Transform-based image coding method and device therefor

    公开(公告)号:US11882289B2

    公开(公告)日:2024-01-23

    申请号:US17894745

    申请日:2022-08-24

    CPC classification number: H04N19/132 H04N19/105 H04N19/176 H04N19/18

    Abstract: An image decoding method, according to the present document, may comprise the steps of: deriving transform coefficients for a current block on the basis of residual information; determining whether a significant coefficient is present in a second region excluding a first region in the top-left end of the current block; parsing a LFNST index from a bitstream if the significant coefficient is not present in the second region; deriving modified transform coefficients by applying a LFNST matrix, derived on the basis of the LFNST index, to transform coefficients of the first region; and deriving residual samples of the current block on the basis of an inverse primary transform of the modified transform coefficients.

    Image coding method and device on basis of wide-angle intra prediction and transform

    公开(公告)号:US11641471B2

    公开(公告)日:2023-05-02

    申请号:US17610985

    申请日:2020-05-27

    Abstract: An image decoding method according to the present document comprises the steps of: obtaining intra prediction mode information and an LFNST index; deriving an intra prediction mode of a current block on the basis of intra prediction mode information; when wide-angle intra prediction is applied to the current block, deriving a modified intra prediction mode by means of intra prediction mode remapping; deciding an LFNST set comprising LFNST matrices on the basis of the modified intra prediction mode; selecting one of the LFNST matrices on the basis of the LFNST set and LFNST index; and deriving transform coefficients for the current block on the basis of the selected LFNST matrix.

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