SAN DIEGO — While promoting the 30th anniversary DVD/Blu-ray release of “Aliens” at Comic-Con Saturday, director James Cameron explained why his “Avatar” series needs the scope of the three sequels he announced at Cinema-Con in April. He also finally dropped details on a Blu-ray release of his 1989 sci-fi film “The Abyss.”

“The ‘Avatar’ story arc was originally meant to be a trilogy, but I overwrite, and my writers overwrote as well,” Cameron told Variety in an interview. “But basically the first of the sequels cloned itself and became two films, so now it’s four films. And the studio’s very happy with it. They have an opportunity to make more money, but it’s also an opportunity to spend a lot more money, too, so there’s a clench factor.”

The aim, he said, is to orchestrate production in such a way that he can drop the films a year apart. But he’s unsure if that will ultimately be possible.

He also spoke about breaking out the world of the films in other media. With television enjoying such a exciting new golden age — just look around at Comic-Con, where the small screen has nudged out theatrical to rule the roost — could that be a realm worth exploring?

“You could with animation,” Cameron said. “If you found a style of animation with it that Lucas did with the ‘Clone Wars’ animated series, then you could do it. But to maintain the production value — it’s not like just getting good actors. ‘The Sarah Connor Chronicles,’ they got some good actors and they did some scaled-down production value. But you can’t do scaled-down production value for ‘Avatar.’ One minute of an ‘Avatar’ close-up of Jake or Neytiri or any of the other characters is like a million-plus dollars, even if there’s nothing happening in the shot. So do the math. It just doesn’t work for television.”

With the proliferation of audio media online and the popularity of podcasts and people dealing with their daily commutes, however, Cameron said he has toyed with the idea of expanding the universe in that arena.

“Radio dramas could fill in and create detail,” he said. “I think that with all the drive time people have, if they can learn more about the characters and their backstory and the things that are happening off-camera in the movies, that’s a pretty fun idea and I could get some writers in there. So there are ways to expand it, but TV is not one.”

Finally, given the excitement around what he’s in San Diego to promote, as well as 3D theatrical releases of “Titanic” (2012) and “Terminator 2: Judgment Day” (this October), going back to the well of his successes is a business prospect not at all lost on Cameron. On that note, he has some good news for fans who have been clamoring for a Blu-ray release of “The Abyss.”

“We’ve done a wet-gate 4K scan of the original negative, and it’s going to look insanely good,” Cameron said. “We’re going to do an authoring pass in the DI for Blu-ray and HDR at the same time.”

He said to expect that some time early next year. In the meantime, the 30th anniversary “Aliens” DVD/Blu-ray hits shelves Sept. 13.