ddress of the macroblock above the current macroblock and its availability status, luma8x8BlkIdxB: the index of the 8x8 luma block above the 8x8 block with index luma8x8BlkIdx and its availability status. mbAddrN and luma8x8BlkIdxN (with N being A or B) are derived as specified by the following ordered steps: The difference of luma location ( xD, yD ) is set according to Table 6-2. 2. The luma location ( NN, yN ) is specified by xN = luma8x8BlkIdx%2)*8+xD (6-23) yN = (luma8x8BlkIdx/2)*8+yD (6-24) The derivation process for neighbouring locations as specified in clause 6.4.12 is invoked for luma locations with xN, yN) as the input and the output is assigned to mbAddrN and ( xW, yW) The variable luma8x8BlkIdxN is derived as follows: If mbAddrN is not available, luma8x8BlkIdxN is marked as not available. Otherwise (mbAddrN is available), the derivation process for 8x8 luma block indices as specified in clause 6.4.13.3 is invoked with the luma location ( xW, yW) as the input and the output is assigned to luma8x8BlkIdxN. Rec. ITU-T H.264 (01/2012) 6.4.11.3 Derivation process for neighbouring 8x8 chroma blocks for ChromaArrayType equal to 3 This process is only invoked when ChromaArrayType is equal to 3. The derivation process for neighbouring 8x8 chroma block is identical to the derivation process for neighbouring 8x8 luma block as specified in clause 6.4.11.2 when substituting the term "luma" with the term "Cb" or the term "Cr", and substituting the term "luma8x8BlkIdx" with the term "cb8x8BlkIdx" or the term "cr8x8BlkIdx" in all places in clause 6.4.11.2. 6.4.11.4 Derivation process for neighbouring 4x4 luma blocks Input to this process is a 4x4 luma block index luma4x4BlkIdx. Outputs of this process are: mbAddrA: either equal to CurrMbAddr or the address of the macroblock to the left of the current macroblock and its availability status, luma4x4BlkIdxA: the index of the 4x4 luma block to the left of the 4x4 block with index luma4x4BlkIdx and its availability status, mbAddrB: either equal to CurrMbAddr or the addres