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

    公开(公告)号:US20240291992A1

    公开(公告)日:2024-08-29

    申请号:US18571605

    申请日:2022-06-16

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

    Abstract: An image decoding method according to this document comprises the steps of: deriving an LFNST matrix for a current block on the basis of an LFNST index derived from LFNST index information and an LFNST set index; deriving modified transform coefficients on the basis of transform coefficients and the LFNST matrix; and generating residual samples for the current block on the basis of the modified transform coefficients, wherein when the width or height of the current block has a value of 16 and both the width and height have a value of 16 or more, the LFNST matrix may be derived as a 96×32 dimensional matrix. Therefore, coding performance achievable by the LFNST can be maximized within the implementation complexity permitted in forthcoming standards.

    IMAGE CODING METHOD AND APPARATUS THEREFOR
    104.
    发明公开

    公开(公告)号:US20240205456A1

    公开(公告)日:2024-06-20

    申请号:US18286706

    申请日:2022-04-12

    Abstract: An image decoding method according to this document comprises a step of deriving, for transform coefficients, modified transform coefficients on the basis of inverse secondary transform, wherein: the step of deriving the modified transform coefficients may comprise a step of deriving a transform kernel to be applied to the inverse secondary transform; on the basis of both the horizontal and vertical lengths of a target block being greater than or equal to 8 and the horizontal or vertical length being 8, the transform kernel may be set to a 64×32 matrix; and on the basis of both the horizontal and vertical lengths of the target block being 8, a 64×16 matrix sampled from the 64×32 matrix may be applied to the inverse secondary transform of the target block.

    IMAGE CODING METHOD ON BASIS OF TRANSFORMATION AND DEVICE THEREFOR

    公开(公告)号:US20240146965A1

    公开(公告)日:2024-05-02

    申请号:US18545642

    申请日:2023-12-19

    Abstract: An image decoding method performed by means of a decoding device according to the present invention comprises the steps of: deriving quantized transform coefficients with respect to a target block from a bitstream; performing inverse quantization with respect to the quantized transform coefficients with respect to the target block and deriving transform coefficients; deriving residual samples with respect to the target block on the basis of reduced inverse transform with respect to the transform coefficients; and generating a reconstructed picture on the basis of the residual samples with respect to the target block and prediction samples with respect to the target block. The reduced inverse transform is performed on the basis of a reduced inverse transform matrix. The reduced inverse transform matrix is a non-square matrix of which the number of columns is smaller than the number of rows.

    METHOD AND APPARATUS FOR PROCESSING IMAGE SIGNAL

    公开(公告)号:US20240114166A1

    公开(公告)日:2024-04-04

    申请号:US18520383

    申请日:2023-11-27

    CPC classification number: H04N19/593 H04N19/122 H04N19/176

    Abstract: Embodiments of the present disclosure provide a method and device for processing a video signal. A method for decoding an image signal according to an embodiment of the present disclosure comprises the steps of: determining a non-separable transform set index indicating a non-separable transform set used for a non-separable transform of a current block from among non-separable transform sets predefined on the basis of an intra-prediction mode of the current block; determining. as a non-separable transform matrix, a transform kernel indicated by a non-separable transform index for the current block from among transform kernels included in the non-separable transform set indicated by the non-separable transform set index; and applying the non-separable transform matrix to an upper left region which of the current block, which is determined according to the width and height of the current block, wherein each of the predefined non-separable transform sets includes two transform kernels.

    METHODS AND APPARATUSES FOR PROCESSING VIDEO SIGNAL

    公开(公告)号:US20230379501A1

    公开(公告)日:2023-11-23

    申请号:US18197529

    申请日:2023-05-15

    CPC classification number: H04N19/61 H04N19/91 H04N19/124 H04N19/18 H04N19/176

    Abstract: Embodiments of the present invention provide video signal processing methods. A video signal encoding method according to an embodiment of the present invention comprises checking a transform block including residual samples except a prediction sample from a picture of the video signal, generating transform coefficients through a transform for the residual samples of the transform block based on a size of the transform block, and performing quantization and entropy coding the transform coefficients, wherein generating the transform coefficients includes, applying a forward primary transform to each of a horizontal direction and vertical direction of the transform block including the residual samples, and not applying a forward non-separable secondary transform to the transform block to which the primary transform has been applied when the size of the transform block is smaller than or equal to 4×4, and applying the forward non-separable secondary transform to the transform block when the size of the transform block is greater than 4×4.

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