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Post to Production-Part 2


With the digital intermediate workflow pretty well established, bringing tremendous flexibility and convenience to the entire postproduction process, a new generation of high-end electronic cinematography cameras are starting to work out the kinks in their workflows and offer viable production models. These are digital cameras with high data rates that are almost purpose-built to feed right into the DI process, skipping the film scanning step.But, as always, it’s a matter of costs versus trade offs. Thomson’s Viper, Panavision’s Genesis, Arri’s D-20 and Dalsa’s Origin currently occupy the top of the pyramid—each, in its own way trying to compete with film cameras in the feature film world by offering alternative workflows that mesh nicely with the DI process.What has emerged is two workflows—tape and data. The former is more or less the same as it always was, while the latter still needs to be proven before producers are going to be willing to risk their budgets.Viper has been on the market for over two years and yet the upcoming film Silence Becomes You (scheduled for release later this year) is the first feature to attempt to use it in its uncompressed 4:4:4 RGB FilmStream mode for the entire production. Others have used FilmStream for shorts, commercials, greenscreen shots and visual effects shots, but until recently, the idea of posting over 30 terabytes of data hasn’t been an easy sell.“The problem up until now is that the workflow has not been there and it has not been proven out,” said Mark Chiolis, senior marketing manager, acquisitions and production, Thomson Broadcast and Media Solutions. “If you look at what’s been done so far in uncompressed, it’s mainly commercials and shorts. But it’s been leading up to something bigger. And now that they’ve proven this out—that it works—I think you’re going to see more of this happen.”On the technical side, the driving force behind the film, which was shot on location in Lithuania and posted at London-based Motion FX, was Steve Shaw. Shaw fills what is more or less a new role on the crew—that of a Digital Imaging Technician, (DIT), Digital Imaging Engineer (DIE) or in Shaw’s case, Digital Film Consultant (DFC). He also served as visual effects supervisor.Shaw explained that the two-camera shoot used S.two’s D.Mag hard drive arrays to store the day’s footage. “Basically we backed up every day’s shooting that evening onto LTO2 data tapes. We generated copies—a master and a safety. The master was sent back to the UK once a week, to Motion FX, where it was loaded and reconstituted off the data tapes.”But the production was able to achieve an incredibly low shooting ratio of 16:1, which kept the data to a minimum (just under 30 terabytes).“It’s so low because we were able to delete takes on set,” explained Shaw. “We actually shot a lot more than that, but the information that we ended up saving was 16:1. Instantaneously, we could say ‘there’s no way we’re ever going to use that shot’ and delete it.”Shaw explained that in order to compensate for Viper’s characteristically green image, Motion FX developed a series of magenta optical filters. The reason for the green is that the camera oversamples the green channel, since the human eye is most sensitive to those shades. But that is something that has to compensated for—either optically at acquisition, or later during color correction.“We have taken the route that we prefer to filter it out in the camera optically, because it gives us a more balanced signal to work with in postproduction—but it doesn’t really matter, you can do it either way,” Shaw said.“What they did kind of typifies what we believe the uncompressed workflow is,” said Chiolis. “If you are shooting for theatrical, the recommendation is that you shoot 4:4:4 to give you the higher quality on the big screen. And if you’re going to do that your two choices are: if you wanted to work in the tape domain, you could shoot HDCAM SR dual link, and still maintain a tape workflow; if you want the highest quality, then you would shoot to disk and get the disk workflow from there.”Panavision’s Genesis is also outputting a 4:4:4 RGB image, (using a 35mm image sensor in order to accommodate cine-style lenses), but it resides in the tape world.John Galt, Panavision’s senior VP, advanced digital imaging, explained that the workflow behind Genesis isn’t all that different from the traditional tape-based workflow.“The Genesis post process is very close to what people are already used to,” he said. “We tried to make everything as friendly as possible to the workflow processes and practices on set as we possibly could.”But he explained that, as is the case with the Viper’s green tint, Genesis footage also requires post processing.“What you’re recording is a SMPTE-standard digital video—a dual-link RGB 4:4:4 image at low compression,” he said. “But you’re not recording a traditional video signal. The camera has a 14-bit A–D converter and there are no 14-bit recorders out there, so we have created a logarithmic transfer from the 14-bit linear to 10-bit log data. So it’s recording something like a Cineon-type of file. That allows you to get a much greater dynamic range than 10 bits would normally give you. So if you plug it into a monitor the picture looks sort of flat and strange.”Panavision is offering a Display Processor that will bring the image back to baseband and give it a normal appearance. But, Galt explained, “That’s just to give people on the set confidence that the picture looks okay. It’s not changing any of the data you’re recording.”So the manipulation comes later in the post process. “In the DI world, it’s very easy for them because they’re used to dealing with Cineon files. But in the video world it’s a little more difficult,” said Galt.But it can be done. In terms of TV production the camera is being used on the upcoming series Nightstalker, which is being posted at Encore.In terms of features, aside from the highly publicized shoot of Superman Returns, Genesis is being used to lens the film Fly Boys, being posted at Global Entertainment Partners, as well as the upcoming Adam Sandler film, Click.“Efilm has actually set up a whole dailies system for Click, so that they can look at their Genesis dailies as though it was printed on film,” said Galt.The real behemoth on the scene is Dalsa’s Origin. Like the Genesis, Dalsa is using a 35mm image sensor, enabling cinematographers to work with familiar lenses and the same depth of field as film, and like the Viper, Origin oversamples the green, but the camera captures an uncompressed 4K image and resides entirely in the data world.It stores to a Maximum Throughput data recorder that can hold over three hours of 4K data at 24fps.The company, based near Toronto, has basically built a miniature postproduction house at its Woodland Hills, Calif. rental facility to test out their workflow and test out various infrastructures.Keep in mind that increases in resolution have an exponential impact on data rates, and pushing the limits of technology requires some trade offs. So in order to get three hours of 4K storage on hard drives, the camera captures raw Bayer pattern data—basically taking the signal straight from the image sensor to the hard drive, with no image processing, (not even the conversion to RGB).According to Patrick Palmer of Dalsa Digital Cinema Center’s Special Projects team, that’s a conversion that other cameras do on board in circuitry in order to output a normal RGB image, but, “The good thing about capturing the raw data is, it’s less data than the full RGB image. Itâ€�
��s capturing what the CCD sees. We don’t filter it in any way. We don’t have a gain setting or anything like that. We literally take what’s on the CCD and record it. Then we reconstruct after the fact.“We do that with a render farm at the post house, which is a very different approach than what’s done in a lot of cameras that have to record to HDCam SR,” explained Palmer.But that conversion to RGB can take up to 10 seconds per frame on a render farm for the full 4K output to render. That’s before you can do anything with it. At the post house, you’ll be able to output a low-res proxy in real time, but ingesting the 4K data will prove to be a massive job.Alan Laskie, who heads Dalsa Digital Cinema Center’s Special Projects team reported that the company is currently certifying post houses around Los Angeles to handle the data—and giving them the algorithms to unlock Origin footage, including Lowry Digital and Ascent Media.Laskie reported that while the camera has been rented out for a number of projects, there were no specific films that he was able to announce at press time.But he reported that one area where it really shines, is as a visual effects camera.“This is the best visual effects camera ever made—removing the scanning step to get 4K data,” he explained. “All of us came out of visual effects in my group. The visual effects post model is exactly analogous to what we’re doing now, which is using file-based data-centric image workflows in order to do all of the manipulation, and then shoot back out to film at the end. The only difference between their workflow and our workflow is they’re taking the scanner out of the loop, but the pipeline is the same.“Ten years ago we were scanning film,” he added. “So that pipeline has been around for a long time, but now with the digital intermediate, that same workflow is becoming more ubiquitous.”

Written by Scott Lehane

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