Method for encoding/decoding image signal and apparatus therefor
An image signal decoding method according to an embodiment of the present disclosure comprises the steps of: splitting a current picture into a plurality of tiles; decoding split information indicating a slice type, wherein the split information indicates whether a rectangular slice is to be applied; and when the split information indicates that the rectangular slice is to be applied, determining a slice on the basis of information indicating the size of a slice.
1 . A method of decoding a video, the method comprising:
partitioning a picture into a plurality of tile columns;
partitioning the picture into a plurality of tile rows; and
in response to a plurality of tiles is included in the picture, decoding, from a bitstream, slice type flag of 1-bit indicating one of a raster scan slice definition method and a rectangular slice definition method,
wherein when the slice type flag indicates the rectangular slice definition method, the method further comprises:
determining, based on slice number information, a number of slices included in the picture; and
in response to the number of slices being greater than 1, decoding width information and height information for slices in the picture,
wherein the width information for a slice has a value subtracting 1 from a number of tile columns included in the slice,
wherein the height information for the slice has a value subtracting 1 from a number of tile rows included in the slice,
wherein whether to decode the width information of the slice from the bitstream or not is determined based on whether a tile located at top-left of the slice is included in rightmost one among the plurality of tile columns, and
wherein when the tile located at top-left of the slice is included in the rightmost tile column, decoding the width information of the slice from the bitstream is omitted, and a value thereof is inferred to be 0.
2 . The method of claim 1 ,
wherein whether to decode the height information of the slice from the bitstream or not is determined based on whether the tile located at top-left of the slice is included in lowest one among the plurality of tile rows, and
wherein when the tile located at top-left tile of the slice is included in the lowest tile row, decoding the height information of the slice from the bitstream is omitted, and a value thereof is inferred to be 0.
3 . The method of claim 2 , wherein when the tile located at top-left of the slice is not included in the lowest tile row, whether to decode the height information of the slice from the bitstream is determined further based on whether the tile located at top-left of the slice is included in leftmost one among the plurality of tile columns.
4 . The method of claim 3 ,
wherein when tile located at top-left of the slice is not included in the leftmost tile column,
decoding the height information of the slice is omitted, and a value thereof is set to be the same as another slice comprising a tile included in the leftmost tile column.
5 . The method of claim 1 ,
wherein when the slice type flag indicates the rectangular slice definition method, the method further comprises:
decoding a difference information present flag indicating whether tile index difference information between slices is present in the bitstream or not, and
wherein when the picture is configured with a single slice, decoding the difference information present flag is omitted, and a value thereof is inferred to be 0.
6 . The method of claim 5 ,
wherein when the difference information present flag indicates that the tile index difference information is present in the bitstream, the tile index difference information of the slice is decoded from the bitstream, and
wherein the tile index difference information represents an index difference between a tile included in the slice and a tile included in a subsequent slice.
7 . A method of encoding a video, the method comprising:
partitioning a picture into a plurality of tile columns;
partitioning the picture into a plurality of tile rows; and
in response to a plurality of tiles is included in the picture encoding, into a bitstream, slice type flag of 1-bit indicates one of a raster scan slice definition method and a rectangular slice definition method,
wherein when the slice type flag indicates the rectangular slice definition method, the method further comprises:
encoding, into the bitstream, slice number information specifying a number of slices included in the picture; and
encoding width information and height information for slices in response to the number of slices being greater than 1,
wherein the width information for a slice has a value subtracting 1 from a number of tile columns included in the slice,
wherein the height information for the slice has a value subtracting 1 from a number of tile rows included in the slice,
wherein whether to encode the width information of the slice into the bitstream or not is determined based on whether a tile located at top-left of the slice is included in rightmost one among the plurality of tile columns, and
wherein when the tile located at top-left of the slice is included in the rightmost tile column, encoding the width information of the slice into the bitstream is omitted.
8 . The method of claim 7 ,
wherein whether to encode the height information of the slice into the bitstream or not is determined based on whether the tile located at top-left of the slice is included in a lowest one among the plurality of tile rows, and
wherein when the tile located at top-left tile of the slice is included in the lowest tile row, encoding the height information of the slice into the bitstream is omitted.
9 . The method of claim 8 , wherein when the tile located at top-left of the slice is not included in the lowest tile row, whether to encode the height information of the slice into the bitstream is determined further based on whether the tile located at top-left of the slice is included in a leftmost one among the plurality of tile columns.
10 . The method of claim 7 , wherein when the slice type flag indicates the rectangular slice definition method, the method further comprises:
encoding a difference information present flag indicating whether tile index difference information between slices is present in the bitstream or not, and
wherein when the picture is configured with a single slice, encoding the difference information present flag is omitted.
11 . The method of claim 10 , wherein the tile index difference information represents an index difference between a tile included in the slice and a tile included in a subsequent slice.