It's been said that a movie is made three times: in the writing, in the shooting and in the editing.

At a recent installment of the Envelope Screening Series, filmmaker David O. Russell and editor Jay Cassidy talked about the third and final stage of making the new 1970s-set con film "American Hustle," starring Christian Bale, Jennifer Lawrence, Bradley Cooper and Amy Adams.

Russell said he and his cast enjoyed playing scenes multiple times in different ways and then putting the most compelling pieces together in the editing room.

"That's fun for me and the actors, I think, to play the scene at three or four levels, instead of doing it the same way three or four times," he said. "We do it different ways, and you make great discoveries in the editing room. You get surprised — you thought something should be loud, it really should be quiet, and vice versa."

VIDEO: Watch 'American Hustle' director, editor discuss film

Cassidy, who previously worked with Russell on "Silver Linings Playbook," described the editing of "American Hustle" as a gradual process.

"You have these ideas and they don't all work the first time, and they don't all work the first day," he said. "We did some of the intercutting and [said], 'Wow, this is promising.' And then a week or so later, we said, 'Well, let's take it farther.' The process is very much getting confident with the way you're telling the story and with the actors and with the moments that you're creating, and then it kind of frees you up to take it a little farther. We took advantage of it, and we'll always know in our hearts that those last few moments in the editing room were of supreme importance."

Those last few moments weren't long ago, by the way. Cassidy said he and Russell were polishing the film, which opens Dec. 13, "till they put the bag over our head."

For more from Russell and Cassidy, watch the full video above and check back for more highlights.

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