Abstract: A method of coding implemented by a decoding device, comprising: setting a value of candidate intra prediction mode of a current block to be a default value, wherein the current block is predicted using an intra prediction mode but not a Matrix-based Intra Prediction (MIP) mode and a neighboring block adjacent to the current block is used to derive the value of candidate intra prediction mode of the current block and is predicted using MIP mode; obtaining a value of the intra prediction mode of the current block according to the default value.

Abstract: A method of decoding includes partitioning a rectangular transform tree node (TTN) using either a vertical binary tree split or a horizontal binary tree split to generate square child TTNs when a maximum transform unit (TU) size for the TTN is smaller than either dimension of the TTN. The method further includes partitioning the child TTNs using a quadtree split to generate transform units (TUs) when the first child TTN dimension and the second child TTN dimension are larger than the maximum TU size, determining that the child TTNs are TUs when the first child TTN dimension and the second child TTN dimension are less than or equal to the maximum TU size, applying the TUs to transform coefficients to generate residuals, and generating a reconstructed block based on the residuals.

Abstract: The present disclosure relates to encoding and decoding of video images. Motion vectors are used as predictors for prediction of an image for a current coding unit CU, which is within a current coding tree unit CTU. The motion vectors are taken from a list of motion vector candidates MVCs. The list is generated for the current CU using a pattern of positions of allowed motion vectors, and in dependence on the positions of the pattern relative to the current CU, and on the position of the current CU within the current CTU. From the pattern, a subset of positions is selected and positions are restricted to positions within the current CTU, while other pattern positions not available or not stored in a buffer are excluded. Other excluded pattern positions may be substituted and/or adjusted to as to become available and/or are being stored in the buffer.

Abstract: A video coding mechanism for viewpoint dependent video coding is disclosed. The mechanism includes mapping a spherical video sequence into a plurality of sub-picture video sequences. The mechanism further includes encoding the plurality of sub-picture video sequences as sub-picture bitstreams to support merging of the plurality of sub-picture bitstreams, the encoding ensuring that each sub-picture bitstream is self-referenced and two or more of the sub-picture bitstreams can be merged to generate a single video bitstream using a lightweight bitstream rewriting process that does not involve changing of any block-level coding results. A mergeable indication is encoded to indicate that the sub-picture bitstream containing the indication is compatible with a multi-bitstream merge function for reconstruction of the spherical video sequence. A set of the sub-picture bitstreams and the mergeable indication are transmitted toward the decoder to support decoding and displaying a virtual reality video viewport.

Abstract: A method comprises: receiving, by a video decoder, a video bitstream comprising an RPL flag, wherein the RPL flag equal to a first value specifies that RPL signaling is present in a PH, and wherein the RPL flag equal to a second value specifies that RPL signaling is not present in the PH and may be present in slice headers; and decoding, by the video decoder using the RPL flag, a coded picture to obtain a decoded picture. A comprises: receiving, by a video decoder, a video bitstream comprising an SAO flag, wherein the SAO flag specifies that SAO information may be present or is not present in a PH or specifies that the SAO information may be present or is not present in slice headers; and decoding, by the video decoder using the SAO flag, a coded picture to obtain a decoded picture.

Abstract: Disclosed is a mechanism for selecting an interpolation filter for use in conjunction with an affine block in video coding. A motion vector is determined for a sub-block of the affine block based on control points. A sub-block size of the sub-block is also determined. The interpolation filter is selected for application to a reference block corresponding to the sub-block. The interpolation filter is selected based on the sub-block size. The motion vector of the sub-block and an offset of a current sample of the sub-block are employed to determine a reference sample at the reference block. This includes applying the interpolation filter to the reference block to determine the reference sample when the motion vector at the offset points to a fractional position at the reference block. The reference samples are employed to determine residual information in order to encode the affine block.

Abstract: The present disclosure relates to the field of picture processing. In particular, the present disclosure relates to improving intra prediction (such as the chroma intra prediction) using a cross component linear model (CCLM) and, more particularly, relating to spatial filtering used in a cross-component linear model for intra prediction with different chroma formats. An apparatus, an encoder, a decoder and corresponding methods for cross-component prediction for a picture, in which the set of down-sampling filters applied during the prediction depends on a chroma format, that may be one of multiple supported chroma formats are provided, so as to improve coding efficiency.

Abstract: A video coding mechanism is disclosed. The mechanism includes receiving a bitstream including a first slice of a coded image. The coded image is associated with a picture parameter set (PPS) in the bitstream. The first slice is associated with a slice header in the bitstream. A list of identifiers (IDs) is parsed from the PPS. A first ID is parsed from the slice header of the first slice. The first ID matches one of the IDs in the list of IDs in the PPS. A list of tiles coded in the first slice is determined based on the first ID. The first slice is determined to generate a reconstructed sub-image of the coded image.

Abstract: The present disclosure provides a coding method, wherein the coding includes decoding or encoding, and the method comprises determining whether a current coding unit is predicted by application of combined inter-intra prediction (CHIP); and in response to determining that the current coding unit is predicted by application of CIIP, setting a boundary strength of a boundary of the current coding unit to a first value.

Abstract: Techniques are described for using an inter-intra-prediction block. A video coder may generate a first prediction block according to an intra-prediction mode and generate a second prediction block according to an inter-prediction mode. The video coder may weighted combine, such as based on the intra-prediction mode, the two prediction blocks to generate an inter-intra-prediction block (e.g., final prediction block). In some examples, an inter-intra candidate is identified in a list of candidate motion vector predictors, and an inter-intra-prediction block is used based on identification of the inter-intra candidate in the list of candidate motion vector predictors.

Abstract: A method of obtaining a chrominance quantization parameter (QP) for chrominance components based on a luminance QP for a luminance component, wherein the method is performed by a decoder, and comprises parsing a received bitstream to obtain the luminance QP and information of a mapping function (ƒ) which associates a QP index (QPi) to a chrominance QP (QPc); obtaining the QPi based at least in part on the luminance QP; obtaining the mapping function based on the obtained information of the mapping function; and obtaining a QPc based on the obtained mapping function and the obtained QPi.

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: The present disclosure provides a chroma block prediction method and a device. The method includes: parsing a bitstream to obtain first indication information; downsampling a first luma block by a first filter when a value of the first indication information is a first value or by using a second filter when a value of the first indication information is a second value, to obtain a second luma block; obtaining a plurality of chroma samples and a plurality of luma samples; obtaining linear model coefficients based on the plurality of chroma samples and the plurality of luma samples; and obtaining a prediction value of the current chroma block based on the second luma block and the linear model coefficients.

Abstract: A method of decoding video data, including receiving a first block of video data encoded using an inter-prediction mode associating a first intra-prediction mode with the first block of video data, wherein the first intra-prediction mode is associated with a second block of video data, and determining a second intra-prediction mode for a neighbor block of video data based at least in part on the first intra-prediction mode.

Abstract: The present disclosure provides methods and devices. A video method of coding implemented by a decoding device, comprising: when a prediction mode of a current coding block is intra prediction, and the current coding block is processed by using Intra sub-partition coding mode, determining whether a width of a current transform block is larger than or equal to a first threshold or not, and whether the width of the current transform block is smaller than or equal to a second threshold or not, the current transform block corresponding to the current coding block; when the width of the current transform block is larger than or equal to the first threshold and the width of the current transform block is smaller than or equal to the second threshold, performing transform process on the current transform block, wherein a transform core based on DST 7 is used on horizontal direction transform.

Abstract: A mechanism for position dependent spatial varying transform (SVT) for video coding. A prediction block and a corresponding transformed residual block are received at a decoder. A type of spatial varying transform (SVT) employed to generate the transformed residual block is determined. A position of the SVT relative to the transformed residual block is also determined. An inverse of the SVT is applied to the transformed residual block to reconstruct a reconstructed residual block. The reconstructed residual block is then combined with the prediction block to reconstruct an image block.

Abstract: The present disclosure relates generally to video coding and picture partitioning methods. In particular, the disclosure is concerned with relations between partition constraint elements, by setting partitioning rules for different picture partitioning methods. The disclosure provides devices and corresponding methods for generating or processing a bitstream including encoded pictures, particularly for setting and including partition constraint element into the bitstream. One of the devices is configured to determine a minimum luma size of a leaf block resulting from quadtree splitting (MinQtSizeY), determine a maximum luma size of a coding block where partitioning using a binary tree splitting is allowed (MaxBtSizeY) based on the MinQtSizeY, and include information for the determined MinQtSizeY into the bitstream.

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: An example device for filtering decoded video data includes a memory configured to store video data; and one or more processors implemented in circuitry and configured to: decode a picture of video data; code a value for a syntax element representing a neural network model to be used to filter a portion of the decoded picture, the value representing an index into a set of pre-defined neural network models, the index corresponding to the neural network model in the set of pre-defined neural network models; and filter the portion of the decoded picture using the neural network model corresponding to the index.

Abstract: A method of decoding a coded video bitstream implemented by a video decoder is provided. The method includes the video decoder determining whether a value for a first flag is provided by an external input; setting a first flag equal to the value provided by the external input and a second flag equal to the value of the first flag to prevent a gradual decoding refresh (GDR) picture from being output when the value for the first flag is provided by the external input; decoding the GDR picture; and storing the GDR picture in a decoded picture buffer (DPB).