TRANSFORM-BASED IMAGE CODING METHOD AND DEVICE

    公开(公告)号:US20230133403A1

    公开(公告)日:2023-05-04

    申请号:US18089100

    申请日:2022-12-27

    Abstract: An image decoding method according to the present disclosure includes deriving transform coefficients through dequantization based on the quantized transform coefficients for the target block; deriving modified transform coefficients based on an inverse reduced secondary transform (RST) for the transform coefficients; deriving residual samples for the target block based on an inverse primary transform for the modified transform coefficients; and generating a reconstructed samples based on the residual samples, and prediction samples derived based on an intra prediction mode for the target block, wherein the inverse RST is performed based on a transform kernel matrix selected from a transform set including a plurality of transform kernel matrices, the transform set is determined based on a mapping relationship according to the intra prediction mode applied to the target block, and a plurality of intra prediction modes including the intra prediction mode of the target block are mapped to one transform set.

    TRANSFORM-BASED IMAGE CODING METHOD AND DEVICE THEREFOR

    公开(公告)号:US20230064931A1

    公开(公告)日:2023-03-02

    申请号:US17792122

    申请日:2021-01-12

    Abstract: An image decoding method according to the present document may comprise deriving transform coefficients for a current block, based on the residual information; deriving residual samples for the current block from the transform coefficients, based on LFNST or MTS; and receiving an LFNST index related to an LFNST matrix when the LFNST is applied to the current block, wherein the LFNST index is signaled at a transform unit level for the current block, after deriving the transform coefficients for the current block.

    TRANSFORM-BASED IMAGE CODING METHOD AND DEVICE FOR SAME

    公开(公告)号:US20230063796A1

    公开(公告)日:2023-03-02

    申请号:US17789483

    申请日:2020-12-28

    Abstract: An image decoding method according to the present document comprises the steps of: receiving residual information in a bitstream, wherein the residual information includes a transform skip flag for each individual component of the current block; deriving corrected transform coefficients, wherein the step for deriving includes a step for setting a variable indicating whether effective coefficients exist at positions other than that of a DC component of the current block to 0 when even one of the values of the transform skip flags for the individual components is 0, and a step for parsing an LFNST index on the basis of the variable being 0; and deriving an LFNST kernel for applying LFNST on the basis of the LFNST index, wherein the variable being 0 may indicate that effective coefficients exist at positions other than that of the DC component.

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

    公开(公告)号:US20230030970A1

    公开(公告)日:2023-02-02

    申请号:US17952901

    申请日:2022-09-26

    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.

    TRANSFORM-BASED IMAGE CODING METHOD AND DEVICE

    公开(公告)号:US20220417518A1

    公开(公告)日:2022-12-29

    申请号:US17762150

    申请日:2020-09-21

    Abstract: An image decoding method includes a step of deriving a residual sample, wherein the step of deriving the residual sample includes the steps of: when a current block is divided into sub-partition blocks, deriving a transform kernel for an inverse primary transform applied to a sub-partition block based on a horizontal or a vertical length of the sub-partition block; and deriving the residual sample from transform coefficients based on the transform kernel.

    TRANSFORMATION-BASED IMAGE CODING METHOD AND DEVICE THEREFOR

    公开(公告)号:US20220400266A1

    公开(公告)日:2022-12-15

    申请号:US17775693

    申请日:2020-11-09

    Abstract: An image decoding method according to the present document comprises the steps of: determining whether or not an effective coefficient is present in a second area not including an upper-left first area of a current block; parsing an MTS index from a bitstream on the basis that the effective coefficient is not present in the second area; and deriving residual samples for the current block by applying a transform kernel, which is derived on the basis of the MTS index, to transform coefficients in the first area, wherein the MTS index can be parsed on the basis that the effective coefficient, which is present in a scan sub-block which is scanned for the effective coefficient, is not present in the second area.

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