公开(公告)号：US11570438B2

公开(公告)日：2023-01-31

申请号：US17556099

申请日：2021-12-20

Applicant: LG Electronics Inc.

Inventor： Junghak Nam ,  Moonmo Koo ,  Jaehyun Lim ,  Seunghwan Kim

IPC: H04N19/12 ,  H04N19/132 ,  H04N19/176 ,  H04N19/18

Abstract: An image decoding method includes: acquiring a multiple transform selection (MTS) index and residual information from a bitstream; deriving transform coefficients for the current block on the basis of the residual information; and generating residual samples of the current block on the basis of the MTS index and the transform coefficients, wherein the MTS index indicates a transform kernel set to be applied to the current block among transform kernel set candidates, at least one bin among bins of a bin string of the MTS index is derived on the basis of context coding, the context coding is performed on the basis of values of increase and decrease in a context index pertaining to the MTS index, and a single value of increase and decrease in the context index can be used for the context coding of the first bin among the bins of the bin string.

公开(公告)号：US11563944B2

公开(公告)日：2023-01-24

申请号：US17316049

申请日：2021-05-10

Applicant: LG Electronics Inc.

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

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

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.

公开(公告)号：US20220394257A1

公开(公告)日：2022-12-08

申请号：US17775818

申请日：2020-11-13

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo Koo ,  Seunghwan Kim ,  Jaehyun Lim

IPC: H04N19/12 ,  H04N19/176 ,  H04N19/96 ,  H04N19/70 ,  H04N19/186 ,  H04N19/61 ,  H04N19/167

Abstract: An image decoding method according to the present document comprises the step of deriving modified transform coefficients by applying LFNST to transform coefficients, wherein the step of deriving the modified transform coefficients comprises the steps of: deriving a variable indicating whether an effective coefficient is present in a DC component of a current block; and parsing an LFNST index on the basis of whether the variable indicates that the effective coefficient is present in a position other than the DC component, wherein the variable may be derived on the basis of an individual transform skip flag value for a color component of the current block.

公开(公告)号：US11457227B2

公开(公告)日：2022-09-27

申请号：US17581154

申请日：2022-01-21

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo Koo ,  Jaehyun Lim ,  Seunghwan Kim

IPC: H04N19/18 ,  H04N19/176 ,  H04N19/70 ,  H04N19/60 ,  H04N19/96 ,  H04N19/124 ,  H04N19/186

Abstract: An image decoding method according to the present document comprises the steps of: deriving a transform coefficient for a current block on the basis of residual information; deriving a residual sample by applying, to the transform coefficient, at least one of LFNST and MTS; and generating a reconstructed picture on the basis of the residual samples, wherein the LFNST is performed on the basis of an LFNST index indicating an LFNST kernel, the MTS is performed on the basis of an MTS index indicating an MTS kernel, and the LFNST index may be parsed before the MTS index.

公开(公告)号：US11405614B2

公开(公告)日：2022-08-02

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 ,  H04N19/167 ,  H04N19/176 ,  H04N19/18 ,  H04N19/91

Abstract: Systems and techniques for reconstructing a video signal include: 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：US11330261B2

公开(公告)日：2022-05-10

申请号：US17476190

申请日：2021-09-15

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo Koo ,  Jaehyun Lim ,  Junghak Nam ,  Seunghwan Kim

IPC: H04N19/12 ,  H04N19/96 ,  H04N19/159 ,  H04N19/70 ,  H04N19/61 ,  H04N19/132

Abstract: An image decoding method according to the present document comprises a step for performing inverse first-order transform and inverse non-separable transform on a residual sample. The inverse non-separable transform is performed on the basis of a transform index indicating a predetermined transform kernel matrix, the inverse first-order transform is performed on the basis of a multiple transform selection (MTS) index indicating MTS for a horizontal transform kernel and a vertical transform kernel, and a syntax element bin string for the transform index is derived on the basis of first context information when a tree type for a split structure of a target block is not a single tree type and is derived on the basis of second context information when the tree type is the single tree type.

公开(公告)号：US11218731B2

公开(公告)日：2022-01-04

申请号：US16772934

申请日：2018-12-13

Applicant: LG Electronics Inc.

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

IPC: H04N19/00 ,  H04N19/60 ,  H04N19/105 ,  H04N19/124 ,  H04N19/176 ,  H04N19/18 ,  H04N19/70

Abstract: An image decoding method performed by means of a decoding device according to the present invention comprises the steps of: deriving quantized transform coefficients with respect to a target block from a bitstream; performing inverse quantization with respect to the quantized transform coefficients with respect to the target block and deriving transform coefficients; deriving residual samples with respect to the target block on the basis of reduced inverse transform with respect to the transform coefficients; and generating a reconstructed picture on the basis of the residual samples with respect to the target block and prediction samples with respect to the target block. The reduced inverse transform is performed on the basis of a reduced inverse transform matrix. The reduced inverse transform matrix is a non-square matrix of which the number of columns is smaller than the number of rows.

公开(公告)号：US11184618B2

公开(公告)日：2021-11-23

申请号：US16904985

申请日：2020-06-18

Applicant: LG Electronics Inc.

Inventor： Mehdi Salehifar ,  Seunghwan Kim ,  Moonmo Koo ,  Jaehyun Lim ,  Seethal Paluri

IPC: H04N19/132 ,  H04N19/105 ,  H04N19/18 ,  H04N19/176

Abstract: A method for decoding an image by a decoding device according to the present invention comprises the steps of: deriving, from a bit stream, transform coefficients of a block to be decoded; deriving residual samples of the block to be decoded, on the basis of a selective transform of the transform coefficients; and generating a reconstructed picture on the basis of the residual samples of the block to be decoded and prediction samples of the block to be decoded, wherein the selective transform is performed on the basis of a modified transform matrix, the modified transform matrix comprises a matrix including a modified basis vector, and the modified basis vector contains a certain number of elements selected from N elements.

公开(公告)号：US11166045B2

公开(公告)日：2021-11-02

申请号：US16652952

申请日：2018-10-11

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo Koo ,  Jaehyun Lim

IPC: H04N19/625 ,  H04N19/124 ,  H04N19/132 ,  H04N19/129 ,  H04N19/136 ,  H04N19/176 ,  H04N19/18 ,  H04N19/184 ,  H04N19/70

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：US11146816B2

公开(公告)日：2021-10-12

申请号：US16899910

申请日：2020-06-12

Applicant: LG ELECTRONICS INC.

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

IPC: H04N19/593 ,  H04N19/122 ,  H04N19/176

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.