ups of the picture or, in the case of a picture that is coded using three separate colour planes, with the slices of one or more other slice groups within the same colour plane. auxiliary coded picture: A picture that supplements the primary coded picture that may be used in combination with other data not specified by this Recommendation | International Standard in the display process. An auxiliary coded picture has the same syntactic and semantic restrictions as a monochrome redundant coded picture. An auxiliary coded picture must contain the same number of macroblocks as the primary coded picture. Auxiliary coded pictures have no normative effect on the decoding process. See also primary coded picture and redundant coded picture. B slice: A slice that may be decoded using intra prediction or inter prediction using at most two motion vectors and reference indices to predict the sample values of each block. bin: One bit of a bin string. binarization: A set of bin strings for all possible values of a syntax element. binarization process: A unique mapping process of all possible values of a syntax element onto a set of bin strings. bin string: A string of bins. A bin string is an intermediate binary representation of values of syntax elements from the binarization of the syntax element. bi-predictive slice: See B slice. bitstream: A sequence of bits that forms the representation of coded pictures and associated data forming one or more coded video sequences. Bitstream is a collective term used to refer either to a NAL unit stream or a byte stream. block: An MxN (M-column by N-row) array of samples, or an MxN array of transform coefficients. bottom field: One of two fields that comprise a frame. Each row of a bottom field is spatially located immediately below a corresponding row of a top field. bottom macroblock (of a macroblock pair): The macroblock within a macroblock pair that contains the samples in the bottom row of samples for the macroblock pair. For a field macroblock pair, the bottom macroblock represents