Context coding for information on transform kernel set in image coding system

    公开(公告)号:US11622114B2

    公开(公告)日:2023-04-04

    申请号:US17555837

    申请日:2021-12-20

    Abstract: An image decoding method, according to the present document, comprises a step of generating residual samples for a current block on the basis of residual information, wherein the residual samples are generated on the basis of information on a transform kernel set and transform coefficients for the current block, the transform coefficients are derived on the basis of the residual information, and the information on the transform kernel set represents a transform kernel set to be applied to the current block from among transform kernel set candidates. At least one bin from among bins of a bin string of the information on the transform kernel set is derived on the basis of context coding, and the context coding is performed on the basis of at least one context model.

    Method and apparatus for decoding image on basis of prediction based on MMVD in image coding system

    公开(公告)号:US11595660B2

    公开(公告)日:2023-02-28

    申请号:US17366722

    申请日:2021-07-02

    Abstract: A decoding apparatus performs an image decoding method by receiving a bit stream including prediction information of a current block; deriving motion information of the current block on the basis of a merge candidate indicated by a candidate flag of the current block in a merge candidate list; deriving a MVD of the current block on the basis of MVD information of the current block and whether or not integer sample precision or fractional sample precision is used in the motion information; deriving modified motion information of the current block on the basis of the motion information and the MVD; and performing prediction of the current block on the basis of the modified motion information.

    Transform for matrix-based intra-prediction in image coding

    公开(公告)号:US11558641B2

    公开(公告)日:2023-01-17

    申请号:US17503042

    申请日:2021-10-15

    Abstract: An image coding method according to the present document comprises the steps of: deriving transform coefficients for a current block on the basis of residual-related information; and generating residual samples of the current block on the basis of the transform coefficients. The residual-related information comprises low frequency non-separable transform (LFNST) index information, showing information relating to non-separable transform for low-frequency transform coefficients of the current block, on the basis of a matrix-based intra-prediction (MIP) flag showing whether or not MIP is applied to the current block. The residual samples are generated from the transform coefficients on the basis of the LFNST index information.

    Image decoding method and device thereof

    公开(公告)号:US11523134B2

    公开(公告)日:2022-12-06

    申请号:US17612186

    申请日:2020-05-22

    Abstract: An image decoding method performed by a decoding device according to the present document comprises the steps of: acquiring a block-based delta pulse code modulation (BDPCM) flag for a current block; on the basis of the BDPCM flag indicating that BDPCM is applied to the current block, acquiring a BDPCM direction flag for the current block; and storing, as an intra-prediction mode of the current block, an intra-prediction mode of a prediction direction derived on the basis of the BDPCM direction flag.

    Method and device for image coding using motion vector differences

    公开(公告)号:US11523119B2

    公开(公告)日:2022-12-06

    申请号:US17550995

    申请日:2021-12-14

    Abstract: According to embodiments of the present document, a prediction procedure may be performed for image/video coding, and the prediction procedure may include symmetric motion vector differences (SMVDs) and merge mode motion vector differences (MMVDs) according to an inter prediction. The inter prediction may be performed on the basis of reference pictures of a current picture, and types (e.g., a long term reference picture, a short term reference picture, etc.) of the reference pictures may be considered for the inter prediction. Therefore, performance and coding efficiency in the prediction procedure can be improved.

    Transform-based image coding method and device therefor

    公开(公告)号:US11470324B2

    公开(公告)日:2022-10-11

    申请号:US17535090

    申请日:2021-11-24

    Abstract: An image decoding method, according to the present document, may comprise the steps of: deriving transform coefficients for a current block on the basis of residual information; determining whether a significant coefficient is present in a second region excluding a first region in the top-left end of the current block; parsing a LFNST index from a bitstream if the significant coefficient is not present in the second region; deriving modified transform coefficients by applying a LFNST matrix, derived on the basis of the LFNST index, to transform coefficients of the first region; and deriving residual samples of the current block on the basis of an inverse primary transform of the modified transform coefficients.

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