Intra prediction-based image coding method and apparatus using unified MPM list

    公开(公告)号:US11902572B2

    公开(公告)日:2024-02-13

    申请号:US17431348

    申请日:2020-02-26

    Abstract: An image decoding method according to the present document comprises the steps of: acquiring, from a bitstream, reference line index information indicating a reference line to be used for intra prediction of a current block; constructing a most probable mode (MPM) list by deriving candidate intra prediction modes of the current block on the basis of the value of the reference line index information; deriving the intra prediction mode of the current block on the basis of the MPM list; generating prediction samples for the current block on the basis of the intra prediction mode; and generating restoration samples for the current block on the basis of the prediction samples, wherein, on the basis of the case in which the value of the reference line index information is not zero, one of the candidate intra prediction modes is a DC mode and the number of candidate intra prediction modes including the DC mode is 5.

    CCLM-based intra-prediction method and apparatus therefor

    公开(公告)号:US11805244B2

    公开(公告)日:2023-10-31

    申请号:US17834532

    申请日:2022-06-07

    Abstract: A picture decoding method, performed by a decoding apparatus according to the present disclosure, comprises the steps of: when an intra-prediction mode of a chroma block is a cross-component linear model (CCLM) mode, deriving neighboring chroma reference samples with respect to the chroma block; deriving neighboring luma reference samples of a luma block corresponding to the chroma block and luma samples in the luma block; deriving down-sampled neighboring luma reference samples and downsampled luma samples by down sampling the neighboring luma reference samples and the luma samples, respectively; deriving a linear model parameter on the basis of the down-sampled neighboring luma reference samples and the neighboring chroma reference samples; generating prediction samples with respect to the chroma block on the basis of the linear model parameter and the down-sampled luma samples of the luma block; and reconstructing the chroma block on the basis of the prediction samples with respect to the chroma block.

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