Watermarking: Altering Audio To Ward Off Pirates
Piracy of film and video entertainment has become an ever-growing problem. As consumer grade equipment becomes more accessible, pirates have greater means of capturing superior quality images and peddling this material to unsuspecting consumers.
At the SMPTE summit held at the beginning of November, Joe Winograd, Executive Vice President of Verance Corporation, spoke about the concerns the production industry has regarding piracy, and the developments made by Verance in the realm of watermarking content to deter piracy. One product in particular, Cinavia, has been so successful in applying a watermark that the AACS (Advanced Access Content System) Licensing Administrator, LLC, a consortium that includes Disney, Intel, Microsoft, Panasonic, Warner Bros., IBM, Toshiba and Sony, has passed a mandate requiring that Cinavia technology be included in all blu ray players at the start of 2010.
There are many types of watermarking currently available, including video watermarking. Verance’s Cinavia deals primarily with audio watermarking the copywrite protection of theatrical and home video distributed content.
“Audio watermarking in and of itself is a really fascinating and interesting new technology,” said Winograd. “It takes the confluence of increases in computing power, increases in the understanding of the science of the human hearing process, and advances in telecommunication technologies. It takes the technologies from each of these three areas and brings them together to create a capability for transmitting information directly in the soundtrack of recorded work. We basically can inscribe, into the soundtrack, some piece of data that will survive all the different transmissions that content goes through and then can be read by some algorithm device or circuit downstream to recover that information.”
Audio Watermarking is a process that actually alters the audio track, embedding metadata that contains copywrite data about the film.
“It is actually a set of changes to the sound that fundamentally alter the structure of the sound,” said Winograd. “Classically, content has been tagged with a header file on the sprocket area of the film print. The problem is that if that movie gets picked up by a microphone or a camcorder, and goes through a series of conversions, that metadata gets lost. The power of a watermark is by putting it in perceptively in the soundtrack of the video that data will stay with the content no matter how it is transmitted or reprocessed. There doesn’t need to be a separate technical interface to ensure that that information gets carried along downstream.”
Because the audio track is being altered in the watermarking process, a great amount of research has gone into ensuring the quality of the recorded audio is not affected.
“Because the watermark is carried right in the essence of the A/V content, it is very important that the technology be designed in a way that it doesn’t degrade the picture or the sound,” said Winograd. “That’s where psychophysics comes in to it. There’s been a long body of research starting in the 50s and on through the 90s as to what your eyes and ears can actually discriminate. This research has been the foundation of all the advances in digital video and sound encoding and distribution. Psychophysics tells us which parts of the content you can change or distort without it being perceptible to the viewer.”
To ensure that the quality of the audio has not been perceivably altered, extensive testing is done in conditions that replicate ideal listening environments.
“We’ve had extensive perception studies where scientists play the audio in ideal listening conditions: the motion picture sound mixing sound stages, or the home video sound mixing post production studios,” said Winograd. “We conduct careful testing to ensure that to the highest trained listeners or and in the most careful test scenarios possible, that it doesn’t interfere with the sound quality that a consumer is going to receive.”
The watermark is added into a release at the sound mixing stage or the sound signal stage when applied to theatrical releases. There is also a software tool that is available for post production houses that do audio processing. Although many of the major studios are already utilizing watermarking in the products they distribute, Winograd feels confident the technology will filter down to independent studios and facilities in time.
“I think this technology, like many new technologies in the entertainment space, is at a point where it is primarily being used by the major motion pictures studios in-house operations,” said Winograd. “It’s likely to trickle down through out the industry in the coming years as clients ask for it. For the most part, our technology is being deployed in players worldwide. And embedding technology will be available to people who are producing content not just in the United States but also in countries overseas.”
For more information about Verance and the Cinavia technology, please visit: