Method for constructing candidate motion information list, inter prediction method, and apparatus

A non-transitory computer-readable medium having processor-executable instructions stored thereon for constructing a candidate motion information list, wherein the processor-executable instructions, when executed, facilitate performance of the following:

• generating the candidate motion information list comprising at least one candidate motion information set obtained from a neighboring affine image block of a current image block by using an inherited control point motion vector prediction method, wherein generating the candidate motion information list comprises sequentially performing a first processing process on neighboring image blocks of the current image block in a first preset order, until a quantity of candidate motion information sets in the candidate motion information list is equal to a first preset value or until all neighboring image blocks of the current image block have been traversed, wherein the first processing process comprises:
• for an ith (i∈[1, n]) neighboring image block, based on the ith neighboring image block being an affine coding block, determining whether the ith neighboring image block and a candidate motion information set that has been stored in the candidate motion information list come from a same coding unit;
• and
• in case that no candidate motion information set from the coding unit to which the ith neighboring image block belongs exists in the candidate motion information list, determining candidate motion information of x control points of the current image block based on motion information of x control points of the ith neighboring image block, and storing, in the candidate motion information list, a candidate motion information set including the candidate motion information of the x control points of the current image block, where n is a quantity of neighboring image blocks of the current image block, and both x and n are integers greater than or equal to 2;
• storing, in the candidate motion information list, an extra to-be-selected motion information set that satisfies a preset condition, wherein the extra to-be-selected motion information set comprises extra to-be-selected motion vectors of at least two control points of the current image block, a respective extra to-be-selected motion vector of a respective control point is a motion vector of an inter-coded image block adjacent to the current image block, and reference frame indexes of all control points in the extra to-be-selected motion information set that satisfies the preset condition are the same;
• and
• based on the quantity of candidate motion information sets in the candidate motion information list being less than a preset quantity value after having sequentially performed the first processing process on the neighboring image blocks of the current image block in the first preset order and after having stored the extra to-be-selected motion information set in the candidate motion information list, filling the candidate motion information list with a first preset candidate motion information set until the quantity of candidate motion information sets in the candidate motion information list is equal to the preset quantity value.