Video coding method based on secondary transform, and device therefor

    公开(公告)号:US12143585B2

    公开(公告)日:2024-11-12

    申请号:US17344410

    申请日:2021-06-10

    Abstract: A video decoding method according to the present document comprises the steps of: deriving transform coefficients by performing de-quantization on the basis of quantized transform coefficients for a target block; deriving modified transform coefficients on the basis of an inverse reduced secondary transform (RST) of the transform coefficients; and generating a reconstructed picture on the basis of residual samples for the target block on the basis of an inverse primary transform of the modified transform coefficients, wherein an inverse RST using a transform kernel matrix is performed on transform coefficients of an upper-left 4×4 region of an 8×8 region of the target block, and modified transform coefficients of the upper-left 4×4 region, an upper-right 4×4 region, and a lower-left 4×4 region of the 8×8 region are derived through the inverse RST.

    METHOD AND APPARATUS FOR DERIVING RICE PARAMETER IN VIDEO/IMAGE CODING SYSTEM

    公开(公告)号:US20240333944A1

    公开(公告)日:2024-10-03

    申请号:US18737596

    申请日:2024-06-07

    CPC classification number: H04N19/18 H04N19/132 H04N19/176 H04N19/70

    Abstract: A video decoding method performed by a decoding apparatus comprises the steps of: acquiring, from a bitstream, residual information for a current transform block, wherein the residual information includes at least one of information indicating a level value of a target transform coefficient within the current transform block or information indicating a residual level value; based on a neighboring transform coefficient of the target transform coefficient, deriving a rice parameter for at least one of the information indicating the level value of the target transform coefficient or the information indicating the residual level value; based on the rice parameter, deriving a bin string for at least one of the information indicating the level value of the target transform coefficient or the information indicating the residual level value; and based on the bin string, deriving the level value of the target transform coefficient.

    VIDEO OR IMAGE CODING METHOD AND DEVICE THEREFOR

    公开(公告)号:US20240298034A1

    公开(公告)日:2024-09-05

    申请号:US18605477

    申请日:2024-03-14

    Abstract: According to the disclosure of the present document, an image decoding method performed by a decoding device comprises the steps of: acquiring, through a bitstream, image information including prediction mode information and residual information; deriving a prediction mode of a current block on the basis of the prediction mode information; deriving prediction samples on the basis of the prediction mode; deriving residual samples on the basis of the residual information; generating reconstruction samples on the basis of the prediction samples and the residual samples; deriving filter coefficients for an adaptive loop filter (ALF) procedure for the reconstruction samples; and generating modified reconstruction samples on the basis of the reconstruction samples and the filter coefficients, wherein the image information includes a first adaptation parameter set (APS) including an ALF data field, and the ALF data field includes ALF parameters used to derive the filter coefficients.

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