A method for compressing video data comprising: generating, from video graphics data which have not been rendered and for providing modeling objects to be rendered, vertex data corresponding to said objects; said objects comprising movable objects; rendering said video graphics data to produce a current frame of pixel data and a reference frame of pixel data; identifying the position of each of said movable objects within said reference frame ; based upon said vertex data, defining a search area within said reference frame for calculating a motion vector for a block of pixel data within said current frame , said block containing at least a portion of a respective identified movable object, wherein the vertex data is used for the primitives for a respective identified movable object within said reference frame , and the search area for said blocks (405 - 411) is restricted to, with using the identified position of a respective identified movable object as a reference, a region surrounding the position of a respective identified movable object ; and compressing said current frame based upon said motion vector; characterized in that said search area is defined based upon the viewport coordinates of vertexes corresponding to a respective identified movable object within said reference frame by defining the outer boundaries and vertexes of a rectangular region within the reference frame containing a respective identified movable object by the viewpoint coordinates of vertexes of the respective identified movable object ; and uniformly expanding the boundaries of said rectangular region for defining said search area . generating, from video graphics data which have not been rendered and for providing modeling objects to be rendered, vertex data corresponding to said objects; said objects comprising movable objects; rendering said video graphics data to produce a current frame of pixel data and a reference frame of pixel data; identifying the position of each of said movable objects within said reference frame ; based upon said vertex data, defining a search area within said reference frame for calculating a motion vector for a block of pixel data within said current frame , said block containing at least a portion of a respective identified movable object, wherein the vertex data is used for the primitives for a respective identified movable object within said reference frame , and the search area for said blocks (405 - 411) is restricted to, with using the identified position of a respective identified movable object as a reference, a region surrounding the position of a respective identified movable object ; and compressing said current frame based upon said motion vector; characterized in that said search area is defined based upon the viewport coordinates of vertexes corresponding to a respective identified movable object within said reference frame by defining the outer boundaries and vertexes of a rectangular region within the reference frame containing a respective identified movable object by the viewpoint coordinates of vertexes of the respective identified movable object ; and uniformly expanding the boundaries of said rectangular region for defining said search area . <EOS>