Accuracy improvement and cost reduction of 3-step search block matching algorithm for video coding

Proposes three modifications on the 3-step hierarchical search for video coding: the multiple-candidate search that improves the estimation accuracy, a method of subsampling that reduces computation and input data amount, and an overlapping strategy to improve the accuracy of a large-area search. Experimental results show that combining these techniques provides high-speed and high-precision motion estimators with reduced on-chip buffers and lower input bandwidth requirements