Image encoding/decoding method and apparatus, and recording medium for storing bitstream
An image encoding/decoding method is disclosed. An method of decoding an image of the present invention may comprise deriving at least one merge candidate of a current block, generating an initial merge candidate list of the current block by using the derived at least one merge candidate and generating a reconfigured merge candidate list by using the initial merge candidate list.
1. A method of decoding an image, the method comprising:
deriving a sub-block based temporal merge candidate of a current block;
generating a sub-block based merge candidate list by using the sub-block based temporal merge candidate of the current block; and
deriving a motion vector for each of a plurality of sub-blocks of the current block by using the sub-block based merge candidate list,
wherein the sub-block based temporal merge candidate is derived on a collocated block of the current block derived by a motion vector of a neighbor block of the current block,
wherein the collocated block is included in a collocated picture of the current block, and
wherein the collocated block is a block in which the current block is moved based on the motion vector of the neighbor block of the current block, inside the collocated picture.
2. A method of encoding an image, the method comprising:
deriving a sub-block based temporal merge candidate of a current block;
generating a sub-block based merge candidate list by using the sub-block based temporal merge candidate of the current block; and
deriving a motion vector for each of a plurality of sub-blocks of the current block by using the sub-block-based merge candidate list,
wherein the sub-block based temporal merge candidate is derived on a collocated block of the current block derived by a motion vector of a neighbor block of the current block,
wherein the collocated block is included in a collocated picture of the current block, and
wherein the collocated block is a block in which the current block is moved based on the motion vector of the neighbor block of the current block, inside the collocated picture.
3. A non-transitory storage medium including a bitstream, wherein the bitstream is generated by an image encoding method including:
deriving a sub-block based temporal merge candidate of a current block;
generating a sub-block based merge candidate list by using the sub-block based temporal merge candidate of the current block; and
deriving a motion vector for each of a plurality of sub-blocks of the current block by using the sub-block-based merge candidate list,
wherein the sub-block based temporal merge candidate is derived based on a collocated block of the current block derived by a motion vector of a neighbor block of the current block,
wherein the collocated block is included in a collocated picture of the current block, and
wherein the collocated block is a block in which the current block is moved based on the motion vector of the neighbor block of the current block, inside the collocated picture.
4. The method of claim 1 , wherein the motion vector of the neighbor block is not used to derive the collocated block, when the neighbor block is predicted by a prediction mode using a current picture as a reference picture.
5. The method of claim 1 , wherein when the neighbor block is predicted by the prediction mode using the current picture as the reference picture, the collocated block of the current block is derived by a default vector.
6. The method of claim 1 , wherein when the neighbor block includes a refined motion vector, the motion vector used for deriving the collocated block is a non-refined motion vector of the neighbor block.
7. The method of claim 1 , wherein the sub-block based temporal merge candidate is not derived, when the collocated block is predicted by a prediction mode using a current picture as a reference picture.
8. The method of claim 1 , wherein the collocated block includes a plurality of sub-collocated blocks corresponding to the plurality of sub-blocks of the current block, and
wherein the sub-block based temporal merge candidate is derived using motion vectors of sub-collocated blocks corresponding to sub-blocks of the current block.
9. The method of claim 2 , wherein the motion vector of the neighbor block is used to derive the collocated block, when the neighbor block is predicted by a prediction mode using a current picture as a reference picture.
10. The method of claim 2 , wherein when the neighbor block is predicted by the prediction mode using the current picture as the reference picture, the collocated block of the current block is derived by a default vector.
11. The method of claim 2 , wherein when the neighbor block includes a refined motion vector, the motion vector used for deriving the collocated block is a non-refined motion vector of the neighbor block.
12. The method of claim 2 , wherein the sub-block based temporal merge candidate is not derived, when the collocated block is predicted by a prediction mode using a current picture as a reference picture.
13. The method of claim 2 , wherein the collocated block includes a plurality of sub-collocated blocks corresponding to the plurality of sub-blocks of the current block, and
wherein the sub-block based temporal merge candidate is derived using motion vectors of sub-collocated blocks corresponding to sub-blocks of the current block.