Encoding method and device, and decoding method and device
Provided is a video decoding method including: obtaining affine parameter group candidates of a current block based on whether adjacent blocks of the current block are decoded; determining an affine parameter group of the current block from among the affine parameter group candidates, according to affine parameter information of the current block; and reconstructing the current block, based on one or more affine parameters included in the affine parameter group.
1 . A video decoding method, comprising:
obtaining affine parameter group candidates of a current block based on whether adjacent blocks of the current block are decoded;
determining an affine parameter group of the current block from among the affine parameter group candidates, according to affine parameter information of the current block; and
reconstructing the current block, based on two or three affine parameters included in the affine parameter group,
wherein the affine parameter group candidates include a first affine parameter group candidate, a second affine parameter group candidate and a third affine parameter group candidate,
wherein the first affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a top-left point of the current block,
wherein the second affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a bottom-left point of the current block, and
wherein the third affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a bottom-right point of the current block.
2 . A video encoding method, comprising:
determining affine parameter group candidates of a current block based on whether adjacent blocks of the current block are decoded;
determining an affine parameter group for predicting the current block; and
determining affine parameter information of the current block indicating the affine parameter group of the current block,
wherein the affine parameter group candidates include a first affine parameter group candidate, a second affine parameter group candidate and a third affine parameter group candidate,
wherein the first affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a top-left point of the current block,
wherein the second affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a bottom-left point of the current block, and
wherein the third affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a bottom-right point of the current block.
3 . A method of transmitting a bitstream generated by encoding a video, the method comprising:
determining affine parameter group candidates of a current block based on whether adjacent blocks of the current block are decoded;
determining an affine parameter group for predicting the current block;
determining affine parameter information of the current block indicating the affine parameter group of the current block; and
transmitting the bitstream including the affine parameter information,
wherein the affine parameter group candidates include a first affine parameter group candidate, a second affine parameter group candidate and a third affine parameter group candidate,
wherein the first affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a top-left point of the current block,
wherein the second affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a bottom-left point of the current block, and
wherein the third affine parameter group candidate is determined based on a motion vector obtained from one or more adjacent blocks corresponding to a bottom-right point of the current block.