list as the input, the sequence of scaling list entries is mapped to the positions in the corresponding scaling matrix. For this mapping, the inverse zig-zag scan is used. Figure 8-9 illustrates the scans. H.264(09)_F8-9 Figure 8-9 - 8x8 block scans. (a) 8x8 zig-zag scan. (b) 8x8 field scan (informative) Table 8-14 provides the mapping from the index idx of the input list of 64 elements to indices i and j of the two-dimensional array C. Rec. ITU-T H.264 (01/2012) Table 8-14 - Specification of mapping of idx to Cij for 8x8 zig-zag and 8x8 field scan zig-zag field Table 8-14 (continued) - Specification of mapping of idx to cij for 8x8 zig-zag and 8x8 field scan zig-zag field Table 8-14 (continued) - Specification of mapping of idx to cij for 8x8 zig-zag and 8x8 field scan zig-zag field Table 8-14 (concluded) - Specification of mapping of idx to cij for 8x8 zig-zag and 8x8 field scan zig-zag field 8.5.8 Derivation process for chroma quantisation parameters Outputs of this process are: QPc: the chroma quantisation parameter for each chroma component Cb and Cr, QSc: the additional chroma quantisation parameter for each chroma component Cb and Cr required for decoding SP and SI slices (if applicable). NOTE 1 - QP quantisation parameter values QPy and QSy are always in the range of -QpBdOffsety to 51, inclusive. QP quantisation parameter values QPc and QSc are always in the range of -QpBdOffsetc to 39, inclusive. The value of QPc for a chroma component is determined from the current value of QPy and the value of chroma_qp_index_offset (for Cb) or second_chroma_qp_index_offset (for Cr). NOTE 2 - The scaling equations are specified such that the equivalent transform coefficient level scaling factor doubles for every increment of 6 in QPy. Thus, there is an increase in the factor used for scaling of approximately 12 % for each increase of 1 in the value of QPy. The value of QPc for each chroma component is determined as specified in Table 8-15 based on the index denoted as The variable qPOffset for each chroma component is