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
decoding, from a bitstream, slice type information indicating one of a raster scan slice definition method and a rectangular slice definition method,
wherein when the slice type information indicates the rectangular slice definition method, the method further comprises:
determining, based on slice number information, a number of slices included in the picture;
determining, based on width information of a slice, a number of tile columns included in the slice; and
determining, based on height information of the slice, a number of tile rows included in the slice,
wherein the width information has a value subtracting 1 from the number of tile columns included in the slice,
wherein whether to decode the width information of the slice from the bitstream 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 the height information has a value subtracting 1 from the number of tile rows included in the slice, and
wherein whether to decode the height information of the slice from the bitstream 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 information 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
encoding, into a bitstream, slice type information indicates one of a raster scan slice definition method and a rectangular slice definition method,
wherein when the slice type information indicates the rectangular slice definition method, the method further comprises:
encoding, into the bitstream, slice number information which specifying a number of slices included in the picture
selectively encoding width information of a slice which is determined based on a number of tile columns included in the slice; and
selectively encoding height information of the slice which is determined based on a number of tile rows included in the slice,
wherein the width information has a value subtracting 1 from the number of tile columns included in the slice,
wherein whether to encode the width information of the slice into the bitstream 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 the height information has a value subtracting 1 from the number of tile rows included in the slice, and
wherein whether to encode the height information of the slice into the bitstream 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 information 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.
12. 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:
tile column number information for partitioning a picture into a plurality of tile columns;
tile row number information for partitioning the picture into a plurality of tile rows; and
slice type information indicating one of a raster scan slice definition method and a rectangular slice definition method,
wherein when the slice type information indicates the rectangular slice definition method, the data stream further comprises:
slice number information which specifying a number of slices included in the picture;
width information of a slice which specifying a number of tile columns included in the slice; and
height information of the slice which specifying a number of tile rows included in the slice,
wherein the width information has a value subtracting 1 from the number of tile columns included in the slice,
wherein whether to insert the width information of the slice into the data stream or not is determined based on whether a tile located at top-left of the slice is included in a 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, the width information of the slice is not inserted in the data stream, and a value thereof is inferred to be 0.