新的低码率视频编码快速半像素搜索算法

运动搜索一直是混合视频编码方案中最占编码时间的模块。典型的运动搜索由整像素搜索和半像素搜索组成。随着整像素搜索算法的不断改进 ,被普遍使用的半像素全搜索方法在整个运动搜索中所占运算量已经不容忽视。为了加速半像素搜索 ,提出了一种基于抛物面预测的半像素快速搜索算法。实验结果表明该算法能显著地提高半像素搜索速度 ,并且不会对编码效率和图像质量产生明显的影响。在QCIF格式下采用 H.2 6 3编码器时实际节省运算量约为5 7%。该算法的预测过程简单 ,易于实现 ,能够方便地集成到现有的编码系统中

Novel fast half pixel motion estimation for low bit rate video coding

In hybrid video coding schemes, the motion estimation is the most computationally expensive module. Typical motion estimation is composed of two stages: one at integer pixel accuracy and the other at half pixel accuracy. Since the motion estimation complexity at the integer pixel accuracy level has continually decreased, the computation complexity for the full half pixel search has taken a relatively large part of the whole motion estimation. The efficiency of the half pixel search is improved by using a paraboloid prediction based fast half pixel motion estimation algorithm. Experimental results show that the proposed algorithm gives almost the same image quality and bit rate as that of the full half pixel search and it reduces the computational load by about 57% for the QCIF H.263 encoder. Furthermore the simple prediction process in the proposed algorithm makes the algorithm be easily integrated into existing video coding systems.