Opened 4 years ago
Closed 4 years ago
#1187 closed defect (invalid)
[geo partitioning] 8.5.7.2 implementation : Diff VTM versus spec ?
Reported by: | fbarbier | Owned by: | |
---|---|---|---|
Priority: | minor | Milestone: | |
Component: | VTM | Version: | VTM-9.3 |
Keywords: | Cc: | ksuehring, XiangLi, fbossen, jvet@… |
Description
In 8.5.7.2, equation 1015 (spec JVET-S2001-vC)
offset1 = 1 << ( shift1 − 1 )
In VTM code (source/Lib/CommonLib/InterpolationFilter.cpp):
offsetWeighted = (1 << (shiftWeighted - 1)) + (IF_INTERNAL_OFFS << log2WeightBase);
That's seems to match something like :
offset1 = (1 << (shift1 - 1)) + (32 << 3);
Am i missing something ? Is is due to an offset on the pixels elsewhere?
Change history (3)
comment:1 Changed 4 years ago by fbossen
comment:2 Changed 4 years ago by fbarbier
ok ! thanks for the information !
comment:3 Changed 4 years ago by fbarbier
- Resolution set to invalid
- Status changed from new to closed
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Intermediate values in the MC process are offset by -IF_INTERNAL_OFFS such as to avoid overflows when using 16-bit signed values for storage. This offset has to be removed when computing the final prediction values.
BTW, IF_INTERNAL_OFFS should be 8192, not 32.