id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
1011	Mismatch on top/left neighbouring luma samples padding in CCLM	wangyang.cs		"**There is a mismatch on top/left neighbouring luma samples padding in CCLM between the spec and software.**
**In JVET-Q2001-vE, luma sample (-2, -1) will be used in (373) but is not derived with padding for 4:2:0 and 4:2:2 color format. Similarly, luma sample (-1, -2) will be used in (376) and is not derived with padding for 4:2:0 color format. However, these two luma samples are padded using (-2, 0) and (0, -2) in VTM-8.0.**

pSelDsY[ idx ] = ( F3[ 1 ][ 0 ] * pY[ − SubWidthC ][ SubHeightC * y − 1 ] +
		F3[ 0 ][ 1 ] * pY[ −1 − SubWidthC ][ SubHeightC * y ] +
		F3[ 1 ][ 1 ] * pY[ −SubWidthC ][ SubHeightC * y ]  + 	                             (373)
		F3[ 2 ][ 1 ] * pY[ 1 − SubWidthC ][ SubHeightC * y ] +
		F3[ 1 ][ 2 ] * pY[ −SubWidthC ][ SubHeightC * y + 1 ] + 4 ) >> 3

pSelDsY[ idx ] = ( F3[ 1 ][ 0 ] * pY[ SubWidthC * x ][ − 1 − SubHeightC ] +
		F3[ 0 ][ 1 ] * pY[ SubWidthC * x − 1 ][ −SubHeightC ] +
		F3[ 1 ][ 1 ] * pY[ SubWidthC * x ][ −SubHeightC] +	                  (376)
		F3[ 2 ][ 1 ] * pY[ SubWidthC * x + 1 ][ −SubHeightC] +
		F3[ 1 ][ 2 ] * pY[ SubWidthC * x ][ 1 − SubHeightC ] + 4 ) >> 3


**Suggest changes in JVET-Q2001-vE as follows:**

8.4.5.2.13 Specification of INTRA_LT_CCLM, INTRA_L_CCLM and INTRA_T_CCLM intra prediction mode

The prediction samples predSamples[ x ][ y ] with x = 0..nTbW − 1, y = 0..nTbH − 1 are derived as follows:
  –	If both numSampL and numSampT are equal to 0, the following applies:
    predSamples[ x ][ y ] = 1  <<  ( BitDepth − 1 )		(359)
 *  –	Otherwise, the following ordered steps apply:
  1. The collocated luma samples pY[ x ][ y ] with x = 0..nTbW * SubWidthC − 1, y= 0..nTbH * SubHeightC − 1 are set equal to the reconstructed luma samples prior to the deblocking filter process at the locations ( xTbY + x, yTbY + y ).
  2. The neighbouring luma samples pY[ x ][ y ] are derived as follows:

     –	When numSampL is greater than 0, the neighbouring left luma samples pY[ x ][ y ] with x = −1..− 3, y = 0..SubHeightC * numSampL − 1, are set equal to the reconstructed luma samples prior to the deblocking filter process at the locations ( xTbY + x , yTbY +y ).

    –	When availT is equal to FALSE, the neighbouring top luma samples pY[ x ][ y ] with x = −[[ticket:1|1]][[span(style=color: #0000FF, SubWidthC)]]..SubWidthC * [[ticket:1|numSampT]][[span(style=color: #0000FF, nTbW)]] − 1, y = −1..−2, are set equal to the luma samples pY[ x ][ 0 ].

    [[ticket:1|–	When availL is equal to FALSE, the neighbouring left luma samples pY[ x ][ y ] with x = −1..−3, y = −1..SubHeightC * numSampL − 1, are set equal to the luma samples pY[ 0 ][ y ].]]

    –	When numSampT is greater than 0, the neighbouring top luma samples pY[ x ][ y ] with x = 0..SubWidthC * numSampT − 1, y = −1, −2, are set equal to the reconstructed luma samples prior to the deblocking filter process at the locations ( xTbY+ x, yTbY + y ).

    [[span(style=color: #0000FF,–	When availL is equal to FALSE, the neighbouring left luma samples pY[ x ][ y ] with x = −1..−3, y = −SubHeightC..SubHeightC * nTbH − 1, are set equal to the luma samples pY[ 0 ][ y ].)]]

    –	When availTL is equal to TRUE, the neighbouring top-left luma samples pY[ x ][ y ] with x = −1, y = −1, −2, are set equal to the reconstructed luma samples prior to the deblocking filter process at the locations ( xTbY+ x, yTbY + y )."	defect	closed	minor		spec	VVC D8 vB	fixed		ksuehring bbross XiangLi fbossen jvet@… jvet@…