Opened 6 years ago
Closed 6 years ago
#175 closed defect (fixed)
Incorrect derivation of CCLM parameter b
| Reported by: | yyasugi | Owned by: | |
|---|---|---|---|
| Priority: | major | Milestone: | VVC D4 v2 |
| Component: | spec | Version: | VVC D4 v3 |
| Keywords: | CCLM | Cc: | ksuehring, bbross, XiangLi, fbossen, jvet@… |
Description
In 8.3.4.2.8 (Specification of INTRA_LT_CCLM, INTRA_L_CCLM and INTRA_T_CCLM intra prediction mode), the equation 8-219 is incorrect.
b = ( ( 3 + x − y ) < 1 ) ? Sign( a ) * 15 : a (8-219)
It should be a calculation of intercept:
b = ( ( 3 + x − y ) < 1 ) ? minC - ( a * minY ) : minC - ( ( a * minY ) >> k ) (8-219)
Change history (4)
comment:1 Changed 6 years ago by bbross
- Version changed from VVC D4 v1 to VVC D4 v2
comment:2 Changed 6 years ago by bbross
- Version changed from VVC D4 v2 to VVC D4 v3
comment:3 Changed 6 years ago by Tomohiro Ikai
comment:4 Changed 6 years ago by bbross
- Resolution set to fixed
- Status changed from new to closed
Fixed in v4 of VVC D4
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The reported fix seems not correct. Could you use the following fix?
b = minC − ( ( a * minY ) >> k ) (8 219)
# This text is the same as proposed in JVET-M0064-v1 and matchs with VTM-4.0 software.
# I talked with the reporter and he confirmed the above fix.