The proliferation of electronic devices capable of displaying video information in the form of movies, television programs and games, for example, has prompted great demand for video content. The advent of low cost video recording devices and the ability to circumvent anti-copy protection techniques has lead to unauthorized copying and distribution of such video content. In an effort to reduce the incidence of unauthorized copying, content creators now place a forensic mark, sometimes referred to as a watermark, within the video content for identification. By tracing the forensic mark, the content creator can isolate the source of the unauthorized copies.
The forensic mark can take various forms. For example, a content creator can apply a unique serial number to each copy or to a batch of copies. Alternatively, the content creator could apply a unique combination of alphanumeric characters or graphical symbols. The nature of the mark will depend on various factors, including but not limited to, the nature of the content itself.
Present day techniques for forensically marking video content suffer from several difficulties. Placing a forensic mark within the image itself incurs the disadvantage that the forensic mark becomes easy to spot and easy to circumvent by either editing or applying pixilation to the mark for example. Altering the video format to create a forensic mark incurs the disadvantage that converting the video content from one format to another can destroy the mark.
Thus, a need exists for a technique for forensically marking video content that overcomes the aforementioned disadvantages.