A U.S. appeals court has revived lawsuits by Viacom Inc, the English Premier League, and various film studios and television networks accusing Google Inc of allowing copyrighted videos on its YouTube service without permission.

The 2nd U.S. Circuit Court of Appeals said on Thursday that a reasonable jury could have found that YouTube knew of specific infringing activity on its website. As a result, it said a lower court made a mistake in dismissing the case.

Viacom had no immediate comment. Google and both the companies' lawyers did not immediately respond to requests for comment.

The original $1 billion lawsuit filed by Viacom in 2007 went to the heart of a major issue facing media companies, specifically how to win Internet viewers without ceding control of TV shows, movies and music.

It was seen as a test of the Digital Millennium Copyright Act, a 1998 federal law making it illegal to produce technology to circumvent anti-piracy measures, and limiting liability of online service providers for copyright infringement by users.

The plaintiffs in the cases before the 2nd Circuit collectively accused YouTube of improperly broadcasting about 79,000 copyrighted videos on its website between 2005 and 2008.

Viacom had contended that Google and YouTube did nothing to stop the infringements relating to such programming as The Daily Show with Jon Stewart, South Park and SpongeBob SquarePants.

The 2nd Circuit found that while Google and YouTube were entitled to a safe harbor provision of the copyright law, it was an open question as to whether they had actual knowledge or 'red flag' awareness of specific instances of infringement.

It also said the lower court should consider whether YouTube demonstrated willful blindness in allowing copyrighted videos to remain on its website.

The cases are Viacom International Inc et al v. YouTube Inc et al; 2nd U.S. Circuit Court of Appeals, No. 10-3270; and The Football Association Premier League Ltd et al v. YouTube Inc in the same court, No. 10-3342.

(Reporting By Jonathan Stempel in New York; Additional reporting by Yinka Adegoke in New York; Editing by Gerald E. McCormick and Tim Dobbyn)

Google Viacom Video Lawsuit