Motion vector selection method for resolution down-sampling of motion video

A method for setting a motion vector for reducing resolution of digital motion picture is provided to improve the quality of reduced digital motion picture and to improve refinement processing speed by reducing the size of a refinement range. Two motion vectors having high correlation with each other are selected among motion vectors of adjacent four macroblocks(SP1). A motion vector located between the two motion vectors is obtained(SP2). The motion vector is operated to obtain a motion vector to be assigned to a scale-downed macroblock(SP3). Refinement of the motion vector to be assigned to the scale-downed macroblock is executed by applying the refinement to a small region preliminarily set by a user(SP4).