YouTube's long-awaited anti-piracy technology has met with mixed responses from the litigious content owners it is designed to placate.

Copyright holders, many furious over persistent bootlegging on Google’s video-sharing site, are being called to submit their content so it can be digitally "fingerprinted" by a new proprietary YouTube system.

The process is designed to make a copyrighted video identifiable if it passes through YouTube again. Content owners will then be able to block a clip if a member of the public tries to post it on the site illegally.

Alternatively, owners have the option to monitor how many times a clip is viewed or to "monetise" it, by having advertising attached and taking a portion of the proceeds.

The move comes after YouTube was sued for $1 billion by Viacom in March. The owner of MTV and Paramount, the film studio, alleges that its pirated content has been viewed more than 1.5 billion times on YouTube.

Mike Fricklas, Viacom's general counsel, said: "Google appears to be stepping up to its responsibility."

However, Louis Solomon, a partner at Proskauer Rose, a New York-based law firm representing the English FA Premier League, which is a lead plaintiff in a copyright class-action suit against Google, said the system was "too little ... too late".

He said: "Fingerprinting technology has been available for years, but Google and YouTube have deliberately not used it." He added that content owners should not have to supply Google with content in order to defend themselves against piracy.

A YouTube spokesman said: "Only the rights owner can know whether their content is available online with their permission or not -- no technology can replace this.

"But what technology can do is make it easier for rights owners to express their decisions about how their content is used online. This is what we have built - a simpler way for rights owners to express their content policies."

The new system has been tested privately by YouTube and nine of its content partners, understood to include Time Warner, Disney, and CBS. This week it is being opened as a public beta - or test - tool.

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