IMAGE CODING METHOD BASED ON SECONDARY TRANSFORM, AND DEVICE THEREFOR

    公开(公告)号:US20220182677A1

    公开(公告)日:2022-06-09

    申请号:US17592301

    申请日:2022-02-03

    Abstract: An image decoding method according to the present document 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, on the basis of an inverse primary transform for the modified transform coefficients, a restoration picture based on residual samples for the target block, wherein the modified transform coefficients derived according to the inverse RST are two-dimensionally arranged according to the order of a row priority direction or a column priority direction according to an intra prediction mode to be applied to the target block.

    METHOD FOR CODING IMAGE ON BASIS OF SECONDARY TRANSFORM AND DEVICE THEREFOR

    公开(公告)号:US20220174319A1

    公开(公告)日:2022-06-02

    申请号:US17671788

    申请日:2022-02-15

    Abstract: An image decoding method according to the present document comprises a step of deriving modified transform coefficients on the basis of an inverse reduced secondary transform (RST) regarding transform coefficients regarding a target block. The inverse RST is performed on the basis of transform sets determined on the basis of a mapping relation following an intra prediction mode applied to the target block, and a transform kernel matrix selected from two transform kernel matrices included in the transform sets, respectively, and and is performed on the basis of whether or not the inverse RST is applied, and a transform index indicating one of the transform kernel matrices included in the transform sets. A syntax element bin string regarding the transform index is decoded on the basis of a different context set according to the tree type regarding the division structure of the target block.

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

    公开(公告)号:US20220159303A1

    公开(公告)日:2022-05-19

    申请号:US17592768

    申请日:2022-02-04

    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.

    CODING OF INFORMATION ABOUT TRANSFORM KERNEL SET

    公开(公告)号:US20220150497A1

    公开(公告)日:2022-05-12

    申请号:US17556099

    申请日:2021-12-20

    Abstract: An image decoding method includes: acquiring a multiple transform selection (MTS) index and residual information from a bitstream; deriving transform coefficients for the current block on the basis of the residual information; and generating residual samples of the current block on the basis of the MTS index and the transform coefficients, wherein the MTS index indicates a transform kernel set to be applied to the current block among transform kernel set candidates, at least one bin among bins of a bin string of the MTS index is derived on the basis of context coding, the context coding is performed on the basis of values of increase and decrease in a context index pertaining to the MTS index, and a single value of increase and decrease in the context index can be used for the context coding of the first bin among the bins of the bin string.

    TRANSFORM-BASED IMAGE CODING METHOD AND DEVICE THEREFOR

    公开(公告)号:US20220132134A1

    公开(公告)日:2022-04-28

    申请号:US17572476

    申请日:2022-01-10

    Abstract: An image decoding method according to the present document can comprise the steps of: acquiring, from a bitstream, intra prediction mode information and an LFNST index; deriving, as a cross-component linear model (CCLM) mode, an intra prediction mode of a chroma block on the basis of the intra prediction mode information; changing the intra prediction mode of the chroma block from the CCLM mode to an intra prediction mode of a luma block corresponding to the chroma block; determining an LFNST set, including LFNST matrices, on the basis of the intra prediction mode of the luma block; selecting one of the LFNST matrices on the basis of the LFNST set and the LFNST index; and deriving transform coefficients for the chroma block on the basis of the selected LFNST matrix.

    VIDEO OR IMAGE CODING METHOD AND DEVICE THEREFOR

    公开(公告)号:US20220109888A1

    公开(公告)日:2022-04-07

    申请号:US17600001

    申请日:2020-03-19

    Abstract: According to the disclosure of the present document, an image decoding method performed by a decoding device comprises the steps of: acquiring, through a bitstream, image information including prediction mode information and residual information; deriving a prediction mode of a current block on the basis of the prediction mode information; deriving prediction samples on the basis of the prediction mode; deriving residual samples on the basis of the residual information; generating reconstruction samples on the basis of the prediction samples and the residual samples; deriving filter coefficients for an adaptive loop filter (ALF) procedure for the reconstruction samples; and generating modified reconstruction samples on the basis of the reconstruction samples and the filter coefficients, wherein the image information includes a first adaptation parameter set (APS) including an ALF data field, and the ALF data field includes ALF parameters used to derive the filter coefficients.

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