Image coding method based on quadratic transform, and apparatus therefor

    公开(公告)号:US11483589B2

    公开(公告)日:2022-10-25

    申请号:US17394734

    申请日:2021-08-05

    Abstract: An image decoding method according to the present document comprises the steps of: receiving a quantized transform coefficient for a target block and a transform index for non-separable quadratic transform; deriving transform coefficients by inversely quantizing the quantized transform coefficient; deriving corrected transform coefficients on the basis of a transform kernel matrix in a predetermined transform set indicated by the transform index; and deriving residual samples for the target block on the basis of inverse linear transform for the corrected transform coefficients, wherein when the target block is divided into a predetermined number of sub-blocks and is coded by intra prediction, the corrected transform coefficients are derived in units of the sub-blocks, and the transform index is received for the target block.

    IMAGE/VIDEO ENCODING/DECODING METHOD AND APPARATUS USING SAME

    公开(公告)号:US20220329782A1

    公开(公告)日:2022-10-13

    申请号:US17843468

    申请日:2022-06-17

    Abstract: A video decoding method performed by a video decoding apparatus according to the present document may comprise the steps of: parsing a prediction weighted table syntax from a bitstream; parsing number information about weighted reference pictures in a reference picture list from the prediction weighted table syntax; deriving a weighting factor-related flag about the reference picture list on the basis of the number information; performing weighted prediction on a current block on the basis of the weighting factor-related flag so as to derive prediction samples of the current block; generating residual samples on the basis of residual information obtained from the bitstream; and reconstructing a current picture on the basis of the prediction samples and the residual samples, wherein the prediction weighted table syntax is parsed from a picture header of the bitstream.

    Method and device for decoding images using CCLM prediction in image coding system

    公开(公告)号:US11463686B2

    公开(公告)日:2022-10-04

    申请号:US17277621

    申请日:2019-09-20

    Abstract: An image decoding method performed by a decoding device according to the present document comprises: a step for deriving the number of samples of upper peripheral chroma samples and left peripheral chroma samples of a current chroma block on the basis of a specific value and the width and height of the current chroma block; a step for deriving said number of upper peripheral chroma samples and said number of left peripheral chroma samples; and a step for deriving CCLM parameters on the basis of the upper peripheral chroma samples, the left peripheral chroma samples, and down-sampled peripheral luma samples, wherein, when the specific value is derived as 2 and the width and the height of the current chroma block are larger than the specific value, the number of samples is derived as the specific value.

    Matrix-based intra prediction device and method

    公开(公告)号:US11445204B2

    公开(公告)日:2022-09-13

    申请号:US17526930

    申请日:2021-11-15

    Abstract: An image decoding method according to the present document may comprise the steps of: receiving flag information indicating whether or not matrix-based intra prediction (MIP) is to be used for a current block; receiving matrix-based intra prediction (MIP) mode information on the basis of the flag information; generating intra prediction samples for the current block on the basis of the MIP mode information; and generating reconstructed samples for the current block on the basis of the intra prediction samples, wherein a syntax element bin string for the MIP mode information is binarized by using a truncated binarization method.

    METHOD AND DEVICE FOR DECODING IMAGES USING CCLM PREDICTION IN IMAGE CODING SYSTEM

    公开(公告)号:US20220272327A1

    公开(公告)日:2022-08-25

    申请号:US17740712

    申请日:2022-05-10

    Abstract: An image decoding method performed by a decoding device according to the present document comprises: a step for deriving the number of samples of upper peripheral chroma samples and left peripheral chroma samples of a current chroma block on the basis of a specific value and the width and height of the current chroma block; a step for deriving said number of upper peripheral chroma samples and said number of left peripheral chroma samples; and a step for deriving CCLM parameters on the basis of the upper peripheral chroma samples, the left peripheral chroma samples, and down-sampled peripheral luma samples, wherein, when the specific value is derived as 2 and the width and the height of the current chroma block are larger than the specific value, the number of samples is derived as the specific value.

    Method for decoding image on basis of CCLM prediction in image coding system, and device therefor

    公开(公告)号:US11412236B2

    公开(公告)日:2022-08-09

    申请号:US17180474

    申请日:2021-02-19

    Abstract: A video decoding method performed by a decoding apparatus according to the present disclosure includes deriving one of a plurality of cross-component linear model (CCLM) prediction mode as a CCLM prediction mode of the current chroma block, deriving a sample number of neighboring chroma samples of the current chroma block based on the CCLM prediction mode of the current chroma block, a size of the current chroma block, and a specific value; deriving the neighboring chroma samples of the sample number, calculating CCLM parameters based on the neighboring chroma samples and the down sampled neighboring luma samples, deriving prediction samples for the current chroma block based on the CCLM parameters and the down sampled luma samples and generating reconstructed samples for the current chroma block based on the prediction samples, wherein the specific value is derived as 2.

    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.

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