#1097 closed defect (invalid)

Mismatch spec/VTM in PDPC process (8.4.5.2.14)

Reported by: audrey.turquin Owned by:
Priority: minor Milestone:
Component: VTM Version:
Keywords: Cc: ksuehring, XiangLi, fbossen, jvet@…

Description

In VTM, in IntraPrediction.cpp, in function xPredIntraAng, there is the following code :

  if( intraPredAngle == 0 )  // pure vertical or pure horizontal                                                                                                                                                                             
  {                                                                                                                                                                                                                                          
    for( int y = 0; y < height; y++ )                                                                                                                                                                                                        
    {                                                                                                                                                                                                                                        
      for( int x = 0; x < width; x++ )                                                                                                                                                                                                       
      {                                                                                                                                                                                                                                      
        pDsty[x] = refMain[x + 1];                                                                                                                                                                                                           
      }                                                                                                                                                                                                                                      
                                                                                                                                                                                                                                             
      if (m_ipaParam.applyPDPC)                                                                                                                                                                                                              
      {                                                                                                                                                                                                                                      
        const int scale   = (floorLog2(width) + floorLog2(height) - 2) >> 2;                                                                                                                                                                 
        const Pel topLeft = refMain[0];                                                                                                                                                                                                      
        const Pel left    = refSide[1 + y];                                                                                                                                                                                                  
        for (int x = 0; x < std::min(3 << scale, width); x++)                                                                                                                                                                                
        {                                                                                                                                                                                                                                    
          const int wL  = 32 >> (2 * x >> scale);                                                                                                                                                                                            
          const Pel val = pDsty[x];                                                                                                                                                                                                          
          pDsty[x]      = ClipPel(val + ((wL * (left - topLeft) + 32) >> 6), clpRng);                                                                                                                                                        
        }                                                                                                                                                                                                                                    
      }                                                                                                                                                                                                                                      
                                                                                                                                                                                                                                             
      pDsty += dstStride;                                                                                                                                                                                                                    
    }                                                                                                                                                                                                                                        
  }

But in the loop

for (int x = 0; x < std::min(3 << scale, width); x++)

the condition "min(3 << scale, width)" is not present in the specification text (section 8.4.5.2.14, case where predModeIntra is equal to INTRA_ANGULAR18 or INTRA_ANGULAR50).
According to the specification, x should be between 0 and nTbW - 1.

Change history (1)

comment:1 Changed 16 months ago by audrey.turquin

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

Actually, this is related to software implementation only.
This is to avoid issue with the right shift to calculate wL.
There is no impact on the final pDsty[x] value, so there is no issue.

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