Opened 9 years ago

Closed 9 years ago

#828 closed defect (invalid)

collocated_from_l0_flag is not used properly in temporal MV process

Reported by: pieterkapsenberg Owned by:
Priority: minor Milestone: HM-9.1
Component: HM Version: HM-9.0
Keywords: Cc: fbossen, ksuehring, davidf, jct-vc@…

Description

In TComDataCU.cpp, line 3542, the following correction should be made:

eColRefPicList = getSlice()->getCheckLDC() ? eRefPicList : RefPicList(getSlice()->getColFromL0Flag());

should be changed to:

eColRefPicList = getSlice()->getCheckLDC() ? eRefPicList : RefPicList(1-(getSlice()->getColFromL0Flag()));

Change History (4)

comment:1 Changed 9 years ago by DefaultCC Plugin

  • Cc fbossen ksuehring davidf jct-vc@… added

comment:2 Changed 9 years ago by bheng

I believe the existing code is correct as is. The current HM behavior is consistent with this section of text:

  • If PicOrderCnt( pic ) of every picture pic in every reference picture list of the current slice is less than or equal to PicOrderCntVal, mvCol, refIdxCol, and listCol are set equal to MvLX[ xPCol ][ yPCol ], RefIdxLX[ xPCol ][ yPCol ] and LX, respectively with X being the value of X this process is invoked for.
  • Otherwise, mvCol, refIdxCol and listCol are set equal to MvLN[ xPCol ][ yPCol ], RefIdxLN[ xPCol ][ yPCol ] and LN, respectively with N being the value of collocated_from_l0_flag.

The function getCheckLDC() returns TRUE for the "All POC less than current POC" case.

The "Otherwise" case is the normal situation where the motion vectors are intentionally selected from the opposite list. For example, if the collocated picture is from L1 then the L0 motion vectors are used. So, RefPicList(getSlice()->getColFromL0Flag()) would be correct.

comment:3 Changed 9 years ago by pieterkapsenberg

Ok, I agree that it matches the text, although it does seem counter-intuitive to selected the opposite list (but not harmful).

comment:4 Changed 9 years ago by fbossen

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