Encoder, decoder, encoding method, and decoding method

A decoder that decodes an image, the decoder comprising:

• circuitry;
• and
• memory coupled to the circuitry,
• wherein in operation, the circuitry:
• derives a motion vector of a current block on a block-by-block basis;
• performs a Dynamic Motion Vector Refreshing (DMVR) process for each of sub-blocks of the current block on a sub-block-by-sub-block basis, by searching in a vicinity of a position specified by the motion vector to correct the motion vector, the sub-blocks being included in the current block;
• determines whether to apply deblocking filtering to each of sub-block boundaries between neighboring ones of the sub-blocks upon which the DMVR process is performed;
• and
• applies the deblocking filtering to the sub-block boundaries, based on a result of the determination,
• wherein a width of each of the sub-blocks is 16.

A non-transitory computer readable medium storing a bitstream, the bitstream comprising decoding information that causes a decoder to execute a decoding process, the decoding process comprising:

• deriving a motion vector of a current block on a block-by-block basis;
• performing a Dynamic Motion Vector Refreshing (DMVR) process for each of sub-blocks of the current block on a sub-block-by-sub-block basis, by searching in a vicinity of a position specified by the motion vector to correct the motion vector, the sub-blocks being included in the current block;
• determining whether to apply deblocking filtering to each of sub-block boundaries between neighboring ones of the sub-blocks upon which the DMVR process is performed;
• and
• applying the deblocking filtering to the sub-block boundaries, based on a result of the determination,
• wherein a width of each of the sub-blocks is 16.