A video digital watermarking algorithm based on DCT domain

21st Century, The rapid development of information superhighway, such as Internet and mobile communication network. Digital audio and video products are easy to tamper and to copy in large-scale with low-cost. great dissemination capabilities of the Internet gave copyright protection poses a serious impact. For large-scale audio-video products distribution, MPEG-2 Audio-visual products, as verify the carrier, Network audio and video products trading platform is built, the platform has the ability to track the source of piracy. the platform has three core functions. Including home copy generated and encrypted, audio-visual products User copy generated aud encrypted audio-visual products to track pirates. Among them, the digital fingerprint technology the user to copy audio and video products throughout the production, distribution and tracking process. The first, digital works assigned unique identification information. this fingerprint encoded information embedded in digital works, so that different users get different copies of data.