Potential issue with reference sample filtering process in VVC D2 v4

[vdrugeon]

In the function IntraPrediction::useFilteredIntraRefSamples in VTM-2.0.1, when PDPC is enabled, there is the following condition to decide if the reference samples are filtered or not:
if (dirMode == PLANAR_IDX)

{

return tuArea.blocks[compID].width * tuArea.blocks[compID].height > 32 ? true : false;

}

I cannot find this condition within the current VVC draft when determining if the reference samples should be filtered or not. Is this missing?

Assuming that it is indeed missing, I think that the following text added to section 8.2.4.2.4 Reference sample filtering process when deriving the variable filterFlag should fix the problem:

• If predModeIntra is equal to INTRA_PLANAR, the following applies:
  • If nTbW * nTbH > 32, filterFlag is set equal to 1
  • Otherwise, filterFlag is set equal to 0

Could you please check the issue and the proposed fix?

[bbross]

Integrated the fix as follows:

• If one or more of the following conditions is true, filterFlag is set equal to 0:
  • predModeIntra is equal to INTRA_DC,
  • predModeIntra is equal to INTRA_PLANAR and nTbW * nTbH is less than or equal to 32,
  • cIdx is not equal to 0.
• Otherwise, if predModeIntra is equal to INTRA_PLANAR and nTbW * nTbH is greater than 32, filterFlag is set equal to 1.
• Otherwise, the following applies:
  • The variable minDistVerHor ...

[bbross]

Fixed in VVC D2 v6