A video data inter prediction method, comprising: determining a candidate motion information list of a current picture block to be coded using an affine merge mode, wherein the candidate motion information list comprises at least one first candidate motion information group and at least one second candidate motion information group both comprising motion vectors for a first group of at least two control points of the current picture block, wherein a plurality of pieces of index information indicate the first candidate motion information group and the second candidate motion information group respectively, the first candidate motion information group is a motion information group determined based on motion information of control points of a first affine neighboring picture block of the current picture block and a motion model of the first affine neighboring picture block, and the second candidate motion information group is based on a set of motion information of at least two sample locations that are respectively neighboring to control points of a second group of at least two control points of the current picture block, and the at least two sample locations are located on at least one second neighboring picture block of the current picture block; determining target motion information from the candidate motion information list; and performing inter prediction on the current picture block based on the target motion information; wherein the determining the candidate motion information list of the current picture block comprises: when the second group of control points is different from the first group of control points, further deriving the second candidate motion information group according to a location transformation formula and based on motion information corresponding to the second group of control points; wherein the location transformation formula is based on a 4-parameter affine model or a 6-parameter affine model and the coordinates of the first group of control points and the second group of control points. determining a candidate motion information list of a current picture block to be coded using an affine merge mode, wherein the candidate motion information list comprises at least one first candidate motion information group and at least one second candidate motion information group both comprising motion vectors for a first group of at least two control points of the current picture block, wherein a plurality of pieces of index information indicate the first candidate motion information group and the second candidate motion information group respectively, the first candidate motion information group is a motion information group determined based on motion information of control points of a first affine neighboring picture block of the current picture block and a motion model of the first affine neighboring picture block, and the second candidate motion information group is based on a set of motion information of at least two sample locations that are respectively neighboring to control points of a second group of at least two control points of the current picture block, and the at least two sample locations are located on at least one second neighboring picture block of the current picture block; determining target motion information from the candidate motion information list; and performing inter prediction on the current picture block based on the target motion information; wherein the determining the candidate motion information list of the current picture block comprises: when the second group of control points is different from the first group of control points, further deriving the second candidate motion information group according to a location transformation formula and based on motion information corresponding to the second group of control points; wherein the location transformation formula is based on a 4-parameter affine model or a 6-parameter affine model and the coordinates of the first group of control points and the second group of control points. when the second group of control points is different from the first group of control points, further deriving the second candidate motion information group according to a location transformation formula and based on motion information corresponding to the second group of control points; wherein the location transformation formula is based on a 4-parameter affine model or a 6-parameter affine model and the coordinates of the first group of control points and the second group of control points.