Abstract: A method of coding implemented by a decoding device or an encoding device, comprising obtaining indication information for a luma position (cbWidth/2, cbHeight/2) of a current coding block, relative to a top-left luma sample position (xCb, yCb) of the current coding block; setting a value of a luma intra prediction mode associated with the current coding block to a first default value, when the indication information indicates that an Intra Block Copy (IBC) mode or palette mode is applied for the luma component at the luma position (cbWidth/2, cbHeight/2), relative to the top-left luma sample position (xCb, yCb) of the current coding block; and obtaining a value of a chroma intra prediction mode based on the value of the luma intra prediction mode of the current coding block.

Abstract: The general intra prediction process is unnecessarily complicated with inclusion of the reference sample filtering. This application provides solutions for this problem. A method for intra prediction is provided. The method includes: during an intra predicted sample generation stage, obtaining a filtering indication, which indicates whether a filtered value or an unfiltered value of reference samples of the current coding block will be used. When the value of the filtering indication is true, a prediction sample is generated by using the filtered value of the reference samples based on the planar mode. When the value of the filtering indication is false, a prediction sample is generated by using the unfiltered value of the reference samples based on the planar mode. As a result, the reference sample filtering stage can be fully removed or can be combined with other stage.

Abstract: A partitioning method comprises determining whether a current block of a picture is a boundary block and whether the size of the current block is larger than a minimum allowed quadtree leaf node size; and if the current block is the boundary block and the size of the current block is not larger than the minimum allowed quadtree leaf node size (MinQTSize), applying forced binary tree (BT) partitioning to the current block. A method comprises making a determination that a current block of a picture is a boundary block and that a size of the current block is less than or equal to a minimum allowed quadtree (QT) leaf node size (MinQTSize); and applying, in response to the determination, forced binary tree (BT) partitioning to the current block.

Abstract: A method of coding implemented by a decoding device is provided. The method includes parsing a bitstream to obtain a flag from a picture header of the bitstream, wherein the flag indicates whether a current picture is I picture. when the flag indicates that the current picture is I picture, a syntax element designed for inter prediction is inferred to a default value; or when the flag indicates that the current picture is P or B picture, obtaining a syntax element designed for inter prediction from the picture header.

Abstract: Devices and methods for Intra prediction are provided. The method includes: obtaining a value of an indication information of a current block. When the value of the indication information indicates the intra prediction mode of the current block is not comprised in the set of most probable modes, deriving the intra prediction mode IntraPredModeY of the current block by the following ordered steps: i. IntraPredModeY is set equal to intra_luma_mpm_remainder[xCb][yCb], ii. The value of IntraPredModeY is incremented by one. The method can improve the efficiency to determine the intra prediction mode of the current block.

Abstract: 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.

Abstract: A method for operating a two-dimensional (2D) separable interpolation filter for coding a video, wherein the two-dimensional separable interpolation filter comprises a first and a second one-dimensional (1D) interpolation filter and a temporal buffer of a predetermined buffer size, wherein the method comprises: obtaining filter coefficients for the first one-dimensional interpolation filter of the two-dimensional interpolation filter; comparing a sum of positive filter coefficients of the obtained filter coefficients with a threshold; and upon determining that the sum of positive filter coefficients is larger than the threshold, amending one or more of the filter coefficients to obtain amended filter coefficients, wherein the one or more filter coefficients are amended such that a sum of positive filter coefficients of the amended filter coefficients is not larger than the threshold; applying the amended filter coefficients to samples of the video to obtain a value of a fractional sample position of the video

Abstract: An apparatus and a method for filtering reconstructed images, in particular, video images, with adaptive multiplicative filters. The efficiency of the filtering operation is increased by restricting the allowable values of the filter coefficients to those that have only a limited number of “ones” in the binary representation.

Abstract: A method of coding implemented by a decoding device, a decoder, an encoder are disclosed, the method comprising: obtaining a bitstream; obtaining a value of a syntax element sps_num_subpics_minus1 according to parse the bitstream; when the value of the syntax element sps_num_subpics_minus1 is greater than a preset value, obtaining a value of a syntax element sps_independent_subpics_flag from the bitstream.

Abstract: A method of coding implemented by a decoding device or an encoding device, comprising obtaining indication information for a luma position (cbWidth/2, cbHeight/2) of a current coding block, relative to a top-left luma sample postion (xCb, yCb) of the current coding block; setting a value of a luma intra prediction mode associated with the current coding block to a first default value, when the indication information indicates that a Matrix-based Intra Prediction (MIP) is applied for the luma component at the luma position (cbWidth/2, cbHeight/2), relative to the top-left luma sample postion (xCb, yCb) of the current coding block; and obtaining a value of a chroma intra prediction mode based on the value of the luma intra prediction mode of the current coding block.

Abstract: A deblocking filter of an image processing device is provided. The deblocking filter is used in an image coding process, for deblocking a block edge between a first coding block and a second coding block of an image. The first block has SA samples perpendicular to the block edge by N samples parallel to the block edge, and the second block has SB samples perpendicular to the block edge by N samples parallel to the block edge. No more than IA samples of the first coding block are used as first filter input values, and no more than IB samples of the second coding block are used as second filter input values. No more than MA samples of the first coding block are modified as first filter output values, and no more than MB samples of the second coding block are modified as second filter output values.

Abstract: A method for inverse quantization of a current block of a picture or a frame, where the method is performed by a decoder, and includes obtaining, by a decoder, from a bitstream, a joint chrominance residual (JCCR) mode for a current block of a picture or a frame, obtaining one or more quantization parameter (QP) offset values for chrominance components from the bitstream, determining at least one QP value for the current block depending on the JCCR mode, and performing an inverse quantization process on a chrominance component of the current block using the determined QP value.

Abstract: An apparatus and method of partitioning of an image or an image slice is described herein. In particular, on an image processing apparatus, the image or image slice is split into an integer number of coding tree units in both vertical and horizontal directions. The remaining boundary portion is then at least partly forced-split so that the deepest partitioning level is a result of binary partitioning, i.e. includes a coding unit which is longer on one side than on the other side. The longer side is parallel or concurrent to the image or image slice boundary.

Abstract: A method of decoding of a picture from a video bitstream is disclosed. The video bitstream includes a slice header of a current slice and data representing the current slice. The method comprises: obtaining a parameter used to derive a number of tiles in the current slice from the slice header when a slice address of the current slice is not an address of a last tile in the picture where the current slice located; and reconstructing the current slice using the number of tiles in the current slice and the data representing the current slice.

Abstract: A method for deblocking a chroma block edge between a first chroma block of a first image block and a second chroma block of a second image block. The method includes a decision process which includes: determining a first chroma quantization parameter for the first chroma block based on a first luma quantization parameter of a first luma block of the first image block and a chroma QP mapping table for the first chroma block; determining a second chroma quantization parameter for the second chroma block based on a second luma quantization parameter of a second luma block of the second image block and a chroma QP mapping table for the second chroma block; determining an averaged and rounded chroma quantization parameter based on the first chroma quantization parameter and the second chroma quantization parameter; and determining a threshold parameter based on the averaged and rounded chroma quantization parameter.

Abstract: A motion information storing method comprises: determining a distance between a sample set in the current block and the common boundary; and comparing the distance with a threshold to determine whether third motion information is stored for the sample set, wherein the third motion information is derived by the first motion information and the second motion information.

Abstract: The present disclosure provides apparatuses and methods for splitting an image into coding units. An image is divided into coding tree units (CTUs) which are hierarchically partitioned. Hierarchical partitioning includes multi-type partitioning such as binary tree or quad tree splitting. For CTUs completely within the image and CTUs on the boundary, respective multi-type partition depths are chosen. The present disclosure provides for multi-type partitioning flexibility in a boundary portion of the image.

Abstract: Signalling of syntax elements in a sequence parameter set of a video bitstream is addressed. Particularly, it is provided a method of decoding a video bitstream wherein a sequence parameter set, SPS, is coded that contains syntax elements that apply to a video sequence, the method comprising obtaining a value of a first syntax element from the SPS used to specify whether a decoded picture buffer, DPB, parameters syntax structure is present in the SPS and obtaining a value of a second syntax element from the SPS, at least when determining that the value of the first syntax element specifies that the DPB parameters syntax structure is present in the SPS, used to specify the presence of a DPB syntax element in the DPB parameters syntax structure, wherein the DPB syntax element is applied to a temporal sublayer except for the highest temporal sublayer in the video sequence.

Abstract: An apparatus and method for marking availability of a candidate coding block for merge estimation of a current coding block within a coding tree unit (CTU). The candidate block may be marked as unavailable if a splitting depth of the current coding block is equal to or larger than a predetermined threshold and a first location of the candidate block and a second location of the current block are included in a same merge estimation region (MER). Otherwise, the candidate block is marked as available. A candidate block may be marked as unavailable also, when a parent block “parentCurr” of the current block and a parent block “parentCand” of the candidate block, with both parent blocks obtained by splitting, are the same block and when the size of the parentCand is smaller than a threshold.

Abstract: A method of coding implemented by a decoding device, comprising obtaining a video bitstream; decoding the video bitstream to obtain an initial intra prediction mode value for chroma component of a current coding block; determining whether a ratio between a width for luma component of the current coding block and a width for chroma component of the current coding block is equal to a threshold or not; obtaining a mapped intra prediction mode value for chroma component of the current coding block according to a predefined mapping relationship and the initial intra prediction mode value, when it's determined that the ratio is equal to the threshold; obtaining a prediction sample value for chroma component of the current coding block according to the mapped intra prediction mode value.