e to the upper-left luma sample of a macroblock, a macroblock type mbType, when mbType is equal to P_8x8, P_8x8ref0, or B_8x8, a list of sub-macroblock types subMbType with 4 elements. Outputs of this process are: a macroblock partition index mbPartIdx, a sub-macroblock partition index subMbPartIdx. The variable svcDirectModeFlag is derived as follows: If currDQId is greater than 0 and any of the following conditions are true, svcDirectModeFlag is set equal to 1. mbType is equal to B_Skip or B_Direct_16x16 mbType is equal to B_8x8 and subMbType[ 2 * yP/8) + (xP/8) is equal to B_Direct_8x8 Otherwise, svcDirectModeFlag is set equal to 0. Depending on svcDirectModeFlag, the following applies: If svcDirectModeFlag is equal to 0, the derivation process for macroblock and sub-macroblock partition indices as specified in clause 6.4.13.4 is invoked with the luma location (xP, yP ), the macroblock type mbType, and, when mbType is equal to P_8x8, P_8x8ref0, or B_8x8, the list of sub-macroblock types subMbType as the inputs and the outputs are the macroblock partition index mbPartIdx and the sub-macroblock partition index subMbPartIdx. Otherwise, if mbType is equal to B_Skip or B_Direct_16x16, mbPartIdx is set equal to 0 and subMbPartIdx is set equal to 0. Otherwise (currDQId is greater than 0, mbType is equal to B_8x8, andsubMbType[2*(yP/8)+(xP/8) ] is equal to B_Direct_8x8), mbPartIdx is set equal to (2*(yP/8)+(xP/8))and subMbPartIdx is set equal to 0. Syntax and semantics This clause specifies syntax and semantics for coded video sequences that conform to one or more of the profiles specified in this annex. G.7.1 Method of specifying syntax in tabular form The specifications in clause 7.1 apply. Rec. ITU-T H.264 (01/2012) G.7.2 Specification of syntax functions, categories, and descriptors The specifications in clause 7.2 apply. G.7.3 Syntax in tabular form G.7.3.1 NAL unit syntax The syntax table is specified in clause 7.3.1. G.7.3.1.1 NAL unit header SVC extension syntax nal_unit_header_sve_extension() Descriptor idr_f