#1172 closed defect (fixed)

Text/SW mismatch in TMVP scaling with ILRPs (8.5.2.12)

Reported by: fbossen Owned by:
Priority: minor Milestone:
Component: spec Version: VVC D10 vA
Keywords: Cc: ksuehring, bbross, XiangLi, fbossen, jvet@…

Description

There is a condition such as:

– If RefPicList[ X ][ refIdxLX ] is an LTRP, or colPocDiff is equal to currPocDiff, mvLXCol is derived as follows:
mvLXCol = Clip3( −131072, 131071, mvCol ) (598)

As far as I can tell, to match the behaviour of the software, this should be

– If RefPicList[ X ][ refIdxLX ] is marked as "used for long-term reference", or colPocDiff is equal to currPocDiff, mvLXCol is derived as follows:
mvLXCol = Clip3( −131072, 131071, mvCol ) (598)

Change history (4)

comment:1 Changed 17 months ago by yk

Frank, is replacing "an LTRP" with "marked as "used for long-term reference"" the only change suggested herein? If that's the case, then they are equivalent, as LTRP is defined as a picture that is marked as "used for long-term reference".

comment:2 Changed 17 months ago by fbossen

Ye-Kui: yes, that is the only change. However my understanding is that LTRP and marked as "used for long-term reference" are two different things:
LTRP means LTRP
marked as "used for long-term reference" means LTRP or ILRP

For reference, definitions of LTRP and ILRP are as follows:
3.85 long-term reference picture (LTRP): A picture with nuh_layer_id equal to the nuh_layer_id of the current picture and marked as "used for long-term reference".
3.66 inter-layer reference picture (ILRP): A picture in the same AU with the current picture, with nuh_layer_id less than the nuh_layer_id of the current picture, and is marked as "used for long-term reference".

comment:3 Changed 17 months ago by yk

I see, Frank, you are right. Indeed, the intention (I think) was to cover both (usual) LTRPs and ILRPs, thus your suggested change is good.

Then what about the following condition that appeared twice in clause 8.5.2.7 (Derivation process for merge motion vector difference)?

– If RefPicList[ 0 ][ refIdxL0 ] is not an LTRP and RefPicList[ 1 ][ refIdxL1 ] is not an LTRP, the following applies:

I guess we should make the same change herein?

comment:4 Changed 17 months ago by jlchen

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

Ye-kui, the issue you mentioned was reported in #1171 by Frank.

Seems we agreed on the reported issue and the solution. Will be fixed in JVET-S2001-vC.

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