Patent ID: 11910011
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An image decoding method performed by a decoding apparatus, comprising:
deriving an intra prediction type for a current block as Multi Reference Line intra prediction (MRL), wherein the MRL is an intra prediction type based on an intra prediction reference line not adjacent to the current block;
constructing an intra prediction mode candidate list including a DC intra prediction mode based on intra prediction modes of neighboring blocks of the current block;
deriving an intra prediction mode of the current block based on the intra prediction mode candidate list; and
generating a prediction sample of the current block based on the intra prediction type and the intra prediction mode,
wherein based on the intra prediction mode of the current block being derived as the DC intra prediction mode, and a width of the current block being equal to a height of the current block, a DC value is derived based on an equation as follows:, deVal
  =
  
   
    (
    
     
      
       ∑
       
        
         x
         ′
        
        =
        0
       
       
        nTbW
        
         -
         1
        
       
      
      
       
        p
        [
        
         x
         ′
        
        ]
       
       [
       
        
         -
         1
        
        -
        refIdx
       
       ]
      
     
     +
     
      
       ∑
       
        
         y
         ′
        
        =
        0
       
       
        nTbH
        
         -
         1
        
       
      
      
       
        p
        [
        
         
          -
          1
         
         -
         refIdx
        
        ]
       
       [
       
        y
        ′
       
       ]
      
     
     +
     nTbW
    
    )
   
   ≫
   
    (
    
     
      Log
      ⁢
      2
      ⁢
      
       (
       nTbW
       )
      
     
     +
     1
    
    )
   
  
 

where dcVal represent the DC value and nTbW represent the width of the current block, and refIdx is a value of a reference line index for the intra prediction reference line, and the prediction sample is derived as the DC value.