IMAGE ENCODING/DECODING METHOD AND APPARATUS FOR SELECTIVELY ENCODING SIZE INFORMATION OF RECTANGULAR SLICE, AND METHOD FOR TRANSMITTING BITSTREAM

1 . An image decoding method performed by an image decoding apparatus, the image decoding method comprising:

acquiring size information indicating a size of a current slice corresponding to at least a portion of a current picture from a bitstream; and

determining the size of the current slice based on the size information,

wherein the size information includes width information indicating a width of the current slice in units of tile columns and height information indicating a height of the current slice in units of tile rows,

wherein the acquiring the size information is performed based on whether the current slice belongs to a last tile column or a last tile row of the current picture,

wherein the height information of the current slice is not acquired from the bitstream based on whether a top left tile of the current slice belongs to a last tile row of the current picture, and

wherein the width information of the current slice is not acquired from the bitstream based on whether a top left tile of the current slice belongs to a last tile column of the current picture.

2 . The image decoding method of claim 1 , wherein the height information of the current slice is acquired from the bitstream based on a top left tile of the current slice not belonging to a last tile row of the current picture.

3 . The image decoding method of claim 1 , wherein the height information of the current slice is not acquired from the bitstream and is determined to be a predetermined value based on a top left tile of the current slice belonging to a last tile row of the current picture.

4 . The image decoding method of claim 3 , wherein the predetermined value indicates one tile row.

5 . The image decoding method of 1 , wherein the current slice is a rectangular slice.

6 . The image decoding method of claim 1 ,

wherein the acquiring the size information is performed based on the number of slices partitioning the current picture,

wherein the number of slices partitioning the current picture is determined by:

determining availability of partitioning of the current picture;

determining the number of tile rows and the number of tile columns, both of which partition the current picture, based on the availability of the partitioning of the current picture;

determining a width of each tile column partitioning the current picture based on the number of tile columns;

determining a height of each tile row partitioning the current picture based on the number of tile rows;

determining whether the current picture is partitioned into rectangular slices based on the number of tiles partitioning the current picture; and

acquiring the number of slices partitioning the current picture from a bitstream based on whether the current picture is partitioned into rectangular slices.

7 . An image encoding method performed by an image encoding apparatus, the image encoding method comprising:

determining a current slice corresponding to at least one a portion of a current picture; and

generating a bitstream including size information of the current slice,

wherein the size information includes width information indicating a width of the current slice in units of tile columns and height information indicating a height of the current slice in units of tile rows,

wherein the generating the bitstream is performed based on whether the current slice belongs to a last tile column or a last tile row of the current picture,

wherein the height information of the current slice is not encoded in the bitstream based on a top left tile of the current slice belonging to a last tile row of the current picture, and

wherein the width information of the current slice is not encoded in the bitstream based on a top left tile of the current slice belonging to a last tile column of the current picture.

8 . The image encoding method of claim 7 , wherein the current slice is a rectangular slice.

9 . A method of transmitting a bitstream, the method comprising:

generating a bitstream based on an image encoding method,

transmitting the bitstream,

wherein the image encoding method comprising:

determining a current slice corresponding to at least one a portion of a current picture; and

generating a bitstream including size information of the current slice,

wherein the size information includes width information indicating a width of the current slice in units of tile columns and height information indicating a height of the current slice in units of tile rows,

wherein the generating the bitstream is performed based on whether the current slice belongs to a last tile column or a last tile row of the current picture,

wherein the height information of the current slice is not encoded in the bitstream based on a top left tile of the current slice belonging to a last tile row of the current picture, and

wherein the width information of the current slice is not encoded in the bitstream based on a top left tile of the current slice belonging to a last tile column of the current picture.