公开(公告)号：US20210360247A1

公开(公告)日：2021-11-18

申请号：US17059027

申请日：2019-05-31

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo KOO ,  Mehdi SALEHIFAR ,  Seunghwan KIM ,  Jaehyun LIM

IPC: H04N19/122 ,  H04N19/60 ,  H04N19/13 ,  H04N19/176 ,  H04N19/124

Abstract: The present invention provides a method for reconstructing a video signal by using a layered-givens transform, comprising the steps of: generating a transform block by performing entropy decoding and inverse quantization on a current block; performing an inverse secondary transformation on a left top specific area of the transform block by using the layered-givens transform; performing an inverse primary transformation on the block on which the inverse secondary transformation has been performed; and reconstructing the current block by using the block on which the inverse primary transformation has been performed, wherein the layered-givens transform includes a plurality of rotation layers and a permutation matrix.

公开(公告)号：US20210329249A1

公开(公告)日：2021-10-21

申请号：US17349215

申请日：2021-06-16

Applicant: LG Electronics Inc.

Inventor： Moonmo KOO ,  Seunghwan KIM ,  Jaehyun LIM

IPC: H04N19/132 ,  H04N19/30 ,  H04N19/46 ,  H04N19/159 ,  H04N19/18 ,  H04N19/176

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 a non-separable secondary transform; dequantizing the quantized transform coefficients to derive transform coefficients; deriving modified transform coefficients on the basis of a matrix operation of a transform kernel matrix in a transform set indicated by the transform index and a transform coefficient list corresponding to the magnitude of dequantized transform coefficients; clipping the modified transform coefficients to a predetermined range of values; and deriving residual samples for the target block on the basis of an inverse primary transform with respect to the modified transform coefficients clipped.

公开(公告)号：US20210281842A1

公开(公告)日：2021-09-09

申请号：US17258367

申请日：2019-07-03

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo KOO ,  Mehdi SALEHIFAR ,  Seunghwan KIM ,  Jaehyun LIM

IPC: H04N19/122 ,  H04N19/14 ,  H04N19/44 ,  H04N19/625 ,  H04N19/18

Abstract: Embodiments of the present invention provide a video signal processing method and apparatus. The video signal processing method according to an embodiment of the present invention comprises checking a length of a signal to which a transform is to be applied in the video signal, wherein the length of the signal corresponds to a width or height of a current block to which the transform is applied, determining a transform type based on the length of the signal, and applying, to the signal, the transform matrix determined based on the transform type, wherein DST-4 or DCT-4 is determined as the transform type if the length of the signal corresponds to a first length, and wherein DST-7 or DCT-8 is determined as the transform type if the length of the signal corresponds to a second length different from the first length.

公开(公告)号：US20210235119A1

公开(公告)日：2021-07-29

申请号：US15734806

申请日：2019-06-07

Applicant: LG ELECTRONICS INC.

Inventor： Seunghwan KIM ,  Medhi SALEHIFAR ,  Moonmo KOO ,  Jaehyun LIM

IPC: H04N19/61 ,  H04N19/11 ,  H04N19/176 ,  H04N19/593

Abstract: The present disclosure, in a method of decoding a video signal, provides a method including checking whether a transform skip is applied to a current block; acquiring a transform index indicating transform types applied to a horizontal direction and a vertical direction of the current block from among a plurality of predefined transform types from the video signal when the transform skip is not applied to the current block; and performing an inverse primary transform on the current block using the transform types indicated by the transform index, wherein the transform types applied to the horizontal direction and the vertical direction of the current block are determined from among transform types defined according to an intra prediction mode of the current block based on the transform index.

公开(公告)号：US20210099704A1

公开(公告)日：2021-04-01

申请号：US17117785

申请日：2020-12-10

Applicant: LG Electronics Inc.

Inventor： Moonmo KOO ,  Mehdi Salehifar ,  Seunghwan Kim ,  Jaehyun Lim

IPC: H04N19/122 ,  H04N19/159 ,  H04N19/176 ,  H04N19/61

Abstract: Embodiments of the disclosure provide a method and apparatus for processing video signals. An image signal decoding method according to an embodiment of the disclosure comprises the steps of: determining, on the basis of the height and width of a current block, an input length and output length of a non-separable transform; determining a non-separable transform matrix corresponding to the input length and output length of the non-separable transform; and applying the non-separable transform matrix to the current block, wherein, when the height and width of the current block are 4 each, the input length and output length of the non-separable transform are determined to be 8 and 16 respectively.

公开(公告)号：US20210084314A1

公开(公告)日：2021-03-18

申请号：US16954026

申请日：2018-12-13

Applicant: LG ELECTRONICS INC.

Inventor： Mehdi SALEHIFAR ,  Seunghwan KIM ,  Jaehyun LIM ,  Moonmo KOO

IPC: H04N19/18 ,  H04N19/184 ,  H04N19/176 ,  H04N19/46 ,  H04N19/91 ,  H04N19/60

Abstract: An image information decoding method performed by means of a decoding device according to the present invention comprises the steps of: decoding a non-separable secondary transform (NSST) index from a bitstream if NSST is applied to a target block; decoding information relating to transform coefficients with respect to the target block from the bitstream on the basis of the decoded NSST index; and deriving the transform coefficients with respect to the target block on the basis of the decoded information relating to the transform coefficients, wherein the NSST index is decoded prior to the information relating to the transform coefficients with respect to the target block.

公开(公告)号：US20210029357A1

公开(公告)日：2021-01-28

申请号：US17043494

申请日：2019-05-02

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo KOO ,  Mehdi SALEHIFAR ,  Seunghwan KIM ,  Jaehyun LIM

IPC: H04N19/122 ,  H04N19/176 ,  H04N19/625 ,  H04N19/14

Abstract: Reconstructing a video signal based on low-complexity DST7 design including obtaining a transform index of a current block from the video signal and deriving a transform combination corresponding to the transform index. The transform index corresponds to any one of a plurality of transform combinations including a combination of DST7 and/or DCT8, and the transform combination includes horizontal and vertical transforms that correspond to at least one of the DST7 or the DCT8. The reconstruction also includes performing an inverse transform in a vertical direction by using the DST7, performing an inverse transform in a horizontal direction by using the DCT8, and reconstructing the video signal by using the current block on which the inverse transform is performed. The DST7 includes Discrete Fourier Transform (DFT) and has a different type of DFT structure based on a size of the current block.

公开(公告)号：US20210014493A1

公开(公告)日：2021-01-14

申请号：US17031089

申请日：2020-09-24

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo KOO ,  Mehdi SALEHIFAR ,  Seunghwan KIM ,  Jaehyun LIM

IPC: H04N19/122 ,  H04N19/176 ,  H04N19/18 ,  H04N19/91 ,  H04N19/167

Abstract: The present disclosure provides a method for reconstructing a video signal, which includes: obtaining a transform coefficient block by performing an entropy decoding and a dequantization for a current block; deriving a secondary transform corresponding to a specific area in the transform coefficient block, wherein the specific area represents an area including a top-left block of the transform coefficient block; performing an inverse secondary transform for each of subblocks within the specific area using the secondary transform; performing an inverse primary transform for a block which the inverse secondary transform is applied to; and reconstructing the current block using a block which the primary inverse transform is applied to.

公开(公告)号：US20200322635A1

公开(公告)日：2020-10-08

申请号：US16652952

申请日：2018-10-11

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo KOO ,  Jaehyun LIM

IPC: H04N19/625 ,  H04N19/124 ,  H04N19/176 ,  H04N19/136 ,  H04N19/184 ,  H04N19/18 ,  H04N19/129 ,  H04N19/132

Abstract: An image decoding method according to the present invention comprises the steps of: deriving, from a bitstream, quantized transform coefficients for a block to be decoded; deriving transform coefficients through dequantization on the basis of the quantized transform coefficients for the block to be decoded; determining a transform configuration group for the block to be decoded; deriving a horizontal transform kernel and a vertical transform kernel on the basis of the transform configuration group and transform index information acquired from the bitstream; deriving residual samples by performing a separable transform on the basis of the horizontal transform kernel and the vertical transform kernel; and generating a reconstructed picture on the basis of the residual samples and prediction samples of the block to be decoded, wherein the transform configuration group includes an identity transform kernel as a candidate transform kernel for the horizontal transform kernel or the vertical transform kernel. According to the present invention, the efficiency of residual coding can be improved.

公开(公告)号：US20200314426A1

公开(公告)日：2020-10-01

申请号：US16901857

申请日：2020-06-15

Applicant: LG Electronics Inc.

Inventor： Mehdi SALEHIFAR ,  Seunghwan KIM ,  Jaehyun LIM ,  Moonmo KOO

IPC: H04N19/122 ,  H04N19/176 ,  H04N19/91 ,  H04N19/167

Abstract: An image decoding method performed by means of a decoding device according to the present disclosure comprises the steps of: deriving transform coefficients of a target block from a bitstream; deriving a non-separable secondary transform (NSST) index with respect to the target block; performing inverse transform with respect to the transform coefficients of the target block on the basis of the NSST index and thus deriving residual samples of the target block; and generating a reconstructed picture on the basis of the residual samples.