Opened 4 years ago

Closed 4 years ago

#679 closed defect (fixed)

Mismatch between SW and spec on CG size for TS Chroma

Reported by: wzeng Owned by:
Priority: minor Milestone:
Component: spec Version: VVC D7 vB
Keywords: Cc: ksuehring, bbross, XiangLi, fbossen, jvet@…

Description

In VVC D7 vB, coding group size for chroma residual_ts_coding is set to 2x2 in case of Nx2 chroma block as indicated below:

log2SbSize = ( Min( log2TbWidth, log2TbHeight ) < 2 ? 1 : 2)

But in VTM7.0rc1, coding group size in such case is set to 8x2, aligned with regular residual coding case.

So it's suggested to align the spec text with VTM.

Change history (1)

comment:1 Changed 4 years ago by bbross

  • Resolution set to fixed
  • Status changed from new to closed

Thanks for reporting! I will it it in JVET-P2001-vC by introducing log2SbW and logSbH as for the regular coding case as follows:

log2SbW = ( Min( log2TbWidth, log2TbHeight ) < 2 ? 1 : 2 )
log2SbH = log2SbW
if( log2TbWidth + log2TbHeight > 3 ) {

if( log2TbWidth < 2 ) {

log2SbW = log2TbWidth
log2SbH = 4 − log2SbW

} else if( log2TbHeight < 2 ) {

log2SbH = log2TbHeight
log2SbW = 4 − log2SbH

}

}
numSbCoeff = 1 << ( log2SbW + log2SbH )
lastSubBlock = ( 1 << ( log2TbWidth + log2TbHeight − ( log2SbW + log2SbH ) ) ) − 1

and all occurrences of

xS = DiagScanOrder[ log2TbWidth − log2SbW ][ log2TbHeight − log2SbH ][ i ][ 0 ]
yS = DiagScanOrder[ log2TbWidth − log2SbW ][ log2TbHeight − log2SbH ][ i ][ 1 ]

and

xC = ( xS << log2SbW ) + DiagScanOrder[ log2SbW ][ log2SbH ][ n ][ 0 ]
yC = ( yS << log2SbH ) + DiagScanOrder[ log2SbW ][ log2SbH ][ n ][ 1 ]

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