Method for partitioning block including image and device therefor

1. A method for decoding an image, the method comprising:

partitioning, by a processor, a current coding tree block into a plurality of coding blocks, based on the current coding tree block being out of a boundary of a current picture;

parsing, by the processor, a first syntax element including information whether a current coding block is partitioned into a plurality of subblocks based on the current coding block satisfying a predetermined condition, wherein the current coding block is partitioned into the plurality of subblocks when a value of the first syntax element is 1, and the current coding block is not partitioned when the value of the first syntax element is 0;

parsing, by the processor, a second syntax element including information whether the current coding block is partitioned by using a quad-tree structure based on the first syntax element including information that the current coding block is partitioned;

parsing, by the processor, at least one of a third syntax element including information whether the current coding block is partitioned by using a binary-tree structure or whether the current coding block is partitioned by using a ternary-tree structure and a fourth syntax element including information about a split direction of the current coding block, based on the second syntax element including information that the current coding block is not partitioned by using the quad-tree structure; and

determining, by the processor, a split mode of the current coding block based on at least one of the first syntax element, the second syntax element, the third syntax element, and the fourth syntax element.

2. The method for decoding an image of claim 1 , wherein the partitioning of the current coding tree block into the plurality of coding blocks comprises partitioning the current coding tree block into the plurality of coding blocks by using the binary-tree structure or the ternary-tree structure until reaching a valid region in the current coding tree block, wherein the valid region represents a region which is located within the boundary of the current picture in the current coding tree block.

3. The method for decoding an image of claim 1 , wherein the partitioning of the current coding block into the plurality of coding blocks further includes parsing a fifth syntax element including information whether quad-tree splitting is allowed based on the current coding tree block being out of the boundary of the current picture, and

wherein based on the fifth syntax element including information that the quad-tree splitting is not allowed, the current coding tree block is partitioned into the plurality of coding blocks by using the binary-tree structure or the ternary-tree structure.

4. The method for decoding an image of claim 3 , wherein the fifth syntax element is signaled through a Sequence Parameter Set, a Picture Parameter Set, a Tile Group Header, or a header of a Network Abstract Layer unit.

5. The method for decoding an image of claim 1 , wherein the partitioning of the current coding tree block into the plurality of coding blocks comprises partitioning the current coding tree block into the plurality of coding blocks by using the quad-tree structure when a height or width of the current coding tree block is greater than a maximum transform size of 64.

6. A method for encoding an image, comprising:

partitioning, by a processor, a current coding tree block into a plurality of coding blocks, based on the current coding tree block being out of a boundary of a current picture;

generating, by the processor, a first syntax element including information whether a current coding block is partitioned into a plurality of subblocks based on the current coding block satisfying a predetermined condition, wherein the current coding block is partitioned into the plurality of subblocks when a value of the first syntax element is 1, and the current coding block is not partitioned when the value of the first syntax element is 0;

generating, by the processor, a second syntax element including information whether the current coding block is partitioned by using a quad-tree structure based on the first syntax element including information that the current coding block is partitioned;

generating, by the processor, at least one of a third syntax element including information whether the current coding block is partitioned by using a binary-tree structure or whether the current coding block is partitioned by using a ternary-tree structure and a fourth syntax element including information about a split direction of the current coding block, based on the second syntax element including information that the current coding block is not partitioned by using the quad-tree structure; and

determining, by the processor, a split mode of the current coding block based on at least one of the first syntax element, the second syntax element, the third syntax element, and the fourth syntax element.

7. The method of claim 6 , wherein the partitioning of the current coding tree block into the plurality of coding blocks comprises partitioning the current coding tree block into the plurality of coding blocks by using the binary-tree structure or the ternary-tree structure until reaching a valid region in the current coding tree block, wherein the valid region represents a region which is located within the boundary of the current picture in the current coding tree block.

8. The method of claim 6 , the partitioning of the current coding block into the plurality of coding blocks further includes generating a fifth syntax element including information whether quad-tree splitting is allowed based on the current coding tree block being out of the boundary of the current picture, and

wherein based on the fifth syntax element including information that the quad-tree splitting is not allowed, the current coding tree block is partitioned into the plurality of coding blocks by using the binary-tree structure or the ternary-tree structure.

9. The method of claim 8 , wherein the fifth syntax element is inserted into a Sequence Parameter Set, a Picture Parameter Set, a Tile Group Header, or a header of a Network Abstract Layer unit.

10. The method of claim 6 , wherein the partitioning of the current coding tree block into the plurality of coding blocks comprises partitioning the current coding tree block into the plurality of coding blocks by using the quad-tree structure when a height or width of the current coding tree block is greater than a maximum transform size of 64.

11. A method, comprising:

obtaining, by a processor, a bitstream; and

transmitting the bitstream,

wherein the bitstream is generated by performing steps of:

partitioning, by the processor, a current coding tree block into a plurality of coding blocks, based on the current coding tree block being out of a boundary of a current picture;

generating, by the processor, a first syntax element including information whether a current coding block is partitioned into a plurality of subblocks based on the current coding block satisfying a predetermined condition, wherein the current coding block is partitioned into the plurality of subblocks when a value of the first syntax element is 1 and the current coding block is not partitioned when the value of the first syntax element is 0;

generating, by the processor, a second syntax element including information whether the current coding block is partitioned by using a quad-tree structure based on the first syntax element including information that the current coding block is partitioned;

generating, by the processor, at least one of a third syntax element including information whether the current coding block is partitioned by using a binary-tree structure or whether the current coding block is partitioned by using a ternary-tree structure and a fourth syntax element including information about a split direction of the current coding block, based on the second syntax element including information that the current coding block is not partitioned by using the quad-tree structure; and

determining, by the processor, a split mode of the current coding block based on at least one of the first syntax element, the second syntax element, the third syntax element, and the fourth syntax element.

12. The method of claim 11 , wherein the partitioning of the current coding tree block into the plurality of coding blocks comprises partitioning the current coding tree block into the plurality of coding blocks by using the binary-tree structure or the ternary-tree structure until reaching a valid region in the current coding tree block, wherein the valid region represents a region which is located within the boundary of the current picture in the current coding tree block.

13. The method of claim 11 , the partitioning of the current coding block into the plurality of coding blocks further includes generating a fifth syntax element including information whether quad-tree splitting is allowed based on the current coding tree block being out of the boundary of the current picture, and

wherein based on the fifth syntax element including information that the quad-tree splitting is not allowed, the current coding tree block is partitioned into the plurality of coding blocks by using the binary-tree structure or the ternary-tree structure.

14. The method of claim 13 , wherein the fifth syntax element is inserted into a Sequence Parameter Set, a Picture Parameter Set, a Tile Group Header, or a header of a Network Abstract Layer unit.

15. The method of claim 11 , wherein the partitioning of the current coding tree block into the plurality of coding blocks comprises partitioning the current coding tree block into the plurality of coding blocks by using the quad-tree structure when a height or width of the current coding tree block is greater than a maximum transform size of 64.