1. A method for encoding motion vectors, comprising the steps of: determining motion vectors and flags for sub-blocks of a macroblock (“MB”) as a function of SAD calculations for the MB; generating one or more merged motion vectors for the sub-blocks of the MB as a function of the determined motion vectors and the determined flags; generating a merged macroblock motion vector for the MB as a function of the generated merged motion vectors and of the determined flags; and encoding the determined motion vectors as a function of the generated merged motion vectors and the generated merged macroblock motion vector.