Video Subblock Merging for Bi-Directional Optical Flow Coding

The patent combines multiple subblocks with identical or similar motion vectors into a single combined subblock. The BDOF process is then applied once on this combined subblock instead of separately on each original subblock. This merging approach maintains motion compensation precision for regions with uniform motion while significantly reducing the number of BDOF calculations required, thus lowering computational complexity.

The patent applies the BDOF process selectively based on local motion characteristics. By identifying subblocks with identical or similar motion vectors and combining only those with homogeneous motion patterns, the method ensures that local motion details are preserved. The combining operation maintains precision for regions where motion is uniform, while avoiding precision loss in regions with complex or varying motion patterns.

The patent merges subblocks with similar motion characteristics into combined subblocks before applying BDOF. This reduces the total number of BDOF operations required, directly decreasing processing time. The method maintains coding efficiency by ensuring that the combining operation is performed only when motion vectors are identical or similar, preserving the quality of motion compensation while accelerating the overall encoding process.