Abstract: Disclosed herein are a video decoding method and apparatus and a video encoding method and apparatus. Coding decision information of a representative channel of a target block is shared as coding decision information of a target channel of the target block, and decoding of the target block is performed using the coding decision information of the target channel. Since the coding decision information of the representative channel is shared with an additional channel, repeated signaling of identical coding decision information may be prevented. By means of this prevention, the efficiency of encoding and decoding of the target block or the like may be improved.

Abstract: An intra prediction method and a device using the intra prediction method are provided. The intra prediction method includes the steps of: deriving a current prediction mode as a prediction anode of a current block; constructing neighboring samples of the current block with available reference samples; filtering the available reference samples; and generating predicted samples of the current block on the basis of the filtered available reference samples,. The filtering step includes performing the filtering using the available reference sample located in the prediction direction of the current prediction mode and a predetermined number of available reference samples neighboring to the prediction direction of the current prediction mode.