id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc 223,Mismatch between Spec and Software related to ISP,k-unno,,"There are mismatches between VTM-4.0 and VVC D4 on decision of intra interpolation filter for angular prediction in case of using ISP. As written in bellow, the specification written in VVC D4 seems be not correct. In VTM-4.0, if the width (or height which decided dependent on angle of prediction) of block is less than or equal to 8 pixels, DCTIF (reffered as Cubic in the software) will be applied. {{{ #if JVET_M0102_INTRA_SUBPARTITIONS const bool useCubicFilter = useISP ? ( width <= 8 ) : ( !useFilteredPredSamples || multiRefIdx > 0 ); #else }}} On the other hand, in VVC D4, if the width (or height which decided dependent on angle of prediction) of block is greater than 8 pixels, DCTIF (reffered as fC) will be applied. > – If one or more of the following conditions is true, filterFlag is set equal to 0. > • predModeIntra is equal to INTRA_ANGULAR2, INTRA_ANGULAR34 or INTRA_ANGULAR66 > • refIdx is not equal to 0 > • IntraSubPartitionsSplitType is not equal to ISP_NO_SPLIT and cIdx is equal to 0 and predModeIntra is greater than or equal to INTRA_ANGULAR34 and nW is greater than 8 > • IntraSubPartitionsSplitType is not equal to ISP_NO_SPLIT and cIdx is equal to 0 and predModeIntra is less than INTRA_ANGULAR34 and nH is greater than 8. According to previous specification (e.g. JEM), specification in the VTM-4.0 seems be correct. Additionally, nW and nH in VVC D4 means CU width and height in case of ISP applied, but width in VTM-4.0 means TU width or height.",defect,closed,minor,,spec,VVC D5 v5,fixed,,ksuehring bbross XiangLi fbossen jvet@…