People who "pirate" music and movies on the internet in the US face up to three years in jail under a new law signed by President Bush on Wednesday.
Hit films soon appear on sale around the world on pirate DVDs
The bill targets file-sharers who put copies of new songs and films online before their commercial release.
It also introduces tough new penalties for anyone caught in a cinema filming a movie with a video camera.
The movie and music industries both complain that hi-tech piracy stops fans paying for their products.
The Motion Picture Association of America (MPAA) said 90% of pirated films were "stolen" by people in cinemas with camcorders taping films to put online or on DVDs.
They will also now face up to three years in jail.
MPAA president Dan Glickman said: "There is evidence that criminal gangs use this kind of theft to support and expand their criminal enterprises."
The Family Entertainment and Copyright Act also makes it easier for parents to prevent children seeing and hearing sex, violence and bad language on DVDs.
It protects companies such as ClearPlay, who provide "filters" to mute or skip offensive parts of films.
Film-makers had complained that such alterations violated their copyright - but the bill has made the companies exempt from copyright law.