Abstract: The present disclosure relates to deblocking filtering, which may be advantageously applied for block-wise encoding and decoding of images or video signals. In particular, the present disclosure relates to an improved memory management in an automated decision on whether to apply or skip deblocking filtering for a block and to selection of the deblocking filter. The decision is performed on the basis of a segmentation of blocks in such a manner that memory usage is optimized. Preferably, the selection of appropriate deblocking filters is improved so as to reduce computational expense.

Abstract: An image includes a plurality of rows of largest coding units (LCUs). Encoding the image includes determining whether or not wavefront parallel processing is enabled, and partitioning the plurality of rows of LCUs to comprise a normal slice and a group of dependent slices. The normal slice includes at least one LCU, and the group of dependent slices includes at least one LCU and consists of every dependent slice that uses information from a slice header of the normal slice for encoding. Based on the determination that wavefront parallel processing is enabled, the partitioning of the plurality of rows of LCUs is restricted such that a last LCU in the group of dependent slices belongs in a same row as a first LCU of the normal slice when the first LCU of the normal slice is not a first LCU of the row.

Abstract: The present disclosure relates to a method and device of decoding video data. The device and method use a mapping process to simplify the calculation procedure for intra prediction, to improve coding efficiency. The decoding of encoded data comprises: obtaining an indication indicating whether the intra-prediction mode for a picture block is in a set of most probable modes, MPM, or not; if the indication indicates that the intra prediction mode for the picture block is not in the set of MPMs, generating a mapping relationship between at least one intra prediction mode in the first set of intra prediction modes and at least one intra prediction mode in the set of non-MPMs; decoding the encoded data to obtain an intra prediction mode codeword for the picture block; and obtaining the intra prediction mode for the picture block according to the mapping relationship and the intra prediction mode codeword.

Abstract: Embodiments provide an apparatus and method of partitioning of an image or an image slice. 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. Boundary coding tree units are then at least partially forced-split so that at least one resulting coding unit is a result of binary-tree 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. Recursively partitioning coding units that span the picture boundary without the requirement for signaling partition information in a bitstream can be achieved.

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, includes obtaining a bitstream wherein at least one bit in the bitstream representing a syntax element for a current block, wherein the syntax element specifies the clipping index of the clipping value for an adaptive loop filter (ALF); parsing the bitstream to obtain a value of the syntax element for the current block, wherein the syntax element is coded using a fixed length code; applying adaptive loop filtering on the current block, based on the value of the syntax element for the current block. Herein fixed length code means that all possible values of the syntax element are signaled using the same number of bits.

Abstract: A coding apparatus configured to select an intra prediction mode for a current block, encode the selected intra prediction mode using truncated binary coding every time the selected intra prediction mode is a remaining mode, and encode the selected intra prediction mode using N bits when the selected intra prediction mode is included in a first portion from remaining modes and using N+1 bits when the selected intra prediction mode is included in a second portion of the remaining modes.

Abstract: A system and method for processing a video stream are provided. When coding or decoding a video stream a de-blocking filtering may be applied for reducing discontinuities caused by use of a block-based video coding. The de-blocking filtering is performed using a filter grid. The size of the filter grid is chosen adaptively based on the processing parameters. The adaptive size of the filtering grid is determined based on the number of samples used and modified in de-blocking filtering of an edge of a coding block. The filtering grid may be used both for vertical and horizontal edge filtering.

Abstract: An in-loop deblocking filter apparatus (120) for processing a current row or column of samples into a filtered row or column of samples. The current row or column of samples comprises a plurality of samples from a first sample block and a horizontally or vertically neighboring second sample block of a reconstructed picture of a video stream. The samples of the current row or column of samples have sample values pN?1?p0, q0?qN?1 wherein N is an even integer greater than 2. If a first condition or a second condition is satisfied, the current row or column is processed by: determining a filtered sample value q0? by applying a (2N?1)-tap filter to the sample values pN?2, . . . , p0, q0, . . . , qN?1 of the current row or column; and/or determining a filtered sample value p0? by applying a (2N?1)-tap filter to the sample values pN?1, . . . , p0, q0, . . . , qN?2 of the current row or column.

Abstract: The present invention relates to the performance of motion vector refinement in a search space for multi-reference inter-prediction. Two or more reference pictures are selected, one of those used for motion vector refinement. Based on an initial estimate of a motion vector to the reference picture for motion vector refinement, a search space in this reference image is constructed. Using template matching, the first motion vector is refined. The second motion vector to another reference picture is calculated using its initial estimate, the initial estimate of the first motion vector and the refined first motion vector.

Abstract: The present disclosure provides a method of coding implemented by a decoding device, the method comprising: obtaining a splitting mode index value for a current coding block; obtaining an angle index value angleIdx for the current coding block according to the splitting mode index value and a table that specifies the angle index value angleIdx based on the splitting mode index value; setting an index value partIdx according to the angle index value angleIdx; and decoding the current coding block according to the index value partIdx.

Abstract: The present disclosure relates to means to enable reduction of memory access in motion vector determination and/or refinement for a prediction block. In particular, the present disclosure relates to means to enable reduction of memory access in motion vector determination and/or refinement performed on a sub prediction block basis. In other words, a prediction block is split into sub prediction blocks for which at least the motion vector refinement is performed individually. The memory access window which limits the samples accessible during the motion vector determination and refinement of the sub prediction blocks does not exceed the memory access window for performing the motion vector determination and/or refinement for the prediction block.

Abstract: Apparatuses and methods for encoding and decoding a video are provided. A method includes determining whether at least one of two blocks of an image in a video is predicted with a combined inter-intra prediction (CIIP), wherein the two blocks include a first block (block Q) and a second block (block P). There is a boundary between the two blocks. The method further includes setting a boundary strength (Bs) for the boundary to a first value based on determining that at least one of the two blocks is predicted with the CIIP, and performing deblocking for the boundary between the first block and the second block based on the Bs to generate a modified reconstructed block for each of the first block and the second block.

Abstract: The present disclosure relates to deblocking filtering which is applicable to smoothing the block boundaries in an image or video coding and decoding. In particular, the deblocking filtering is either strong or weak, wherein the clipping is performed differently in the strong filtering and the weak filtering.

Abstract: The present disclosure provides an encoding apparatus and a decoding apparatus, as well as an encoding method and a decoding method. In particular, the present disclosure relates to block partitioning and signaling the partitioning parameters in a bitstream. An override flag in a slice header indicates whether or not a block is to be partitioned according to a first partition constraint information. The override flag is included in the bitstream and the block is partitioned accordingly.

Abstract: A method of coding implemented by a decoding device, comprising obtaining a value of a parameter for a current block, the value of the parameter indicating a partition mode for the current block; obtaining a first prediction mode for the current block; obtaining a second prediction mode for the current block; generate a first prediction value for a chroma sample in the current block according to the first prediction mode; generate a second prediction value for a chroma sample in the current block according to the second prediction mode; obtaining a combined prediction value by combining the first prediction value and the second prediction value.

Abstract: A method of coding implemented is provided. The method includes the following operations: obtained the height and width of a prediction block without applying clipping operation; calculating a value of a vertical component of an intra prediction sample based on the height and width of the prediction block; calculating a value of a horizontal component of the intra prediction sample based on the height and width of the prediction block; and generating the intra prediction sample based on the value of the vertical component and the value of the horizon component.

Abstract: A deblocking method, for deblocking a transform block boundary within a coding block in an image encoding and/or an image decoding is provided, wherein the coding block comprising transform blocks is coded in inter prediction mode and the transform blocks comprises a first transform block and a second transform block; wherein the method comprises: determining, when the boundary between the first transform block and the second transform block is a transform block boundary and at least one of the first transform block and the second transform block has one or more non-zero transform coefficients, a value of a BS parameter for the boundary between the first transform block and the second transform block to be a first value; and performing de-blocking filtering process to the boundary between the first transform block and the second transform block at least based on the value of the boundary strength parameter.

Abstract: A method of intra prediction of a block, comprising obtaining two lines of reconstructed neighboring samples; deriving a set of reference samples based on the two lines of reconstructed neighboring samples; obtaining a set of MIP coefficients based on a intra prediction mode obtained from a bitstream, wherein a MIP coefficient CMIP of the set of MIP coefficients is obtained based on CMIP=vsgn·(q<<s), where q is a magnitude of the MIP coefficient, wherein s is a left shift value and vsgn is a sign value of the MIP coefficient; and obtaining a prediction block based on the set of reference samples and the set of MIP coefficients, wherein a reconstruct picture is obtained based on the prediction block.

Abstract: A method of coding implemented by a decoding device or an encoding device comprises determining an intra prediction mode of a current block; and determining selecting of a secondary transform of the current block based on the intra prediction mode determined for the current block.