Birdman, Alejandro Gonzalez Inarritu's best picture Oscar winner, has been widely praised for looking as if the entire 119-minute movie was shot in one uninterrupted take — an inventive feat that earned it four Oscars, including best direction and cinematography for its director of photography Emmanuel Lubezki. During awards season, the filmmakers left the impression that the movie — which actually consists of a series of long individual shots, some in the ten-minute range — was something of a high-wire act. Once the cameras were rolling, there was no room for an actor to blow a line or miss a mark without destroying that shot. As Inarritu told The Hollywood Reporter, "It's like a live concert. You can't fix it, so if you f— it up, everything goes nuts. Everything you see in the film is real."

But now that awards season is over, the visual effects team responsible for stitching the individual takes together into one seamless whole is admitting that a fair amount of digital manipulation was involved. For example, in one scene where Michael Keaton's and Ed Norton's characters are seen together on stage, the film actually uses performances from separate takes, blending them together in the finished shot. Explains the film's executive VFX producer Jordan Soles of Rodeo FX, "Alejandro liked one [take] of Michael Keaton and a different take of Ed Norton. So when the camera pans around Keaton to Norton, different takes of the same scene were blended together. [Norton's take] was framed a little different so we re-created some of the stage and [theater] seating in CG" in order to make the final result look as if it had been filmed in one uninterrupted shot.

In the months leading up to the Oscars, the filmmakers did acknowledge that editing and VFX were used to complete the illusion. Since the film was shot entirely with handheld cameras or with a Steadicam, editing and VFX were necessary to bridge the transitions between the individual shots. But very little was disclosed about the amount of VFX work that went into the individual shots themselves. When asked for specifics, the editors or members of the VFX team said on more than one occasion that the director and studio wanted to maintain the "magic."

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But with awards season behind them, Soles and VFX producer Isabelle Langlois of the Montreal-headquartered Rodeo FX, agreed to speak with THX about the amount of digital effects created for the movie.

Since transitions between each of the extended shots couldn't precisely match up, VFX work, including CG, was required so that one shot would flow directly into the next.

Inarritu also shot various takes of each scene, but rather than just use one of those takes in the finished film, he often chose elements from different takes and combined them in the final, finished shot. "Alejandro would prefer different performance takes from different actors," Soles explains, "so it was not just stitching takes together, but stitching performances, in some cases morphing heads and torsos."

According to the company, it crafted roughly 100 "stitches" to bring together the different performances and takes. Plus, it completed an additional 60 VFX shots for things like the destruction and flying sequences, all of which meant that about 90 minutes of the film passed through Rodeo FX.

In order to bridge the moments between individual scenes, VFX were used to extend one shot to get to the next. CG was used in some cases to create CG windows, doorways or backgrounds; in other instances, VFX involved painting things out of a frame. "We were limited in the amount of reframing we could do," Soles said, noting that Lubezki and Inarritu preplanned the framing of the shots. "We had to reconstruct what was missing."

The pair said Rodeo FX also contributed to the pacing, explaining that it had to slow down or speed up the shots to match the drum beat in the score.

To create the Birdman character in shots in which he appeared alongside Katon, the actor first was filmed reading the Birdman lines against a green screen. For the shoot, a stunt double was used for Birdman, and then the VFX team replaced the face with a CG version of Keaton's face.

More "traditional" VFX work also involved creating CG backgrounds such as the reflections in the dressing room mirrors. (Without that, the production crew would have appeared in the reflections). And in the scene during which Keaton gets angry in his dressing room and appears to telekinetically move things like posters and chairs, those objects were all CG creations.

Email: Carolyn.Giardina@THR.com

Twitter: @CGinLA