METHOD AND APPARATUS FOR PROCESSING VIDEO SIGNAL BY USING APPROXIMATION TRANSFORM ON BASIS OF PREPROCESSING/POSTPROCESSING MATRIX

    公开(公告)号:US20210218996A1

    公开(公告)日:2021-07-15

    申请号:US17047849

    申请日:2019-04-17

    Abstract: The present invention provides a method for reconstructing a video signal by using an approximation transform on the basis of a preprocessing/postprocessing matrix, the method comprising: obtaining a transform index of a current block from a video signal, wherein the transform index corresponds to any one of a plurality of transform combinations including at least one of DST7, DCT8, DST6, or flipped DST7, and a transform combination includes a horizontal transform and a vertical transform; deriving a primary transform for horizontal/vertical directions corresponding to the transform index; performing an inverse primary approximation transform by using the primary transform for the horizontal/vertical directions, wherein the inverse primary approximation transform is generated by multiplying the primary transform for the horizontal/vertical directions by a preprocessing matrix and a postprocessing matrix; and reconstructing the video signal by using the inverse primary approximation-transformed current block.

    METHOD AND APPARATUS FOR PROCESSING IMAGE SIGNAL

    公开(公告)号:US20210160490A1

    公开(公告)日:2021-05-27

    申请号:US17168571

    申请日:2021-02-05

    Abstract: Embodiments of the present invention provide a method and apparatus for processing a video signal. A method for decoding an image signal according to an embodiment of the present invention comprises the steps of: for a current block having a width and a height different from each other, determining a modified intra prediction mode from an intra prediction mode, on the basis of a ratio between the width and the height of the current block and the intra prediction mode; determining an inverse non-separable transform set on the basis of the modified intra prediction mode; and applying an inverse non-separable transform matrix selected from the inverse non-separable transform set with respect to the top-left region of the current block, which is determined according to the width and the height of the current block.

    METHOD AND APPARATUS FOR PROCESSING IMAGE SIGNAL

    公开(公告)号:US20200374554A1

    公开(公告)日:2020-11-26

    申请号:US16899910

    申请日:2020-06-12

    Abstract: Embodiments of the present disclosure provide a method and device for processing a video signal. A method for decoding an image signal according to an embodiment of the present disclosure comprises the steps of: determining a non-separable transform set index indicating a non-separable transform set used for a non-separable transform of a current block from among non-separable transform sets predefined on the basis of an intra-prediction mode of the current block; determining. as a non-separable transform matrix, a transform kernel indicated by a non-separable transform index for the current block from among transform kernels included in the non-separable transform set indicated by the non-separable transform set index; and applying the non-separable transform matrix to an upper left region which of the current block, which is determined according to the width and height of the current block, wherein each of the predefined non-separable transform sets includes two transform kernels.

    IMAGE CODING METHOD AND APPARATUS BASED ON INTRA PREDICTION USING MPM LIST

    公开(公告)号:US20200304780A1

    公开(公告)日:2020-09-24

    申请号:US16868768

    申请日:2020-05-07

    Abstract: An image decoding method performed by a decoding apparatus according to the present disclosure includes receiving intra prediction information including at least one of most probable mode (MPM) flag information representing whether to derive an intra prediction mode for a current block based on MPM candidates for the current block or planar flag information representing whether to determine the intra prediction mode for the current block as a planar mode, deriving the intra prediction mode for the current block based on the MPM flag information and the planar flag information, deriving a predicted block for the current block based on the intra prediction mode for the current block, and generating a reconstructed picture based on the predicted block.

    IMAGE CODING APPARATUS AND METHOD THEREOF BASED ON A QUANTIZATION PARAMETER DERIVATION

    公开(公告)号:US20200260084A1

    公开(公告)日:2020-08-13

    申请号:US16859105

    申请日:2020-04-27

    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.

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