Motion vector obtaining method and apparatus, computer device, and storage medium

An encoder, comprising:

• at least one processor;
• and
• one or more memories coupled to the at least one processor and storing programming instructions, which when executed by the at least one processor, cause the encoder to:
• obtain identification information;
• obtain an initial motion vector of a coding unit of a picture based on the identification information;
• obtain a plurality of candidate final motion vectors based on the initial motion vector and a plurality of preset offset vectors;
• obtain a final motion vector from the plurality of candidate final motion vectors, wherein the final motion vector has a minimum distortion cost amongst the plurality of candidate final motion vectors, wherein the distortion cost is calculated by using a sum of absolute differences;
• and
• calculate a difference between the final motion vector and the initial motion vector, wherein the difference represents a motion vector residual of a picture block to be processed,
• wherein the final motion vector comprises a first forward motion vector and a first backward motion vector, and the initial motion vector comprises a second forward motion vector and a second backward motion vector;
• the first forward motion vector and the second forward motion vector indicate a motion compensation block based on a first reference frame list of the picture block, the distortion cost of the first forward motion vector is same as that of the first backward motion vector, and the first backward motion vector and the second backward motion vector indicate a motion compensation block based on a second reference frame list of the picture block.

A coding apparatus, comprising:

• at least one processor;
• a memory for storing a bitstream having identification information, wherein the identification information is used to obtain an initial motion vector of a coding unit;
• and
• an encoder operatively coupled to the memory and configured by the at least one processor to:
• obtain identification information;
• obtain an initial motion vector of a coding unit of a picture based on the identification information;
• obtain a plurality of candidate final motion vectors based on the initial motion vector and a plurality of preset offset vectors;
• obtain a final motion vector from the plurality of candidate final motion vectors, wherein the final motion vector has a minimum distortion cost amongst the plurality of candidate final motion vectors, wherein the distortion cost is calculated by using a sum of absolute differences;
• and
• calculate a difference between the final motion vector and the initial motion vector, wherein the difference represents a motion vector residual of a picture block to be processed,
• wherein the final motion vector comprises a first forward motion vector and a first backward motion vector, and the initial motion vector comprises a second forward motion vector and a second backward motion vector;
• the first forward motion vector and the second forward motion vector indicate a motion compensation block based on a first reference frame list of the picture block, the distortion cost of the first forward motion vector is same as that of the first backward motion vector, and the first backward motion vector and the second backward motion vector indicate a motion compensation block based on a second reference frame list of the picture block.