Video watermarking technique embeds some information into videos by modifying video content slightly. The embedded information, named watermark, may be ownership information, customer information, integrity information, redundancy information, and so forth. Thus, this technique can be used for copyright protection, piracy tracing, content authentication, advertisement surveillance, error resilience, and so forth. In this chapter, we give an overview on video watermarking technology, including its architecture, performance requirement, typical algorithms, hot topics, and open issues.
Watermarking is a technology with the aim of embedding information into carrier (image, video, audio, text, program, web, database, etc.), and related early work can be traced back as far as 1954. The last 10 years has seen considerable interest in digital video watermarking, due in large part to ever growing of digital video content everywhere and concerns on spreading of pirate programs.
A general video watermarking system, shown in Figure 1, is composed of three parts: watermarking embedding, attack channel and watermark detection. According to the structure, the message (watermarking) is embedded into the original signal under the control of the embedding key, which produces the watermarked signal. In transmission channel, the watermarked signal may be attacked or distorted. The attacks include cutting, rotation, scaling or translation, and so on. The distortion includes such signal processing operations as compression, filtering, adding noise, A/D, D/A, etc. Then, the test signal, including the attacked or distorted signal or an arbitrary signal, is detected under the control of detection key, which tells the detected watermark or the existence of the watermark.
General watermarking system
Since it is still a technology in development, summarizing all its aspects is quite hard. In this chapter, we try to give an overview on video watermarking, briefly summarize its development, present its potential applications, give some performances requirements, present its research progress, and give the hot topics and open issues in research.
The rest of the chapter is arranged as follows. First, the brief history will be introduced in Section 2. The requirements and applications will be described in Section 3 and Section 4 respectively. In Section 5, the research achievements, including patent and paper publications, will be summarized. The typical attacks to video watermarking are given in Section 6. In Section 7, the ongoing work is presented. Hot topics and open issues are given in Section 8. Finally, some conclusions are drawn in Section 9.Top
Performance Requirement Of Video Watermarking
For video watermarking, some performances are required, both the ones same to image watermarking and its extra ones, such as security, robustness, transparency, oblivious, vindicability and efficiency.
Key Terms in this Chapter
Fragile Watermarking: The watermarking technology that makes the embedded information sensitive to any operations. This technology is suitable for content authentication.
Collusion Attack: The operations that combine several media copies together to produce a new copy. The operations include averaging, replacement, linear combination, etc. They are often used to break a video fingerprinting technology.
Semi-Fragile Watermarking: The watermarking technology that makes the embedded information survive such acceptable operations as compression, slight noising, filtering, A/D or D/A conversion, etc., while be sensitive to such tampering operations as cutting, rotation, shifting, etc. This technology is suitable for content authentication.
Authentication Watermarking: The watermarking technology that embeds the integrity information into multimedia content. By detecting the embedded information, whether the media content is tampered and even where it is tampered can be told.
Video Fingerprinting: The technology to embed unique information into video content with watermarking technology. The produced copy contains the unique information that can be used to trace the distributor.
Desynchronization Attack: The operations that change the media content in spatial domain, temporal domain or transformation domain while still keeping its usability. The operations include frame removing, frame insertion, frame replacement, picture rotation, picture shifting, etc. This technology is often used to break a watermarking technology.
Robust Watermarking: The watermarking technology that makes the embedded information survive such operations as compression, adding noise, filtering, A/D or D/A conversion, cutting, rotation, resizing, etc. This technology is suitable for ownership protection.
Video Watermarking: The technology to embed information into video content by modifying parts of video data. The produced video data are still usable, from which, the information can be detected or extracted.