【正文】 CU size. Default is 64. MaxPartitionDepth Defines the depth of the CU tree. Default is 4. Shorthand form is –h. Page: 4 Date Saved: 20210124 QuadtreeTULog2MaxSize Maximum TU size in logarithm base 2. Default is 6 (64). QuadtreeTULog2MinSize Minimum TU size in logarithm base 2. Default is 2 (4). QuadtreeTUMaxDepthIntra Defines depth of TU tree for intra CUs. Default is 1. QuadtreeTUMaxDepthInter Defines depth of TU tree for inter CUs. Default is 2. Coding structure parameters IntraPeriod Defines intra frame period. Default is 1 (first frame only). Shorthand form is –ip. DecodingRefreshType Defines the type of decoding refresh to apply for the picture at the intra frame period. A value of 0 applies an I picture (not a clean random access point). A value of 1 applies a nonIDR clean random access point (opened GOP). A value of 2 applies an IDR random access point (closed GOP). Default is 0. Shorthand form is –dr. GOPSize Defines size of picture hierarchy. Default is 1. Shorthand form is –g. RateGOPSize Defines size of picture hierarchy for QP assignment. Default is the value of GOPSize. Shorthand form is –rg. NumOfReference Defines number of reference frames used for prediction in P pictures. Default is 1. Shorthand form is –r. NumOfReferenceB_L0 Defines number of reference frames used for prediction in B pictures (list 0). Default is 1. Shorthand form is –rb0. NumOfReferenceB_L1 Defines number of reference frames used for prediction in B pictures (list 1). Default is 1. Shorthand form is –rb1. ListCombination Defines use of bined reference list for uniprediction in Bslices. A value of 1 indicates that the bined reference list is derived from reference list 0 and reference list 1. A value of 0 indicates that Page: 5 Date Saved: 20210124 reference list 0 and reference list 1 are identical and reference list 0 is used as the bined reference list. LComb can only be 0 if and only if LowDelayCoding and GPB are both 1. Default is 1 (tr ue). Shorthand form is –lc. LCModification Defines the derivation of the bined reference list. A value of 0 indicates that the bined reference list is implicitly derived from reference list 0 and reference list 1. A value of 1 indicates that the derivation of the bined reference list from reference list 0 and reference list 1 is explicitly signaled in the syntax. Default is 0 (false). HierarchicalCoding Defines use of hierarchical coding structure. Default is 1 (true). LowDelayCoding Defines use of lowdelay coding structure, which disables all backward inter prediction modes. Default is 0 (false). Table 1 Combination of parameters and their resultant coding structures. LowDelayCoding GPB GOPSize Resultant coding structure 0 0 / 1 1 Hierarchical B (HE default) 1 0 1 Hierarchical P 1 1 1 Hierarchical B, no backward prediction 0 / 1 0 1 IPPP 0 / 1 1 1 IBBB (LC default) Default hierarchicalQP assignments vary according to this parameter. They can be overridden by the parameter BQP. Table 2 Example hierarchical QP assignments according to LowDelayCoding and BQP. Temporal Level LowDelayCoding=0 LowDelayCoding=1 and BQP=0 0 (first frame) QP QP 0 (key frame except the first frame) QP+1 QP+1 1 QP+2 QP+4 2 QP+3 QP+5 3 QP+4 QP+6 GPB Defines use of B pictures for all nonintra pictures. If list 1 reference list is empty when this option is specified, all entries of list 0 reference list are copied into the list 1 reference list. Default is 0 (false). Page: 6 Date Saved: 20210124 NRF Defines marking of pictures in lowest temporal layer as not used for reference. Default is 1 (true). BQP Defines use of hierarchical QP assignment assuming no delay restriction even in lowdelay mode. (See Table 2) Default is 0 (false). TLayeringBasedOnCodingStruct Defines use of temporal layer ID assignment based on the hierarchical coding structure. If this is defined, picture