In a bid to defray an ongoing fight with large media companies, Google today finally unveiled the long-promised video filtering system for its YouTube video-sharing service, which will enable it to identify copyrighted material as it is being uploaded.

The technology requires a great deal of involvement from media companies, of course. Content owners must provide Google with a copy of their content so that it can be matched to their material on YouTube and then specify whether they want to block users from uploading copies of it. The filtering system will also give owners of copyrighted videos the choice of leaving their copyrighted material on YouTube and make money from video advertising provided by Google.

Viacom, which sued Google earlier this year alleging "massive" copyright infringement by YouTube, along with other media firms said to be delighted that Google appears to be taking a more proactive stance in fighting piracy and is "ending the practice of profiting from infringement." However, there are no immediate signs of any let-up in the $1 billion copyright-infringement class-action lawsuit from Viacom.