1. A computer-implemented method for video imaging comprising: determining a first motion vector to a single reference frame for a first plurality of 4×4 regions corresponding to a first motion vector region of a macroblock; determining a second motion vector to the single reference frame for a second plurality of 4×4 regions corresponding to a second motion vector region of the macroblock, wherein the second motion vector is determined using a motion vector delta; and performing motion compensation based on the first motion vector and the second motion vector to determine pixel luminance values for the macroblock including at least the first and second motion vector regions, the first and second motion vector regions each being signaled in a received bitstream, wherein boundaries of the first and second motion vector regions correspond to one or more boundaries of the corresponding plurality of 4×4 regions.