Derived intra prediction modes and most probable modes in video coding

A device for encoding or decoding video data, the device comprising:

• a memory to store the video data;
• and
• one or more processors implemented in circuitry, the one or more processors configured to:
• for each respective intra prediction mode of a plurality of intra prediction modes in a most-probable mode (MPM) list:
• generate, based on reference samples for a template region and using the respective intra prediction mode, prediction samples for the template region, wherein the template region is above or left of a block of the video data;
• and
• determine a respective cost for the respective intra prediction mode based on differences between (1) the prediction samples for the template region and (2) reconstructed samples for the template region;
• determine a first intra prediction mode in the MPM list and a second intra prediction mode in the MPM list, wherein the first intra prediction mode and the second intra prediction mode are intra prediction modes in the MPM list having lowest determined respective costs, the lowest determined respective costs including a first determined cost for the first intra prediction mode and a second determined cost for the second intra prediction mode;
• determine a weight for the first intra prediction mode based on the first determined cost for the first intra prediction mode and a weight for the second intra prediction mode based on the second determined cost for the second intra prediction mode;
• determine a preliminary prediction block for the first intra prediction mode and a preliminary prediction block for the second intra prediction mode;
• generate a prediction block based on a fusion of the preliminary prediction block for the first intra prediction mode and the preliminary prediction block for the second intra prediction mode weighted according to the weight for the first intra prediction mode and the weight for the second intra prediction mode;
• and
• reconstruct the block based on the prediction block, or encode the block based on the prediction block.

A device for encoding or decoding video data, the device comprising:

• for each respective intra prediction mode of a plurality of intra prediction modes in a most-probable mode (MPM) list:
• means for generating, based on reference samples for a template region and using the respective intra prediction mode, prediction samples for the template region, wherein the template region is above or left of a block of the video data;
• and
• means for determining a respective cost for the respective intra prediction mode based on differences between (1) the prediction samples for the template region and (2) reconstructed samples for the template region;
• means for determining a first intra prediction mode in the MPM list and a second intra prediction mode in the MPM list, wherein the first intra prediction mode and the second intra prediction mode are intra prediction modes in the MPM list having lowest determined respective costs, the lowest determined respective costs including a first determined cost for the first intra prediction mode and a second determined cost for the second intra prediction mode;
• means for determining a weight for the first intra prediction mode based on the first determined cost for the first intra prediction mode and a weight for the second intra prediction mode based on the second determined cost for the second intra prediction mode;
• means for determining a preliminary prediction block for the first intra prediction mode and a preliminary prediction block for the second intra prediction mode;
• means for generating a prediction block based on a fusion of the preliminary prediction block for the first intra prediction mode and the preliminary prediction block for the second intra prediction mode weighted according to the weight for the first intra prediction mode and the weight for the second intra prediction mode;
• and
• means for reconstructing the block based on the prediction block or means for encoding the block based on the prediction block.