Image prediction method and device

An image prediction method, the method comprising:

• obtaining a first reference unit of an image unit,
• obtaining motion information comprising motion vector information and position information of two or more control points in the first reference unit;
• and
• obtaining motion information comprising motion vector information of a pixel point of the image unit according to the position information and the motion information of the two or more control points in the first reference unit;
• wherein the first reference unit is an affine motion prediction unit;
• wherein respective predicted images are obtained for the image unit and the first reference unit by using a same affine model;
• and
• wherein obtaining the motion information comprises performing a first set of operations or performing a second set of operations;
• wherein the first set of operations comprises:
• obtaining motion vector information of two control points of the image unit according to the position information of three control points in the first reference unit and the motion vector information of three control points in the first reference unit;
• and
• obtaining motion vector information of all pixel points of the image unit according to the motion vector information of the two control points of the image unit and the position information of the two control points of the image unit:
• wherein the second set of operations comprises:
• obtaining motion vectors of two control points of the image unit according to the position information of three control points in the first reference unit and motion vectors of the three control points in the first reference unit;
• obtaining, by parsing a bitstream, residuals of the motion vectors of the two control points of the image unit;
• obtaining updated motion vectors of the two control points of the image unit by adding the residuals of the motion vectors of the two control points of the image unit to the motion vectors of the two control points of the image unit;
• and
• obtaining motion vector information of all pixel points of the image unit according to the updated motion vectors of the two control points of the image unit and the position information of the two control points of the image unit.

A non-transitory computer-readable storage medium storing computer instructions for image prediction of a video image that, when executed by one or more processors, cause the one or more processors to perform operations comprising:

• obtaining a first reference unit of an image unit,
• obtaining motion information comprising motion vector information and position information of two or more control points in the first reference unit;
• and
• obtaining motion information comprising motion vector information of a pixel point of the image unit according to the position information and the motion information of the two or more control points in the first reference unit;
• wherein the first reference unit is an affine motion prediction unit;
• wherein respective predicted images are obtained for the image unit and the first reference unit by using a same affine model;
• and
• wherein obtaining the motion information comprises performing a first set of operations or performing a second set of operations;
• wherein the first set of operations comprises:
• obtaining motion vector information of two control points of the image unit according to the position information of three control points in the first reference unit and the motion vector information of three control points in the first reference unit;
• and
• obtaining motion vector information of all pixel points of the image unit according to the motion vector information of the two control points of the image unit and the position information of the two control points of the image unit:
• wherein the second set of operations comprises:
• obtaining motion vectors of two control points of the image unit according to the position information of three control points in the first reference unit and motion vectors of the three control points in the first reference unit;
• obtaining, by parsing a bitstream, residuals of the motion vectors of the two control points of the image unit;
• obtaining updated motion vectors of the two control points of the image unit by adding the residuals of the motion vectors of the two control points of the image unit to the motion vectors of the two control points of the image unit;
• and
• obtaining motion vector information of all pixel points of the image unit according to the updated motion vectors of the two control points of the image unit and the position information of the two control points of the image unit.