There was good news for Apple and Comcast, but bad news for Blockbuster woven into Time Warner’s conference call with investors today.

Jeff Bewkes, Time Warner’s chief executive, said that the company’s Warner Brothers studio will now release movies for video-on-demand systems on the same day they are released as DVDs.

Until now, people who wanted to watch movies on cable pay-per-view systems or rental download systems like Apple TV had to wait a few weeks after the same movie was released as a DVD. (And the DVD comes out, of course, four or five months after a film hits the theaters.)

Warner Brothers has been experimenting with the new approach for the last few months. It has found that DVD rentals only fell by 3 percent to 5 percent and sales of DVDs actually increased, perhaps because of the increased promotion and fewer used rental discs available for sale.

Mr. Bewkes boasted to investors that the shift from DVDs to digital distribution, on the “day and date” of DVD release, will be better for Warner Brothers because it will eliminate some of the costs of manufacturing and distributing discs.

“Taking a customer and moving that person over from rental-physical over moving them to VOD day-and-date is like a 60 to 70 percent margin instead of a 20 to 30,” Mr. Bewkes said. “So it’s about a three-to-one trade.”

All this represents the beginning of the end for the Hollywood system of sales “windows” that are used to extract the most profits from a movie. Still, films are released first to theaters, and they are only available on video-on-demand systems for several months. Six months later, they are sold exclusively to pay TV networks like HBO. Later they show up on commercial television, and so on, although those deals mostly don’t prohibit rentals on pay-per-view systems.

I spoke briefly this afternoon to Kevin Tsujihara, the president of Warner’s home video unit. He said that we are moving to an era when there will be thousands of titles available to rent on systems like Apple TV. (The cable systems don’t currently have the capacity to offer that many movies.)

He said that, of the movies in Warner’s library, only 40 or 50 are now not available for pay-per-view or online rental because of its contract with its corporate cousin, HBO. That won’t disappoint the vast majority of movie watchers, he said because “after six months, most titles have played themselves out.”

For consumers, this moves Hollywood closer to what most people want: The ability to get any movie, on any device, at any time.

In addition to the windows, there is one other issue that the studios need to confront: For now, all of these pay-per-view systems require users to watch movies within a 24-hour period.

That means if you fall asleep watching a film one night, you can’t watch the second half at the same time the next night. Mr. Tsujihara said these rules were built into complex Hollywood contracts that he didn’t explain. But he acknowledged that if Time Warner wants those higher margins from video on demand, it will have to make sure that the rules for a digital rental are at least as lenient as renting a DVD from Blockbuster.