Matrix-based intra prediction device and method

1 . An image decoding method performed by a decoding apparatus, the method comprising:

receiving residual information;

receiving second flag information related to whether an intra prediction type for a current block is matrix-based intra prediction (MIP) based on first flag information related to whether the MIP is enabled;

receiving MIP mode information based on the second flag information;

generating intra prediction samples for the current block based on the MIP mode information;

deriving quantized transform coefficients based on the residual information;

deriving transform coefficients based on the quantized transform coefficients;

deriving residual samples based on the transform coefficients; and

generating reconstructed samples for the current block based on the intra prediction samples and the residual samples,

wherein the MIP mode information is index information related to an MIP matrix for the current block,

wherein the MIP matrix is derived based on a size of the current block and the index information,

wherein the intra prediction samples is generated based on the MIP matrix,

wherein a syntax element bin string for the MIP mode information is binarized by a TB (truncated binarization) method,

wherein a maximum length of the syntax element bin string is set to different three values based on the size of the current block, and

wherein based on a width and a height of the current block being 4, the maximum length has a largest value.

2 . An image encoding method performed by an encoding apparatus, the method comprising:

deriving whether matrix-based intra prediction (MIP) is applied to a current block;

deriving intra prediction samples for the current block based on that the MIP is applied to the current block;

deriving residual samples for the current block based on the intra prediction samples;

deriving transform coefficients based on the residual samples;

deriving quantized transform coefficients based on the transform coefficients;

generating residual information based on the quantized transform coefficients; and

generating a bitstream by encoding the residual information and information on the MIP,

wherein the information on the MIP comprises first flag information related to whether the MIP is enabled, second flag information related to whether an intra prediction type for the current block is the MIP and MIP mode information which is index information related to an MIP matrix for the current block,

wherein the MIP matrix is derived based on a size of the current block and the index information,

wherein the intra prediction samples is derived based on the MIP matrix,

wherein a syntax element bin string for the MIP mode information is binarized by a TB (truncated binarization) method,

wherein a maximum length of the syntax element bin string is set to different three values based on the size of the current block, and

wherein based on a width and a height of the current block being 4, the maximum length has a largest value.

3 . A transmitting method of data for an image, the method comprising:

obtaining a bitstream for the image, wherein the bitstream is generated based on deriving whether matrix-based intra prediction (MIP) is applied to a current block, deriving intra prediction samples for the current block based on that the MIP is applied to the current block, deriving residual samples for the current block based on the intra prediction samples, deriving transform coefficients based on the residual samples, deriving quantized transform coefficients based on the transform coefficients, generating residual information based on the quantized transform coefficients, and generating a bitstream by encoding the residual information and information on the MIP; and

transmitting the data comprising the bitstream,

wherein the information on the MIP comprises first flag information related to whether the MIP is enabled, second flag information related to whether an intra prediction type for the current block is the MIP and MIP mode information which is index information related to an MIP matrix for the current block,

wherein the MIP matrix is derived based on a size of the current block and the index information,

wherein the intra prediction samples is derived based on the MIP matrix,

wherein a syntax element bin string for the MIP mode information is binarized by a TB (truncated binarization) method,

wherein a maximum length of the syntax element bin string is set to different three values based on the size of the current block, and

wherein based on a width and a height of the current block being 4, the maximum length has a largest value.