US Patent 11388436 Bit-width control for bi-directional optical flow

A method for controlling bit-width for bi-directional optical flow (BDOF) for video coding includes decoding a first reference picture and a second reference picture, the second reference picture being different than the first reference picture, wherein the first reference picture is displayed before a current picture and the second reference picture is displayed after the current picture. A motion refinement of a coding unit (CU) is calculated by minimizing a difference between a first prediction L