H.264句法和语法总结（十二）子宏块预测句法

sub_mb_pred( mb_type ) {

for( mbPartIdx = 0; mbPartIdx < 4; mbPartIdx++ )

// sub_mb_type[ mbPartIdx ] 指明子宏块的预测类型，在不同的宏块类型中这个句法元素的语义不一样。

sub_mb_type[
mbPartIdx ] //表示子宏块的类型

for( mbPartIdx = 0; mbPartIdx < 4; mbPartIdx++ )

if( ( num_ref_idx_l0_active_minus1 > 0 | |

mb_field_decoding_flag ) &&

mb_type != P_8x8ref0 &&

sub_mb_type[ mbPartIdx ] != B_Direct_8x8 &&

SubMbPredMode( sub_mb_type[ mbPartIdx ] ) != Pred_L1 )

ref_idx_l0[
mbPartIdx ] //与宏块预测语法中含义相同

for( mbPartIdx = 0; mbPartIdx < 4; mbPartIdx++ )

if( (num_ref_idx_l1_active_minus1 > 0 | | mb_field_decoding_flag )

&&

sub_mb_type[ mbPartIdx ] != B_Direct_8x8 &&

SubMbPredMode( sub_mb_type[ mbPartIdx ] ) != Pred_L0 )

ref_idx_l1[
mbPartIdx ] //与宏块预测语法中含义相同

for( mbPartIdx = 0; mbPartIdx < 4; mbPartIdx++ )

if( sub_mb_type[ mbPartIdx ] != B_Direct_8x8 &&

SubMbPredMode( sub_mb_type[ mbPartIdx ] ) != Pred_L1 )

for( subMbPartIdx = 0;

subMbPartIdx < NumSubMbPart( sub_mb_type[ mbPartIdx ] );

subMbPartIdx++)

for( compIdx = 0; compIdx < 2; compIdx++ )

mvd_l0[
mbPartIdx ][ subMbPartIdx ][ compIdx ] //mvd_l0与宏块预测语法中含义相同

for( mbPartIdx = 0; mbPartIdx < 4; mbPartIdx++ )

if( sub_mb_type[ mbPartIdx ] != B_Direct_8x8 &&

SubMbPredMode( sub_mb_type[ mbPartIdx ] ) != Pred_L0 )

for( subMbPartIdx = 0;

subMbPartIdx < NumSubMbPart( sub_mb_type[ mbPartIdx ] );

subMbPartIdx++)

for( compIdx = 0; compIdx < 2; compIdx++ )

mvd_l1[
mbPartIdx ][ subMbPartIdx ][ compIdx ] //mvd_l1与宏块预测语法中含义相同

}