D orthogonal transform coefficients, only a part of the intra prediction modes having the greatest possibility, is chosen for RDO calculation. Experimental results show that the proposed algorithm can increase the speed to 5 times under conditions of the image fidelity and the low bit rate.