At a cost of nearly $1 billion, Netflix said on Tuesday that it would add films from Paramount Pictures, Lions Gate and MGM to its online subscription service.

It was a coup  albeit a costly one  for Netflix, which knows it needs to lock up the digital rights to films as customers stop receiving DVDs by mail and start receiving streams via the Internet. The deal will start Sept. 1.

Ted Sarandos, the chief content officer for Netflix, said he was essentially taking the “huge pile of money” that Netflix paid in postage for DVDs by mail  about $600 million this year  “and starting to pay it to the studios and networks.”

Wall Street analysts estimated that Netflix would pay about $900 million over the course of five years to Epix, a fledgling competitor to HBO that holds the rights to the film output of Paramount, Lions Gate and MGM. Those payments are expected to help the money-losing Epix break even in the next fiscal year.