Kernel based sub-pixel motion estimation

Modern video codecs such as MPEG2, MPEG4-ASP and H.264 depend on computationally complex sub-pixel motion estimation (ME) to optimise rate-distortion efficiency. Sub-pixel ME is implemented within these standards using interpolated values at 1/2 or 1/4 pixel accuracy. This paper presents a novel scheme for sub-pixel ME using a model free kernel method utilising the result of the whole-pixel SAD distribution applied to an H.264 encoder. While giving an equivalent rate distortion performance, this approach approximately halves the number of quarter-pixel search positions giving an overall speed up of approximately 10% compared to the EPZS quarter-pixel method (the state of the art H.264 optimised sub-pixel motion estimator).