feature protecting assets in an IT world
With the proliferation of digital video content and customer
demand to port their content between different devices,
watermarking enables flexible usage models while binding content
to the legitimate user. In fact, MultiMedia Intelligence recently
forecast that applications leveraging content identification
technologies, such as digital watermarking and fingerprinting, are
growing rapidly and could surpass $500 million worldwide by 2012.
Niels Thorwirth, director of media security at Verimatrix, reports.
The impact of
watermarking
in the video value chain
D
igital video is a content for secure point-to-point watermark information as copies are
composition of many delivery, a forensic watermark takes distributed. If an embedded DSN could
individual images and the form of a digital serial number easily be altered in place, tracking
corresponding audio (DSN) that is embedded in the mechanisms might give fatally
information, with a much content itself and remains there even incorrect results. If the DSN integrity is
larger amount of data than if the content has been decrypted, unquestionable, then the information
any other common media file. decoded and possibly re-recorded and on origination of the material can be
Therefore, it offers a broader scope to re-encoded to a different file format. useful for copyright enforcement
embed identifying information with The mark used in this way does not actions.
digital watermarks in a robust and
Niels Thorwirth,
director of media
enforce content use restrictions, but it Robustness ensures that the
hidden manner that cannot be security at allows identification of sources of watermark remains readable through
removed. Digital watermarks allow for
Verimatrix.
content abuse, acting as a deterrent any reasonable manipulation or
unique tracking of individual copies of and encouraging responsible transformation of the media. The most
content and assign ownership of video consumer behaviour. It is a way to robust watermarks will survive multiple
copies, with data like hardware and maintain control over the content transitions from digital to analogue
software serial numbers. (See Figure 1). while enabling more convenient format and back. The approach of re-
content use that can compete with recording from an analogue output of a
The power of forensic free, which is typically of lower playback device, circumventing all
watermarking quality and illegally distributed. (See encryption and other control
Figure 2). mechanisms, is sometimes termed the
One of the most promising techniques Each aspect of forensic ‘analogue hole’ through which content
to track unauthorised copies of media watermarking mentioned above can escape. Robust watermarking
content is known as user-specific benefits from a little amplification: techniques will embed a DSN that can
forensic watermarking, which helps Imperceptible marking is required in survive the passage through the
identify the source of unauthorised order to preserve the important analogue hole, enabling identification of
copies and trace them back to the last quality of the viewer experience and unauthorised copies that are produced
authorised recipient or legitimate
Figure 1: Video to avoid any implication that the
using, for example, a camcorder that is
content owner. Unlike encryption,
watermarks:
delivery channel using watermarking
secure, robust and
placed in front of a TV.
which creates an envelope around imperceptible. reduces the integrity of the original
material. The use of imperceptible Marking the entire video
marking draws a specific contrast to value chain
some visible video overlay techniques
used to help trace illegitimate channel The application of watermarking is not
rebroadcasting. limited to a single insertion point in
Security is necessary to preserve the video value chain. Instead,
the integrity of the inserted watermarking can be applied at
information, and especially to prevent various stages during the content
any modification of embedded distribution cycle: in the studio, in the
34 l ibe l january/february 2010 l www.ibeweb.com
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