Method for coding image on basis of secondary transform and device therefor

    公开(公告)号:US12244860B2

    公开(公告)日:2025-03-04

    申请号:US18241441

    申请日:2023-09-01

    Abstract: An image decoding method according to the present document comprises a step of deriving modified transform coefficients on the basis of an inverse reduced secondary transform (RST) regarding transform coefficients regarding a target block. The inverse RST is performed on the basis of transform sets determined on the basis of a mapping relation following an intra prediction mode applied to the target block, and a transform kernel matrix selected from two transform kernel matrices included in the transform sets, respectively, and is performed on the basis of whether or not the inverse RST is applied, and a transform index indicating one of the transform kernel matrices included in the transform sets. A syntax element bin string regarding the transform index is decoded on the basis of a different context set according to the tree type regarding the division structure of the target block.

    Method for decoding image by using block partitioning in image coding system, and device therefor

    公开(公告)号:US12244802B2

    公开(公告)日:2025-03-04

    申请号:US18383216

    申请日:2023-10-24

    Abstract: The method for decoding an image by a decoding device according to the present document may comprise the steps of: acquiring image information comprising partitioning information for a current block; determining, on the basis of the size of the current block, whether to partition the current block; partitioning the current block into subblocks on the basis of the partitioning information, if it is determined that the current block is to be partitioned, and decoding the subblocks; and not partitioning the current block, if it is determined that the current block is not to be partitioned, and decoding the current block, wherein, if the current block is a chroma block, and the size of the current block is at most the minimum size of a chroma block, then it is determined that the current block is not to be partitioned.

    Matrix-based intra prediction device and method

    公开(公告)号:US12238299B2

    公开(公告)日:2025-02-25

    申请号:US18242962

    申请日:2023-09-06

    Abstract: An image decoding method according to the present document may comprise the steps of: receiving flag information indicating whether or not matrix-based intra prediction (MIP) is to be used for a current block; receiving matrix-based intra prediction (MIP) mode information on the basis of the flag information; generating intra prediction samples for the current block on the basis of the MIP mode information; and generating reconstructed samples for the current block on the basis of the intra prediction samples, wherein a syntax element bin string for the MIP mode information is binarized by using a truncated binarization method.

    Method for transform-based image coding and apparatus therefor

    公开(公告)号:US12212756B2

    公开(公告)日:2025-01-28

    申请号:US18360351

    申请日:2023-07-27

    Abstract: A method for image decoding, according to the present document, may comprise the steps of: deriving an intra prediction mode of a chroma block as a cross-component linear model (CCLM) mode; updating the intra prediction mode of the chroma block on the basis of an intra prediction mode of a luma block corresponding to the chroma block; and determining an LFNST set including LFNST matrices on the basis of the updated intra prediction mode, wherein the updated intra prediction mode is derived as an intra prediction mode corresponding to a specific position in the luma block, and the specific position is set on the basis of a color format of the chroma block.

    Image coding method based on transform, and device therefor

    公开(公告)号:US12206856B2

    公开(公告)日:2025-01-21

    申请号:US17762634

    申请日:2020-09-23

    Abstract: An image decoding method according to the present document comprises the steps of: when an ISP is applied to a current block and the width or height of a sub-partition block is less than or equal to 2, applying LFNST to the transform coefficients to derive modified transform coefficients; deriving residual samples for the objective block on the basis of an inverse primary transform for the modified transform coefficients; and generating a reconstructed picture on the basis of the residual samples for the objective block, wherein when the sub-partition block is an N×2 block or a 2×N block, (M×2) or (2×M) number of modified transform coefficients are derived by applying an LFNST matrix to a predetermined number of transform coefficients in an upper left M×2 area or 2×M (M≤N) area of the sub-partition block.

Patent Agency Ranking