 process is a (PicWidthInSamplesL)x(PicHeightInSamples) array cSL containing constructed luma samples prior to the deblocking filter process of neighbouring macroblocks. Outputs of this process are Intra prediction luma samples for the current macroblock predL_ X, y ]. The 33 neighbouring samples p[x,y ] that are constructed luma samples prior to the deblocking filter process, with x=-1,y=-1..15 andwith x=0..15,y=-1, = - are derived as specified by the following ordered steps: 1. The derivation process for neighbouring locations in clause 6.4.12 is invoked for luma locations with (x,y) assigned to (xN, yN ) as input and mbAddrN and xx, yW) as output. Each sample pl X, y ] with x=-1,y=-1..15 = and with X = 0..15, y=1 is derived as follows: Rec. ITU-T H.264 (01/2012) If any of the following conditions are true, the sample p[x,y ] is marked as "not available for Intra 16x16 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, the macroblock mbAddrN has mb_type equal to SI and constrained_intra_pred_flag is equal to 1. Otherwise, the sample p[ x, y ] is marked as "available for Intra 16x16 prediction" and the value of the sample p[ 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 (xx, yM). 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, x,y]=cSL[xM+xW,yM+2*yW] (8-114) Otherwise (MbaffFrameFlag is equal to 0 or the macroblock mbAddrN is a frame macroblock), [x,y]=cSL[xM+xW,yM+ yW] (8-115) Let predL_ X, y ] with X, y = 0..15 denote the prediction samples for the 16x16 luma block samples. Intra_16x16 prediction modes are specified in Table 8-4. Table 8-4 - 