The present invention employs a mapping function in order to apply a known distortion to an input signal. A file having a hierarchical structure formed from video data and audio data both in the form of compressed data together with information necessary for processing of the video data and audio data is produced and recorded on a predetermined recording medium. The suction head includes a static dewatering screen filter and a screen-washing arrangement cooperating with the suction head. Under this framework, an algorithm iteratively computes the consensus clustering and correspondence matrices using multiplicative updating rules.