YouTube watermarks

Some of the material on video sites like YouTube is "re-purposed", which is a polite way of saying it was uploaded without the copyright holder's permission.

Now, US company Digimarc, which specialises in image recognition and watermarking, has been granted a patent for a novel way of tackling the problem. Instead of preventing copyright infringement altogether, it would turn it into a commercial advantage.

A TV station or movie studio embeds an invisible watermark in whatever it broadcasts. This is done by producing a copy of the original material but with key areas of the image imperceptibly distorted in shape, colour or brightness. The difference between the original and the copy is expressed as a digital code which identifies the copyright owner. The slightly distorted copy is released for TV while the pure original is kept in the owner's vault.

When the clip then reappears on the web, its owner can automatically be identified and viewers can be targeted with adverts that generate revenue for the original copyright owner.

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