A video processing apparatus (700, 800, 900) for performing a video coding and a frame rate conversion on an input video stream, the video processing apparatus (700, 800, 900) comprising: a storage module, for storing the input video stream comprising a plurality of input video frames; a video coding module, for encoding the input video stream, generating a compressed bit-stream according to a plurality of motion vectors; a motion compensation module, coupled to the storage module and the video coding module, for performing the frame rate conversion on the input video stream to generate an output video stream according to the input video stream and the motion vectors when in a conversion mode, wherein the output video stream generated from the frame rate conversion includes interpolated frames and the input video frames; and generating a reconstructed frame according to a reference frame and the motion vectors and storing the reconstructed frame into the storage module when in a coding mode; and a motion estimation module, coupled to the storage module, the video coding module, and the motion compensation module, for extracting the input video stream from the storage module, and generating the motion vectors according to the input video stream; and the motion estimation module comprises: a first motion estimation unit for performing a first motion estimation operation to generate motion vectors; and a second motion estimation unit for receiving information generated from the first motion estimation unit and performing a second motion estimation operation to generate motion vectors according to the information received from the first motion estimation unit and the input video stream; wherein one of the first and second motion estimation units (712, 714) provides the generated motion vectors to the motion compensation module for the frame rate conversion when in the conversion mode, and the other of the first and second motion estimation units (712, 714) provides the generated motion vectors to the motion compensation module for generating the reconstructed frame when in the coding mode. a storage module, for storing the input video stream comprising a plurality of input video frames; a video coding module, for encoding the input video stream, generating a compressed bit-stream according to a plurality of motion vectors; a motion compensation module, coupled to the storage module and the video coding module, for performing the frame rate conversion on the input video stream to generate an output video stream according to the input video stream and the motion vectors when in a conversion mode, wherein the output video stream generated from the frame rate conversion includes interpolated frames and the input video frames; and generating a reconstructed frame according to a reference frame and the motion vectors and storing the reconstructed frame into the storage module when in a coding mode; and a motion estimation module, coupled to the storage module, the video coding module, and the motion compensation module, for extracting the input video stream from the storage module, and generating the motion vectors according to the input video stream; and the motion estimation module comprises: a first motion estimation unit for performing a first motion estimation operation to generate motion vectors; and a second motion estimation unit for receiving information generated from the first motion estimation unit and performing a second motion estimation operation to generate motion vectors according to the information received from the first motion estimation unit and the input video stream; wherein one of the first and second motion estimation units (712, 714) provides the generated motion vectors to the motion compensation module for the frame rate conversion when in the conversion mode, and the other of the first and second motion estimation units (712, 714) provides the generated motion vectors to the motion compensation module for generating the reconstructed frame when in the coding mode.