CCLM-based intra-prediction method and device

    公开(公告)号:US10887596B2

    公开(公告)日:2021-01-05

    申请号:US16801538

    申请日:2020-02-26

    Abstract: A method for decoding a picture based on a cross-component linear model (CCLM) mode includes deriving neighboring luma reference samples of a luma block, deriving down-sampled neighboring luma reference samples, deriving a linear model parameter based on the down-sampled neighboring luma reference samples and the neighboring chroma reference samples, where the neighboring luma reference samples includes top neighboring luma reference samples, and left neighboring luma reference samples, and where when the top boundary of the luma block overlaps with a boundary of a coding tree unit (CTU), the number of the top neighboring luma reference samples used for deriving the down-sampled neighboring luma reference samples among the neighboring luma reference samples is less than that of the left neighboring luma reference samples used for deriving the down-sampled neighboring luma reference samples.

    METHOD FOR DECODING IMAGE ON BASIS OF CCLM PREDICTION IN IMAGE CODING SYSTEM, AND DEVICE THEREFOR

    公开(公告)号:US20250159210A1

    公开(公告)日:2025-05-15

    申请号:US19022299

    申请日:2025-01-15

    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.

    INTRA PREDICTION-BASED IMAGE CODING METHOD AND DEVICE USING MPM LIST

    公开(公告)号:US20250113024A1

    公开(公告)日:2025-04-03

    申请号:US18980322

    申请日:2024-12-13

    Abstract: An image decoding method according to the present document derives a left mode, which is a candidate intra prediction mode for a left peripheral block of a current block, derives an upper mode, which is a candidate intra prediction mode for an upper peripheral block of the current block, constructs an MPM list on the basis of the left mode and the upper mode, derives an intra prediction mode of the current block on the basis of the MPM list, generates prediction samples of the current block on the basis of the intra prediction mode, generates a restoration picture of the current block on the basis of the prediction samples, and derives the left mode or the upper mode as one from among candidate intra prediction modes of the MPM list, on the basis of when the left mode and the upper mode are not the same and the left mode and the upper mode are respectively a planar mode and a DC mode.

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