al to 4:0:0 and separate_colour_plane_ is equal to 0, two corresponding chroma sample arrays. When separate_colour_plane_flag is equal to 1, each macroblock is comprised of one 16x16 luma or chroma sample array. When macroblock-adaptive frame/field decoding is not in use, each macroblock represents a spatial rectangular region of the picture. For example, a picture may be divided into two slices as shown in Figure 6-7. When a picture is coded using three separate colour planes (separate_colour_plane_flag is equal to 1), a slice contains only macroblocks of one colour component being identified by the corresponding value of colour_plane_id, and each colour component array of a picture consists of slices having the same colour plane_i value. Coded slices with different values of colour_plane_id within an access unit can be interleaved with each other under the constraint that for each value of colour plane_ic the coded slice NAL units with that value colour_plane_id shall be in the order of increasing macroblock address for the first macroblock of each coded slice NAL unit. NOTE - When separate_colour_plane_flag is equal to 0, each macroblock of a picture is contained in exactly one slice. When separate_colour_plane_flag is equal to 1, each macroblock of a colour component is contained in exactly one slice (i.e., information for each macroblock of a picture is present in exactly three slices and these three slices have different values of colour_plane_id). Rec. ITU-T H.264 (01/2012) H.264(09)_F6-7 Figure 6-7 - A picture with 11 by 9 macroblocks that is partitioned into two slices When macroblock-adaptive frame/field decoding is in use, the picture is partitioned into slices containing an integer number of macroblock pairs as shown in Figure 6-8. Each macroblock pair consists of two macroblocks. A macroblock pair H.264(09)_F6-8 Figure 6-8 - Partitioning of the decoded frame into macroblock pairs Inverse scanning processes and derivation processes for neighbours This clause specifies inverse scanning processes; i.e.,