rocess for motion vectors and reference frame indices in clause 8.4.1 for direct mode prediction. The following semantics are assigned to the macroblock prediction modes (for macroblocks that are not partitioned) and macroblock partition prediction modes (for macroblocks that are partitioned) specified by MbPartPredMode() in Table 7-14: Direct: no motion vector differences or reference indices are present for the macroblock (in case of B_Skip or B_Direct_16x16) in the bitstream. Direct is an Inter macroblock prediction mode (for macroblocks that are not partitioned) and an Inter macroblock partition prediction mode (for macroblocks that are partitioned, see Table 7-18). Pred L0: the semantics specified for Table 7-13 apply. Pred L1: specifies that the Inter prediction process is invoked using list 1 prediction. Pred L1 is an Inter macroblock prediction mode (for macroblocks that are not partitioned) and an Inter macroblock partition prediction mode (for macroblocks that are partitioned). BiPred: specifies that the Inter prediction process is invoked using list 0 and list 1 prediction. BiPred is an Inter macroblock prediction mode (for macroblocks that are not partitioned) and an Inter macroblock partition prediction mode (for macroblocks that are partitioned). When mb_type is equal to any of the values specified in Table 7-14, the macroblock is coded in an Inter macroblock prediction mode. pcm_alignment_zero_bit is a bit equal to 0. pcm_sample_luma[ is a sample value. The pcm_sample_luma[ i ] values represent luma sample values in the raster scan within the macroblock. The number of bits used to represent each of these samples is BitDepthy. pcm_sample_chroma[ is a sample value. The first MbWidthC * MbHeightC pcm_sample_chroma[ values represent Cb sample values in the raster scan within the macroblock and the remaining MbWidthC * MbHeightC pcm_sample_chroma[ values represent Cr sample values in the raster scan within the macroblock. The number of bits used to represent each of these samples is BitDepthc. coded_blo