he bitstream. For an MxN sub-macroblock partition in a sub-macroblock with sub_mb_type[ mbPartIdx ] being Bi i_MxN, two motion vector difference are present in the bitstream. Rec. ITU-T H.264 (01/2012) The following semantics are assigned to the sub-macroblock prediction modes (or macroblock partition prediction modes) specified by SubMbPredMode() in Table 7-18: Direct: see semantics for Table 7-14. Pred_L0: see semantics for Table 7-13. Pred L1 see semantics for Table 7-14. BiPred: see semantics for Table 7-14. ref_idx_10[ mbPartIdx ] has the same semantics as ref idx 10 in clause 7.4.5.1. ref_idx_l1] mbPartIdx ] has the same semantics as ref idx 11 in clause 7.4.5.1. mvd_10[ mbPartIdx Il subMbPartIdx II compldx ] has the same semantics as mvd 10 in clause 7.4.5.1, except that it is applied to the sub-macroblock partition index with subMbPartIdx. The indices mbPartIdx and subMbPartIdx specify to which macroblock partition and sub-macroblock partition mvd_10 is assigned. mvd_l1[ mbPartIdx II subMbPartIdx Il compIdx ] has the same semantics as mvd_11 in clause 7.4.5.1, except that it is applied to the sub-macroblock partition index with subMbPartIdx. The indices mbPartIdx and subMbPartIdx specify to which macroblock partition and sub-macroblock partition mvd 11 is assigned. 7.4.5.3 Residual data semantics The syntax structure residual_block(), which is used for parsing the transform coefficient levels, is assigned as follows: If entropy_coding_mode_flag is equal to 0, residual block is set equal to residual_block_cavlc, which is used for parsing the syntax elements for transform coefficient levels. Otherwise (entropy_coding_mode_flag is equal to 1), residual_block is set equal to residual_block_cabac, which is used for parsing the syntax elements for transform coefficient levels. The syntax structure residual_luma(i16x16DClevel, i16x16AClevel, level4x4, level8x8, startIdx, endIdx) is used with the first four variables in brackets being its output and being assigned as follows. Intra16x16DCLevel is set equal to i16