MPEG-4 Video Data Protection for Internet Distribution

The increasing availability of multimedia contents and particularly the rapid development of the Internet have determined new ways to distribute information documents. In this scenario a copy protection system allowing to control the distribution of multimedia data is hardly required. A new technology useful for copyright protection is watermarking: a digital code (watermark), indicating the copyright owner, is directly embedded into the video signal. In this paper specific attention has been paid to the standard MPEG-4 and a digital video watermarking system has been designed in such a way that the complexity of the standard and the diversity of its applications are considered. In particular, the possibility of the MPEG-4 standard to directly access objects within a video sequence introduces a new constraint to the watermarking process: even if a video object is transferred from a sequence to another, the copyright data of the single object has to be correctly detected. Moreover, to make the watermarking system robust against format conversions, the code has to be inserted before compression. The method proposed in this paper satisfies the previous requirements by relying on an image watermarking algorithm which embeds the code in the Discrete Wavelet Transform of each frame.