TRANSFORM-BASED IMAGE CODING METHOD AND DEVICE THEREFOR

    公开(公告)号:US20220248018A1

    公开(公告)日:2022-08-04

    申请号:US17719925

    申请日:2022-04-13

    Abstract: An image decoding method according to the present document comprises a step for performing inverse first-order transform and inverse non-separable transform on a residual sample. The inverse non-separable transform is performed on the basis of a transform index indicating a predetermined transform kernel matrix, the inverse first-order transform is performed on the basis of a multiple transform selection (MTS) index indicating MTS for a horizontal transform kernel and a vertical transform kernel, and a syntax element bin string for the transform index is derived on the basis of first context information when a tree type for a split structure of a target block is not a single tree type and is derived on the basis of second context information when the tree type is the single tree type.

    IMAGE DECODING METHOD FOR RESIDUAL DATA CODING IN IMAGE CODING SYSTEM, AND APPARATUS THEREFOR

    公开(公告)号:US20220174324A1

    公开(公告)日:2022-06-02

    申请号:US17673201

    申请日:2022-02-16

    Abstract: An image decoding method performed by a decoding apparatus, according to the present document, comprises the steps of: acquiring syntax elements for a first transform coefficient through an n-th transform coefficient of a current block, wherein the syntax elements are syntax elements according to a first residual data coding structure of TSRC; and acquiring syntax elements for an n+1st transform coefficient through a last transform coefficient of the current block, wherein the syntax elements are syntax elements according to a second residual data coding structure of the TSRC, wherein the number of context-coded syntax elements for the first transform coefficient through the n-th transform coefficient is equal to the maximum number of context-coded bins of the current block, and the syntax elements according to the second residual data coding structure include coefficient level information and a sign flag for a transform coefficient.

    Method and apparatus for processing video signal by using approximation transform on basis of preprocessing/postprocessing matrix

    公开(公告)号:US11350130B2

    公开(公告)日:2022-05-31

    申请号:US17047849

    申请日:2019-04-17

    Abstract: The present invention provides a method for reconstructing a video signal by using an approximation transform on the basis of a preprocessing/postprocessing matrix, the method comprising: obtaining a transform index of a current block from a video signal, wherein the transform index corresponds to any one of a plurality of transform combinations including at least one of DST7, DCT8, DST6, or flipped DST7, and a transform combination includes a horizontal transform and a vertical transform; deriving a primary transform for horizontal/vertical directions corresponding to the transform index; performing an inverse primary approximation transform by using the primary transform for the horizontal/vertical directions, wherein the inverse primary approximation transform is generated by multiplying the primary transform for the horizontal/vertical directions by a preprocessing matrix and a postprocessing matrix; and reconstructing the video signal by using the inverse primary approximation-transformed current block.

    Method for encoding/decoding video signals and apparatus therefor

    公开(公告)号:US11336920B2

    公开(公告)日:2022-05-17

    申请号:US17209854

    申请日:2021-03-23

    Abstract: A method for decoding a video signal based on reduced transform includes the steps of: obtaining, from the video signal, a transform index indicating transform kernels applied to horizontal and vertical directions of a current block; determining a region in which a transform is applied to the current block based on the transform kernels indicated by the transform index and a size of the current block; deriving, as zero, coefficients of a remaining region other than the region to which the transform is applied within the current block; and performing an inverse transform on the region to which the transform is applied using the transform kernels indicated by the transform index.

    Video coding method on basis of secondary transform, and device for same

    公开(公告)号:US11310531B2

    公开(公告)日:2022-04-19

    申请号:US17350790

    申请日:2021-06-17

    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.

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