Lg Electronics Inc.

Tencent America LLC

Guangdong Oppo Mobile Telecommunications Corp., Ltd.

Vivo Mobile Communication Co., Ltd.

Beijing Xiaomi Mobile Software Co., Ltd.

Xiaomi Inc.

Rosedale Dynamics LLC

Tcl King Electrical Appliances (huizhou) Co. Ltd.

Ling Li

Jin Seong Heo

Jangwon Choi

Seunghwan Kim

Sunmi Yoo Yoo

Jungah Choi

Shan Liu

Jaehyun Lim

Xiang Li

Xiang Yang Li

Jung Hak Nam

Junghak Nam

Lien-Fei Chen

Xin Zhao

Stephan Wenger

Naeri Park

Hyeongmoon Jang

Byeongdoo Choi

Guichun Li

Seung Hwan Kim

Cheung Auyeung

Moonmo Koo

Liang Zhao

Jongyeul Suh

Bin Zhu

Tung Chin Lee

Soo-Chul Han

A video decoding method according to the present document is characterized by comprising: obtaining Most Probable Mode (MPM) index information and reference line index information from a bitstream; compiling an MPM list including candidate intra prediction modes for the intra prediction of a current block; deriving an intra prediction mode for the current block from among the candidate intra prediction modes included in the MPM list on the basis of the MPM index information; generating prediction samples for the current block on the basis of the intra prediction mode; and generating reconstructed samples for the current block on the basis of the prediction samples, wherein the step for compiling the MPM list involves deriving a DC mode as one of the candidate intra prediction modes, and including the DC mode in the MPM list, the DC mode being derived on the basis of the value of reference line index information indicating a reference line used for the intra prediction of the current block not being zero.

MPM list-based intra prediction method and device

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus may include determining a chroma array type of a current image, determining an adaptive loop filter (ALF) indicator of a chroma component based on the chroma array type, and performing ALF filtering with respect to a reconstructed image based on a value of the ALF indicator. The value of the ALF indicator may be determined to be a predetermined value without being obtained from a bitstream, based on the chroma array type being a predetermined type, and the value of the ALF indicator may be obtained from the bitstream, based on the chroma array type being not the predetermined type.

Image encoding/decoding method and device for signaling filter information on basis of chroma format, and method for transmitting bitstream

An image decoding method according to the present document comprises the steps of: receiving a bitstream including residual information; deriving a quantized transform coefficient for a current block on the basis of the residual information included in the bitstream; deriving a residual sample for the current block on the basis of the quantized transform coefficient; and generating a restoration picture on the basis of the residual sample for the current block, wherein the residual information includes position information for indicating the position of a transform coefficient, which is not the last 0 in a transform block, and the position information can be derived if a transform skip is not applied to the transform block.

Transform coefficient coding method and device

An image decoding method executed by a decoding apparatus according to the present document comprises the steps of: deriving an intra prediction mode of the current chroma block by means of cross-component linear model (CCLM) mode; deriving downsampled luma samples on the basis of the current luma block; deriving downsampled neighboring luma samples on the basis of neighboring luma samples of the current luma block; and deriving the CCLM parameter on the basis of the downsampled neighboring luma samples and neighboring chroma samples of the current neighboring chroma block, wherein the number of down-sampled neighboring luma samples and number of neighboring chroma samples are equal to the previously set thresh-hold value, and the thresh-hold value is derived on the basis of the width and height of the current chroma block.

CCLM prediction-based image decoding method and apparatus in image coding system

An image decoding method performed by a decoding apparatus according to the present disclosure comprises the steps of: obtaining intra prediction information including at least one of MPM flag information, MRL index information, and planner flag information from a bitstream; checking the MPM flag information; checking the MRL index information on the basis of a case where the MPM flag information indicates that the MRL index information is checked; checking the planner flag information on the basis of a case where a value of the MRL index information is 0; deriving an intra prediction mode for a current block on the basis of the check for the planner flag information; deriving prediction samples for the current block on the basis of the intra prediction mode for the current block; and generating a reconstructed picture on the basis of the prediction samples.

Intra prediction method on basis of MPM list and apparatus therefor

Aspects of the disclosure provide a method and an apparatus including processing circuitry for video decoding. The processing circuitry decodes, from a coded video bitstream, a first syntax element indicating whether a first component in the coded video bitstream is coded based on a second component in the coded video bitstream. The processing circuitry determines whether to decode one or more second syntax elements for a chroma related coding tool based on the first syntax element. The chroma related coding tool is a luma mapping with chroma scaling coding tool or a cross-component adaptive loop filter. The one or more second syntax elements are decoded when the first syntax element indicates that the first component is coded based on the second component. The one or more second syntax elements are not decoded when the first syntax element indicates that the first component is not coded based on the second component.

Signaling presence of chroma component in video bitstream

In a method, coded information of a current block and neighboring blocks of the current block in a current picture is received from a coded video bitstream. A list of merge candidates of the current block is generated based on the neighboring blocks of the current block. The list of merge candidates of the current block is divided into a plurality of subgroups. Each of the plurality of subgroups includes one or more merge candidates. The one or more merge candidates are ordered within each subgroup by a respective template matching (TM) cost associated with each of the one or more merge candidates. The current block is reconstructed based on a merge candidate selected from the list of merge candidates of the current block.

Grouping based adaptive reordering of merge candidate

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus may include determining a prediction mode of a current block, generating a prediction block of the current block based on intra block copy (IBC) prediction mode information, based on the prediction mode of the current block being an IBC prediction mode, determining a size of a transform block of the current block based on a color component of the current block, generating a residual block of the current block based on the size of the transform block; and reconstructing the current block based on the prediction block and the residual block of the current block.

Image encoding/decoding method and device using maximum transform size restriction of chroma component encoding block, and method for transmitting bitstream

In a method of decoding, coded information of a coding unit (CU), a template region, and a plurality of reference regions is received. The coded information includes a first syntax element indicating whether the CU is predicted based on a template matching based multiple reference line (MRL) intra prediction mode. In response to the first syntax element indicating that the CU is predicted based on the template matching based multiple reference line (MRL) intra prediction mode, a plurality of cost values is determined between (i) respective prediction samples of the template region based on samples in each of the plurality of reference regions, and (ii) reconstructed samples of the template region corresponding to the respective prediction samples. A reference region from the plurality of reference regions is determined based on the plurality of cost values. Samples of the CU are reconstructed based on the samples in the determined reference region.

Intra mode selection and signaling

One or more intra mode predictors of a current block are determined, where the one or more intra mode predictors are derived based on the neighboring samples of the current block via either a decoder side intra mode derivation (DIMD) or a template-based intra mode derivation (TIMD). Whether a position dependent intra prediction combination (PDPC) is to be applied is determined based on the one or more intra mode predictors. In response to the determining that the PDPC is to be applied, a fusion process is performed on the one or more intra mode predictors to combine the one or more intra mode predictors into a single intra mode predictor. The PDPC is applied based on the single intra mode predictor to generate a modified predictor of the current block. The current block is reconstructed based on the modified predictor generated by the PDPC.

Applying PDPC after fusion of plural intra mode predictors

In the method, coded information of a coding unit (CU) in a picture of a video is received from a coded video bitstream. The CU is partitioned into a first partition and a second partition based on a geometric partition mode (GPM). The first partition and the second partition are rectangular partitions that are adjacent to each other and divided by a straight partition line. A first intra prediction mode for the first partition of the CU and a second intra prediction mode for the second partition of the CU are determined. The first intra prediction mode is different from the second intra prediction mode. The first partition of the CU is reconstructed based on the first intra prediction mode and the second partition of the CU is reconstructed based on the second intra prediction mode.

Geometric partition based intra prediction

A video decoding method according to this document includes constructing a most probable mode (MPM) list by deriving MPM candidates for a current block based on a neighboring block adjacent to the current block, deriving an intra prediction mode for the current block based on the MPM list, generating predicted samples by performing prediction for the current block based on the intra prediction mode, and generating a reconstructed picture for the current block based on the predicted samples.

Intra prediction-based image coding method and apparatus using MPM list

According to embodiments of the present document, an intra-prediction mode candidate list of a current block can be constructed by means of a process of constructing a common intra-prediction mode list with respect to intra-prediction types. Therefore, the dependency of the intra-prediction types in the process of constructing the intra-prediction mode list is reduced, and thus the coding efficiency of an intra-prediction can be enhanced.

Image decoding method and device and image encoding method and device in image coding system

A method for video encoding includes generating a first syntax element indicating a maximum number of merge motion vector prediction (MVP) candidates, and encoding the first syntax element at a first coding level in a coded video bitstream, the first coding level being higher than a picture parameter set (PPS) level. The video encoding method also includes transmitting the coded video bitstream including the first syntax element. The maximum number of merge MVP candidates indicated by the first syntax element is applicable for reconstructing coding blocks of the coded video bitstream associated with the first coding level.

Signaling a maximum number of merge motion vector prediction candidates for inter prediction

In a method of video encoding, whether an adaptive color transform (ACT) is to be applied to a current block is determined. The current block includes color components, the color components including a luma component, a first chroma component, and a second chroma component. Based on the ACT being determined to be applied to the current block, a color space conversion is applied on the current block based on color space conversion equations to generate modified color components of the current block. The current block is encoded based on the modified color components of the current block.

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Ling Li