TRANSFORM-BASED IMAGE CODING METHOD AND DEVICE FOR SAME

    公开(公告)号:US20220086449A1

    公开(公告)日:2022-03-17

    申请号:US17535095

    申请日:2021-11-24

    Abstract: An image decoding method according to the present document is characterized by including: a step for receiving a bitstream including residual information; a step for deriving transform coefficients for a target block on the basis of the residual information; a step for deriving corrected transform coefficients on the basis of an inverse non-separable transform of the transform coefficients; and a step for deriving residual samples for the target block on the basis of an inverse primary transform of the corrected transform coefficients, wherein the inverse non-separable transform is performed when the size of the target block is equal to or smaller than the size of a prescribed maximum transform application block.

    METHOD AND DEVICE FOR PROCESSING VIDEO SIGNAL BY USING INTRA-PREDICTION

    公开(公告)号:US20220078483A1

    公开(公告)日:2022-03-10

    申请号:US17415707

    申请日:2019-12-19

    Abstract: Embodiments in the present specification provide a video signal processing method and device. A method of processing a video signal according to an embodiment in the present specification comprises the steps of: acquiring an intra-prediction mode for a current block from the video signal; determining a modified intra-prediction mode from the intra-prediction mode for the current block on the basis of the width and height of and the intra-prediction mode for the current block; and applying a transform determined on the basis of the modified intra-prediction mode. The accuracy of prediction can be further improved by deriving a modified intra-prediction mode according to a wide-angle intra-prediction mode according to the shape of and an intra-prediction mode for a current block.

    METHOD AND APPARATUS FOR PROCESSING IMAGE SIGNAL

    公开(公告)号:US20220060747A1

    公开(公告)日:2022-02-24

    申请号:US17473078

    申请日:2021-09-13

    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.

    METHOD AND DEVICE FOR PROCESSING IMAGE SIGNAL

    公开(公告)号:US20220038734A1

    公开(公告)日:2022-02-03

    申请号:US17278481

    申请日:2019-09-20

    Abstract: Embodiments of the present specification provide a method and a device for processing a video signal. A method for processing an image signal, according to an embodiment of the present specification, comprises the steps of: generating a merge candidate list including a first motion vector and a second motion vector from a spatial merge candidate or a temporal merge candidate of a current block; adding, to the merge candidate list, a third motion vector determined as the average value of the first motion vector and the second motion vector, if the number of merge candidates of the merge candidate list is smaller than the maximum number of merge candidates; and generating a prediction sample of the current block by using a motion vector indicated by a merge index in the merge candidate list.

    METHOD AND DEVICE FOR PROCESSING VIDEO SIGNAL BY USING TRANSFORM HAVING LOW COMPLEXITY

    公开(公告)号:US20220030277A1

    公开(公告)日:2022-01-27

    申请号:US17311525

    申请日:2019-12-06

    Abstract: An embodiment of the present specification provides a method and device for processing video data. A method for processing a video signal according to an embodiment of the present specification may comprise the steps of: acquiring a transform index related to one of a plurality of transform combinations including combinations of one or more transform kernels for transforming of a current block of the video signal; deriving a transform combination including a vertical transform and a horizontal transform related to the transform index; and applying each of the vertical transform and horizontal transform of the transform combination to the current block, wherein the transform kernels include DST-7 or DST-8, the DST-7 or DST-8 is designed on the basis of a discrete Fourier transform (DFT) to which a scale value in the form of a power of 2 related to a bit length of a transform coefficient has been applied, and the transform kernels are designed using the DFT to which the scale value has been applied, so as to enable reduction of a calculation complexity for transform.

    IMAGE CODING METHOD BASED ON QUADRATIC TRANSFORM, AND APPARATUS THEREFOR

    公开(公告)号:US20210377568A1

    公开(公告)日:2021-12-02

    申请号:US17394734

    申请日:2021-08-05

    Abstract: An image decoding method according to the present document comprises the steps of: receiving a quantized transform coefficient for a target block and a transform index for non-separable quadratic transform; deriving transform coefficients by inversely quantizing the quantized transform coefficient; deriving corrected transform coefficients on the basis of a transform kernel matrix in a predetermined transform set indicated by the transform index; and deriving residual samples for the target block on the basis of inverse linear transform for the corrected transform coefficients, wherein when the target block is divided into a predetermined number of sub-blocks and is coded by intra prediction, the corrected transform coefficients are derived in units of the sub-blocks, and the transform index is received for the target block.

    IMAGE ENCODING/DECODING METHOD AND DEVICE THEREFOR

    公开(公告)号:US20210329281A1

    公开(公告)日:2021-10-21

    申请号:US17266407

    申请日:2019-08-08

    Abstract: The present invention relates to a video signal decoding method based on a Multiple Transform Selection (MTS). The method may comprise the steps of: parsing a first syntax element representing whether MTS applies to the inverse transformation of a current block, wherein the MTS represents a transform mode which uses a transform type other than a default transform type predefined for the current block; by performing inverse quantization on the current block, deriving an inverse-quantized transform coefficient array having the width and the height of the current block; determining, on the basis of the first syntax element, a vertical transform type applying to the vertical direction of the current block, and a horizontal transform type applying to the horizontal direction of the current block; and, by performing inverse transformation on the inverse-quantized transform coefficient array by using the vertical transform type and the horizontal transform type, deriving a residual sample array having the width and the height of the current block.

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