coding is not in use, a macroblock address is the index of a macroblock in a macroblock raster scan of the picture starting with zero for the top-left macroblock in a picture. When macroblock-adaptive frame/field decoding is in use, the macroblock address of the top macroblock of a macroblock pair is two times the index of the macroblock pair in a macroblock pair raster scan of the picture, and the macroblock address of the bottom macroblock of a macroblock pair is the macroblock address of the corresponding top macroblock plus 1. The macroblock address of the top macroblock of each macroblock pair is an even number and the macroblock address of the bottom macroblock of each macroblock pair is an odd number. macroblock location: The two-dimensional coordinates of a macroblock in a picture denoted by (x,y). For the top left macroblock of the picture (x,y) is equal to (0,0). X is incremented by 1 for each macroblock column from left to right. When macroblock-adaptive frame/field decoding is not in use, y is incremented by 1 for each macroblock row from top to bottom. When macroblock-adaptive frame/field decoding is in use, y is incremented by 2 for each macroblock pair row from top to bottom, and is incremented by an additional when a macroblock is a bottom macroblock. macroblock pair: A pair of vertically contiguous macroblocks in a frame that is coupled for use in macroblock-adaptive frame/field decoding. The division of a slice into macroblock pairs is a partitioning. macroblock partition: A block of luma samples and two corresponding blocks of chroma samples resulting from a partitioning of a macroblock for inter prediction for a picture that has three sample arrays or a block of luma samples resulting from a partitioning of a macroblock for inter prediction for a monochrome picture or a picture that is coded using three separate colour planes. macroblock to slice group map: A means of mapping macroblocks of a picture into slice groups. The macroblock to slice group map consists of a list of numbers, one for ea