Abstract: Embodiments of the present application provide an inter prediction method, an encoder, a decoder, and a storage medium. The method comprises: determining a prediction mode parameter of a current block; when the prediction mode parameter indicates that the current block determines an inter prediction value by using a geometrical partition mode (GPM), constructing a merge candidate list of the current block; constructing a GPM motion information candidate list according to first motion information in the merge candidate list of the current block; and determining an inter prediction value of the current block according to the GPM motion information candidate list.

Abstract: An inter prediction method comprising: determining a prediction mode parameter of a current block which indicates using a GPM to determine an inter prediction value of the current block, obtaining a merge motion information candidate list, wherein the merge motion information candidate list comprises one or more motion candidate information item and the motion candidate information item comprises one or two motion vector generating a GPM motion information candidate list by using the motion vectors included in the motion candidate information items according to a sequence of the motion candidate information items in the merge motion information candidate list comprises a motion vector; selecting, from the GPM motion information candidate list, a first motion vector of a first partition and a second motion vector of a second partition in the current block; and determining the inter prediction value by using the first motion vector and the second motion vector.

Abstract: A method for decoding a picture, a method for encoding a picture, an encoder, and a decoder are provided. The method for encoding a picture includes (i) determining a width and a height of a coding block in the picture; (ii) if the width and the height are equal to N, where N is a positive integer power of 2, determining a matrix-based intra prediction (MIP) size identifier indicating that an MIP prediction size equal to N; (iii) deriving a group of reference samples of the coding block; and (iv) deriving an MIP prediction of the coding block based on the group of reference samples and an MIP matrix corresponding to the MIP size identifier.

Abstract: Provided are inter prediction methods and a decoder. In the method, a bitstream is parsed to determine a prediction mode parameter of a current block; a Geometrical Partition Mode (GPM) parameter of the current block and a merge candidate list of the current block and attribute information of motion information in the merge candidate list are determined when the prediction mode parameter indicates to determine an inter prediction value of the current block by using GPM; a first motion information mapping table of a first partition and a second motion information mapping table of a second partition are determined according to the GPM parameter, merge candidate list and attribute information; and the inter prediction value of the current block is determined based on the first and second motion information mapping tables and merge candidate list.

Abstract: Provided by implementations of the present application are a point cloud encoding method and decoding method, encoder and decoder, and a storage medium. The point cloud encoding method comprises: when an encoder encodes geometric information on the basis of an octree, selecting n adjacent nodes from all encoded adjacent nodes corresponding to a current node, n being an integer greater than or equal to 1 and less than or equal to 7; acquiring occupancy bitmaps of the n adjacent nodes and an occupancy bitmap of the current node, the occupancy bitmaps being used to indicate whether a node comprises at least one point in a point cloud; determining a context according to the occupancy bitmaps of the n adjacent nodes; and using the context to encode the occupancy bitmap of the current node, and obtaining code bitstream of the occupancy bitmap of the current node.

Abstract: A method and device for intra prediction are provided. The method includes: when determining that a current level obtained by partitioning an input point cloud is lower than a target level, obtaining occupation information of a first number of neighbouring nodes of a current node; extracting occupation information of a second number of neighbouring nodes from the occupation information of the first number of neighbouring nodes, the first number being greater than the second number, and the second number of neighbouring nodes being in an association relationship with a child node of the current node, and performing intra prediction on occupation information of the child node of the current node based on the occupation information of the second number of neighbouring nodes to obtain a first prediction result.

Abstract: 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).

Abstract: A method for colour component prediction, applied to an encoder and includes: determining a neighbouring reference sample set of a current block, wherein the neighbouring reference sample set comprises at least one reference sample; determining a preset parameter value corresponding to the current block, including: determining a bitdepth value corresponding to a to-be-predicted colour component of the current block; and performing a shift on 1 by the bitdepth value minus 1 to obtain the preset parameter value. The method further includes: determining an input sample matrix by means of a first preset calculation model based on the neighbouring reference sample set and the preset parameter value; and performing colour component prediction on the current block according to the input sample matrix to obtain a prediction block of the current block.

Abstract: Point cloud coding methods, an encoder, and a decoder are provided. The method includes the following. Morton codes for a point cloud are obtained according to geometry information of the point cloud after geometry decoding is completed and the geometry information is reconstructed. The point cloud is determined as an input point cloud of an iteration. Morton codes for an input point cloud of an i-th iteration are right shifted by K bits according to a number of points in the input point cloud of the i-th iteration, where K is a positive integer. A point is selected from points with a same value of Morton codes after right shifted by K bits. An i-th level of detail (LOD) layer is formed with the point selected. Color information is decoded according to the LOD layer.

Abstract: Disclosed in the implementations of the present disclosure are a mapping method, an encoder, a decoder, and a computer storage medium. The method may include: determining an intra prediction mode used at the time of encoding or decoding a current block; mapping, if the intra prediction mode is a MIP mode, the MIP mode to a first non-MIP mode; and mapping, if the intra prediction mode is a non-MIP mode, the non-MIP mode to a second MIP mode.

Abstract: Chroma intra prediction methods and devices are provided.

Abstract: An image decoding method, a decoder and a storage medium are porovided. The method includes: receiving code stream data, and parsing the code stream data to obtain a coding tree unit corresponding to the code stream data; parsing an i-th node of i-th layer corresponding to the coding tree unit to obtain i-th state parameter and i-th flag parameter corresponding to the i-th node; performing detection processing on the i-th node according to the i-th state parameter and the i-th flag parameter to obtain an i-th detection result; acquiring a (i+1)th node of a (i+1)th layer corresponding to the coding tree unit; continuing to perform detection processing on the (i+1)th node, and traversing all the nodes corresponding to the coding tree unit until all the coding unit data corresponding to the coding tree unit is obtained; and generating a decoded image corresponding to the code stream data.

Abstract: A method for decoding a picture, a method for encoding a picture, an encoder, and a decoder are provided. The method for encoding a picture includes (i) determining a width and a height of a coding block in the picture; (ii) if the width and the height are equal to N, where N is a positive integer power of 2, determining a matrix-based intra prediction (MIP) size identifier indicating that an MIP prediction size equal to N; (iii) deriving a group of reference samples of the coding block; and (iv) deriving an MIP prediction of the coding block based on the group of reference samples and an MIP matrix corresponding to the MIP size identifier.

Abstract: A method and device for predicting colour component and a computer storage medium are provided. The method includes: acquiring at least one threshold value according to first colour component reconstructed values of all samples of a current coding block; performing grouping according to comparison results between a first colour component neighboring reference values of current coding block and the at least one threshold value to obtain at least two groups of first colour component neighboring reference values and second colour component neighboring reference values; establishing at least two computing models; selecting, according to comparison results between the first colour component reconstructed values and at least one threshold value, a computing model corresponding to each sample in current coding block from at least two computing models; and acquiring, according to the computing model corresponding to each sample, second colour component prediction values of all samples in the current coding block.

Abstract: Disclosed in the implementations of the present disclosure are a mapping method, an encoder, a decoder, and a computer storage medium. The method may include: determining an intra prediction mode used at the time of encoding or decoding a current block; mapping, if the intra prediction mode is a MIP mode, the MIP mode to a first non-MIP mode; and mapping, if the intra prediction mode is a non-MIP mode, the non-MIP mode to a second MIP mode.

Abstract: 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).

Abstract: Disclosed are a partitioning method, an encoder, a decoder and a computer storage medium. The method includes: determining location information of a point of a point cloud to be partitioned; when i is less than or equal to M?1, determining right-shift number Ni of ith LOD layer in the point cloud, M representing a preset maximum quantity of layers for LOD partitioning; for the ith LOD layer, shifting location information of the point rightwards by Ni-digit, performing storing in a preset storage area based on right-shifted location information; determining location information of a parent point corresponding to a current point in the ith LOD layer; according to determined location information of the parent point, searching the preset storage area for a neighbor point of the parent point; partitioning the current point into an (i+1)th LOD layer, or the neighbor point into the ith LOD layer.

Abstract: A method for intra prediction includes: enabling intra prediction, and determining occupancy information of a first number of neighboring nodes of a coded node; determining occupancy information of a second number of neighboring nodes of the coded node based on a position association between at least one neighboring node of the coded node and a child node of the coded node, where the first number is greater than the second number; and determining an occupancy prediction result of the child node of the coded node based on the occupancy information of the second number of neighboring nodes. An encoder for implementing the above method is also provided.

Abstract: Implementations of this application provide point cloud partition methods, an encoder, and a decoder. The method includes the following. Morton codes for a point cloud are obtained according to geometry information of the point cloud. The point cloud is determined as an input point cloud of an iteration. Morton codes for an input point cloud of an i-th iteration are right shifted by K bits according to a number of points in the input point cloud of the i-th iteration, where K is a positive integer. A point is selected from points with a same value of Morton codes after right shifted by K bits. An i-th level of detail (LOD) layer is formed with the point selected.

Abstract: An intra prediction method and a decoder are provided. The method includes the following. Coordinate information of a current node and a current level corresponding to the current node are determined. A current quantity is determined based on the current level, where the current quantity is positively correlated with the current level. Current neighbour nodes are determined based on the coordinate information of the current node, where the current neighbour nodes are neighbour nodes of the current quantity among neighbour nodes of a parent node of the current node. Intra prediction is performed on the current node based on the coordinate information of the current node and the current neighbour nodes.