(xD, yD ) for the input and the replacement for N in mbAddrN, mbPartIdxN, subMbPartIdxN, luma8x8BlkIdxN, cb8x8BlkIdxN, cr8x8BlkIdxN, luma4x4BlkIdxN, cb4x4BlkIdxN, cr4x4BlkIdxN, and chroma4x4BlkIdxN for the output. These input and output assignments are used in clauses 6.4.11.1 to 6.4.11.7. The variable predPartWidth is specified when Table 6-2 is referred to. Table 6-2 - Specification of input and output assignments for clauses 6.4.11.1 to 6.4.11.7 predPartWidth Figure 6-14 illustrates the relative location of the neighbouring macroblocks, blocks, or partitions A, B, C, and D to the current macroblock, partition, or block, when the current macroblock, partition, or block is in frame coding mode. Rec. ITU-T H.264 (01/2012) Current Macroblock or Partition or Block Figure 6-14 - Determination of the neighbouring macroblock, blocks, and partitions (informative) 6.4.11.1 Derivation process for neighbouring macroblocks Outputs of this process are: mbAddrA: the address of the macroblock to the left of the current macroblock and its availability status, mbAddrB: the address of the macroblock above the current macroblock and its availability status. mbAddrN (with N being A or B) is derived as specified by the following ordered steps: 1. The difference of luma location (xD, yD ) is set according to Table 6-2. The derivation process for neighbouring locations as specified in clause 6.4.12 is invoked for luma locations with xN, yN ) equal to (xD, yD) and the output is assigned to mbAddrN. 6.4.11.2 Derivation process for neighbouring 8x8 luma block Input to this process is an 8x8 luma block index luma8x8BlkIdx. The luma8x8BlkIdx specifies the 8x8 luma blocks of a macroblock in a raster scan. 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, luma8x8BlkIdxA: the index of the 8x8 luma block to the left of the 8x8 block with index luma8x8BlkIdx and its availability status, mbAddrB: either equal to CurrMbAddr or the a