By Mary Ann Skweres
Nowadays it is a given that computer based editing systems have revolutionized postproduction, but the revolution continues as breakthrough innovations such as Avid’s DNxHD encoding technology, transform editorial workflows and pipelines.
Any film editor who worked on the early non-linear systems can tell stories of out-of-focus shots or even shots with undesirable objects in frame that were unseen due to the low resolutions, but which appeared in living color when the 35mm film was conformed and projected.
But it’s taken a while, but editing systems are starting to catch up with the demand for HD imagery.
“If there is one thing that a film editor would have wanted out of an Avid system for the past five years since the product has been real-time and stable, is better picture quality,” says editor Patrick Ready,COO of Pivotal Post. “What are they asking for? They’re asking for HD.”
Pivotal Post provides postproduction services for the film industry specializing in setting up mini facilities for their clients and pioneering all-HD workflow for feature film editorial. The company has provided Avid HD editing equipment and support to recent and upcoming high profile films such as The Mummy: Tomb of the Dragon Emperor, Leatherheads, 3:10 to Yuma and Ocean’s Thirteen.
Uncompressed high definition media can require seven times more bandwidth and storage than uncompressed standard definition, making offline editing with uncompressed HD unpractical due to the data rates and file sizes. That’s especially true on projects with large amounts of source media, such as feature films or projects with the need for more real-time preview streams, such as multi-cam television editing. Avid has created versions of DNxHD with data rates that range from 36 Mbps for HD offline, creative editorial, up to 220 Mbps for projects that need full mastering quality but don’t have the budget for large capacity storage.
The data rate for Avid’s DNxHD codec however is only 50 percent more than standard definition DV25, allowing for massive amount of dailies to be captured. For instance, 100,000 feet of 35 mm, 4-perf film when captured at 36 will only require 330 GB of storage. Avid introduced DNxHD in April 2004 as a tool for high definition mastering, but the March 2007 introduction of DNxHD 36, that was targeted for the offline, creative editorial workflow, enables HD image quality – virtually indistinguishable from the original image, even compared to uncompressed HD – in the offline edit without the high cost overhead. Customers have a choice of what resolution they want to work at.
The codec is highly optimized so that it gives full-color information with a choice of 10-bit or 8-bit while it preserves the picture quality with no reduction in the horizontal luminance and chroma samples, and thereby providing mastering-quality HD media.
With smaller file sizes, the technology also reduces storage and bandwidth requirements. DNxHD 36 in essence, allows the editor to cut using an offline/online workflow.
“The latest release of Media Composer enabled HD workflow at ultra-low bandwidth with DNxHD 36. What we’ve tried to do is create a system that is an all in one workflow so we can bring more efficiency and cost-reduction to the workflow. We’re trying to create an environment where filmmakers can essentially start a project in high definition and be able to take it as far as they need to in high definition,” says Bill Admans, Avid’s segment director for facilities and services.
A year or two ago, filmmakers would have to stop the editorial process and do a conform to a higher resolution on an Avid Symphony for preview screenings. Now, the native HD offline editing workflow using the DNxHD codec allows the filmmaker to output directly from Media Composer at high quality without the additional cost and time of a conforming step.
According to Adman, feature producers are saving on the average of $45,000 to $65,000 by using the DNxHD codec.
In television, shows are using the DNxHD codec to essentially offline and online at the same time and deliver a final master from Media Composer instead of offlining in SD and then re-digitizing in HD for mastering —again with huge savings in time and money.
Although some companies, such as evergreen television shows, want to work in the highest resolution available today in order to retain their long-term asset life, other companies need to find a scale of economy that fits their markets and deliverable specifications. They are willing to master at a slightly compressed resolution comparable to tape formats such as D5 and HD that are heavily compressed.
For either film or television, ultimately the workflow and resolution should be chosen to support the project’s deliverables. Both Media Composer and Symphony have a very powerful, GUI-driven, color-timing engine that is not just limited to level, hue and saturation. Avid has built into their systems traditional, Da Vinci-like, color correction tools that would normally have been produced by a third party. Clips can be directly color-corrected in the timeline. Each of the layers in effects and composites can be individually corrected. An entire reel can be color corrected to match an individual clip. Layers of color correction can be applied.
“It is a much more organic process, tied to the initial creative intent,” Adman says. “In television, changes can be made up to the last minute. Our color-correction process means that you can make changes to the timeline and the color corrections made on a previous version are carried across to the new version automatically. It doesn’t require laying off to another tape, which is what we had to do in a more linear workflow.”
This new workflow has blurred the traditional job descriptions of offline and online video editors. Although finishing, effects and sound are generally not going to be done by one person, with the availability of new tools, offline editors can have greater control over the look of the picture with real time effects and color timing. On feature films, because there are fewer technical processes to get in the way, the director and the editor are looking at an edit that is closer to the finished product.
“The monikers of offline and online are not as relevant as they used to be,” says Ready. “As far as workflow, there are technical processes and subjective processes. Technical processes can be streamlined through technology – not having to work in a lower format and then go to a higher format; if you’re shooting video versus film, now you don’t have to do the lab and the telecine. What’s left is an editor editing at an online resolution. Is he an online editor? He is, but it’s not that his job has changed. When he finishes his cut, he turns it over for color correction and audio sweetening. But if this editor happens to have the acumen to do that work, Avid has the tools. The door is open for people to take this as far as they like.”
The DNxHD codec supports full 16:9 aspect ratio for use in 1080p/23.976, 1080p/24 and 1080p/25 projects. Xpress Pro and Media Composer running on Mac (Universal Binary – Intel and PowerPC chips) or PC can edit HD and DNxHD, although Xpress Pro does not support DNxHD 36, but can edit the other DNxHD formats (DNxHD 115, 145, 175, 220, etc).
For online, Symphony Nitris and DS Nitris are PC-based systems, that can conform offline Avid projects created on Mac or PC.
Written by Mary Ann Skweres
