Image/video encoding/decoding method and device
A video decoding method performed by a video decoding device according to the present document may comprise: parsing, from a bitstream, number information relating to explicitly signaled height for slices in a tile of a current picture; based on the number information, parsing, from the bitstream, height information relating to explicitly signaled height for the slices, deriving heights of 0-th to (n−1)-th slices in the tile based on the height information; deriving the height of the n-th slice in the tile based on the height of the (n−1)-th slice; deriving a height of a last slice in the tile based on a remaining height.
1. A video decoding method performed by a video decoding apparatus, the method comprising:
parsing number information related to a number of slices of which heights are explicitly signaled within a tile of a current picture from a bitstream;
parsing height information related to heights of the slices of which heights are explicitly signaled from the bitstream based on the number information;
based on the number of slices of which heights are explicitly signaled being equal to n, deriving heights of a 0-th slice to an (n−1)-th slice within the tile based on the height information;
deriving a total number of slices within the tile; and
decoding the current picture based on the slices of the current picture,
wherein the deriving the total number of slices within the tile comprises
obtaining a remaining height of the tile that is calculated by subtracting the heights of the slices starting from the 0-th slice to the (n−1)-th slice from a total height of the tile;
obtaining intermediate number that is equal to n;
comparing the remaining height of the tile with a uniform height of a slice within the tile;
increasing the intermediate number by 1 based on the remaining height of the tile being smaller than the uniform height and being larger than 0; and
deriving the total number of slices within the tile as the increased intermediate number.
2. The video decoding method of claim 1 , wherein the number information and the height information include an Exp-Golomb-coded syntax element.
3. The video decoding method of claim 1 , wherein the number information includes a syntax element num_exp_slices_in_tile, and
wherein the height information includes a syntax element exp_slice_height_in_ctu_minus1.
4. The video decoding method of claim 1 , wherein slices within the tile are rectangular slices.
5. The video decoding method of claim 1 , wherein the number information is parsed based on information related to a width and height of a slice including the tile.
6. A video encoding method performed by a video encoding apparatus, the method comprising:
deriving slices within a tile of a current picture;
generating number information related to a number of slices of which heights are explicitly signaled within the tile and height information related to heights of the slices of which heights are explicitly signaled; and
encoding image information including the number information and the height information,
wherein, based on the number of slices of which heights are explicitly signaled being equal to n, the height information indicates heights of a 0-th slice to an (n−1)-th slice within the tile, and
wherein a total number of slices within the tile is derived by performing:
obtaining a remaining height of the tile that is calculated by subtracting the heights of the slices starting from the 0-th slice to the (n−1)-th slice from a total height of the tile;
obtaining intermediate number that is equal to n;
comparing the remaining height of the tile with a uniform height of a slice within the tile;
increasing the intermediate number by 1 based on the remaining height of the tile being smaller than the uniform height and being larger than 0; and
deriving the total number of slices within the tile as the increased intermediate number.
7. A transmission method of data for a video, the method comprising:
deriving slices within a tile of a current picture;
generating number information related to a number of slices of which heights are explicitly signaled within the tile and height information related to heights of the slices of which heights are explicitly signaled;
encoding image information including the number information and the height information into a bitstream; and
transmitting the data comprising the bitstream,
wherein, based on the number of slices of which heights are explicitly signaled being equal to n, the height information indicates heights of a 0-th slice to an (n−1)-th slice within the tile, and
wherein a total number of slices within the tile is derived by performing:
obtaining a remaining height of the tile that is calculated by subtracting the heights of the slices starting from the 0-th slice to the (n−1)-th slice from a total height of the tile;
obtaining intermediate number that is equal to n;
comparing the remaining height of the tile with a uniform height of a slice within the tile;
increasing the intermediate number by 1 based on the remaining height of the tile being smaller than the uniform height and being larger than 0; and
deriving the total number of slices within the tile as the increased intermediate number.