A video encoder, a video decoder, and a corresponding method are provided. The method includes: parsing a bitstream to obtain an index, where the index indicates a target candidate motion vector group of a current coding block; determining the target candidate motion vector group in an affine candidate motion vector list based on the index, where the affine candidate motion vector list includes at least a first candidate motion vector group, the first candidate motion vector group is obtained based on a first group of control points of a first neighboring affine coding block, and the first group of control points is determined based on a CTU located relative to the current coding block, wherein the first neighboring affine coding block is located in the CTU; and predicting a predicted sample value of the current coding block based on the target candidate motion vector group.

A method for video encoding includes setting a motion vector precision associated with a current block to be encoded in a current picture, and determining a motion vector for encoding the current block based on the motion vector precision. The method also includes determining a motion vector difference for the current block based on (i) the determined motion vector for encoding the current block, (ii) a predicted motion vector of the current block in inter prediction mode, and (iii) the motion vector precision. The method further includes encoding the current block according to the determined motion vector, and generating a coded video bitstream including the encoded current block and including prediction information indicating that the current block is coded in inter prediction mode and indicating the determined motion vector difference for the current block.

A method for video encoding includes setting a motion vector precision associated with a current block to be encoded in a current picture, and determining a motion vector for encoding the current block based on the motion vector precision. The method also includes determining a motion vector difference for the current block based on (i) the determined motion vector for encoding the current block, (ii) a predicted motion vector of the current block in inter prediction mode, and (iii) the motion vector precision. The method further includes encoding the current block according to the determined motion vector, and generating a coded video bitstream including the encoded current block and including prediction information indicating that the current block is coded in inter prediction mode and indicating the determined motion vector difference for the current block.

A method of video encoding includes determining whether a reference block for a current block is located in a different coding tree unit (CTU) than a CTU of the current block. The method also includes, in response to the reference block being located in the different CTU, (i) determining whether a memory location of a reference sample memory for the reference block is available. The second area is collocated in the different CTU with a position of the first area in the CTU of the current block. In response to the determination that the reference block is located in the different CTU, the method also includes, (ii) in response to a determination that the memory location for the reference block is available, retrieving, from the memory location corresponding to the reference block, one or more samples to encode the current block.

A method of video encoding includes determining whether a reference block for a current block is located in a different coding tree unit (CTU) than a CTU of the current block. The method also includes, in response to the reference block being located in the different CTU, (i) determining whether a memory location of a reference sample memory for the reference block is available. The second area is collocated in the different CTU with a position of the first area in the CTU of the current block. In response to the determination that the reference block is located in the different CTU, the method also includes, (ii) in response to a determination that the memory location for the reference block is available, retrieving, from the memory location corresponding to the reference block, one or more samples to encode the current block.

Video processing methods and apparatuses for processing a current block in a current picture by reference picture resampling include receiving input data of the current block, determining a scaling window of the current picture and a scaling window of a reference picture. The current picture and reference picture may have different scaling window sizes. A ratio between a scaling window width, height, or size of the current picture and a scaling window width, height, or size of the reference picture is constrained to be within a ratio constraint. A reference block is generated from the reference picture according to the ratio, and used to encode or decode the current block.

A moving picture decoding apparatus, method, and medium for decoding a current block are provided. A first candidate is derived from a first motion vector that has been used to decode a first block. The first block is adjacent to the current block. A first index identifying a reference picture to be selected for decoding the current block is decoded. A second candidate having a second motion vector that includes a non-zero value is derived. The non-zero value is assigned to the reference picture. A selected candidate is selected from a plurality of candidates, including the first candidate and the second candidate. A second index identifying the selected candidate is decoded. The current block is decoded using the selected candidate. The second candidate includes the non-zero value of the reference picture, with the reference picture being selected from a plurality of referable reference pictures.

A moving picture decoding apparatus, method, and medium for decoding a current block are provided. A first candidate is derived from a first motion vector that has been used to decode a first block. The first block is adjacent to the current block. A first index identifying a reference picture to be selected for decoding the current block is decoded. A second candidate having a second motion vector that includes a non-zero value is derived. The non-zero value is assigned to the reference picture. A selected candidate is selected from a plurality of candidates, including the first candidate and the second candidate. A second index identifying the selected candidate is decoded. The current block is decoded using the selected candidate. The second candidate includes the non-zero value of the reference picture, with the reference picture being selected from a plurality of referable reference pictures.

Obtaining one or more motion vector predictor candidates includes: (a1) generating a motion vector predictor candidate, based on motion vectors of first adjacent blocks adjacent to a block to be processed in a first direction; and (a2) generating a motion vector predictor candidate, based on motion vectors of second adjacent blocks adjacent to the block to be processed in a second direction, and step (a2) includes: determining whether the first adjacent blocks include an inter-predicted block; and searching for a motion vector on which scaling processing can be performed from among the motion vectors of the second adjacent blocks when it is determined that the first adjacent blocks do not include an inter-predicted block, and executing, when the motion vector on which scaling processing can be performed is obtained in the search, scaling processing on the motion vector obtained in the search.

Obtaining one or more motion vector predictor candidates includes: (a1) generating a motion vector predictor candidate, based on motion vectors of first adjacent blocks adjacent to a block to be processed in a first direction; and (a2) generating a motion vector predictor candidate, based on motion vectors of second adjacent blocks adjacent to the block to be processed in a second direction, and step (a2) includes: determining whether the first adjacent blocks include an inter-predicted block; and searching for a motion vector on which scaling processing can be performed from among the motion vectors of the second adjacent blocks when it is determined that the first adjacent blocks do not include an inter-predicted block, and executing, when the motion vector on which scaling processing can be performed is obtained in the search, scaling processing on the motion vector obtained in the search.