US Patent 7245661 Transcoder and method of transcoding

A transcoder and a method of transcoding which reduces computational requirements without picture deterioration. A mode decision unit decides a mode of a scaled output macro block based on an area of the scaled macro block overlapped with a non-scaled macro block of a reference frame and a mode of the overlapped macro block. A motion vector decision unit decides a reference motion vector of the output macro block based on a motion vector with respect to the overlapped macro blocks. A picture quality preference mode selection unit receives a user picture quality preference command. A motion vector compensation unit compensates the motion vector of the output macro block based on the decided reference motion vector and the picture quality preference command.