g process in clause 6.4.5 with luma8x8BlkIdx as the input and the output being assigned to xO, yO) ). The 25 neighbouring samples p[ X, y ] that are constructed luma samples prior to the deblocking filter process, with X = -1, y = -1..7 and X 0..15, y==1, are derived as specified by the following ordered steps: 1. The luma location (xN, yN ) is specified by xN=xO+x (8-74) yN=yO+y (8-75) 2. The derivation process for neighbouring locations in clause 6.4.12 is invoked for luma locations with ( NN, yN ) as input and mbAddrN and (xW, yW as output. 3. Each sample p[ X, y ] with X ==1, y=-1..7and X = 0..15, y = -1 is derived as follows: If any of the following conditions are true, the sample p[ X, y ] is marked as "not available for Intra 8x8 prediction": mbAddrN is not available, the macroblock mbAddrN is coded in an Inter macroblock prediction mode and constrained_intra_pred_flag is equal to 1. Otherwise, the sample p[ X, y ] is marked as "available for Intra_8x8 prediction" and the sample value pl X, y ] is derived as specified by the following ordered steps: The location of the upper-left luma sample of the macroblock mbAddrN is derived by invoking the inverse macroblock scanning process in clause 6.4.1 with mbAddrN as the input and the output is assigned to (xM, yM). b. Depending on the variable MbaffFrameFlag and the macroblock mbAddrN, the sample value p[x,y] is derived as follows: If MbaffFrameFlag is equal to 1 and the macroblock mbAddrN is a field macroblock, p[x,y]=cSL[xM+xW,yM+2*yW ] (8-76) Otherwise (MbaffFrameFlag is equal to 0 or the macroblock mbAddrN is a frame macroblock), p[x,y]=cSL[xM+xW,yM+yW] (8-77) When samples p[ X, -1], with X = 8..15, are marked as "not available for Intra 8x8 prediction," and the sample p[ 7,-1] is marked as "available for Intra_8x8 prediction," the sample value of p[7,-1] is substituted for sample values p| X, -1 ], with X = 8..15, and samples p[ X, ], with X = 8..15, are marked as "available for Intra_8x8 prediction". NOTE - Each block is assumed to be constructed into a pi