Method and device for encoding or decoding image on basis of inter mode
In a method and a device for encoding or decoding an image according to the present invention, motion information for bidirectional prediction of a current block may be derived on the basis of an inter mode previously defined in the device for encoding or decoding an image, and inter prediction may be performed on the current block on the basis of the motion information, wherein the motion information for bidirectional prediction is adjusted to be motion information for unidirectional prediction according to the predefined inter mode.
1. A method of decoding an image with a decoding apparatus, comprising:
dividing, with the decoding apparatus, a current picture in the image based on a plurality of division units including a sub-picture, a tile group, a tile, and a sub-tile; and
decoding, with the decoding apparatus, the divided current picture,
wherein one sub-picture consists of a plurality of tile groups, one tile group consists of a plurality of tiles, and one tile consists of a plurality of sub-tiles,
wherein the current picture is divided into a plurality of tiles based on tile number information and tile size information,
wherein the current picture is divided into a plurality of tile groups based on tile group number information on a number of tile groups belonging to the current picture and tile index information of a top-left tile belonging to the tile group,
wherein the sub-tile is a rectangular region including a group of a plurality of coding tree units (CTUs), and
wherein the sub-tile is restricted from referencing to other sub-tiles that belonging to a same tile as the sub-tile and are spatially adjacent to the sub-tile.
2. The method of claim 1 , wherein the division into the tile groups is performed based on a result of dividing the current picture into the plurality of tiles.
3. The method of claim 1 , wherein the tile is restricted from referencing to other tiles spatially adjacent to the tile.
4. The method of claim 1 , wherein whether to perform filtering on a boundary between sub-tiles is adaptively determined depending on syntax information signaled through a higher-level syntax.
5. The method of claim 4 , wherein the higher-level syntax includes at least one of a sequence parameter set (SPS), a picture parameter set (PPS) or a slice header.
6. A method of encoding an image with an encoding apparatus, comprising:
dividing, with the encoding apparatus, a current picture in the image based on a plurality of division units including a sub-picture, a tile group, a tile, and a sub-tile; and
encoding, with the encoding apparatus, the divided current picture,
wherein one sub-picture consists of a plurality of tile groups, one tile group consists of a plurality of tiles, and one tile consists of a plurality of sub-tiles,
wherein tile number information and tile size information for dividing the current picture into a plurality of tiles is encoded into a bitstream,
wherein tile group number information on a number of tile groups belonging to the current picture and tile index information of a top-left tile belonging to the tile group is encoded into the bitstream,
wherein the sub-tile is a rectangular region including a group of a plurality of coding tree units (CTUs), and
wherein the sub-tile is restricted from referencing to other sub-tiles that belonging to a same tile as the sub-tile and are spatially adjacent to the sub-tile.
7. A non-transitory computer-readable medium for storing a bitstream generated by an image encoding method, the image encoding method comprising:
dividing a current picture in the image based on a plurality of division units including a sub-picture, a tile group, a tile, and a sub-tile; and
encoding the divided current picture,
wherein one sub-picture consists of a plurality of tile groups, one tile group consists of a plurality of tiles, and one tile consists of a plurality of sub-tiles,
wherein tile number information and tile size information for dividing the current picture into a plurality of tiles is encoded into the bitstream,
wherein tile group number information on a number of tile groups belonging to the current picture and tile index information of a top-left tile belonging to the tile group is encoded into the bitstream,
wherein the sub-tile is a rectangular region including a group of a plurality of coding tree units (CTUs), and
wherein the sub-tile is restricted from referencing to other sub-tiles that belonging to a same tile as the sub-tile and are spatially adjacent to the sub-tile.