| 摘要 |
PURPOSE: A method for transformation and inverse transformation by an intra prediction mode, and an encoding and decoding device thereof are provided to reduce complexity, and to increase compression efficiency during image information processing. CONSTITUTION: If types of vertical direction transformation and horizontal direction transformation for a transformation target block are the same, an encoder determines whether an angle of an intra prediction mode applied to the block is in a vertical direction(S810, S820). If the direction of the intra prediction mode is vertical, the encoder performs vertical direction transformation to the transformation target block by applying the types(S830). The encoder performs horizontal direction transformation to the transformation target block by using the types(S840). [Reference numerals] (AA) Start; (BB,DD) No; (CC,EE) Yes; (FF) End; (S810) Horizontal transformation type≠Vertical transformation type ?; (S820) Intra prediction mode angle = Vertical direction ?; (S830,S860) Vertical transformation using a vertical transformation type; (S840,S850) Horizontal transformation using a horizontal transformation type; |
