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 of 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 motion information for the current block based on the merge candidate list; and

performing inter prediction on the current block based on the motion information,

wherein the first partition is restricted to have only motion information for uni-prediction, and

wherein the motion information for the uni-prediction is determined based on one of L0 motion information or L1 motion information of a first merge candidate in the merge candidate list.

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 current block is divided into the plurality of partitions when the current block 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 whether the motion information for the uni-prediction is determined based on the L0 motion information is determined based on whether a first merge index of the first partition for indicating the first merge candidate is even.

6 . The method of claim 5 , wherein when the first merge index of the first partition is even, the motion information for the uni-prediction is determined based on the L0 motion information of the first merge candidate, and

wherein when the first merge index of the first partition is odd, the motion information for the uni-prediction is determined based on the L1 motion information of the first merge candidate.

7 . 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 of 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 motion information for the first partition and the second partition based on the merge candidate list; and

performing inter prediction on the current block based on the motion information,

wherein the first partition is restricted to have only motion information for uni-prediction, and

wherein the motion information for the uni-prediction is determined based on one of L0 motion information or L1 motion information of a first merge candidate in the merge candidate list.

8 . A method of transmitting a bitstream, comprising:

dividing, based on a predetermined division line, a current block in an image into a plurality of partitions, the plurality of partitions including a first partition and a second partition, at least one of 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 motion information for the first partition and the second partition based on the merge candidate list;

performing inter prediction on the current block based on the motion information to generate the bitstream; and

transmitting the bitstream,

wherein the first partition is restricted to have only motion information for uni-prediction, and

wherein the motion information for the uni-prediction is determined based on one of L0 motion information or L1 motion information of a first merge candidate in the merge candidate list.