Video encoding/decoding method and apparatus utilizing merge candidate indices

1. A video signal decoding method, comprising:

configuring a merge candidate list of a current block, the merge candidate list including a plurality of merge candidates;

deriving motion information of the current block based on a merge candidate index and the merge candidate list of the current block; and

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

wherein the current block is divided into a plurality of partitions including a first partition and a second partition,

wherein the merge candidate index includes a first merge candidate index for the first partitions and a second merge candidate index for the second partition,

wherein the first merge candidate index and the second merge candidate index are signaled from a bitstream, respectively,

wherein the motion information of the current block includes first motion information for the first partition and second motion information for the second partition,

wherein the first motion information for the first partition is derived based on a merge candidate with an index equal to the first merge candidate index among the plurality of merge candidates,

wherein based on the second merge candidate index being less than the first merge candidate index, the second motion information for the second partition is derived based on a merge candidate with an index equal to the second merge candidate index among the plurality of merge candidates, and

wherein based on the second merge candidate index being greater than or equal to the first merge candidate index, the second motion information for the second partition is derived based on a merge candidate with an index resulting from adding 1 to the second merge candidate index among the plurality of merge candidates.

2. The method of claim 1 , wherein the current block is divided based on information on a predetermined partitioning line, and

wherein the information includes information on at least one of a start point, an end point, an angle, or a direction of the partitioning line.

3. The method of claim 1 , wherein the current block is divided based on a size of the current block being greater than or equal to a predetermined threshold size, and

wherein a size of the current block is represented as a width, a height, a ratio of the width and the height, or a multiplication of the width and the height of the current block.

4. The method of claim 1 ,

wherein the merge candidates include at least one of a spatial merge candidate, a temporal merge candidate, or motion information stored in a buffer with a predetermined size, and;

wherein the motion information stored in the buffer is representative of motion information of a block which is decoded before the current block.

5. The method of claim 4 , further comprising: decoding number information indicating a maximum number of the merge candidates,

wherein the maximum number of the merge candidates is set based on the decoded number information.

6. The method of claim 1 , wherein the two partitions belonging to the current block share the merge candidate list.

7. The method of claim 1 , wherein the first motion information has one of motion information of an L 0 direction or motion information of an L 1 direction according to a value of the first merge candidate index, and

wherein the second motion information has one of motion information of the L 0 direction or motion information of the L 1 direction according to a value of the second merge candidate index or a value of the index resulting from adding 1 to the second merge candidate index.

8. A video signal encoding method, comprising:

configuring a merge candidate list of a current block, the merge candidate list including a plurality of merge candidates;

deriving motion information of the current block by using the merge candidate list of the current block; and

encoding a merge candidate index indicating the motion information of the current block,

wherein the current block is divided into a plurality of partitions including a first partition and a second partition,

wherein the motion information of the current block includes first motion information for the first partition and second motion information for the second partition,

wherein the merge candidate index includes a first merge candidate index for the first partitions and a second merge candidate index for the second partition,

wherein an index of a first merge candidate having the first motion information among the plurality of merge candidates is encoded as the first merge candidate index for the first partition,

wherein based on an index of a second merge candidate having the second motion information among the plurality of merge candidates being less than the index of the first merge candidate, the index of the second merge candidate is encoded as the second merge candidate index for the second partition, and

wherein based on the index of the second merge candidate being greater than the index of the first merge candidate, an index resulting from subtracting 1 from the index of the second merge candidate is encoded as the second merge candidate index for the second partition.

9. A method of transmitting a bitstream, comprising:

configuring a merge candidate list of a current block, the merge candidate list including a plurality of merge candidates;

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

encoding a merge candidate index indicating the motion information of the current block to generate the bitstream; and

transmitting the bitstream,

wherein the current block is divided into a plurality of partitions including a first partition and a second partition,

wherein the motion information of the current block includes first motion information for the first partition and second motion information for the second partition,

wherein the merge candidate index includes a first merge candidate index for the first partitions and a second merge candidate index for the second partition,

wherein an index of a first merge candidate having the first motion information among the plurality of merge candidates is encoded as the first merge candidate index for the first partition,

wherein based on an index of a second merge candidate having the second motion information among the plurality of merge candidates being less than the index of the first merge candidate, the index of the second merge candidate is encoded as the second merge candidate index for the second partition, and

wherein based on the index of the second merge candidate being greater than the index of the first merge candidate, an index resulting from subtracting 1 from the index of the second merge candidate is encoded as the second merge candidate index for the second partition.