Intraprediction encoding/decoding method and apparatus

Abstract

An intraprediction encoding/decoding method and apparatus are provided. The intraprediction encoding method includes forming a flipped reference block by flipping pixels of a reference block used for intraprediction symmetrically with respect to a straight line of a predetermined direction passing through the center of the reference block, and performing intraprediction using the flipped reference block.

1 . An intraprediction encoding method comprising:
 forming a flipped reference block by flipping pixels of a reference block used for intraprediction symmetrically with respect to a straight line of a predetermined direction passing through the reference block; and   performing intraprediction using the flipped reference block.   
     
     
         2 . The intraprediction encoding method of  claim 1 , wherein the predetermined direction of the straight line is one of a vertical direction and a horizontal direction. 
     
     
         3 . The intraprediction encoding method of  claim 1 , wherein the reference block is a block(s) at least one of adjacent above and adjacent on the left side of the current block. 
     
     
         4 . The intraprediction encoding method of  claim 1 , further comprising adding intraprediction mode information, including information on whether the flipped reference block is used and the predetermined direction of the straight line, to a header of a bitstream of an encoded video, if intraprediction is performed using the flipped reference block. 
     
     
         5 . An intraprediction encoding method comprising:
 forming a flipped current block by flipping pixels of a current block to be intrapredicted symmetrically with respect to a straight line of a predetermined direction passing through the current block; and   performing intraprediction on the flipped current block using pixels of a reference block adjacent to the flipped current block.   
     
     
         6 . The intraprediction encoding method of  claim 5 , wherein the predetermined direction of the straight line is one of a vertical direction and a horizontal direction. 
     
     
         7 . The intraprediction encoding method of  claim 5 , further comprising adding intraprediction mode information, including information on whether the flipped current block is used and the predetermined direction of the straight line, to a header of a bitstream of an encoded video, if intraprediction is performed after flipping the current block. 
     
     
         8 . An intraprediction encoding apparatus comprising:
 a flipping unit which forms a flipped reference block by flipping pixels of a reference block used for intraprediction symmetrically with respect to a straight line of a predetermined direction passing through the reference block; and   an intraprediction performing unit which performs intraprediction using the flipped reference block.   
     
     
         9 . The intraprediction encoding apparatus of  claim 8 , wherein the intraprediction performing unit adds intraprediction mode information, including information on whether the flipped reference block is used and the predetermined direction of the straight line, to a header of a bitstream of an encoded video, if intraprediction is performed using the flipped reference block. 
     
     
         10 . An intraprediction encoding apparatus comprising:
 a flipping unit which forms a flipped current block by flipping pixels of a current block to be intrapredicted symmetrically with respect to a straight line of a predetermined direction passing through the current block; and   an intraprediction performing unit which performs intraprediction on the flipped current block using pixels of a reference block adjacent to the flipped current block.   
     
     
         11 . The intraprediction encoding apparatus of  claim 10 , wherein the intraprediction performing unit adds intraprediction mode information, including information on whether the flipped current block is used and the predetermined direction of the straight line, to a header of a bitstream of an encoded video, if intraprediction is performed after flipping the current block. 
     
     
         12 . An intraprediction decoding method, in which an encoded video bitstream is received and intraprediction decoding is performed, the intraprediction decoding method comprising:
 extracting intraprediction mode information from the received bitstream and determining an intraprediction mode of a current block among a plurality of intraprediction modes including an intraprediction mode using a flipped reference block based on the extracted intraprediction mode information;   forming the flipped reference block by flipping pixels of a reference block used for intraprediction decoding symmetrically with respect to a straight line of a predetermined direction passing through the reference block, if the determined intraprediction mode uses the flipped reference block; and   forming a predicted block by performing intraprediction decoding on the current block using the flipped reference block.   
     
     
         13 . The intraprediction decoding method of  claim 12 , wherein the intraprediction mode information includes information about the predetermined direction of the straight line. 
     
     
         14 . An intraprediction decoding method, in which an encoded video bitstream is received and intraprediction decoding is performed, the intraprediction decoding method comprising:
 extracting intraprediction mode information from the received bitstream and determining an intraprediction mode of a current block among a plurality of intraprediction modes including an intraprediction mode using a flipped current block based on the extracted intraprediction mode information;   forming a predicted block by performing intraprediction on a current block using a reference block adjacent to the current block, if the determined intraprediction mode uses the flipped current block;   forming the flipped current block by adding an error included in the received bitstream to the predicted block; and   forming a decoded current block by flipping pixels of the flipped current block symmetrically with respect to a straight line of a predetermined direction passing through the flipped current block.   
     
     
         15 . The intraprediction decoding method of  claim 14 , wherein the intraprediction mode information includes information about the predetermined direction of the straight line. 
     
     
         16 . An intraprediction decoding apparatus, in which an encoded video bitstream is received and intraprediction decoding is performed, the intraprediction decoding apparatus comprising:
 an intraprediction mode determining unit, which extracts intraprediction mode information from the received bitstream and determines an intraprediction mode of a current block among a plurality of intraprediction modes including an intraprediction mode using a flipped reference block based on the extracted intraprediction mode information;   a flipping unit, which forms the flipped reference block by flipping pixels of a reference block used for intraprediction decoding symmetrically with respect to a straight line of a predetermined direction passing through the reference block, if the determined intraprediction mode uses the flipped reference block; and   an intraprediction performing unit, which forms a predicted block by performing intraprediction decoding on the current block using the flipped reference block.   
     
     
         17 . The intraprediction decoding apparatus of  claim 16 , wherein the intraprediction mode information includes information about the predetermined direction of the straight line. 
     
     
         18 . An intraprediction decoding apparatus, in which an encoded video bitstream is received and intraprediction decoding is performed, the intraprediction decoding apparatus comprising:
 an intraprediction mode determining unit, which extracts intraprediction mode information from the received bitstream and determining an intraprediction mode of a current block among a plurality of intraprediction modes including an intraprediction mode using a flipped current block based on the extracted intraprediction mode information;   an intraprediction performing unit, which forms a predicted block by performing intraprediction on a current block using a reference block adjacent to the current block, if the determined intraprediction mode uses the flipped current block;   an adding unit, which forms the flipped current block by adding an error included in the received bitstream to the predicted block; and   a flipping unit, which forms a decoded current block by flipping pixels of the flipped current block symmetrically with respect to a straight line of a predetermined direction passing through the flipped current block.   
     
     
         19 . The intraprediction decoding apparatus of  claim 18 , wherein the intraprediction mode information includes information about the predetermined direction of the straight line.