Method, apparatus and device for obtaining motion information of video images and template construction method

A method for obtaining motion information of video images, comprising:

• determining, in a first reference frame, one or more first candidate reference blocks that correspond to a current block in a current frame according to known motion information related to the current block;
• determining motion vectors between the one or more first candidate reference block to the current block;
• for each of the one or more first candidate reference blocks, determining, based on a corresponding motion vector of the first candidate reference block and in a second reference frame, a second candidate reference block that is symmetrically positioned about the current block such that the current block is centered in between the first reference block and the second reference block;
• obtaining the similarity between the first candidate reference block and the second candidate reference block and similarities between templates corresponding to the candidate reference blocks and a template corresponding to the current block;
• according to the obtained similarities, selecting the first candidate reference block and the second candidate reference block that have the minimal value in the similarity;
• and
• determining motion information of the current block according to motion information of the selected first candidate reference block and second candidate reference block.