Abstract: At least a method and an apparatus are provided for efficiently encoding or decoding video. For example, a plurality of different motion prediction modes for a current block are obtained. The current block is encoded or decoded based on a combination of the plurality of different motion prediction modes with corresponding weights for a plurality of sub-blocks of the current block, wherein the combination with the corresponding weights comprising an inter prediction mode and an intra prediction mode.

Abstract: Different quantization matrices may be transmitted corresponding to different block sizes, color components and prediction modes. To more efficiently signal the coefficients of the quantization matrices, in one implementation, a unified matrix identifier matrixId is used, based on a size identifier (sizeId) that relates to CU size with larger sizes listed first, and a matrix type (matrixTypeId) with luma QMs listed first. For example, the unified identifier is derived as: matrixId=N*sizeId+matrixTypeId, where N is the number of possible type identifiers, e.g., N=6. This single identifier allows referring to any previously transmitted matrix when using prediction (copy), and transmitting larger matrices first avoids interpolation in the prediction process. When a block uses the Intra Block Copy prediction mode, QM identifier may be derived as if the block uses the INTER prediction mode.

Abstract: A method for decoding comprising obtaining an encoded video stream comprising a bitstream portion gathering high level syntax elements, at least one of said syntax elements providing an information indicating if a use of an encoding tool or feature corresponding to that high level syntax element is allowed in the encoded video stream; and, determining from a high level syntax element comprised in the bitstream portion if a use of an encoding tool or feature is allowed for decoding the encoded video stream, wherein the encoding tool or feature is at least one of Multi-Type Tree, a scaling matrix, Long Term Reference Picture, a maximum transform unit size equal to a predetermined highest possible maximum transform unit size or weighted prediction.

Abstract: Different implementations are described, particularly implementations for video encoding and decoding are presented. Accordingly, the encoding or decoding comprises obtaining parameters of a decoded picture buffer used in decoding an encoded picture. The signaling of parameters relative to the decoded picture buffer is controlled by a syntax data element sps_sublayer_dpb_params_flag related to the control of the presence of syntax elements in a decoded picture buffer parameters syntax structure in a SPS. According to a particular characteristic, the syntax data element sps_sublayer_dpb_params_flag is inferred to zero when the syntax data element sps_ptl_dpb_hrd_params_present_flag specifies that decoded picture buffer parameters syntax structure is not present in the SPS.

Abstract: Methods and apparatus for implementing Discrete Trigonometric transforms are based on maximum transform size. In one embodiment, matrix-based intra prediction is enabled for coding unit sizes up to a specified size, regardless of the maximum transform size. In another embodiment, low-frequency non-separable transforms are used to improve coding gain. Syntax in a bitstream can be used to indicate a coding tool that is used.

Abstract: At least a method and an apparatus are provided for efficiently encoding or decoding video. For example, a plurality of different motion prediction modes for a current block are obtained. The current block is encoded or decoded based on a combination of the plurality of different motion prediction modes with corresponding weights for a plurality of sub-blocks of the current block, wherein the combination with the corresponding weights comprising an inter prediction mode and an intra prediction mode.

Abstract: Different implementations are described, particularly implementations for video encoding and decoding are presented. Accordingly, the encoding or decoding comprises obtaining a residual coding mode of a block of a picture, wherein the residual coding mode is one of regular residual coding mode (RRC) or transform skip residual coding mode (TSRC); decoding the block of the picture according to the obtained residual coding mode. According to a particular characteristic, the residual coding mode is set to regular residual coding mode (RRC) when transform skip is disabled. According to another particular characteristic, the residual coding mode is decoded from a syntax element when transform skip is enabled.

Abstract: A method and apparatus to improve compression efficiency in a video compression scheme enables separate control of a local chroma quantization parameter. The control can be used to disable a local chroma quantization parameter. One embodiment uses an existing local luma quantization parameter control flag for controlling local chroma quantization parameter. Another embodiment includes a separate local chroma quantization parameter control flag. Bitstream syntax is used to convey the flags.

Abstract: In some chroma formats, monochrome processing is performed for each color component. For example, for 4:0:0, only luma components exist, and all chroma related syntax and code are not used. In addition, for 4:4:4 when separable color plane is activated, the chroma components are treated as independent luma components, and the codec may behave as if no chroma is present at all and no chroma related tools are used. To reduce redundancy in coding parameters related to chroma, in one implementation, a flag indicating the availability of chroma components is coded. In another implementation, inter-related syntax is omitted in an intra-only coding mode for video data. In addition, slice level control of LMCS is provided.

Abstract: An apparatus (for example, a decoder) may determine that affine mode is enabled for a video sequence. The apparatus may determine whether an affine mode adaptive motion vector difference resolution (AMVR) enablement indicator is present in a parameter set associated with the video sequence based on a value of an AMVR enablement indicator. If the value of the AMVR enablement indicator indicates AMVR mode is enabled for the video sequence, the apparatus may determine that the affine mode AMVR enablement indicator is present in the parameter set associated with the video sequence. If the value of the AMVR enablement indicator indicates AMVR mode is disabled for the video sequence, the apparatus may determine that the affine mode AMVR enablement indicator is not present in the parameter set associated with the video sequence. The apparatus may decode the video sequence accordingly.

Abstract: An apparatus for processing a video may receive a quantization parameter (QP) adjustment value associated with a syntax level at the syntax level. In examples, the apparatus may obtain the QP adjustment value associated with the syntax level, for example, via signalling at the syntax level. The apparatus may apply the QP adjustment value to a QP associated with the syntax level to obtain an adjusted QP associated with the syntax level. The syntax level may include a coding block level or a transform unit (TU) level. In examples, if the syntax level is a TU level, the decoder may receive the QP adjustment value for a first CU (for example, a current TU) and obtain a QP for the second TU that precedes the first CU in a coding order based on a QP predictor, for example, instead of the QP adjustment value for the first TU.

Abstract: Sub-block merge motion field is combined with triangle partitioning and geometric partitioning modes to further give coding and decoding schemes flexibility. In at least one embodiment, a flag is used to signal if sub-block merge candidates are used in place of regular merge candidates. In another embodiment, regular merge candidates are replaced by sub-block merge candidates. In another embodiment, at least one motion field is stored. In another embodiment, all sub-block merge candidates or only sub-block temporal motion vector predictors or only affine predictors are considered.

Abstract: In an encoding apparatus or a decoding apparatus, an encoding method or decoding method combines various coding tools with intra sub partitioning mode in which a coding unit is split in multiple sub partitions. At least one embodiment particularly aims at the selection of primary transforms among a set of multiple transforms for video encoding or decoding of intra sub block partitions. At least one embodiment particularly aims at intra coding using Ma-trix-Based Intra Prediction mode combined with Intra Sub Partition mode. At least one embodiment particularly aims at intra coding using Multi-Reference-Line intra prediction mode combined with Intra Sub Partition mode.

Abstract: An encoding method is presented. Transform coefficients of a block are first obtained. They are then scanned according to a scan pattern for entropy coding. The scan pattern is determined responsive to a shape of the block. FIG.

Abstract: A decoding method is presented. a type of split of a block into transform units is first decoded. A transform is then determined for each transform unit of said block responsive to said type of split. Finally, decoded transform coefficients of said transform units are inverse transformed using the determined transforms.

Abstract: Some operations associated with transform decoding may provide coding gains for intra-predicted coding blocks but not for coding blocks predicted using certain inter-prediction tools or techniques. These operations may include, for example, multiple transform selection (MTS) and/or transform skip, and the inter-prediction tools or techniques may include one or more of affine motion compensation, combined inter and intra prediction (CIIP), a triangular partition mode (TPM), or a geometric merge mode (GEO). Thus, systems, methods, and instrumentalities associated with versatile video coding may be configured such that the aforementioned operations associated with transform decoding may be disabled for coding blocks that are predicted using one or more the inter-prediction tools or techniques described herein. Many benefits may be derived from disabling these operations including, for example, reduction of encoding time and/or signaling overhead.

Abstract: A method and apparatus comprise signaling and encoding low-frequency non-separable transform (LFNST) such that fast encoder method is supported as well as the traditional rate distortion (RD) search. This allows more flexibility to the encoder to adapt its coding search to its computational capacity. It is also proposed to limit the LNFST to using only the first kernel and uses CAB AC encoding.

Abstract: In a video coding system, it is proposed to determine the quantization matrix based on the block area instead of the maximal value of the block size dimension (width or height). Having specific quantization matrix for each block size actually allows adaptation to image content, and thus results in better visual quality. Indeed, choosing a quantization matrix of equal-area better match the idea of “size” than choosing a quantization matrix of the maximal dimension of the rectangular block. In at least one embodiment, the quantization matrix used for video coding or decoding is selected based on a block area identifier whose value is determined as the integer value of an average of the log 2 of block width and height. Encoding and decoding methods, encoding and decoding apparatuses, non-transitory computer readable medium and computer program are described.

Abstract: A method and apparatus for encoding/decoding a picture use a secondary transform for video encoding and decoding in INTRA mode and more particularly use a secondary transform for the transform units of a coding unit in intra sub partition mode. Different signaling and selection variants are proposed according to various parameters of the coding unit and transform unit.

Abstract: Coding mode information of a current block is propagated to neighbor blocks even when the coding mode is not selected for a current block. Such propagation may be limited, for example to one block only or to multiple generation of copies. Different propagation modes are proposed: left to right direction, top to bottom direction, bottom-right diagonal direction, first available information, or last coded information. The coding mode propagation allows to improve further predictions since a further block will benefit from the information from its neighbors.