Lg Electronics Inc.

Jie Zhao

Seunghwan Kim

Seethal Paluri

Hendry Hendry

Seung Hwan Kim

Jaehyun Lim

Moonmo Koo

Hyeongmoon Jang

Mehdi Salehifar

Junghak Nam

Sunmi Yoo Yoo

An image decoding method according to the present document comprises a step of deriving a corrected transform coefficient by applying low-frequency non-separable transform (LFNST) to a transform coefficient, wherein an LFNST set for applying the LFNST may be derived on the basis of an intra-prediction mode applied to the current block, and an LFNST matrix may be derived on the basis of the size of the current block and the LFNST set, the LFNST matrix derived as a 16×16 dimensional matrix if the width or the height of the current block is 4 and the width and the height are both 4 or greater, and the LFNST matrix derived as a 64×32 dimensional matrix if the width or the height of the current block is 8 and the width and the height are both 8 or greater. Therefore, coding performance capable of being brought by the LFNST can be maximized within the implementation complexity permitted in forthcoming standards.

Method and device for designing low-frequency non-separable transform

An image decoding method performed by a decoding device, according to the present document, comprises the steps of: obtaining image information through a bitstream; and generating a reconstructed picture on the basis of the image information.

Image decoding method and device therefor

An image encoding/decoding method and device are provided. An image decoding method performed by an image decoding device according to the present disclosure may comprise the steps of: determining a prediction mode of the current block on the basis of prediction information obtained from a bitstream; on the basis of the prediction mode of the current block, obtaining a flag indicating whether a color space transform is applied to a residual sample of the current block; determining a quantization parameter of the current block on the basis of the flag; and determining a transform coefficient of the current block on the basis of the quantization parameter.

Image encoding/decoding method and device using adaptive color transform, and method for transmitting bitstream

According to one embodiment of the present specification, provided is an image decoding method performed by a decoding device. The method comprises the steps of: acquiring, from a bitstream, image information comprising information related to decoder-side intra mode derivation (DIMD); determining, on the basis of the information related to DIMD, whether DIMD is applied to a current block; deriving DIMD modes for the current block on the basis that DIMD is applied to the current block; and generating a prediction sample for the current block on the basis of the DIMD modes.

Method and device for intra prediction based on plurality of DIMD modes

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus may comprise parsing weight information specifying a weight for a reference sample from a bitstream according to a weight parameter syntax structure, and decoding a current block by performing inter prediction based on the weight information. The parsing according to the weight parameter syntax structure may comprise obtaining weight number information specifying the number of weight information obtained from the bitstream according to the weight parameter syntax structure and obtaining weight information from the weight parameter syntax structure based on the weight number information.

Image encoding/decoding method using weighted prediction, and method for transmitting bitstream

An image decoding method according to the present document may comprise the steps of: receiving image information including residual information and an LFNST index from a bitstream; deriving a transform coefficient on the basis of the residual information; deriving a flag variable related to whether LFNST is applied to a current block on the basis of the LFNST index; and performing the LFNST on the basis of the flag variable and the transform coefficient, wherein the flag variable is derived for each color component of the current block.

Image coding method and device therefor

According to the disclosure of the present document, a quantization parameter for a quantized escape value in a palette mode can be derived on the basis of minimum quantization parameter information about a conversion skip mode to perform a scaling process on the quantized escape value. Therethrough, the data amount that is required to be signaled for palette mode coding can be reduced, and the efficiency of escape coding in the palette mode can be enhanced.

Image or video coding based on palette coding

A video decoding method performed by a video decoding device may include: parsing a first flag and a second flag from a bitstream, wherein the first flag is related to whether weighted prediction is applied to slices referring to a picture parameter set within the bitstream, and the second flag is related to whether information relating to the weighted prediction exists in a picture header within the bitstream; parsing a prediction weighted table syntax from the picture header based on the first flag and the second flag; generating prediction samples for a current block in a current picture based on syntax elements within the prediction weighted table syntax; generating residual samples based on residual information obtained from the bitstream; and generating reconstructed samples based on the prediction samples and the residual samples, wherein the second flag is parsed from the picture parameter set based on the first flag.

Method and device for weighted prediction for image/video coding

Provided are an image encoding/decoding method and device. An image decoding method performed by an image decoding device according to the present disclosure includes the steps of: determining a quantization parameter of the current block on the basis of whether color space conversion is applied to a residual sample of the current block; determining a transform coefficient of the current block on the basis of the quantization parameter; determining the residual sample of the current block by using the transform coefficient; and resetting the value of the residual sample on the basis of whether the color space conversion is applied.

Method and device for encoding/decoding image using color space conversion, and method for transmitting bitstream

A video decoding method executed by a video decoding apparatus according to the present document comprises the steps of: parsing a flag associated with weighted prediction from a bitstream; on the basis of the flag, parsing a prediction weighted table syntax from the bitstream; and on the basis of the prediction weighted table syntax, executing a weighted prediction on a current block in a current picture to reconstruct the current picture, wherein on the basis of the value of the flag being 1, the prediction weighted table syntax may be parsed from a picture header of the bitstream, and on the basis of the value of the flag being 0, the prediction weighted table syntax may be parsed from a slice header of the bitstream.

Prediction weighted table-based image/video coding method and apparatus

According to the disclosure of the present document, chroma quantization parameter offset-related information can be signaled through palette coding syntax, and index information of a chroma quantization parameter offset list can be efficiently parsed/signaled on the basis of information on the number of entries in the chroma quantization parameter offset list. Accordingly, bits needing to be signaled for video/image coding can be reduced, and the coding efficiency can be improved.

Image or video coding based on quantization-related information

According to the disclosure of the present document, reshaper data and/or an ALF parameter can be signaled adaptively from a parameter set, thereby reducing the amount of data to be signaled for video/image coding and improving coding efficiency.

Video or image coding on basis of conditionally parsed ALF model and reshaping

According to the disclosure of the present document, a luma mapping with chroma scaling (LMCS) process may be simplified, and a linear LMCS may be applied. Accordingly, the complexity of the LMCS may be reduced and video/image coding efficiency may be increased.

Luma mapping- and chroma scaling-based video or image coding

An image decoding method performed by a decoding apparatus, according to the present document, comprises the steps of: acquiring image information including chroma quantization parameter data of at least one chroma QP mapping table for chroma components, and prediction information and residual information regarding the chroma components; deriving the chroma QP mapping table on the basis of the chroma quantization parameter data; deriving a chroma quantization parameter for the chroma components on the basis of the chroma QP mapping table; deriving prediction samples for the chroma components on the basis of the prediction information; deriving residual samples on the basis of the residual information and the chroma quantization parameter; and generating a reconstructed picture on the basis of the prediction samples and the residual samples.

Image decoding method for chroma component and apparatus therefor

An image decoding method performed by a decoding device according to the present document is characterized by including the steps of acquiring chroma quantization parameter data of at least one chroma quantization parameter (QP) mapping table for chroma components; deriving the chroma QP mapping table on the basis of the chroma quantization parameter data; deriving chroma quantization parameters for the chroma components on the basis of the chroma QP mapping table; deriving residual samples for the chroma components on the basis of the chroma quantization parameters; and generating a reconstructed picture on the basis of the residual samples.

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Seoul, South Korea

Jie Zhao