produces identical results to the decoding process described herein conforms to the decoding process requirements of this Recommendation International Standard. 3.137 should: A term used to refer to behaviour of an implementation that is encouraged to be followed under anticipated ordinary circumstances, but is not a mandatory requirement for conformance to this Recommendation International Standard. 3.138 SI slice: A slice that is coded using intra prediction only and using quantisation of the prediction samples. An SI slice can be coded such that its decoded samples can be constructed identically to an SP slice. 3.139 skipped macroblock: A macroblock for which no data is coded other than an indication that the macroblock is to be decoded as "skipped". This indication may be common to several macroblocks. 3.140 slice: An integer number of macroblocks or macroblock pairs ordered consecutively in the raster scan within a particular slice group. For the primary coded picture, the division of each slice group into slices is a partitioning. Although a slice contains macroblocks or macroblock pairs that are consecutive in the raster scan within a slice group, these macroblocks or macroblock pairs are not necessarily consecutive in the raster scan within the picture. The macroblock addresses are derived from the first macroblock address in a slice (as represented in the slice header) and the macroblock to slice group map, and, when a picture is coded using three separate colour planes, a colour plane identifier. 3.141 slice data partition: A non-empty subset of the syntax elements of the slice data syntax structure for a slice. The syntax elements of a slice data partition are associated with the same category. 3.142 slice data partitioning: A method of partitioning selected syntax elements into syntax structures based on a category associated with each syntax element. 3.143 slice group: A subset of the macroblocks or macroblock pairs of a picture. The division of the picture into slice groups is a partitioning of the 