By Peter Bowes
BBC News reporter in Los Angeles
Warner Brothers is to start selling film downloads via the internet using the same technology once blamed for helping people swap illegal copies.
Warner's film catalogue includes the Harry Potter movies
The Hollywood studio has reached a deal with the web company Bit Torrent, which uses peer-to-peer technology to allow the quick distribution of large files.
Warner says users will be able to buy downloads of films and TV shows on the same day they become available on DVD.
Pricing for a feature film will be about the same as the DVD release.
The cost of a television show could be as low as a dollar.
Rivals to follow?
Warner added that whether a TV show or feature film, it will only play on the initial computer used to make the download.
The downloads will not therefore work on other PCs or standard DVD players.
Other Hollywood studios are now likely to launch similar services.
They believe movie fans will prefer to pay a reasonable price for a legal downloaded movie rather than risk illegally swapping a computer file that could contain viruses or be a poor quality copy of a film.
Peer-to-peer connections enable people to quickly swap files between their computers without having to go via an internet server.