id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
438	JVET-O0650 - Chroma QP Signalling - handling of delta_qp_in_val_minus1 = 0	bheng		"For chroma QP signalling tables, it seems like the case of delta_qp_out_val = 0 is not handled well. 

My understanding is that the output QP table for such intervals should be flat and that the following QP step term should always be 0.

    ( delta_qp_out_val[ i ][j + 1] * m + sh ) / ( delta_qp_in_val_minus1[ i ][j + 1] + 1 )

However, with the rounding offset:

    sh = ( delta_qp_in_val_minus1[ i ][j + 1 ] + 2 ) >> 1

Even values of delta_qp_in_val result in a constant step of +1.  This can cause supposedly flat regions to grow linearly beyond the next qpOutVal pivot point, and can cause misalignment with pivot points and potentially out of range QP values.

I would suggest modifying the rounding offset to:

    sh = ( delta_qp_in_val_minus1[ i ][j + 1 ] + 1 ) >> 1



"	defect	closed	minor		spec	VVC D6 vE	fixed		ksuehring bbross XiangLi fbossen jvet@…