Oftentimes, the greatest hurdle a film composer can face is time. Coming into the process so near its conclusion, scorers are usually granted little wiggle-room in which to digest the emotional arc and intricacies of a film, let alone to translate those uniquely and comprehensively into music.

In that sense, John Ottman, who both scored and edited this weekend’s release “Jack the Giant Slayer,” would seem to have a particular advantage. Though he’s scored dozens of films across his two-decade career, Ottman has a special arrangement with “Jack” director Bryan Singer, whom he’s known since the late-’80s. For all of Singer’s films save one, the multihyphenate has also served as editor (indeed, save for his lone directorial effort, “Urban Legends: Final Cut,” all of his editing credits come from Singer projects). With Ottman getting to see and shape every frame of footage beforehand, and having a key role establishing the film’s internal rhythm, one would imagine that the score would come easily.

In this case, one would be wrong.

“I wish I could say that while I’m cutting the film the score is coming into my head, but it’s not,” Ottman said. “The editing of the film is so utterly consuming. And I’m constantly thinking about the music, but I’m only thinking about it in the sense that I’ll have to write this fucking score at some point, and I don’t know when that could possibly be.”

Indeed, Ottman argues that whatever inherent advantages his intimate familiarity with the material might grant him as a composer, they’re wiped out by the sheer demands on his time of the concurrent editing process. That was a particular concern on “Jack,” the reportedly $200 million project that consumed two years of Ottman’s life, requiring endless tinkering to properly align its motion-capture and vfx-heavy equilibrium, and then further revisions after it was pushed back from a planned 2012 release.

“It’s very hard to stay in the zone when I write a score for a Bryan Singer movie,” Ottman said, “because I’m going to be interrupted constantly. (While scoring), I had an Avid console in my room so I could be constantly linked with the editing room, so I’d be running upstairs looking at changes in the cuts or approving vfx scenes, then running downstairs and writing music, then running back upstairs like a hamster in a cage.”

What’s worse, as an editor, Ottman is responsible for assembling the film’s temp score as well, creating an even greater degree of cognitive dissonance when he’s forced to score the film anew, usually while the temp-scored cut is still in test screenings.

“I’ll be in the middle of scoring a scene, and then I’ll go to a test screening and I’ll see the exact same scene with the temp on it, and now I’m full of self-doubt,” Ottman said with a nervous laugh. “I look at the temp and think, ‘oh I didn’t do that (in the score), I missed the flourish there, I didn’t do that either.’ Then I go home and feel like I’m not worthy of the temp I’ve just created. It’s just … literally, I have to take an aspirin.”

For all those headaches, however, “Jack’s” score feels refreshingly light on its feet, displaying a forceful yet never heavy-handed motif-driven approach. Recorded over a week with a full 100-piece orchestra — a traditionalist at heart, Ottman prefers to record with the full component rather than break the orchestra into smaller ensembles — the music manages a difficult balancing act, treating its fairytale subjects seriously, yet never lapsing into ponderousness.

While the fiscal fate of “Jack” remains a rather pressing matter going into the weekend, with tracking indicating a rather disappointing first-frame haul, it does at least demonstrate that the bond between Ottman and Singer remains intact, despite the long layoff since their last collaborative project, 2008’s “Valkyrie.”

The two will reconvene in April to begin work on “X-Men: Days of Future Past,” with Ottman again serving as hybrid editor and scorer. While he concedes that “there may be a latent advantage I won’t admit” to mastering both tasks, he’s acutely aware of the double edge that splitting his talents can create.

“I have a very strange career,” he pondered, “because I like being a filmmaker and calling the shots, but it comes at a great cost to my scoring career. After ‘X-Men,’ I’ll have scored two big films in four years, which is depressing when I watch my peers go off and score five-plus movies a year in the meantime. It’s hard for me sometimes to sit in edit jail, and watch all these projects pass by me.”