x4BlkIdx as the input and the output being assigned to x 0, yO The values of the prediction samples predL[ xO + X, yO + y ] with X, y = 0..3 are derived by pred[xO+x,yO+y]=pred4x4L[x,y = (8-40) The transform coefficient decoding process and picture construction process prior to deblocking filter process in clause 8.5 is invoked with predL and luma4x4BlkIdx as the input and the constructed samples for the current 4x4 luma block S'L as the output. 8.3.1.1 Derivation process for Intra4x4PredMode Inputs to this process are the index of the 4x4 luma block luma4x4BlkIdx and variable arrays Intra4x4PredMode (if available) and Intra8x8PredMode (if available) that are previously (in decoding order) derived for adjacent macroblocks. Output of this process is the variable Intra4x4PredMode[ ]. Table 8-2 specifies the values for Intra4x4PredMode[luma4x4BlkIdx ] and the associated names. Table 8-2 - Specification of Intra4x4PredModeluma4x4BlkIdx ] and associated names Intra4x4PredMode| luma4x4BlkIdx Name of Intra4x4PredMode| luma4x4BlkIdx Intra_4x4_Vertical (prediction mode) Intra_4x4_Horizontal (prediction mode) Intra_4x4_DC (prediction mode) Intra_4x4_Diagonal_Down_Left (prediction mode) Intra_4x4_Diagonal_Down_Right (prediction mode) Intra_4x4_Vertical_Right (prediction mode) Rec. ITU-T H.264 (01/2012) Intra_4x4_Horizontal_Down (prediction mode) Intra_4x4_Vertical_Left (prediction mode) Intra_4x4_Horizontal_Up (prediction mode) Intra4x4PredMode[ luma4x4BlkIdx ] labelled 0, 1, 3, 4, 5, 6, 7, and 8 represent directions of predictions as illustrated in Figure 8-1. H.264(09)_F8-1 Figure 8-1 - Intra_4x4 prediction mode directions (informative) Intra4x4PredMode[ luma4x4BlkIdx ] is derived as specified by the following ordered steps: The process specified in clause 6.4.11.4 is invoked with luma4x4BlkIdx given as input and the output is assigned to mbAddrA, luma4x4BlkIdxA, mbAddrB, and luma4x4BlkIdxB. The variable dcPredModePredictedFlag is derived as follows: If any of the following conditions are true, dcPredModePredictedFlag is 