Transform-based image coding method and device therefor

    公开(公告)号:US12244813B2

    公开(公告)日:2025-03-04

    申请号:US18611275

    申请日:2024-03-20

    Abstract: An image decoding method according to the present document can comprise the steps of: acquiring, from a bitstream, intra prediction mode information and an LFNST index; deriving, as a cross-component linear model (CCLM) mode, an intra prediction mode of a chroma block on the basis of the intra prediction mode information; changing the intra prediction mode of the chroma block from the CCLM mode to an intra prediction mode of a luma block corresponding to the chroma block; determining an LFNST set, including LFNST matrices, on the basis of the intra prediction mode of the luma block; selecting one of the LFNST matrices on the basis of the LFNST set and the LFNST index; and deriving transform coefficients for the chroma block on the basis of the selected LFNST matrix.

    Image coding method and apparatus based on intra prediction using MPM list

    公开(公告)号:US12177420B2

    公开(公告)日:2024-12-24

    申请号:US18131767

    申请日:2023-04-06

    Abstract: An image decoding method performed by a decoding apparatus according to the present disclosure includes receiving intra prediction information including at least one of most probable mode (MPM) flag information representing whether to derive an intra prediction mode for a current block based on MPM candidates for the current block or planar flag information representing whether to determine the intra prediction mode for the current block as a planar mode, deriving the intra prediction mode for the current block based on the MPM flag information and the planar flag information, deriving a predicted block for the current block based on the intra prediction mode for the current block, and generating a reconstructed picture based on the predicted block.

    Inter-prediction method and apparatus in image coding system

    公开(公告)号:US12160583B2

    公开(公告)日:2024-12-03

    申请号:US18368336

    申请日:2023-09-14

    Abstract: An image decoding method performed by a decoding apparatus includes the operations: deriving a correspondence block corresponding to the current block of the current picture, the correspondence block being located in a co-located picture; deriving a movement vector of the correspondence block; scaling the movement vector of the correspondence block based on a first temporal distance and second temporal distance, the first temporal distance being the difference between the POC values of the co-located picture and POC values of the reference picture of the correspondence block, and the second temporal distance being the difference between the POC values of the co-located picture and POC values of the current picture containing the current block; deriving the movement vector updated based on the scaled movement vector and location of the current block; and deriving a movement vector of the current block based on the updated movement vector.

    Method and apparatus for processing image signal

    公开(公告)号:US12132903B2

    公开(公告)日:2024-10-29

    申请号:US18369493

    申请日:2023-09-18

    CPC classification number: H04N19/122 H04N19/167 H04N19/176 H04N19/61

    Abstract: The embodiments of the present disclosure provides a method and apparatus for video signal processing. A method for decoding an image signal according to an embodiment of the present disclosure may include determining an input length and an output length of a non-separable transform based on a height and a width of a current block; determining a non-separable transform matrix corresponding to the input length and the output length of a non-separable transform; and applying the non-separable transform matrix to coefficients by a number of the input length in the current block, wherein the height and the width of a current block is greater than or equal to 8, wherein, if each of the height and the width of a current block is equal to 8, the input length of the non-separable transform is determined as 8.

    INTRA PREDICTION METHOD ON BASIS OF MPM LIST AND APPARATUS THEREFOR

    公开(公告)号:US20240357077A1

    公开(公告)日:2024-10-24

    申请号:US18632155

    申请日:2024-04-10

    Abstract: 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.

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