A novel interpolation-free scheme for fractional pixel motion estimation

Fractional pixel motion estimation (ME), including fractional pixel interpolation and fractional motion vector (MV) prediction, has been implemented within many modern video codecs to optimize the rate-distortion performance. However, it brings about significant computational complexity increase. This paper proposes an interpolation-free fractional pixel ME scheme. Based on the analysis of the property of the error surface established with the block distortion measurement (BDM) of the integer pixel points, a parabolic curve passing the minimum point of the error surface is derived. Then the optimal fractional MV position is determined as the minimum point of the curve. Experimental results show that the proposed algorithm significantly reduces computational complexity of fractional pixel ME and outperforms the state-of-the-art interpolation-free fractional pixel ME algorithms.