A reproduction method ad apparatus for reproducing video data and/or audio data from a medium dedicated to reproduction or recordable medium having video data and/or audio data recorded thereon, the video data and/or audio data being generated by superimposing information concerning an attribute of a video signal and/or an audio signal on a signal of digitized video data and/or a signal of digitized audio data. The information concerning an attribute superimposed on the video data and/or audio data from the medium is reproduced and a type of the medium is identified as a medium dedicated to reproduction or as a recordable medium. Reproduction is stopped in response to a determination that the medium is illegally produced, the determination being based on a combination of the information concerning the attribute which is reproduced and the type of the medium identified.