Abstract: Embodiments of the present invention provide a method and apparatus for processing a video signal. A method for decoding an image signal according to an embodiment of the present invention comprises the steps of: for a current block having a width and a height different from each other, determining a modified intra prediction mode from an intra prediction mode, on the basis of a ratio between the width and the height of the current block and the intra prediction mode; determining an inverse non-separable transform set on the basis of the modified intra prediction mode; and applying an inverse non-separable transform matrix selected from the inverse non-separable transform set with respect to the top-left region of the current block, which is determined according to the width and the height of the current block.

Abstract: A video transform method includes: receiving a quantized transform coefficient for a target block and a transform index for a non-separated secondary transform; inverse-quantizing the quantized transform coefficient; deriving an input transform coefficient size indicating the length of the inverse-quantized transform coefficient to which the non-separated secondary transform has been applied, an output transform coefficient size indicating the length of a modified transform coefficient to which the non-separated secondary transform has been applied, and a transform set mapped to the intra mode of the target block, when the transform index does not indicate that the non-separated secondary transform is not performed; and deriving the modified transform coefficient on the basis of a matrix operation on a transform kernel matrix in the transform set indicated by the transform index, and a transform coefficient list corresponding to the input transform coefficient size.

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.

Abstract: An image decoding method according to the present document comprises a step for deriving a residual sample, wherein the step for deriving the residual sample comprises the steps of: deriving a zero out block for a current block; deriving a context model for last significant coefficient location information on the basis of the width or height of the current block; deriving a value of a last significant coefficient location on the basis of the context model; and deriving the last significant coefficient location on the basis of a value of the last significant coefficient location information and the width or height of the zero out block.

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.

Abstract: Disclosed is a method for decoding a video signal, including: generating a dequantized transform block by performing dequantization for a current block; acquiring an intra prediction mode of the current block; determining a secondary transform set applied to the current block among a plurality of secondary transform sets based on the intra prediction mode; deriving a transform kernel applied to the current block in the determined secondary transform set; and performing secondary transform for a top left specific area of the dequantized transform block by using the derived transform kernel, in which the plurality of secondary transform sets may include at least one mixed secondary transform set.

Abstract: Embodiments of the disclosure provide a method and apparatus for processing a video signal. Particularly, a method for decoding a video signal according to an embodiment of the disclosure may include: determining, among predefined secondary transform sets based on intra-prediction modes of a current block, a secondary transform set applied to the current block; obtaining a first syntax element indicating a secondary transform matrix applied to the current block in the determined secondary transform set; deriving a secondary inverse-transformed block by performing a secondary inverse transform on a left top region of the current block by using the secondary transform matrix specified by the first syntax element; and deriving a residual block of the current block by performing a primary inverse transform on the secondary inverse-transformed block using a primary transform matrix of the current block.

Abstract: A method for processing video signals and an apparatus therefor are disclosed. Specifically, a method for processing video signals on the basis of inter prediction comprises the steps of: deriving a motion vector predictor by using motion information of a neighboring block of the current block; parsing layer information for indicating the current layer, to which a motion vector difference used for the inter prediction of the current block belongs, within a predefined layer structure in which a combination of motion vector differences between one or more horizontal and vertical components is classified into a plurality of layers; parsing index information for indicating a specific combination in the current layer; deriving a motion vector difference of the current block by using the layer information and the index information; and deriving a motion vector of the current block by adding the motion vector difference to the motion vector predictor.

Abstract: A method and device for processing a video signal are disclosed.

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.

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.

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.

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.

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.

Abstract: Disclosed is a method for decoding a video signal, including: generating a dequantized transform block by performing dequantization for a current block; acquiring an intra prediction mode of the current block; determining a secondary transform set applied to the current block among a plurality of secondary transform sets based on the intra prediction mode; deriving a transform kernel applied to the current block in the determined secondary transform set; and performing secondary transform for a top left specific area of the dequantized transform block by using the derived transform kernel, in which the plurality of secondary transform sets may include at least one mixed secondary transform set.

Abstract: The embodiments of the present disclosure provides a method and apparatus for video signal processing. A method for decoding an image signal according to an embodiment of the present disclosure may include determining an input length and an output length of a non-separable transform based on a height and a width of a current block; determining a non-separable transform matrix corresponding to the input length and the output length of a non-separable transform; and applying the non-separable transform matrix to coefficients by a number of the input length in the current block, wherein the height and the width of a current block is greater than or equal to 8, wherein, if each of the height and the width of a current block is equal to 8, the input length of the non-separable transform is determined as 8.

Abstract: The present invention relates to a video signal decoding method based on a Multiple Transform Selection (MTS).

Abstract: Embodiments of the present invention provide a method and apparatus for processing a video signal. A method for decoding an image signal according to an embodiment of the present invention comprises the steps of: for a current block having a width and a height different from each other, determining a modified intra prediction mode from an intra prediction mode, on the basis of a ratio between the width and the height of the current block and the intra prediction mode; determining an inverse non-separable transform set on the basis of the modified intra prediction mode; and applying an inverse non-separable transform matrix selected from the inverse non-separable transform set with respect to the top-left region of the current block, which is determined according to the width and the height of the current block.

Abstract: Embodiments of the present invention provide video signal processing methods.

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.