Block-based optical flow estimation for motion compensated prediction in video coding

Abstract

Motion prediction using optical flow is determined to be available for a current frame in response to determining that a reference frame buffer includes, with respect to the current frame, a forward reference frame and a backward reference frame. A flag indicating whether a current block is encoded using optical flow is decoded. Responsive to determining that the flag indicates that the current block is encoded using optical flow, a motion vector is decoded for the current block; a location of an optical flow reference block is identified within an optical flow reference frame based on the motion vector; subsequent to identifying the location of the optical flow reference block, the optical flow reference block is generated using the forward reference frame and the backward reference frame without generating the optical flow reference frame; and the current block is decoded based on the optical flow reference block.