A video encoder for encoding a video into a data stream using motion compensated prediction for inter predicted blocks, comprising a hypothesis number control, configured to control a number of prediction hypotheses of the inter predicted blocks within a predetermined portion of the video to meet a predetermined criterion.

Encoding or decoding picture information can involve determining a coding mode associated with a current coding unit including picture information; determining, based on the coding mode, a first precision level associated with a first portion of a motion vector information associated with the current coding unit, and a second precision level associated with a second portion of the motion vector information; obtaining a motion vector associated with the current coding unit based on the motion vector information and the first and second precision levels; and encoding or decoding at least a portion of the picture information included in the current coding unit based on the coding mode and the motion vector.

An image decoding method includes: deriving a refined L0 motion vector and a refined L1 motion vector by applying decoder-side motion vector refinement (DMVR) based on an L0 motion vector and an L1 motion vector of a current block, deriving prediction samples for the current block based on L0 prediction samples derived based on the refined L0 motion vector and L1 prediction samples derived based on the refined L1 motion vector, and generating reconstructed samples for the current block based on the prediction samples. The L0 prediction samples are derived based on an L0 reference picture and the refined L0 motion vector, and the L1 prediction samples are derived based on an L1 reference picture and the refined L1 motion vector, and deriving the prediction samples comprises determining whether to apply bi-directional optical flow (BDOF) process based on a first POC difference and a second POC difference are the same.

A method of video processing comprises determining, for a conversion between a first block of video and a bitstream representation of the first block, a range of motion vector difference (MVD) component associated with the first block, wherein the range of MVD component is [−2.sup.M, 2.sup.M−1], where M=17; constraining value of the MVD component to be in the range of MVD component; and performing the conversion based on the constrained MVD component.

The present disclosure provides a video image decoding method in which a size of an affine motion compensation image sub-block in an affine image block is determined based on a motion vector difference, motion vector precision, a distance between control points in the affine image block, and a size of the affine image block, where the size includes a length in a horizontal direction and a length in a vertical direction, so that a length of the affine image block in a horizontal/vertical direction is an integer multiple of the length of the affine motion compensation image sub-block in the horizontal/vertical direction.

A rendering processor assigns varying logical pixel dimensions to regions of an image frame and rendering pixels of the image frame based on the logical pixel dimensions. The rendering processor renders in highest resolution (i.e., with smaller logical pixel dimensions) those areas of the image that are more important (on which the viewer is expected to focus (the “foveal region”), or regions with little-to-no motion), and renders in lower resolution (i.e., with larger logical pixel dimensions) those areas of the image outside the region of interest, or regions that are speedily moving, so that loss of detail in those regions will be less noticeable to the viewer. For regions with less detail or greater magnitude of motion, larger logical pixel dimensions reduce the computational workload without affecting the quality of the displayed graphics as perceived by a user.

A rendering processor assigns varying logical pixel dimensions to regions of an image frame and rendering pixels of the image frame based on the logical pixel dimensions. The rendering processor renders in highest resolution (i.e., with smaller logical pixel dimensions) those areas of the image that are more important (on which the viewer is expected to focus (the “foveal region”), or regions with little-to-no motion), and renders in lower resolution (i.e., with larger logical pixel dimensions) those areas of the image outside the region of interest, or regions that are speedily moving, so that loss of detail in those regions will be less noticeable to the viewer. For regions with less detail or greater magnitude of motion, larger logical pixel dimensions reduce the computational workload without affecting the quality of the displayed graphics as perceived by a user.

The present invention is about an image encoding/decoding method and apparatus. According to present invention, a method of decoding an image, the method comprising, deriving an initial motion vector of a current block; deriving a refined motion vector by using the initial motion vector; and generating a prediction block of the current block by using the refined motion vector.

A picture decoding method includes: determining motion information of a to-be-decoded block; obtaining a first decoding prediction block of the to-be-decoded block based on the motion information; performing motion search with first precision in the prediction reference picture block to obtain at least two second decoding prediction blocks; performing downsampling on the first decoding prediction block and the at least two second decoding prediction blocks to obtain a first sampling pixel array and at least two second sampling pixel arrays, respectively; calculating a difference between the first sampling pixel array and each of the second sampling pixel arrays, and using, as a target prediction motion vector, a motion vector corresponding to a second sampling pixel array with a minimum difference; and obtaining a target decoding prediction block of the to-be-decoded block based on the target prediction motion vector, and decoding the to-be-decoded block based on the target decoding prediction block.

Disclosed is an image encoding method. The method includes deriving a motion refinement candidate from among motion information of spatial neighboring blocks, motion information of a temporal neighboring blocks, predefined motion information, and motion information that most frequently occurs in a reference picture, performing a motion information refinement on the derived motion refinement candidate, and generating a prediction block of a current block by using the motion refinement candidate having undergone the motion information refinement.