Method and apparatus for encoding/decoding a video using a motion compensation
The present invention relates to a method for encoding/decoding a video. To this end, the method for decoding a video may include: deriving a spatial merge candidate from at least one of spatial candidate blocks of a current block, deriving a temporal merge candidate from a co-located block of the current block, and generating a prediction block of the current block based on at least one of the derived spatial merge candidate and the derived temporal merge candidate, wherein a reference picture for the temporal merge candidate is selected based on a reference picture list of a current picture including the current block and a reference picture list of a co-located picture including the co-located block.
1. An image decoding method performed by a decoding apparatus, the method comprising:
obtaining a plurality of sub-blocks by dividing the current block into sub-block units;
deriving motion information of each of the plurality of sub-blocks;
deriving a sub-block-based temporal merge candidate of the current block based on the motion information of each of the sub-blocks; and
generating a predicted block of the current block based on the sub-block-based temporal merge candidate,
wherein for deriving motion information of each of the plurality of sub-blocks,
based on that motion information of a co-located sub-block for a sub-block is available, motion information of the sub-block is derived by using the motion information of the co-located sub-block,
based on that the motion information of the co-located sub-block for the sub-block is not available, the motion information of the sub-block is derived by using motion information of a center sub-block in a co-located block comprising the co-located sub-block,
wherein the co-located block and co-located sub-blocks are derived by using a motion vector of a neighboring block, wherein the neighboring block includes a left neighboring block adjacent to a left side of the current block, and
wherein a size of the current block is equal to or greater than 8×8.
2. The method of claim 1 , wherein based on that 4 center sub-blocks are adjoining a central point of the co-located block, the center sub-block is a center right bottom sub-block among 4 center sub-blocks adjoining the central point of the co-located block.
3. An image encoding method performed by an encoding apparatus, the method comprising:
obtaining a plurality of sub-blocks by dividing the current block into sub-block units;
deriving motion information of each of the plurality of sub-blocks;
deriving a sub-block-based temporal merge candidate of the current block based on the motion information of each of the sub-blocks; and
generating a predicted block of the current block based on the sub-block-based temporal merge candidate,
wherein for deriving motion information of each of the plurality of sub-blocks,
based on that motion information of a co-located sub-block for a sub-block is available, motion information of the sub-block is derived by using the motion information of the co-located sub-block,
based on that the motion information of the co-located sub-block for the sub-block is not available, the motion information of the sub-block is derived by using motion information of a center sub-block in a co-located block comprising the co-located sub-block,
wherein the co-located block and co-located sub-blocks are derived by using a motion vector of a neighboring block, wherein the neighboring block includes a left neighboring block adjacent to a left side of the current block, and
wherein a size of the current block is equal to or greater than 8×8.
4. The method of claim 3 , wherein based on that 4 center sub-blocks are adjoining a central point of the co-located block, the center sub-block is a center right bottom sub-block among 4 center sub-blocks adjoining the central point of the co-located block.
5. A non-transitory computer-readable storage medium storing a bitstream generated by an image encoding method, the image encoding method comprising:
obtaining a plurality of sub-blocks by dividing the current block into sub-block units;
deriving motion information of each of the plurality of sub-blocks;
deriving a sub-block-based temporal merge candidate of the current block based on the motion information of each of the sub-blocks; and
generating a predicted block of the current block based on the sub-block-based temporal merge candidate,
wherein for deriving motion information of each of the plurality of sub-blocks,
based on that motion information of a co-located sub-block for a sub-block is available, motion information of the sub-block is derived by using the motion information of the co-located sub-block,
based on that the motion information of the co-located sub-block for the sub-block is not available, the motion information of the sub-block is derived by using motion information of a center sub-block in a co-located block comprising the co-located sub-block,
wherein the co-located block and co-located sub-blocks are derived by using a motion vector of a neighboring block, wherein the neighboring block includes a left neighboring block adjacent to a left side of the current block, and
wherein a size of the current block is equal to or greater than 8×8.
6. The non-transitory computer-readable storage medium of claim 5 , wherein based on that 4 center sub-blocks are adjoining a central point of the co-located block, the center sub-block is a center right bottom sub-block among 4 center sub-blocks adjoining the central point of the co-located block.