A method of decoding a video, the method comprising: obtaining, from a bitstream, a skip flag for a coding unit which indicates whether the coding unit is decoded according to a skip mode, when the skip flag indicates the skip mode, obtaining, from the bitstream, a merge index indicating one block among a candidate block group, when the skip flag indicates a non-skip mode, obtaining, from the bitstream, a partition type and merge information of a partition, wherein the merge information of the partition indicates whether the partition among one or more partitions is decoded in a merge mode, when the merge information for the partition indicates the merge mode, a merge index indicating one block among the candidate block group for the partition is obtained from the bitstream, and performing motion compensation on the partition using a motion information of the block which the merge index indicates, wherein when the partition type is obtained from the bitstream, the one or more partitions, including the partition, are determined by splitting the coding unit based on the partition type; characterized in that the candidate block group for the partition includes one or more blocks from among the following three neighboring blocks of the partition: a left-lower block located on a left side of a leftmost block among lower blocks directly below a lower border of a partition, the left-lower block being located below a lowermost block among left blocks adjacent to a left border of the partition, a left-upper block located on a left side of a leftmost block among upper blocks directly above an upper border of the partition, the left-upper block being located above an uppermost block among the left blocks adjacent to the left border of the partition, and a right-upper block located on a right side of a rightmost block among the upper blocks directly above the upper border of the partition. obtaining, from a bitstream, a skip flag for a coding unit which indicates whether the coding unit is decoded according to a skip mode, when the skip flag indicates the skip mode, obtaining, from the bitstream, a merge index indicating one block among a candidate block group, when the skip flag indicates a non-skip mode, obtaining, from the bitstream, a partition type and merge information of a partition, wherein the merge information of the partition indicates whether the partition among one or more partitions is decoded in a merge mode, when the merge information for the partition indicates the merge mode, a merge index indicating one block among the candidate block group for the partition is obtained from the bitstream, and performing motion compensation on the partition using a motion information of the block which the merge index indicates, wherein when the partition type is obtained from the bitstream, the one or more partitions, including the partition, are determined by splitting the coding unit based on the partition type; characterized in that the candidate block group for the partition includes one or more blocks from among the following three neighboring blocks of the partition: a left-lower block located on a left side of a leftmost block among lower blocks directly below a lower border of a partition, the left-lower block being located below a lowermost block among left blocks adjacent to a left border of the partition, a left-upper block located on a left side of a leftmost block among upper blocks directly above an upper border of the partition, the left-upper block being located above an uppermost block among the left blocks adjacent to the left border of the partition, and a right-upper block located on a right side of a rightmost block among the upper blocks directly above the upper border of the partition. a left-lower block located on a left side of a leftmost block among lower blocks directly below a lower border of a partition, the left-lower block being located below a lowermost block among left blocks adjacent to a left border of the partition, a left-upper block located on a left side of a leftmost block among upper blocks directly above an upper border of the partition, the left-upper block being located above an uppermost block among the left blocks adjacent to the left border of the partition, and a right-upper block located on a right side of a rightmost block among the upper blocks directly above the upper border of the partition.