Systems and methods for partition-based prediction mode reordering

A method of video encoding performed at a computing system having memory and one or more processors, the method comprising:

• receiving video data comprising a plurality of blocks, including a first block and a reference block associated with the first block, wherein the first block comprises at least two partitions and is to be predicted via a partition-based prediction;
• obtaining a set of partition modes for partitioning the first block, each partition mode being uniquely associated with a partition line that partitions the first block into the at least two partitions, wherein each partition mode in the set of partition modes corresponds to a respective partition angle of a set of partition angles and a respective partition offset of a set of partition offsets;
• generating both a reference template using samples of the reference block and a reconstruction template using samples of the first block, wherein the reference template is generated using integer samples of the reference block and blended using additional fractional samples of the reference block;
• calculating, for each partition mode of the set of partition modes, a cost between the reference template and the reconstruction template;
• reordering the set of partition angles corresponding to the set of partition modes based on the calculated cost between the reference template and the reconstruction template for each partition mode;
• selecting a partition angle from the reordered set of partition angles;
• signaling, via a video bitstream, an index value indicating the selected partition angle;
• and
• encoding the first block according to the selected partition angle and a partition offset of the set of partition offsets.

A method for obtaining a video bitstream, the video bitstream comprising coded information for a plurality of blocks of video data, the plurality of blocks including a first block, and an indicator indicating an index value indicating a partition angle for the first block, the method comprising:

• obtaining a set of partition modes for partitioning the first block, each partition mode being uniquely associated with a partition line that partitions the first block into at least two partitions, wherein each partition mode in the set of partition modes corresponds to a respective partition angle of a set of partition angles and a respective partition offset of a set of partition offsets;
• generating both a reference template using samples of the reference block and a reconstruction template using samples of the first block, wherein the reference template is generated using integer samples of the reference block and blended using additional fractional samples of the reference block;
• calculating, for each partition mode of the set of partition modes, a cost between the reference template and the reconstruction template;
• reordering the set of partition angles corresponding to the set of partition modes based on the calculated cost between the reference template and the reconstruction template for each partition mode;
• selecting a partition angle from the reordered set of partition angles;
• signaling the index value indicating the selected partition angle;
• and
• encoding the first block according to the selected partition angle and a partition offset of the set of partition offsets.