for Digital Cinema

Since George Eastman worked with Thomas Edison on the first moving picture systems, Kodak has worked with the motion picture industry to define standards and develop products that make the movie experience so compelling. As digital cinema—capture, processing, and projection—develops over the coming years, Kodak continues in the tradition of Eastman and Edison. Defining the picture quality needed for digital capture and projection and developing the products to deliver that quality are obvious elements of this collaboration. But as the industry faces the challenges to digital projection, we discover new ways to address some old challenges as well.

At the industry’s recent ShoWest trade event, Kodak demonstrated one valuable benefit of the company’s close relationship with the industry. Beyond working on delivering the best possible viewing experience and the most flexible capture, Kodak technologists showed how the company’s watermarking technology could help protect the creative content in any film (link to previous Tech Brief on invisible watermarking).

Illicit copying of movies has long been a concern of the motion picture industry, and technology developments over the last few decades are making piracy an even bigger threat. According to the Motion Picture Association of America (MPAA), movie piracy costs the studios over $3 billion dollars in lost revenue each year. Fortunately, Kodak researchers have been working on a way to help combat piracy through the use of invisible watermarking.

Although there are many ways for pirates to acquire illegal copies of movies, the simplest and one of the most common is to use a camcorder to record the movie as it is projected in a theater. As the digital distribution and projection of movies (aka ‘digital cinema’) becomes more common, strong encryption technology promises to make it harder to steal a movie before it’s projected. But as it’s projected, the possibility of ‘pirates’ making an ‘untraceable’ camcorder copy will be much more difficult because of Kodak’s invisible watermarking technology.

With this technology, every screening of every digitally projected movie could have its own unique code. This code, which is buried in the pixels, is invisible to the audience but is copied into the pirated version. These ‘watermarks’ provide the ‘fingerprints’ for tracing where and when the movie was stolen. While watermarking doesn’t directly prevent theft, it can

• identify the scene of the crime and repeat offenders
• identify breaks in the chain of trust during the distribution process
• improve the conviction rate and reduce the time and expense of litigation
• act as a deterrent to future piracy

The information contained in a watermark can be just about anything, but at a minimum, it should include a unique ID code that identifies the theater (and the specific screen) and the date and time of the movie showing. The invisible watermark is carried along with the movie content as it is pirated onto a camcorder and subsequently distributed. If an illegal copy is recovered, the watermark information can be extracted from the copy, and the time and place of the original theft is known.

While there are several watermarking solutions available on the general market, the Digital Cinema applications pose some particularly difficult problems. The issue is whether the watermark can survive the numerous degradations that occur when a movie is copied from the screen using a camcorder. These degradations include magnification changes, the warping of perspective, loss of sharpness, effects of interlacing, changes in contrast and color, temporal sampling rate changes, and more. Many watermarking techniques cannot survive even simple alterations to the watermarked data, but Kodak’s technology for robust, invisible watermarking can be applied to Digital Cinema with exceptional results. Besides its performance, Kodak’s watermarking process includes secure keys for embedding and extracting the watermarks, which prevents unauthorized tampering and extraction of the watermark.

Kodak is currently the only company to publicly announce and demonstrate (at ShoWest in March 2001) that its watermarking technique can hold up in real-world testing; that is, the watermark can survive the actual process of capturing a projected movie with a camcorder. Moreover, the amplitude of the Kodak watermark is such that it is invisible to the viewer in the theater, thus maintaining the image quality that is such an important part of the movie-going experience. In the ShoWest demo, 16 bits of information were embedded in each frame of the movie, and it took less than 15 frames (0.5 sec) of captured video to extract the 16 bits with 100% reliability. Often, the watermark was successfully extracted using fewer than 15 frames, sometimes only one or two frames.

While piracy can never be stopped, legal enforcement of copyright laws is critical to minimizing it. That legal enforcement depends on good evidence. And one way to provide that evidence is Kodak’s invisible watermarking technology. Invisible watermarks provide the "fingerprints" for tracing where and when a movie was stolen. While watermarking doesn’t directly prevent theft, it can provide key evidence of when and where the copy was made.

Kodak is actively engaged in improving its watermarking capability for Digital Cinema. Recent testing has demonstrated robust watermark extraction, using 32 bits per frame at even lower watermark amplitudes. With 32 bits of information, there are more than enough unique IDs for every showing of every movie that has been—or will be—produced.