METHOD AND DEVICE FOR DESIGNING LOW-FREQUENCY NON-SEPARABLE TRANSFORM

    公开(公告)号:US20240373011A1

    公开(公告)日:2024-11-07

    申请号:US18571622

    申请日:2022-06-16

    Abstract: An image decoding method according to the present document comprises a step of deriving a corrected transform coefficient by applying low-frequency non-separable transform (LFNST) to a transform coefficient, wherein an LFNST set for applying the LFNST may be derived on the basis of an intra-prediction mode applied to the current block, and an LFNST matrix may be derived on the basis of the size of the current block and the LFNST set, the LFNST matrix derived as a 16×16 dimensional matrix if the width or the height of the current block is 4 and the width and the height are both 4 or greater, and the LFNST matrix derived as a 64×32 dimensional matrix if the width or the height of the current block is 8 and the width and the height are both 8 or greater. Therefore, coding performance capable of being brought by the LFNST can be maximized within the implementation complexity permitted in forthcoming standards.

    IMAGE CODING METHOD AND APPARATUS THEREFOR
    212.
    发明公开

    公开(公告)号:US20240357110A1

    公开(公告)日:2024-10-24

    申请号:US18571385

    申请日:2022-06-16

    CPC classification number: H04N19/122 H04N19/14 H04N19/176 H04N19/61

    Abstract: An image decoding method according to this document comprises a step for deriving, for transform coefficients, modified transform coefficients on the basis of inverse secondary transformation, wherein the step for deriving the modified transform coefficients comprises a step for deriving a transform kernel to be applied to the inverse secondary transformation, the transform kernel may be derived as a 16×16 matrix on the basis of horizontal and vertical lengths of a target block being both greater than or equal to 4 and the horizontal or vertical length being 4, and the transform kernel may be derived as a 48×16 matrix on the basis of the horizontal and vertical lengths of the target block being both greater than or equal to 8 and the horizontal or vertical length being 8.

    VIDEO CODING METHOD ON BASIS OF SECONDARY TRANSFORM, AND DEVICE FOR SAME

    公开(公告)号:US20240244262A1

    公开(公告)日:2024-07-18

    申请号:US18611214

    申请日:2024-03-20

    CPC classification number: H04N19/619 H04N19/132 H04N19/159 H04N19/176

    Abstract: A video decoding method according to the present document is characterized by comprising: a step for deriving transform coefficients through inverse quantization on the basis of quantized transform coefficients for a target block; a step for deriving modified transform coefficients on the basis of an inverse reduced secondary transform (RST) of the transform coefficients; and a step for 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 the inverse RST using a transform kernel matrix is performed on transform coefficients of the upper-left 4×4 region of an 8×8 region of the target block, and the modified transform coefficients of the upper-left 4×4 region, upper-right 4×4 region, and lower-left 4×4 region of the 8×8 region are derived through the inverse RST.

    IMAGE CODING METHOD BASED ON SECONDARY TRANSFORM, AND DEVICE THEREFOR

    公开(公告)号:US20240171776A1

    公开(公告)日:2024-05-23

    申请号:US18414206

    申请日:2024-01-16

    Abstract: An image decoding method comprises the steps of: deriving transform coefficients through inverse 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) for the transform coefficients; and generating a restoration picture on the basis of residual samples for the target block, on the basis of an inverse primary transform for the modified transform coefficients, wherein the inverse RST is performed on the basis of: transform sets determined by a mapping relation according to an intra prediction mode applied to the target block; and a transform kernel matrix selected from among two transform kernel matrices included in each of the transform sets, and is performed on the basis of: whether the inverse RST is applied; and a transform index for indicating any one of the transform kernel matrices included in the transform sets.

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