ded as field macroblocks. G.3.33 macroblock address: When macroblock-adaptive frame/field decoding is not in use, a macroblock address is the index of a macroblock in a macroblock raster scan of the picture or layer picture starting with zero for the top-left macroblock in a picture or layer 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 or layer 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. G.3.34 macroblock location: The two-dimensional coordinates of a macroblock in a picture or layer picture denoted by (x,y For the top left macroblock of the picture or layer 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 1 when a macroblock is a bottom macroblock. G.3.35 macroblock pair: A pair of vertically contiguous macroblocks in a frame or layer frame that is coupled for use in macroblock-adaptive frame/field decoding. The division of a slice into macroblock pairs is a partitioning G.3.36 macroblock to slice group map: A means of mapping macroblocks of a picture or layer picture into slice groups. The macroblock to slice group map consists of a list of numbers, one for each coded macroblock, specifying the slice group to which each coded macroblock belongs. G.3.37 map unit to slice group map: A means of mapping slice group ma