Method and apparatus for intra-prediction coding of video data

1. An apparatus for encoding video data, comprising:

an encoder configured to encode, into a bitstream, a syntax element indicating an intra-prediction type of a current luma block of the video data, the intra-prediction type being indicated from among matrix based intra-prediction (MIP) and regular intra-prediction; and

an intra-predictor configured to generate a prediction block for the current luma block by selectively performing the MIP or the regular intra-prediction based on the intra-prediction type of the current luma block,

wherein, as a part of the generating of the prediction block for the current luma block by performing the regular intra-prediction, the intra-predictor is further configured to:

determine a regular intra-prediction mode for the current luma block,

derive Most Probable Mode (MPM) candidates based on a regular intra-prediction mode of each of neighboring blocks adjacent to the current luma block to configure an MPM list for the current luma block, wherein the regular intra-prediction mode of the neighboring block is set as a PLANAR mode when an intra-prediction type of the neighboring block is the MIP; and

encode, into the bitstream, at least one syntax element indicating the regular intra-prediction mode for the current luma block based on the MPM list, and

wherein, as a part of the generating of the prediction block for the current luma block by performing the MIP, the intra-predictor is further configured to:

encode, into the bitstream, a syntax element indicating an MIP mode for the current luma block;

derive a boundary vector using neighboring samples adjacent to the current luma block based on a width and a height of the current luma block;

generate predicted samples for the current luma block based on matrix-vector multiplication between the boundary vector and a matrix predefined for the MIP mode; and

derive the prediction block for the current luma block based on the predicted samples, and

wherein the deriving of the boundary vector using the neighboring samples adjacent to the current luma block includes:

encoding, into the bitstream, a syntax element indicating a concatenation order of first entries of the boundary vector derived from the left neighboring samples adjacent to the current luma block and second entries of the boundary vector derived from the above neighboring samples adjacent to the current luma block; and

concatenating the first entries and the second entries according to the concatenation order and thereby generating the boundary vector.

2. The apparatus of claim 1 , wherein the syntax element indicating the MIP mode for the current luma block is a truncated binary code which specifies one of a plurality of MIP modes allowed for the width and the height of the current luma block.

3. The apparatus of claim 2 , wherein the deriving of the boundary vector using the neighboring samples adjacent to the current luma block includes:

deriving the boundary vector from one or two sets selected from between a set of left neighboring samples and a set of above neighboring samples adjacent to the current luma block, depending on the MIP mode for the current luma block.

4. The apparatus of claim 2 , wherein entries of the boundary vector are derived based on down-sampled values from left neighboring samples adjacent to the current luma block or the left neighboring samples adjacent to the current luma block according to the width and the height of the current luma block.

5. The apparatus of claim 2 , wherein the deriving of the prediction block for the current luma block based on the predicted samples includes:

allocating the predicted samples to positions in the prediction block; and

generating predicted sample values for positions to which the predicted samples are not allocated in the prediction block, based on using linear interpolation for the predicted samples, left neighboring samples adjacent to the current luma block, and above neighboring samples adjacent to the current luma block.

6. An apparatus for decoding video data, comprising:

a decoder configured to decode, from a bitstream, a syntax element indicating an intra-prediction type of a current luma block of the video data, the intra-prediction type being indicated from among matrix based intra-prediction (MIP) and regular intra-prediction; and

an intra-predictor configured to generate a prediction block for the current luma block by selectively performing the MIP or the regular intra-prediction based on the intra-prediction type of the current luma block indicated by the syntax element,

wherein, as a part of the generating of the prediction block for the current luma block by performing the regular intra-prediction, the intra-predictor is further configured to:

derive Most Probable Mode (MPM) candidates based on a regular intra-prediction mode of each of neighboring blocks adjacent to the current luma block to configure an MPM list for the current luma block, wherein the regular intra-prediction mode of the neighboring block is set as a PLANAR mode when an intra-prediction type of the neighboring block is the MIP; and

derive a regular intra-prediction mode for the current luma block based on the MPM list, and

wherein, as a part of the generating of the prediction block for the current luma block by performing the regular intra-prediction, the intra-predictor is further configured to:

decode, from the bitstream, a syntax element indicating an MIP mode for the current luma block;

derive a boundary vector using neighboring samples adjacent to the current luma block based on a width and a height of the current luma block;

generate predicted samples for the current luma block based on matrix-vector multiplication between the boundary vector and a matrix predefined for the MIP mode; and

derive the prediction block for the current luma block based on the predicted samples, and

wherein the deriving of the boundary vector using the neighboring samples adjacent to the current luma block includes:

decoding, from the bitstream, a syntax element indicating a concatenation order of first entries of the boundary vector derived from the left neighboring samples adjacent to the current luma block and second entries of the boundary vector derived from the above neighboring samples adjacent to the current luma block; and

concatenating the first entries and the second entries according to the concatenation order and generating the boundary vector.

7. The apparatus of claim 6 , wherein the syntax element indicating the MIP mode for the current luma block is a truncated binary code which specifies one of a plurality of MIP modes allowed for the width and the height of the current luma block.

8. The apparatus of claim 7 , wherein the deriving of the boundary vector using the neighboring samples adjacent to the current luma block includes:

deriving the boundary vector from one or two sets selected from between a set of left neighboring samples and a set of above neighboring samples adjacent to the current luma block, depending on the MIP mode for the current luma block.

9. The apparatus of claim 7 , wherein entries of the boundary vector are derived based on down-sampled values from left neighboring samples adjacent to the current luma block or the left neighboring samples adjacent to the current luma block according to the width and the height of the current luma block.

10. The apparatus of claim 7 , wherein the deriving of the prediction block for the current luma block based on the predicted samples includes:

allocating the predicted samples to positions in the prediction block; and

generating predicted sample values for positions to which the predicted samples are not allocated in the prediction block, based on using linear interpolation for the predicted samples, left neighboring samples adjacent to the current luma block, and above neighboring samples adjacent to the current luma block.

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

decoding, from the bitstream, a syntax element indicating an intra-prediction type of a current luma 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 luma block by selectively performing the MIP or the regular intra-prediction based on the intra-prediction type of the current luma block indicated by the syntax element,

wherein the generating of the prediction block for the current luma block by performing the regular intra-prediction includes:

deriving Most Probable Mode (MPM) candidates based on a regular intra-prediction mode of each of neighboring blocks adjacent to the current luma block to configure an MPM list for the current luma block, wherein the regular intra-prediction mode of the neighboring block is set as a PLANAR mode when an intra-prediction type of the neighboring block is the MIP; and

deriving a regular intra-prediction mode for the current luma block based on the MPM list, and

wherein the generating of the prediction block for the current luma block by performing the MIP includes:

decoding, from the bitstream, a syntax element indicating an MIP mode for the current luma block;

deriving a boundary vector using neighboring samples adjacent to the current luma block based on a width and a height of the current luma block;

generating predicted samples for the current luma block based on matrix-vector multiplication between the boundary vector and a matrix predefined for the MIP mode; and

deriving the prediction block for the current luma block based on the predicted samples, and

wherein the deriving of the boundary vector using the neighboring samples adjacent to the current luma block includes:

decoding, from the bitstream, a syntax element indicating a concatenation order of first entries of the boundary vector derived from the left neighboring samples adjacent to the current luma block and second entries of the boundary vector derived from the above neighboring samples adjacent to the current luma block; and

concatenating the first entries and the second entries according to the concatenation order and thereby generating the boundary vector.