id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
484	Text bug on reference index derivation for temporal merging candidate	huiyong	bbross	"In ""8.5.2.1.1 Derivation process for luma motion vectors for merge mode"", the reference index for temporal merging candidate is derived as follows:

{{{
If the following conditions are true, refIdxLX is set equal to refIdxLX[ xP − 1, yP + nPSH − 1 ].
    –	the prediction unit covering luma location ( xP − 1, yP + nPSH − 1 ) is available  
    –	the PartIdx is equal to 0
    –	PredMode is not MODE_INTRA
    –	(xP >> (log2_parallel_merge_level_minus2 + 2)) ! = 
((xP − 1) >> (log2_parallel_merge_level_minus2 + 2))	| |
(yP >> (log2_parallel_merge_level_minus2 + 2)) ! = 
((yP + nPSH − 1) >> (log2_parallel_merge_level_minus2 + 2)

Otherwise, refIdxLX is set equal to 0.
}}}

When the singleMCLFlag is equal to 1, however, this may leads to the second PU of a 8x8 CU use a different reference index than the first PU of the same CU, which is incorrect.

The suggested fix is to modify the second condition of the first ""If"" statement as:

{{{
    –	the PartIdx is equal to 0 or the singleMCLFlag is equal to 1 
}}}

Note that the HM6.1 software already operates as suggested. Thus we don’t need to modify the software. For more detail, please check the getInterMergeCandidates() function, which is called with uiPUIdx==0 whenever the singleMCLFlag condition is true."	defect	closed	minor	D7	Text	D6 (H1003) dI/dJ/dK	fixed		bbross wjhan jct-vc@…