In this paper, a novel algorithm for object-oriented motion estimation is presented. The algorithm initially determines a macro-block partition based on the computed current frame difference, using the hidden information that a foreground-moving object produces high absolute frame difference values in the neighborhood of the object boundaries. An inter-frame coding algorithm, adopting a modified version of classical block matching is then applied on separate slices of each macro-block. Resulting data are used to obtain preliminary object segmentation. The algorithm further splits each macro-block if characterized by the presence of more than one motion vector into sub-areas. The approach allows obtaining global object segmentation - with the possibility of tracking - and lower prediction errors with respect to classical Block Matching, without increasing the computational complexity.