Method and apparatus of matrix based intra prediction in image and video processing

An apparatus for performing image or video processing, comprising:

• a computer processor configured for receiving input data and programming executable on the computer processor for image or video encoding by performing steps comprising:
• receiving input data associated with a current block to be coded by a Matrix-based Intra Prediction (MIP) mode in a current picture;
• determining whether transposing is applied in coding the current block by the MIP mode;
• signaling a transpose flag for the current block indicating whether transposing is applied based on the determining;
• deriving reference samples of the current block from neighboring boundary samples of the current block in the current picture according to whether transposing is applied;
• selecting a matrix for the current block from a matrix set of the current block based on information about the MIP mode, wherein the transpose flag is signaled before the information about the MIP mode is signaled;
• generating predicted samples of the current block by multiplying the reference samples and the matrix;
• adaptively performing a transposing process by replacing the predicted samples of the current block with a transpose of the predicted samples according to whether transposing is applied;
• and
• encoding the current block in the current picture according to the predicted samples of the current block.

A method of processing video data in an image or video decoding system, comprising:

• receiving input data associated with a current block coded by a Matrix-based Intra Prediction (MIP) mode in a current picture;
• parsing a transpose flag for the current block indicating whether transposing is applied;
• determining whether transposing is applied in coding the current block by the MIP mode based on the transpose flag;
• deriving reference samples of the current block from neighboring boundary samples of the current block in the current picture according to whether transposing is applied;
• selecting a matrix for the current block from a matrix set of the current block based on information about the MIP mode, wherein the transpose flag is parsed before the information about the MIP mode is parsed;
• generating predicted samples of the current block by multiplying the reference samples and the matrix;
• adaptively performing a transposing process by replacing the predicted samples of the current block with a transpose of the predicted samples according to whether transposing is applied;
• and
• decoding the current block in the current picture according to the predicted samples of the current block.

An apparatus for performing image or video processing, comprising:

• a computer processor configured for receiving input data and programming executable on the computer processor for image or video decoding by performing steps comprising:
• receiving input data associated with a current block coded by a Matrix-based Intra Prediction (MIP) mode in a current picture;
• parsing a transpose flag for the current block indicating whether transposing is applied;
• determining whether transposing is applied in coding the current block by the MIP mode based on the transpose flag;
• deriving reference samples of the current block from neighboring boundary samples of the current block in the current picture according to whether transposing is applied;
• selecting a matrix for the current block from a matrix set of the current block based on information about the MIP mode, wherein the transpose flag is parsed before the information about the MIP mode is parsed;
• generating predicted samples of the current block by multiplying the reference samples and the matrix;
• adaptively performing a transposing process by replacing the predicted samples of the current block with a transpose of the predicted samples according to whether transposing is applied;
• and
• decoding the current block in the current picture according to the predicted samples of the current block.