US Patent 10582212 Warped reference motion vectors for video compression

A motion vector candidate list is generated that can be used to encode or decode a motion vector used to predict the current block. A motion mode and motion information for a source block is determined. A motion vector used to predict the source block is added to the list responsive to determining that the motion mode for the source block is a translational motion mode and that a reference frame for the source block matches the reference frame for the current block. A warped reference motion vector is instead added to the list responsive to determining that the motion mode for the source block is a warped motion mode and that the reference frame for the source block matches the reference frame for the current block. A reference motion vector from the list is selected for encoding or decoding the current block motion vector.