An optimally scalable and cost-effective fractional-pixel motion estimation algorithm for HEVC

Fractional-pixel motion compensation is still one of the most time-consuming parts in the upcoming High Efficiency Video Coding (HEVC) standard. In this paper, we propose an optimally scalable and cost-effective fractional-pixel motion estimation (FPME) algorithm to optimally fit to different and varying constrains of computing resources. Our main contribution include two aspects. Firstly, an optimally scalable and cost-effective FPME algorithm based on a cost-benefit analysis is proposed, where we present a improved fractional-pixel MV prediction method and a new cost-effective priority for each search point in HEVC. Secondly, a complexity adjustment strategy is delivered to enable the ability for the FPME to adjust its complexity to match different given constraints on time. Experiments show that the proposed algorithm can achieve best R-D performance while optimally adjust its complexity, based on any given time constraints. As a side product, the proposed algorithm can also serve as the best fast algorithm which has already reduced computing complexity by a factor 74% with almost no loss on PSNR and bitrates.