Method and apparatus for intra-prediction coding of video data involving matrix-based intra-prediction

An apparatus of encoding video data, comprising:

• an encoder configured to encode a syntax element indicating an intra-prediction type of a current block of the video data, the intra-prediction type being indicated from among matrix based intra-prediction (MIP) and regular intra-prediction, and to encode a residual block that is a difference between the current block and a prediction block;
• an intra-predictor configured to generate the prediction block for the current block by selectively performing the MIP or the regular intra-prediction based on the intra-prediction type of the current block indicated by the syntax element;
• and
• wherein, in generating the prediction block for the current block by performing the MIP, the intra-predictor is configured to:
• encode a syntax element indicating an MIP mode for the current block, the syntax element being represented as a truncated binary code specifying one of a plurality of MIP prediction modes allowed for a width and a height of the current block;
• derive an input boundary vector using neighboring samples adjacent to the current block based on the width and the height of the current block;
• generate predicted samples for the current block based on matrix-vector multiplication between the input boundary vector and a matrix predefined for the MIP mode;
• and
• derive the prediction block for the current block based on the predicted samples,
• wherein deriving the input boundary vector using the neighboring samples adjacent to the current block comprises:
• generating an initial boundary vector filled with the neighboring samples adjacent to the current block or down-sampled values from the neighboring samples according to the width and the height of the current block;
• and
• wherein the input boundary vector is generated by subtracting a value of a first entry from each entry of the initial boundary vector.

A non-transitory computer readable medium storing a bitstream containing encoded data for video data, the bitstream being decoded by processes of:

• decoding, from a bitstream, a syntax element indicating an intra-prediction type of a current block of the video data, the intra-prediction type being indicated from among matrix based intra-prediction (MIP) and regular intra-prediction;
• and
• generating a prediction block for the current block by selectively performing the MIP or the regular intra-prediction based on the intra-prediction type of the current block indicated by the syntax element,
• wherein generating the prediction block for the current block by performing the MIP comprises:
• decoding, from the bitstream, a syntax element indicating an MIP mode for the current block, the syntax element being represented as a truncated binary code specifying one of a plurality of MIP prediction modes allowed for a width and a height of the current block;
• deriving an input boundary vector using neighboring samples adjacent to the current block based on the width and the height of the current block;
• generating predicted samples for the current block based on matrix-vector multiplication between the input boundary vector and a matrix predefined for the MIP mode;
• and
• deriving the prediction block for the current block based on the predicted samples,
• wherein deriving the input boundary vector using the neighboring samples adjacent to the current block comprises:
• generating an initial boundary vector filled with the neighboring samples adjacent to the current block or down-sampled values from the neighboring samples according to the width and the height of the current block;
• and
• from the initial boundary vector, generating an input boundary vector to which the matrix-vector multiplication is applied, and
• wherein the input boundary vector is generated by subtracting a value of a first entry from each entry of the initial boundary vector.