Opened 3 years ago

Last modified 3 years ago

#115 new text missing

Rounding offsets for illumination compensation are missing in HEVCv3 spec.

Reported by: parkmw Owned by: tech
Priority: major Component: 3D-HEVC text
Version: 3D-HEVC Draft Text 7 Keywords:
Cc: tech, jct-3v@…

Description

Rounding offsets for illumination compensation are missing in HEVCv3 spec.

There is a mismatch between HEVCv3 spec. and HTM16.2 software.
In HEVCv3 text, the rounding offsets, which are used to find the nearest integer pixel position, are missing in "I.8.5.3.3.2.1 Derivation process for illumination compensation mode availability and parameters". However, the HTM software has the rounding offsets.
During 3D-HEVC standardization, JCT-3V decided to use the rounding offsets.

Therefore, equations I-208 and I-209 in the HEVCv3 spec.

xRefBlkLX = xC + ( mvLX[ 0 ]  >>  ( 2 + ( cIdx ? 1 : 0 ) ) ) (I−208)
yRefBlkLX = yC + ( mvLX[ 1 ]  >>  ( 2 + ( cIdx ? 1 : 0 ) ) ) (I−209)

should be replaced by

xRefBlkLX = xC + ( ( mvLX[ 0 ] + ( cIdx ? 4 : 2 ) )  >>  ( 2 + ( cIdx ? 1 : 0 ) ) ) (I−208)
yRefBlkLX = yC + ( ( mvLX[ 1 ] + ( cIdx ? 4 : 2 ) )  >>  ( 2 + ( cIdx ? 1 : 0 ) ) ) (I−209)

Change history (1)

comment:1 Changed 3 years ago by yk

Thanks for the bug report. The issue has been taken care of, and the suggested fix has been confirmed and integrated into a version of the HEVC spec that has been submitted for ITU-T consent. The editors will also try to find a way to have it integrated into a future version of the ISO/IEC text.

BR, YK

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