1. An apparatus comprising a video bitstream stored on non-transitory machine-readable media, the bitstream characterized by: picture frames comprising picture regions in a compressed format, wherein the compressed format for at least one picture region within a picture frame comprises: a signal indicating the size of a picture region of the at least one picture region comprises 16×16 pixels; one or more signals indicating the picture region being subdivided into at least three sub-regions, wherein each of the at least three sub-regions is adjacent to at least one of the other sub-regions, and wherein the at least three sub-regions comprise a 4×8 pixel sub-region and a 8×8 pixel sub-region; at least one motion vector for each of the at least three sub-regions; and one or more signals indicating pixel interpolation modes for the at least three sub-regions, wherein a first interpolation mode is used for determining pixel values for a first sub-region of the at least three sub-regions, wherein a second interpolation mode is used for determining pixel values for a second sub-region of the at least three sub-regions, and wherein the first interpolation method is different from the second interpolation method.