Opened 2 weeks ago

Last modified 7 days ago

#568 new defect

RPR - Sub-PU Grouping

Reported by: bheng Owned by:
Priority: minor Milestone:
Component: VTM Version: VTM-6.1
Keywords: Cc: ksuehring, XiangLi, fbossen, jvet@…

Description

In the function InterPrediction::xSubPuMC( ), the optimization used to group identical SBTMVP motion vector blocks together into larger blocks for interpolation cannot be used with RPR.

RPR generates different results when it is applied to a small (8x8) block versus a larger combined block. Therefore, the optimization mentioned above will change the results.

Either the optimization needs to be removed, or the following code needs a check for scaled reference pictures, so that the grouping is not applied in this case.

if (laterMi == curMi)
{

length += secStep;

}
else
{

break;

}

Note that the PU::isRefPicSameSize( ) function doesn’t seem to work for this purpose, since I believe pu.refIdx[0/1] are set based on the default SBTMVP vector. Even if this default vector doesn’t require scaling, one of the 8x8 sub-blocks might.

Change history (1)

comment:1 Changed 7 days ago by bheng

Potential fixes for this issue are available in the following merge request:

https://vcgit.hhi.fraunhofer.de/jvet/VVCSoftware_VTM/merge_requests/997

Note: See TracTickets for help on using tickets.