Prime Focus World handles stereo conversion for 'Avengers'
Issue: May 1, 2015

Prime Focus World handles stereo conversion for 'Avengers'

In the May issue of Post magazine, and here online, we are offering readers extensive coverage of the VFX and previs/post work studios such as ILM, Trixter and The Third Floor completed for the summer blockbuster, Avengers: Age of Ultron. Here, in a Web exclusive, Post speaks with Richard Baker, senior stereo supervisor of Prime Focus World, on his studio’s stereo 3D contributions to the film that has earned a whopping $200M+ thus far. 

What’s involved in creating the stereo 3D delivery for a film?

“The process generally begins with a meeting with the client stereo supervisor or the director, to discuss their thoughts on how they envisage the stereo working for their movie. Based on this discussion I’ll review the latest version of the cut (assuming the film is already in the can) and put together a depth summary, which will include how we intend to approach the stereo, how the stereo will play across the film and where we can use the depth to create ‘3D moments’. 

“When we receive turnover of the reels or shots, they’ll enter Prime Focus World’s conversion pipeline through editorial and production, going into roto, matchmove, tracking, geometry, paint and elements departments — it’s essentially a VFX process. Any CG elements that we need for conversion will be harvested from the VFX vendors using our proprietary tools and incorporated into the comp. Then it’s depth creation, internal reviews, notes and approvals, and finally client review and delivery.

“Increasingly nowadays I’m getting called in earlier in the process, before the shoot, to have pre-production meetings with the director and DP to discuss considerations in shooting for stereo conversion. This can involve many different elements, from framing considerations and camera move recommendations to lens choices. When shooting 2D with stereo conversion in mind, it is preferable to use slightly wider lenses. You can still get good stereo conversion results with longer lenses, and we have, but the nature of the fall-off, compression and the heavily out-of-focus backgrounds should be a consideration.

“It is always best to be involved early in the process — just like in VFX — because you can make decisions and choices that are going to give you a better end result. And early discussions with the VFX vendors on a movie gives similar benefits — our collaboration on Age of Ultron with Double Negative (with whom we merged last year) gave rise to many benefits, streamlining the VFX / conversion process to allow time and cost savings and ensure even higher levels of quality in the conversion.”

Are the stereo aspects of a film like Avengers: Age of Ultron different/more challenging than other films (or from other projects you worked on, such as Guardians of the Galaxy, Edge of Tomorrow, Maleficent and Gravity)?

“We took a similar approach to Avengers: Age of Ultron and Guardians of the Galaxy — they are both big VFX heavy action movies for the same studio and they shared a common approach driven by Marvel and the directors. Other films, such as Maleficent for Disney, require a very different approach and style. The stereo should always contribute to the cinematic experience rather than dominating it in any way, and the type of film, the style and feel of the cinematography along with the direction of the client stereo supervisor and the director will guide us in this. Every film is different, and this is not an automated process — every single shot is designed with consideration for how the stereo is playing out across the sequence and across the film as a whole.

“Avengers: Age of Ultron was challenging mostly in terms of the timelines. With a huge VFX show like this we know up front that the VFX vendors are going to need every hour of every day that they have available to deliver their work, and stereo conversion sits towards the end of the production process, so we know we’re going to hit time crunches, and that the last month is going to be super-intense. But we’re well seasoned, and we know that this is just the way it is, and our USP at PFW is that we can mobilize our global scale and resources to ensure that we still deliver on time at the highest quality levels.”

What exactly did you do on Avengers? Can you talk about some key scenes you worked on?

“Prime Focus World delivered the stereo conversion of some of the biggest action sequences in the movie — all our work on Avengers: Age of Ultron was on VFX heavy scenes. 

“First, there was the opening sequence of the movie, in which the Avengers are introduced fighting their way through the forest towards the castle stronghold. This was a really important sequence that set the tone for the action in the film, grabbing the audience from the offset and throwing them straight into the fray. It also features that iconic shot that has been used in the trailers, of the Avengers flying across the screen in slow motion.

“The next big sequence was the truck chase in Seoul, South Korea, in which Captain America, Black Widow and Hawkeye attempt to stop Ultron in an exciting chase across the city. Double Negative provided the VFX for this sequence and we collaborated closely with them, getting VFX temps and elements early, allowing us to start work on the stereo earlier in the process.

“The final main sequence we worked on was the Avengers’ showdown with Ultron and his minions in the abandoned church towards the end of the movie. This was another huge sequence, and featured a slo-mo shot rotating around the action with hundreds of VFX layers from ILM. That was one big shot!”

Does your work really begin in the post stages? 

“If you put aside all the preparation and advice and supervision, the conversion work itself begins in the post stage using the footage the director and DP acquired on-set (there is no additional kit on-set — the shoot proceeds as a normal 2D shoot).”

Is there any special gear required? (cameras? Software for the post process?) What tools are you using?

“No special cameras are required. In terms of software packages, the main ones we use are Fusion, Silhouette, Nuke, Maya and PFTrack. We also use Framecycler for editorial and TVIPs for live stereo reviews with the client.  

“We also build and maintain a whole set of proprietary stereo tools in-house, that cater to specific requirements that off-the-shelf tools can’t handle, or don’t handle well. One of the benefits of maintaining an R&D department and developing tools in-house is that you can create them to be exactly what you want them to be. And sometimes we need do things that no one else is doing, or has thought to do. We specify, build and rigorously test our tools, then roll them out across our global network.

“Prime Focus World’s AssistedBreakout tool is a great example of this. It’s a semi-automated tool that helps us harvest the VFX elements that we require for the conversion process direct from the VFX vendors’ comps, reducing the time required for the process, reducing the file-size of the data that needs to be transferred and reducing the cost to the client.”

What were your biggest challenges on this film?

“The most challenging shots on Avengers: Age of Ultron, from a stereo point of view, were the opening forest chase sequence and the big VFX slo-mo in the abandoned church. 

“The forest chase was probably the most challenging because it’s a one-minute long continuous shot featuring a huge amount of action — and as one of the biggest shots in the movie, it was also one of the last to deliver to us. VFX vendor ILM had split the shot up into three parts — we had to split it into eight parts for conversion, to make it more manageable to work on and for review. It was challenging artistically and logistically from a production and editorial standpoint — and as the opening shot of the movie it had to look amazing!”

How much time did you have for your contributions? 

“I went out to see an early cut of the film in LA towards the end of 2014, and we started production on the show in January 2015. The work really ramped up with turnovers delivering in March, and we were very busy on the film across Prime Focus World’s global network throughout March up until the delivery in early April.”

Anything you want to add?

We really value our collaborative relationship with Marvel — they are a great client to work with, always open and transparent about every aspect of the production and very supportive — after all, everyone is always working towards the same goal, which is to deliver the film on time and to the best possible quality. Our next project with Marvel is Ant-Man, which will be a new challenge and have it’s own style in terms of the stereo.

“I’m also very excited to be working with David Yates again after our collaboration on the stereo conversions of Harry Potter and the Deathly Hallows Parts 1 & 2. I am the show stereo supervisor on his next film, Tarzan for Warner Bros., as well as supervising the conversion work at Prime Focus World.”