The present disclosure relates to motion vector refinement. As a first step, an initial motion vector and a template for the block are obtained. Then, the refinement of the initial motion vector is determined by template matching with said template in a search space. The search space is located on a position given by the initial motion vector and includes one or more fractional sample positions, wherein each of fractional sample positions belonging to the search space is obtained by interpolation filtering with a filter of a predefined tap-size assessing integer samples only within a window, said window being formed by integer samples accessible for the template matching in said search space.

A motion vector coding unit executes processing including a neighboring block specification step of specifying a neighboring block which is located in the neighborhood of a current block; a judgment step of judging whether or not the neighboring block has been coded using a motion vector of another block; a prediction step of deriving a predictive motion vector of the current block using a motion vector calculated from the motion vector of the other block as a motion vector of the neighboring block; and a coding step of coding the motion vector of the current block using the predictive motion vector.

A motion vector coding unit executes processing including a neighboring block specification step of specifying a neighboring block which is located in the neighborhood of a current block; a judgment step of judging whether or not the neighboring block has been coded using a motion vector of another block; a prediction step of deriving a predictive motion vector of the current block using a motion vector calculated from the motion vector of the other block as a motion vector of the neighboring block; and a coding step of coding the motion vector of the current block using the predictive motion vector.

This application provides an image block matching method performed at a computing device, the method including: obtaining a target image block and an image; identifying a candidate image block within the image and multiple search points in the candidate image block; calculating a plurality of differences between the target image block and the candidate image block, each difference corresponding to a respective search point; choosing, among the plurality of differences, a smallest value and a corresponding smallest-value search point; and when the smallest-value search point is at the center of the target image block, choosing the candidate image block as a match of the target image block.

This application provides an image block matching method performed at a computing device, the method including: obtaining a target image block and an image; identifying a candidate image block within the image and multiple search points in the candidate image block; calculating a plurality of differences between the target image block and the candidate image block, each difference corresponding to a respective search point; choosing, among the plurality of differences, a smallest value and a corresponding smallest-value search point; and when the smallest-value search point is at the center of the target image block, choosing the candidate image block as a match of the target image block.

The present disclosure relates to motion vector refinement. As a first step, an initial motion vector and a template for the block are obtained. Then, the refinement of the initial motion vector is determined by template matching with said template in a search space. The search space is located on a position given by the initial motion vector and includes one or more fractional sample positions, wherein each of the fractional sample positions belonging to the search space is obtained by interpolation filtering with a filter of a predefined tap-size assessing integer samples only within a window, said window being formed by integer samples accessible for the template matching in said search space.

Processing methods for motion compensation, an encoder, and a decoder are provided. The method includes the following. Determine a search position constellation with a point pointed by an initial motion vector as a center point, where the search position constellation includes N directions, search for at least one search point by using at least one type of step lengths in the directions, where the at least one search point at least includes at least one search point in diagonal directions. Search for at least one search position from the search position constellation based on a preset range coverage rule, where the preset range coverage rule is to arrange search points in the directions for search. Obtain a new motion vector according to the at least one search position, and perform motion compensation based on the new motion vector to obtain a prediction value of a coding unit (CU).

Video decoder and/or video encoder, configured to determine a set of search area location candidates in a reference picture of a video; match the set of search area location candidates with a current template area adjacent to a current block of a current picture to obtain a best matching search area location candidate; select, out of a search area positioned in the reference picture at the best matching search area location candidate, a set of one or more predictor blocks by matching the current template area against the search area; and predictively decode/encode the current block from/into a data stream based on the set of one or more predictor blocks.

Motion information for an internal sub-block of a larger block can be derived for use in encoding or decoding the video block or a coding unit by using the motion information for sub-blocks on the left or top edge of the coding block. The left column of edge sub-blocks and the top row of sub-blocks has motion information, such as motion vectors, derived using such techniques as template matching. The motion vectors of these edge sub-blocks are used in deriving the motion vectors of internal sub-blocks, which leads to better prediction and improved coding efficiency. In another embodiment, other motion information for internal sub-blocks is derived from corresponding information of the edge sub-blocks.

A video encoding method of estimating a motion vector of a current block in a current frame includes identifying a reference block in a reference frame, a first location of the current block within the current frame corresponding to a second location of the reference block within the reference frame, setting a search range in the reference frame, searching for candidate blocks from the search range of the reference frame, each of the candidate blocks satisfying a corresponding first motion estimation criterion of first motion estimation criteria, searching for a prediction block from among the candidate blocks, the prediction block satisfying a second motion estimation criterion, estimating, as the motion vector of the current block, a motion vector corresponding to a displacement between the reference block and the prediction block, and encoding the current block based on the estimated motion vector.