SAN DIEGO — Steven Spielberg and Peter Jackson surprised audiences at Comic-Con with stunning new 3-D footage of The Adventures of Tintin: The Secret of the Unicorn. They mentioned plans for a sequel and hinted at a forthcoming Jurassic Park 4.

The duo, who received a standing ovation in Hall H, showed just over four minutes of unseen footage of Tintin in 3-D and discussed working together to create the film. Spielberg directed and Jackson produced the adaptation the Belgian comic strip by Georges Remi, aka Hergé. Jackson’s company Weta Digital handled the performance-capture animation.

“This was the medium that was begging us to use it, I think, to the best of the current state of the art,” Spielberg said. “Every person who animated every frame of this, animated every frame of Avatar. We were very lucky to land in Peter’s backyard.”

Jackson also touted motion-capture’s ability to give directors every kind of character they could want to create, even if the actors don’t entirely fit the bill. For example, he noted, “you’d never cast Simon Pegg and Nick Frost as twins.”

“I could put the camera in places I never could in a live-action movie,” said Spielberg, who was making his first appearance at Comic-Con. “If all of you decide this is worth seeing — it’s up to you — then Peter gets to direct the next one.”

“I want to make my Tintin film,” Jackson responded.

The Tintin footage they presented showed a lot more action than has been revealed in previous trailers (including the boy reporter’s first encounter with Captain Haddock). Each frame of Tintin took five hours to animate, and Jackson noted that about 2,000 computers are currently in use at Weta Digital.

When the filmmakers opened up the panel to questions, motion-caption actor Andy Serkis was the first at the mike, joking with Spielberg, Jackson and the crowd by asking, “When Daniel Craig met Clint Eastwood was he wearing mo-cap tights?”

During that Q&A period, Spielberg encouraged the audience to “keep taking us to task” on the quality of their films. He also hinted at an upcoming Jurassic Park 4.

“We have a story, I’m happy to announce right now,” Spielberg said, garnering a round of applause. “We have a writer who is writing a treatment and hopefully we are going to make a Jurassic Park 4 in all of our foreseeable futures.”

The directors both said that ultimately, they were “trying to make movies for the kid I was,” as Jackson put it.

“I wouldn’t be here without you … supporting these movies and supporting what we do and staying kids no matter what your age,” Spielberg said. “I’m not ready to grow up. If I start growing up that’s when I’ll stop making movies, which I don’t intend to do.”

The Adventures of Tintin: The Secret of the Unicorn, not yet rated, hits theaters December 23.