Image signal encoding/decoding method and device therefor

1. A method of decoding a video, the method comprising:

partitioning a current picture into a plurality of tiles;

decoding slice type information representing whether a rectangular slice partitioning method is applied or not;

decoding slice number information representing a number of slices included in the current picture; and

determining a size of a slice in the current picture,

wherein, in response that the slice type information indicates that the rectangular slice partitioning method is applied, tile index difference information specifying an index difference between a top-left tile of a first slice and a top-left tile of a second slice is decoded from a bitstream, and

wherein an index of the top-left tile of the second slice is derived by adding the index difference specified by the tile index difference information to an index of the top-left tile of the first slice.

2. The method of claim 1 , wherein the method further comprises decoding a difference information present flag representing whether the tile index difference information is present in the bitstream or not, and

wherein the difference information present flag is decoded from the bitstream only when the number of slices included in the current picture is equal to or greater than a threshold value.

3. The method of claim 2 , wherein when the number of slices included in the current picture is equal to or less than the threshold value, decoding the difference information present flag is omitted and a value of the difference information present flag is inferred to 0.

4. The method of claim 1 , wherein determining the size of the slice comprises:

selectively decoding width information representing a width of the first slice; and

selectively decoding height information representing a height of the first slice,

wherein whether the height information is decoded for the first slice or not is determined based on whether the first slice adjoins a left boundary of the current picture.

5. The method of claim 4 , wherein when the first slice does not adjoin the left boundary of the current picture, decoding the height information is omitted and the height of the first slice is set the same as a height of another slice which adjoins the left boundary of the current picture.

6. The method of claim 1 , wherein partitioning the current picture into the plurality of tiles comprising:

decoding width information representing a width of at least one of a plurality of tile columns included in the current picture; and

partitioning the current picture into the plurality of tile columns based on the width information,

wherein when decoding the width information is omitted for a first tile column among the plurality of tile columns, a width of the first tile column is determined based on width information of a second tile column which is lastly decoded.

7. A method of encoding a video, the method comprising:

partitioning a current picture into a plurality of tiles;

determining whether a rectangular slice partitioning method is applied or not;

determining a size of a slice;

encoding slice type information, representing whether the rectangular slice partitioning method is applied or not, into a bitstream; and

encoding slice number information, representing a number of slices included in the current picture, into the bitstream,

wherein, in response that the rectangular slice partitioning method is applied, tile index difference information specifying an index difference between a top-left tile of a first slice and a top-left tile of a second slice is encoded into the bitstream, and

wherein a value of the tile index difference information is derived by subtracting an index of the top-left tile of the first slice from an index of the top-left tile of the second slice.

8. The method of claim 7 , wherein the method further comprises encoding a difference information present flag representing whether the tile index difference information is present in the bitstream or not, and

wherein the difference information present flag is encoded into the bitstream only when the number of slices included in the current picture is equal to or greater than a threshold value.

9. The method of claim 8 , wherein when the number of slices included in the current picture is equal to or less than the threshold value, encoding the difference information present flag is omitted.

10. The method of claim 7 , wherein determining the size of the slice comprises:

selectively encoding width information representing a width of the first slice; and

selectively encoding height information representing a height of the first slice,

wherein whether to encode the height information for the first slice or not is determined based on whether the first slice adjoins a left boundary of the current picture.

11. The method of claim 10 , wherein when the first slice does not adjoin the left boundary of the current picture, encoding the height information is omitted and the height of the first slice is set the same as a height of another slice who adjoins the left boundary of the current picture.

12. The method of claim 7 , wherein partitioning the current picture into the plurality of tiles comprising:

partitioning the current picture into a plurality of tile columns; and

encoding width information representing a width of at least one of the plurality of tile columns, and

wherein when widths of an N-th tile column to a last tile column are the same, encoding the width information from an (N+1)-th tile column to the last tile column is omitted.

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

a data stream stored in the non-transitory computer-readable medium, the data stream comprising:

slice type information representing whether a rectangular slice partitioning method is applied to a current picture or not; and

slice number information representing a number of slices included in the current picture,

wherein, in response that the slice type information indicates that the rectangular slice partitioning method is applied, the data stream further comprises tile index difference information specifying an index difference between a top-left tile of a first slice and a top-left tile of a second slice, and

wherein an index of the top-left tile of the second slice is derived by adding the index difference specified by the tile index difference information to an index of the top-left tile of the first slice.