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DI Innovations

Aug 1, 2004 12:00 PM, By Michael Goldman

Spider-Man 2’s 4K Data Path and I, Robot’s iQ Assembly

Many of the big effects movies that debuted in the summer of 2004 went through a digital intermediate mastering phase at several prominent facilities around the world. The process is now so common that the use of DI, in and of itself, is no longer news. That said, the industry saw plenty of DI innovations this year. Two of the biggest effects films of the summer illustrate this fact. Spider-Man 2 became the first major studio feature to undergo a DI maintained on a 4K data path all the way through the process at Efilm, Hollywood. I, Robot, meanwhile, underwent a high-end DI of its own at Modern VideoFilm, Glendale, requiring a delicate assembly using Quantel's iQ system to accommodate the movie with more than 1,000 digital effects.

Following are two case studies examining the DI pipeline and processes used on both movies. The two projects exemplify some of the latest trends and tools currently at work in the rapidly proliferating digital intermediate universe.

Spider-Man 2's 4K Journey

Cinematographer Bill Pope was already eager to participate in his first digital intermediate on a major feature film with Spider-Man 2 when he was told producers and director Sam Raimi were considering taking up Efilm, Hollywood, on its offer to perform the entire job using a 4K data path from beginning to end.

“Efilm was claiming they could handle it — a 4K transfer, a 4K scan, and a 4K filmout,” Pope recalls. “I immediately jumped for that idea, but first, of course, we had to do tests to make sure they could do it, make sure it would make a difference, and to make sure it was worth the added cost. It was a blind test. They scanned three scenes I shot, and scanned them all at 2K and filmed them out at 2K. Then we scanned them at 4K and outputted them at 2K. And then we scanned them at 4K and outputted at 4K. We took the film down to Sony Studios and projected them all for Sam, the editors, and a producer or two, without telling them which was which. To a man, everyone picked the 4K scan and 4K output as the highest-quality image.”

True 4K

And so what is being billed as the first true, end-to-end 4K data path DI job got underway at Efilm. Filmmakers, however, issue a caveat: The film's visual effects shots (about 850 of them) were output at 4K at Sony Pictures Imageworks but then down-rezzed to 2K and delivered to Efilm on Ultra 320 SCSI drives with Seagate disks, each carrying about 1TB of information. There, after being incorporated into the digital master, those 2K files were eventually up-rezzed again to 4K for the filmout. Because digital effects for movies like Spider-Man 2 often consist of dozens of layers, the time and cost implications of maintaining multi-layered digital effects at 4K made it more practical to bring those shots from Imageworks to Efilm at 2K.

Still, says Efilm president Joe Matza, “All the live action had a full, true 4K data path all the way through, and that is an important development.” He points out that this data path was used for 989 live-action scenes and 43 digital opticals in addition to the 850-plus visual effects scenes that were down-rezzed to 2K. (By “true 4K,” Efilm is talking about files with 4096 horizontal lines of resolution and 3112 vertical lines, approximately 50MB per file, as opposed to 2048×1556 and 13MB for a typical 2K file. In other words, Efilm increased the average pixel count on the movie by about 400 percent from a typical 2K DI.)

“Most of the time, of course, a 2K path, or a combination, works fine for most movies,” says Matza. “We do that all the time, especially 4K scans to 2K working resolution and then back out at 4K. But in this case, being able to meet the requests of the studio and the filmmaker to maintain all the resolution and content captured on the camera negative in the final release version was important. So I think it was worth the studio's investment, and ours, to make this possible. This particular film is an important and very valuable asset to the studio, so it made sense for them to invest in creating the highest-quality film master for release printing and archival purposes.”

The ability to churn out higher-resolution, first-generation answer prints with increased detail and texture seems to be among the biggest advantages of the 4K DI, according to Pope, and Efilm colorist Steve Bowen, who worked with Pope and Raimi on Spider-Man 2.

“To do digital negatives [nine Estar negatives were filmed out following the DI, according to Bowen] for the 10,000 first-generation domestic prints that we made — you can spit out nine to 10 negatives, and you don't ever have to do a dupe,” says Pope. “The quality control is greatly enhanced — negative to negative, they are all perfectly matched. No gained contrast, no lost detail. That's true, in general, for any DI situation. But at 4K, we get so much more detail onto the answer prints — all the latitude and detail that we captured on film, with increased contrast and richness.”

Robust and Ready

Matza says Efilm did not have to make wholesale changes to its infrastructure to handle a 4K pipeline on the project while simultaneously keeping up with its work on several other films. For the most part, the company simply had to add some additional meat to an already sophisticated pipeline.

“Our storage and film recording capabilities had to grow,” he says. “We already had a strong SGI-based SAN storage solution, which worked fantastically on this project, so we were pretty confident at the outset that we could pull it off.”

Prior to bringing Spider-Man 2 into the facility, the company installed more than 200TB of high-speed storage, including over 120TB of serial ATA drives from SGI's TP9500S line, and Overland Storage tape robots, controlled by Veritas software. Company officials say that by the time the job got underway in May, about 40TB was added to what Efilm previously had to accommodate Spider-Man. About 50TB of storage overall was dedicated just to this project, which lasted until late June, when the last reel of film was recorded. (Efilm also added two additional ArriLaser recorders for the project.)

“We had a couple of small hiccups but far fewer than I expected going in, to be honest,” says Bowen. “We were not worried at all about overloading our capacity. Our main pipeline handled it fine, but some ancillary things would pop up a couple times, and our engineers dealt with them promptly. None of that slowed us down at all. The big problem I anticipated was being on time for delivery since we had so many negatives to make, but we ended up being ahead of schedule at the end, so it all worked out.”

To handle the job, Efilm scanned the film using four modified Imagica Imager XE 4K scanners. Later, the company dedicated 13 ArriLaser recorders with high-speed upgrades and customized, high-speed front-end pre-processing computers to film out the movie at 4K, says Bob Eicholz, Efilm's vice president of corporate development. Bowen color-timed the movie relying on Efilm's proprietary software, built on Color Front (of Hungary) technology.

It's important to note that Efilm maintained its standard approach of viewing lower-resolution proxy images during color-timing sessions. Filmmakers viewed the images at 2K resolution during color-timing sessions, watching them projected onto screens by new Barco DP100 digital projectors.

“We had to work viewing proxy images in the suite because that's where the digital projectors are right now,” says Bowen. “They don't project past 2K, so even though we had access to 4K image data, it only made sense to work on the proxies and then see the improved resolution on the filmout. You aren't judging resolution in the color suite anyway — you are judging color fidelity, and the color path is identical.”

In any case, Matza emphasizes that this is a logical procedure. Efilm has a well-tested method of applying changes made during the color-timing phase to the final images existing in its SAN by way of its render farm.

“A proxy is a proxy — it's just an efficient way to work, regardless of our resolution data path,” explains Matza. “After the artist makes his color adjustments, we take the metadata file from the proxy file. When he turns those knobs to create his color settings and other adjustments, those exact settings are sent to our render farm [about 48 Linux-based PCs were used to render out the movie] and are applied directly to the 4K images. They are rendered into the 4K images, in other words, from the metadata. That's how we do all our movies, regardless of the resolution path, because it is simply an efficient way to work.”

Therefore, the more detailed 4K resolution becomes visually obvious only on filmouts. “Grain structure is reduced and tighter, and just generally, it's all sharper,” says Bowen. During the day-to-day process of color-timing the movie, Bowen says he essentially worked as he always has.

“During color-timing you don't know if it is 2K or 4K, to be honest, but on the filmout, it quickly becomes apparent because of the depth and better textures,” says Bowen. “But in terms of how I do my job timing the picture, I didn't have to change anything, so this process was fairly benign in terms of how it impacted my life.”

How such a 4K DI pipeline will affect the feature film industry more generally is another question. Matza, as a provider of such services, sees the 4K path as the eventual destination for most major feature films, but not necessarily an urgent destination.

“This is not appropriate for all films right now,” he says. “It depends on the studio, the film, the preferences of the filmmakers, the budget — all those things. For most films, the 2K model is the way to go. Right now, it's more costly to do at DI at 4K. But then again, with technology advancing so quickly, in the next year or two storage will be cheaper, and image processing will be faster. So 4K will become more affordable and frequent as time goes on.”

Creatively, though, it's the way to go for those precious few who can get a studio to pay for such a pipeline, says DP Pope. “The amount of control is just too great, from a cinematographer's point of view. We put this approach through its paces. There were some kinks, but overall, I wish I could always work this way. Digital intermediates are here to stay, so I guess it won't be too long before 4K DIs are viable for more and more projects.”

DI Robot

At 20th Century Fox, there was very little debate about whether to have a digital intermediate performed to finish I, Robot. The film has more than 1,000 digital effects — a large chunk of the movie. So many elements coming from so many places made filmmakers quickly realize an all-digital assembly and finish was the most efficient option.

“We've done a few other DIs here at Fox, but this is the first one where we did not go from the cut negative,” explains Patrick Esposito, Fox's postproduction producer on the project. “On a show of this size, with so many visual effects coming in so quickly, often all at once from different places, like Digital Domain and Weta Digital and other places, it would be difficult to try and finish this film traditionally. It would have been too time-consuming and would have required far too much handling of the negative. Instead, we created a 4K digital negative and are making our separations all from that.”

Modern Approach

To handle the job, Fox took the project to Modern VideoFilm, Glendale. Although Modern had done a few DI jobs on smaller projects before I, Robot, this was the biggest, most sophisticated studio feature the company had ever worked on. But Esposito and others at Fox were impressed with the company's pipeline, which revolves around a Northlight film scanner for high-end 4K scans, use of Quantel's iQ system to finish and conform the work, and da Vinci 2K color-correction technology, among other factors.

DP Simon Duggan says the Northlight scanner was a big deal from his perspective, because the issue of quality really jumped out. “It gives a 4K scan, and all the detail you can get out of a 4K image, rather than a 2K image. Even though the movie was then down-rezzed to 2K for the DI, we retained much of that information. This was the closest thing to the original negative that I'd seen from any of the scanners out there.”

Esposito adds that the iQ approach was likewise crucial on a film with so many elements coming in and out of the evolving cut.

“With so many changes on a show of this size, with a compressed schedule, where you have the director and so many different producers and the studio and the DP and others all giving notes and making changes, we needed to turn changes around quickly,” Esposito explains. “The iQ gave us a huge amount of flexibility in this regard.”

Roger Berger, Modern's iQ editor on the project, calls this need for flexibility “staying on top of a moving target.”

“We could do instant changes as scenes became available since iQ is designed as a full-blown editorial system,” he says. “We had optical elements, including motion effects, some composited shots, and then resizes and refocuses and camera shading, speed ramps, motion effects, all those things. The iQ can take in different elements and formats and keep track of everything in such situations. Plus, it has a lot of visual effects tools, and that helped us take the load off the effects people because certain things could be finished up in our suite.”

Modern's overall pipeline for the job was to scan selects at 4K on the Northlight scanner and bring that data into its SAN, down-rez that material (using proprietary filters) to 2K for all editorial functions, have Berger conform the piece on the iQ, and then hand off elements to colorist Skip Kimball. He then color-corrected the movie on a da Vinci 2K before up-rezzing back to 4K and filming out on two ArriLaser film recorders.

Modern senior engineer Marvin Hall says the company has a SAN featuring about 40TB of storage, and he adds that most of that network was dedicated to I, Robot during the project's stay at Modern.

“This was a huge project — I believe we used just about every bit of available storage we had, and we also utilized around 20TB of host-attached, additional storage with the iQ system,” Hall explains. “Bright Systems [Reno, Nev.] implemented the SAN for us, using Xyratex drives and a StorNext File software system [from Advanced Digital Information Corporation (ADIC), Redmond, Wash.] to run the SAN and allow seamless sharing of files from all major operating systems.”

“I worked with Skip in sort of tag-team fashion,” says Berger, explaining the process for conforming and color-correcting the material. “Editorial first fed us a cut list and an EDL. We scanned selects based on that cut list and brought them all into the iQ as individual clips. I then conformed them into finished timelines according to the EDL and passed sequences along to Skip as they were ready. One nice thing about the iQ is that I'm able to bring in the offline cut and essentially attach it to the timeline, constantly keeping the reference picture with the finished track as we went along. Its editing capabilities and effects tools were very useful in a DI situation of this type.”

Satisfying Needs

Because the nature of the film required some kind of a DI approach, Esposito says that from the studio's point of view, the financial implications of performing a high-end DI were less important than finding an approach that could satisfy the creative desires of filmmakers like director Alex Proyas, DP Duggan, visual effects supervisor John Nelson, and various producers and studio officials.

“For instance, Alex and John Nelson had many conversations with everyone involved in which they emphasized that with the lead robot character in the film, Sonny, they wanted to make sure he was physically ‘in’ the frame, rather than being CG'ed somehow on top of the frame,” says Esposito. “With the Power Windows and effects tools they had at their disposal during the DI, they were therefore able to make that robot, and others, seem more real. That was a creative issue helped by the DI. It was all about giving the filmmakers more control and maintaining the integrity of the final image. That's not to say, financially, the studio is always psyched about doing a DI, but in this case, it was about how much the movie really needed it. On any project, that should really be the telling factor.”

Duggan and Kimball agree, with both saying that the DI was crucial in nuancing the look of Sonny and other robots. “I could say to Skip, put a vignette around the robot, make him stand out more, or do other things with his face that, in the old optical world, would not have been easy to do,” says Duggan. “It made a big difference.”

“That's true,” adds Kimball. “On Sonny, I often went in and isolated on his eyes, making them more intense blue or less intense blue to match what they captured on set, shot by shot. There are always imperfections that happen between shots on set, or between live-action shots and stuff composited in. This project featured a lot of work on things like that — getting everything to match up. In fact, I don't believe we could have matched all the opticals to the original camera negative and achieve the same look or balance photochemically. The range we have with the da Vinci 2K allowed me to match the highlights and skin tones of each individual robot, if need be. The skin tone on the robots was very important — keeping it consistent was crucial. So, in that sense, this would not have been the same movie without the digital intermediate.”

© 2008 Penton Media, Inc.