Encoder, decoder, encoding method, and decoding method
An encoder includes circuitry and memory. Using the memory, the circuitry, in inter prediction processing: derives a first motion vector of a current block to be processed, using a motion vector of a previous block which has been previously processed; derives a second motion vector of the current block by performing motion estimation in the vicinity of the first motion vector; and generates a prediction image of the current block by performing motion compensation using the second motion vector.
1. A decoder, comprising:
circuitry; and
memory, wherein
using the memory, the circuitry, in inter prediction processing:
derives a first motion vector of a first current block to be processed, using a motion vector of a previous block which has been previously processed;
derives a second motion vector of the first current block by performing motion estimation in vicinity of a position specified by the first motion vector;
generates a prediction image of the first current block by performing motion compensation using the second motion vector;
derives a third motion vector of a second current block to be processed after the first current block, using the first motion vector of the first current block indicated on a motion vector list, when the second current block is included in a first picture including the first current block;
derives a third motion vector of the second current block, using the second motion vector of the first current block indicated on the motion vector list, when the second current block is included in a second picture different from the first picture;
derives a fourth motion vector of the second current block by performing motion estimation in vicinity of a position specified by the third motion vector; and
generates a prediction image of the second current block by performing motion compensation using the fourth motion vector.
2. The decoder according to claim 1 ,
wherein the circuitry generates the motion vector list indicating a plurality of motion vector predictors using the first motion vector or the second motion vector of the first current block.
3. An encoder, comprising:
circuitry; and
memory, wherein
using the memory, the circuitry, in inter prediction processing:
derives a first motion vector of a first current block to be processed, using a motion vector of a previous block which has been previously processed;
derives a second motion vector of the first current block by performing motion estimation in vicinity of a position specified by the first motion vector;
generates a prediction image of the first current block by performing motion compensation using the second motion vector;
derives a third motion vector of a second current block to be processed after the first current block, using the first motion vector of the first current block indicated on a motion vector list, when the second current block is included in a first picture including the first current block;
derives a third motion vector of the second current block, using the second motion vector of the first current block indicated on the motion vector list, when the second current block is included in a second picture different from the first picture;
derives a fourth motion vector of the second current block by performing motion estimation in vicinity of a position specified by the third motion vector; and
generates a prediction image of the second current block by performing motion compensation using the fourth motion vector.