1. A method of decoding a video bit stream, wherein the bit stream comprises a representation of a sequence of image data structures, wherein each of the image data structures comprises a group of macroblock data structures, wherein each macroblock data structure comprises a group of block data structures, wherein the block data structures comprise luminance or chrominance data structures, the method comprising: decoding a block data structure before another block data structure is decoded, wherein the block data structure is at least a portion of a current macroblock data structure, and wherein the macroblock data structure is at least a portion of a current image data structure.