IMAGE ENCODING/DECODING METHOD AND APPARATUS INVOLVING MERGE CANDIDATE LIST AND TRIANGULAR SHAPE PARTITIONS

1 . A method of decoding an image, comprising:

dividing, based on a predetermined division line, a current block in the image into a plurality of partitions, the plurality of partitions including a first partition and a second partition, at least one the first partition or the second partition having a triangular shape;

constructing a merge candidate list of the current block, the merge candidate list of the current block being shared by the first partition and the second partition;

deriving, based on the merge candidate list, motion information of the first partition and the second partition, respectively; and

performing, based on the motion information of the first partition and the second partition, inter prediction on the current block.

2 . The method of claim 1 , wherein the division line is determined based on division information obtained from a bitstream, and

wherein the division information indicates an angle of the division line and a distance from a center of the current block to the division line.

3 . The method of claim 1 , wherein the division into the plurality of partitions is performed only for a coding block which is no longer divided into smaller coding blocks through a tree-based block division.

4 . The method of claim 3 , wherein the tree-based block division includes at least one of a quad-tree division, a binary-tree division or a ternary-tree division.

5 . The method of claim 1 , wherein the motion information of the first partition is derived based on a first merge candidate index indicating a first merge candidate among a plurality of merge candidates in the merge candidate list.

6 . The method of claim 5 , wherein the motion information of the second partition is derived based on the first merge candidate index for deriving the motion information of the first partition.

7 . The method of claim 6 , wherein both the first partition and the second partition are restricted to have only motion information for uni-directional prediction.

8 . The method of claim 7 , wherein whether the first partition has motion information in an L0 direction or motion information in an L1 direction is variably determined based on the first merge candidate index.

9 . A method of encoding an image, comprising:

dividing, based on a predetermined division line, a current block in the image into a plurality of partitions, the plurality of partitions including a first partition and a second partition, at least one the first partition or the second partition having a triangular shape;

constructing a merge candidate list of the current block, the merge candidate list of the current block being shared by the first partition and the second partition; and

performing, based on motion information of the first partition and the second partition, inter prediction on the current block, the motion information of the first partition and the second partition being determined based on the merge candidate list, respectively.

10 . A non-transitory computer-readable storage medium for storing data associated with a video signal, comprising:

a bitstream to be decoded by a decoding method comprising:

dividing, based on a predetermined division line, a current block into a plurality of partitions, the plurality of partitions including a first partition and a second partition, at least one the first partition or the second partition having a triangular shape;

constructing a merge candidate list of the current block, the merge candidate list of the current block being shared by the first partition and the second partition;

deriving, based on the merge candidate list, motion information of the first partition and the second partition, respectively; and

performing, based on the motion information of the first partition and the second partition, inter prediction on the current block.