Method for processing image and apparatus therefor

1. A video decoding method, comprising:

parsing, by a processor, a first syntax element indicating whether a current block is split into a plurality of sub-blocks, based on a value of a horizontal direction coordinate of a top left sample of the current block added by a width of the current block being equal to or less than a width of a current picture, and a value of a vertical direction coordinate of the top left sample of the current block added by a height of the current block being equal to or less than a height of the current picture;

parsing, by the processor, a second syntax element indicating whether the current block is split based on a stripe-tree structure in which a non-square block is split into subblocks of a same size, based on the first syntax element including information that the current block is split and one of the width and the height being equal to or greater than four times of the other of the width and the height;

parsing, by the processor, a third syntax element and a fourth syntax element, based on the second syntax element including information that the current block is not split based on the stripe-tree structure, the third syntax element indicating whether the current block is split based on a binary-tree structure or a ternary-tree structure, the fourth syntax element indicating a split direction of the current block; and

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

wherein the first, second, third, and fourth syntax elements are parsed in an order of the first syntax element, the second syntax element, and two of the third syntax element and the fourth syntax element.

2. The method of claim 1 , further comprising:

calling, by the processor, a coding unit syntax for a decoding process of the current block, based on the first syntax element including information that the current block is not split.

3. The method of claim 1 , further comprising:

calling, by the processor, a coding tree unit syntax for determining a split structure of the sub-block split from the current block based on the split mode.

4. The method of claim 1 , wherein the first syntax element, the second syntax element, the third syntax element and the fourth syntax element are parsed from a syntax of a same level.

5. The method of claim 1 , further comprising:

parsing, by the processor, a fifth syntax element indicating whether the current block split from a block of higher node based on the stripe-tree structure, the binary-tree structure or the ternary-tree structure is split based on a quad-tree structure.

6. The method of claim 5 , wherein the fifth syntax element is parsed based on the width being equal to the height, and the first syntax element is parsed further based on the fifth syntax element indicating that the current block is not split based on the quad-tree structure.

7. A video encoding method, comprising:

generating, by a processor, a first syntax element indicating whether a current block is split into a plurality of sub-blocks, based on a value of a horizontal direction coordinate of a top left sample of the current block added by a width of the current block being equal to or less than a width of a current picture, and a value of a vertical direction coordinate of the top left sample of the current block added by a height of the current block being equal to or less than a height of the current picture;

generating, by the processor, a second syntax element indicating whether the current block is split based on a stripe-tree structure in which a non-square block is split into subblocks of a same size, based on the first syntax element including information that the current block is split and one of the width and the height being equal to or greater than four times of the other of the width and the height;

generating, by the processor, a third syntax element and a fourth syntax element, based on the second syntax element including information that the current block is not split based on the stripe-tree structure, the third syntax element indicating whether the current block is split based on a binary-tree structure or a ternary-tree structure, the fourth syntax element indicating a split direction of the current block; and

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

wherein the first to fourth syntax elements are generated in an order of the first syntax element, the second syntax element and two of the third syntax element and the fourth syntax element.

8. The method of claim 7 , wherein the first syntax element, the second syntax element, the third syntax element and the fourth syntax element are generated at a same level.

9. The method of claim 7 , further comprising:

generating, by the processor, a fifth syntax element indicating whether the current block split from a block of higher node based on the stripe-tree structure the binary-tree structure or the ternary-tree structure is split based on a quad-tree structure.

10. The method of claim 9 , wherein the fifth syntax element is generated based on the width being equal to the height, and the first syntax element is generated further based on the fifth syntax element indicating that the current block is not split based on the quad-tree structure.

11. A non-transitory decoder-readable medium for storing one or more instructions executable by one or more processors and a bitstream generated by a video encoding apparatus, the one or more instructions controlling a video decoding apparatus to:

parse a first syntax element indicating whether a current block is split into a plurality of sub-blocks, based on a value of a horizontal direction coordinate of a top left sample of the current block added by a width of the current block being equal to or less than a width of a current picture, and a value of a vertical direction coordinate of the top left sample of the current block added by a height of the current block being equal to or less than a height of the current picture;

parse a second syntax element indicating whether the current block is split based on a stripe-tree structure in which a non-square block is split into subblocks of a same size, based on the first syntax element including information that the current block is split and one of the width and the height being equal to or greater than four times of the other of the width and the height;

parse a third syntax element and a fourth syntax element, based on the second syntax element including information that the current block is not split based on the stripe-tree structure, the third syntax element indicating whether the current block is split based on a binary-tree structure or a ternary-tree structure, the fourth syntax element indicating a split direction of the current block, and

determining a split mode of the current block based on at least one of the first syntax element, the second syntax element, the third syntax element, or the fourth syntax element,

wherein the first, second, third, and fourth syntax elements are parsed in an order of the first syntax element, the second syntax element, and two of the third syntax element and the fourth syntax element.

12. The medium of claim 11 , wherein the first syntax element, the second syntax element, the third syntax element and the fourth syntax element are managed at a same level.

13. The medium of claim 11 , wherein the one or more instructions control the video decoding apparatus to:

parse a fifth syntax element indicating whether the current block split from a block of higher node based on the stripe-tree structure, the binary-tree structure or the ternary-tree structure is split based on a quad-tree structure.

14. The medium of claim 13 , wherein the one or more instructions control the video decoding apparatus to:

parse the fifth syntax element based on the width being equal to the height; and

parse the first syntax element further based on the fifth syntax element indicating that the current block is not split based on the quad-tree structure.