inputting means for inputting motion picture data that has been subjected to compression including frequency transformation and quantization;

watermark embedding means for generating and embedding a digital watermark pattern of a visible watermark corresponding to a motion compensated prediction in said motion picture data input by said inputting means, wherein said watermark embedding means comprises (i) intra-block processing means for embedding said digital watermark pattern into blocks that have pixel values relevant to all pixels as information among screens constituting said motion picture data, and (ii) motion correction means for embedding a cancellation pattern for canceling the movement of said digital watermark pattern due to motion vectors in a screen that is generated through motion compensated prediction based on motion vectors among screens constituting said motion picture data, wherein said motion correction means removes the embedded digital watermark pattern, generates an image of said cancellation pattern, subjects the image of said cancellation pattern to frequency transformation, and embeds the frequency transformed image in a screen being processed; and

outputting means for outputting motion picture data with the watermark embedded therein by said watermark embedding means.