公开(公告)号：US20220109878A1

公开(公告)日：2022-04-07

申请号：US17428016

申请日：2020-02-06

Applicant: LG ELECTRONICS INC.

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

IPC: H04N19/625 ,  H04N19/176 ,  H04N19/119 ,  H04N19/12 ,  H04N19/157

Abstract: A method and device for processing a video signal using a reduced transform are provided. A method for decoding a video signal includes splitting a current block into a plurality of subblocks based on a first flag for a split direction of the current block, determining a subblock, to which a transform is applied, among the plurality of subblocks based on a second flag for a position of a transform target block, determining a transform target area in the subblock, and applying an inverse transform including a horizontal transform and a vertical transform to transform coefficients of the transform target area. The transform target area is determined based on a transform type applied to the subblock and a size of the subblock.

公开(公告)号：US20220086490A1

公开(公告)日：2022-03-17

申请号：US17430496

申请日：2020-02-12

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo KOO ,  Jaehyun LIM ,  Seunghwan KIM

IPC: H04N19/61 ,  H04N19/625 ,  H04N19/46 ,  H04N19/176

Abstract: Embodiments of the present disclosure provide a method and apparatus for processing a video signal. A method for decoding a video signal according to an embodiment of the present disclosure includes obtaining a sub-block transform (SBT) flag indicating whether an SBT is applied, wherein the SBT represents a transform applied to one of sub-blocks split from a coding unit, determining a transform unit from the coding unit based on the SBT flag, determining a size value of the transform unit as a first reference value if DST-7 (Discrete Sine Transform type 7) or DCT-8 (Discrete Cosine Transform type 8) is applied and the size value of the transform unit is greater than the first reference value and less than a third reference value and determining the size value as a second reference value if DCT-2 (Discrete Cosine Transform type 2) is applied and the size value is equal to or greater than the third reference value, wherein the third reference value is greater than the second reference value and the second reference value is greater than the first reference value, obtaining transform coefficients based on the size value, and performing an inverse transform on the transform coefficients. A data processing time and the amount of data necessary for a transform can be reduced by performing coding in consideration of a region reduced according to a block size.

公开(公告)号：US20220070494A1

公开(公告)日：2022-03-03

申请号：US17420196

申请日：2020-01-02

Applicant: LG ELECTRONICS INC.

Inventor： Moonmo KOO ,  Jaehyun LIM ,  Seunghwan KIM

IPC: H04N19/625 ,  H04N19/105 ,  H04N19/132 ,  H04N19/70 ,  H04N19/18 ,  H04N19/176

Abstract: A method for processing a video signal includes determining a horizontal transform type index for a horizontal transform kernel and a vertical transform type index for a vertical transform kernel of a transform block in the video signal, determining a transform region in which a significant transform coefficient exists in the transform block based on the horizontal transform type index, the vertical transform type index, and a size of the transform block, and applying inverse-transform to the transform region based on the horizontal transform type index and the vertical transform type index. A width of the transform region is determined based on a comparison between the horizontal transform type index and a reference value, and a height of the transform region is determined based on a comparison between the vertical transform type index and the reference value.

公开(公告)号：US20220038741A1

公开(公告)日：2022-02-03

申请号：US17503042

申请日：2021-10-15

Applicant: LG Electronics Inc.

Inventor： Junghak NAM ,  Jaehyun LIM ,  Moonmo KOO ,  Seunghwan KIM

IPC: H04N19/593 ,  H04N19/119 ,  H04N19/159 ,  H04N19/18 ,  H04N19/70 ,  H04N19/176 ,  H04N19/61

Abstract: An image coding method according to the present document comprises the steps of: deriving transform coefficients for a current block on the basis of residual-related information; and generating residual samples of the current block on the basis of the transform coefficients. The residual-related information comprises low frequency non-separable transform (LFNST) index information, showing information relating to non-separable transform for low-frequency transform coefficients of the current block, on the basis of a matrix-based intra-prediction (MIP) flag showing whether or not MIP is applied to the current block. The residual samples are generated from the transform coefficients on the basis of the LFNST index information.

公开(公告)号：US20210281881A1

公开(公告)日：2021-09-09

申请号：US17327242

申请日：2021-05-21

Applicant: LG Electronics Inc.

Inventor： Moonmo KOO ,  Jaehyun LIM ,  Seunghwan KIM

IPC: H04N19/60 ,  H04N19/124 ,  H04N19/18 ,  H04N19/176 ,  H04N19/70 ,  H04N19/159

Abstract: An image decoding method comprises the steps of: deriving transform coefficients through inverse quantization on the basis of quantized transform coefficients for a target block; deriving modified transform coefficients on the basis of an inverse reduced secondary transform (RST) for the transform coefficients; and generating a restoration picture on the basis of residual samples for the target block, on the basis of an inverse primary transform for the modified transform coefficients, wherein the inverse RST is performed on the basis of: transform sets determined by a mapping relation according to an intra prediction mode applied to the target block; and a transform kernel matrix selected from among two transform kernel matrices included in each of the transform sets, and is performed on the basis of: whether the inverse RST is applied; and a transform index for indicating any one of the transform kernel matrices included in the transform sets.

公开(公告)号：US20210258593A1

公开(公告)日：2021-08-19

申请号：US17232719

申请日：2021-04-16

Applicant: LG ELECTRONICS INC.

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

IPC: H04N19/44 ,  H04N19/159 ,  H04N19/176 ,  H04N19/625 ,  H04N19/70

Abstract: A method and a device for processing a video signal are disclosed. In particular, a method for decoding a video signal includes parsing a first syntax element indicating a primary transform kernel applied to a primary transform of a current block; determining whether a secondary transform is applicable to the current block based on the first syntax element; if the secondary transform is applicable to the current block, parsing a second syntax element indicating a secondary transform kernel applied to a secondary transform of the current block; deriving a secondary inverse-transformed block, by performing a secondary inverse-transform for a top-left specific region of the current block using a secondary transform kernel indicated by the second syntax element; and deriving a residual block of the current block, by performing a primary inverse-transform for the secondary inverse-transformed block using a primary transform kernel indicated by the first syntax element.

公开(公告)号：US20210235121A1

公开(公告)日：2021-07-29

申请号：US17058873

申请日：2019-05-31

Applicant: LG ELECTRONICS INC.

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

IPC: H04N19/625 ,  H04N19/62

Abstract: The present disclosure provides a method for reconstructing a video signal through a low-complexity Discrete Sine Transform-7 (DST7) design, including: obtaining a transform index of a current block from the video signal, wherein the transform index corresponds to any one of a plurality of transform combinations including combinations of DST7 and/or a Discrete Cosine Transform-8 (DCT8); deriving a transform combination corresponding to the transform index, wherein the transform combination includes a horizontal transform and a vertical transform, and wherein the horizontal transform and the vertical transform correspond to any one of the DST7 and the DCT8; performing an inverse transform on the current block in a vertical or horizontal direction using the DST7 or the DCT8; and reconstructing the video signal using the inverse transformed current block, wherein a 33-point Discrete Fourier Transform (DFT) is applied to the DST7 when the DST7 is 16×16 and a 65-point DFT is applied to the DST7 when the DST7 is 32×32.

公开(公告)号：US20210211729A1

公开(公告)日：2021-07-08

申请号：US17209854

申请日：2021-03-23

Applicant: LG ELECTRONICS INC.

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

IPC: H04N19/625 ,  H04N19/70 ,  H04N19/132 ,  H04N19/176

Abstract: Disclosed is a method for encoding/decoding video signals and an apparatus therefor. Specifically, a method for decoding a video signal based on reduced transform comprised the steps of: obtaining, from the video signal, a transform index indicating transform kernels applied to horizontal and vertical directions of a current block; determining a region in which a transform is applied to the current block based on the transform kernels indicated by the transform index and a size of the current block; deriving, as zero, coefficients of a remaining region other than the region to which the transform is applied within the current block; and performing an inverse transform on the region to which the transform is applied using the transform kernels indicated by the transform index.

公开(公告)号：US20210120252A1

公开(公告)日：2021-04-22

申请号：US17138662

申请日：2020-12-30

Applicant: LG ELECTRONICS INC.

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

IPC: H04N19/18 ,  H04N19/11 ,  H04N19/122 ,  H04N19/129 ,  H04N19/593 ,  H04N19/61 ,  H04N19/91 ,  H04N19/176 ,  H04N19/124 ,  H04N19/184 ,  H04N19/159

Abstract: An image decoding method according to the present disclosure includes deriving transform coefficients through dequantization based on the quantized transform coefficients for the target block; deriving modified transform coefficients based on an inverse reduced secondary transform (RST) for the transform coefficients; deriving residual samples for the target block based on an inverse primary transform for the modified transform coefficients; and generating a reconstructed samples based on the residual samples, and prediction samples derived based on an intra prediction mode for the target block, wherein the inverse RST is performed based on a transform kernel matrix selected from a transform set including a plurality of transform kernel matrices, the transform set is determined based on a mapping relationship according to the intra prediction mode applied to the target block, and a plurality of intra prediction modes including the intra prediction mode of the target block are mapped to one transform set.

公开(公告)号：US20210021871A1

公开(公告)日：2021-01-21

申请号：US17042722

申请日：2019-05-01

Applicant: LG Electronics Inc.

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

IPC: H04N19/61 ,  H04N19/625 ,  H04N19/159 ,  H04N19/176

Abstract: The present disclosure provides a method for reconstructing a video signal based on low-complexity transform implementation including obtaining a transform index of a current block from the video signal, wherein the transform index corresponds to any one of a plurality of transform combinations including a combination of DST4 and/or DCT4; deriving a transform combination corresponding to the transform index, wherein the transform combination includes a horizontal transform and a vertical transform, and wherein the horizontal transform and the vertical transform correspond to at least one of the DST4 or the DCT4; performing an inverse transform in a vertical direction with respect to the current block by using the DST4; performing an inverse transform in a horizontal direction with respect to the current block by using the DCT4; and reconstructing the video signal by using the current block which the inverse transform is performed.