Image coding method based on transform, and device for same

    公开(公告)号:US11765389B2

    公开(公告)日:2023-09-19

    申请号:US17985577

    申请日:2022-11-11

    Abstract: An image decoding method according to the present document may include the steps of: deriving the position of the final significant coefficient in the current block and transform coefficients for the current block on the basis of residual information; determining whether the index of a sub-block including the final significant coefficient is 0 and whether the position of the final significant coefficient in the sub-block is greater than 0; determining whether a significant coefficient exists in a second area excluding a first area at the upper left end of the current block; and parsing an LFNST index from a bitstream when the position of the final significant coefficient is determined to be greater than 0 in the sub-block in which the index is 0, and the significant coefficient does not exist in the second area.

    TRANSFORM-BASED IMAGE CODING METHOD AND DEVICE THEREFOR

    公开(公告)号:US20230239563A1

    公开(公告)日:2023-07-27

    申请号:US18128132

    申请日:2023-03-29

    CPC classification number: H04N23/60 G06F9/4812 G06F9/4881

    Abstract: An image decoding method according to the present document comprises a step of deriving a corrected transform coefficient, wherein the step of deriving the corrected transform coefficient comprises the steps of: determining whether LFNST can be applied to the height and width of a divided sub-partition block when an ISP is applied to a current block; parsing a LFNST index when the LFNST can be applied; and deriving the corrected transform coefficient on the basis of the LFNST index and a LFNST matrix.

    Modified transform-based image coding method and device for same

    公开(公告)号:US11700377B2

    公开(公告)日:2023-07-11

    申请号:US17535095

    申请日:2021-11-24

    CPC classification number: H04N19/132 H04N19/176 H04N19/18 H04N19/186

    Abstract: An image decoding method according to the present document is characterized by including: a step for receiving a bitstream including residual information; a step for deriving transform coefficients for a target block on the basis of the residual information; a step for deriving corrected transform coefficients on the basis of an inverse non-separable transform of the transform coefficients; and a step for deriving residual samples for the target block on the basis of an inverse primary transform of the corrected transform coefficients, wherein the inverse non-separable transform is performed when the size of the target block is equal to or smaller than the size of a prescribed maximum transform application block.

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