Image signal encoding/decoding method and device therefor
An image decoding method, according to the present invention, may comprise the steps of: splitting a current picture into a plurality of tiles; decoding split information indicating slice type, wherein the split information indicates whether a square-shaped slice is applied; and determining a slice on the basis of tile index difference information if the split information indicates that the square-shaped slice is applied.
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; and
determining slices each of which includes at least one or a part of a tile,
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 included in 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 a number of the 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 the method further 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 decoded lastly.
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 slices each of which includes at least one tile or a part or a tile; and
encoding slice type information, representing whether the rectangular slice partitioning method is applied or not, into a 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 included in 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 a number of the 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 the method further 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 which 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 among the plurality of tile columns 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,
wherein, based on the slice type information, slices each of which includes at least one tile or a part of a tile are determined,
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 included in 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.