Self-guided intra interpolation filter

A method for video encoding, comprising:

• for each combination of (i) an intra interpolation filter in a predefined set of intra interpolation filters and (ii) a line of neighboring reconstructed samples in multiple lines of neighboring reconstructed samples within N adjacent lines from a boundary of a current block in a picture, the current block being encoded in an angular intra prediction mode, N being an integer larger than 1,
• predicting the respective line of neighboring reconstructed samples based on one or more remaining lines in the multiple lines of neighboring reconstructed samples using the respective intra interpolation filter and the angular intra prediction mode to obtain one or more predictions of the respective line;
• and
• obtaining one or more prediction errors based on (i) the one or more predictions of the respective line of neighboring reconstructed samples and (ii) the respective line of neighboring reconstructed samples, the one or more prediction errors being associated with the respective intra interpolation filter, each of the one or more prediction errors being associated with one of the one or more predictions of the respective line of neighboring reconstructed samples;
• selecting one intra interpolation filter from the predefined set of intra interpolation filters based on the obtained prediction errors;
• predicting a sample in the current block using the angular intra prediction mode and the selected one intra interpolation filter;
• encoding the current block based on the predicted sample;
• and
• encoding coding information in a bitstream indicating that the current block is coded in the angular intra prediction mode.

A non-transitory computer-readable storage medium storing instructions which when executed by a processor cause the processor to perform an encoding method comprising:

• for each combination of (i) an intra interpolation filter in a predefined set of intra interpolation filters and (ii) a line of neighboring reconstructed samples in multiple lines of neighboring reconstructed samples within N adjacent lines from a boundary of a current block in a picture, the current block being encoded in an angular intra prediction mode, N being an integer larger than 1,
• predicting the respective line of neighboring reconstructed samples based on one or more remaining lines in the multiple lines of neighboring reconstructed samples using the respective intra interpolation filter and the angular intra prediction mode to obtain one or more predictions of the respective line;
• and
• obtaining one or more prediction errors based on (i) the one or more predictions of the respective line of neighboring reconstructed samples and (ii) the respective line of neighboring reconstructed samples, the one or more prediction errors being associated with the respective intra interpolation filter, each of the one or more prediction errors being associated with one of the one or more predictions of the respective line of neighboring reconstructed samples;
• selecting one intra interpolation filter from the predefined set of intra interpolation filters based on the obtained prediction errors;
• predicting a sample in the current block using the angular intra prediction mode and the selected one intra interpolation filter;
• encoding the current block based on the predicted sample;
• encoding coding information in a bitstream indicating that the current block is coded in the angular intra prediction mode;
• and
• transmitting the bitstream.