This paper addresses the problem of improving motion sampling efficiency for motion-compensated prediction (MCP). We provide a theoretical framework for analyzing the effect of motion sampling structure on MCP efficiency. It is shown that the sampling grid induced by the quadtree partition in H.264/AVC is suboptimal. To improve sampling efficiency, we propose a new pattern, which provides sampling points at both the center and the top-left corner of a macroblcok. When contrasted with conventional NxN/2 block partition, the proposed scheme performs consistently and significantly better in subjective and objective quality.