id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
627	Inferring split_transform_flag: mismatch between HM 7.1 and D9 (I1003) d9 Draft Text	hreddy	bbross	"Hi,

  HM 7.1 decoder seems to use log2MinTUSizeInCU (derived from UInt TComDataCU::getQuadtreeTULog2MinSizeInCU) to decide whether split_transform_flag needs to be inferred or parsed from the bitstream, but in I1003-d9 Draft Log2MinTrafoSize (SPS level parameter) is used directly to decide whether split_transform_flag is inferred or parsed from the bitstream as follows:

	if( log2TrafoSize <= Log2MaxTrafoSize  && 
	    log2TrafoSize > Log2MinTrafoSize  &&
	    trafoDepth < MaxTrafoDepth  &&  !(IntraSplitFlag  &&  trafoDepth  = =  0) )
		split_transform_flag[ x0L ][ y0L ][ trafoDepth ]

For example, if LCU=32x32, log2cbsize=5, log2trafosize=5, Log2MaxTrafoSize=5, Log2MinTrafoSize=4, MaxtrafoDepth=1, part_mode=2Nx2N, pred_mode_flag=Intra, trafoDepth=0

    HM 7.1 decoder computes log2MinTUSizeInCU as 5 and infers the
    split_transform_flag as 0 (with out parsing the
    split_transform_flag from the bit stream).

    However based on the I1003-d9 Draft text, split_transform_flag 
    is parsed from the bit stream in this case.

Can you please clarify whether the Draft text needs to be fixed?

Thanks,
-Hari





"	defect	closed	minor	D8	Text	D7 (I1003) d9	fixed	split_transform_flag	bbross wjhan jct-vc@…