Video coding method on basis of secondary transform, and device for same

    公开(公告)号:US11968397B2

    公开(公告)日:2024-04-23

    申请号:US18099131

    申请日:2023-01-19

    CPC classification number: H04N19/619 H04N19/132 H04N19/159 H04N19/176

    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.

    SYNTAX DESIGN METHOD AND APPARATUS FOR PERFORMING CODING BY USING SYNTAX

    公开(公告)号:US20240080486A1

    公开(公告)日:2024-03-07

    申请号:US18387310

    申请日:2023-11-06

    CPC classification number: H04N19/70 H04N19/176 H04N19/52

    Abstract: An image decoding method performed by a decoding apparatus according to the present disclosure comprises the steps of: decoding, on the basis of a bitstream, an affine flag that indicates whether affine prediction is applicable to a current block and a sub-block TMVP flag that indicates whether a temporal motion vector predictor based on a sub-block of the current block is usable; determining whether to decode a predetermined merge mode flag that indicates whether to apply a predetermined merge mode to the current block, on the basis of the decoded affine flag and the decoded sub-block TMVP flag; deriving prediction samples of the current block on the basis of the determining of whether to decode the predetermined merge mode flag; and generating reconstructed samples of the current block based on the prediction samples of the current block.

    Image coding apparatus and method thereof based on a quantization parameter derivation

    公开(公告)号:US11917155B2

    公开(公告)日:2024-02-27

    申请号:US17944068

    申请日:2022-09-13

    CPC classification number: H04N19/124 H04N19/176 H04N19/186 H04N19/70

    Abstract: According to an embodiment of the present invention, a picture decoding method performed by a decoding apparatus is provided. The method comprises: decoding image information comprising information on a quantization parameter (QP), deriving an expected average luma value of a current block from neighboring available samples, deriving a quantization parameter offset (QP offset) for deriving a luma quantization parameter (luma QP) based on the expected average luma value and the information on the QP, deriving the luma QP based on the QP offset, performing an inverse quantization for a quantization group comprising the current block based on the derived luma QP, generating residual samples for the current block based on the inverse quantization, generating prediction samples for the current block based on the image information and generating reconstructed samples for the current block based on the residual samples for the current block and the prediction samples for the current block.

Patent Agency Ranking