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Reader SurveySR Tape DI Alternative
Aug 1, 2006 12:01 PM, By Dan Ochiva
With the introduction of Sony's 4:4:4 RGB HDCAM SR recorder in 2003, the take on tape changed — it was no longer yesterday's format. The post industry became intrigued, since this HD format offered a full Common Image Format 1920×1080 sampling structure on 1/2in. cassettes. Until then, pre-filtering and compression had nixed high def as too limited in color depth and detail for high-end projects, let alone fitting into the ongoing move toward digital intermediate workflows. With SR's debut, however, a more cost-effective route than 2K looked ready to deliver the benefits of digital intermediate post to a wider audience.
PostWorks created a full DI workflow for the indie feature Padre Nuestro, employing Sony’s HDCAM SR format, Avid DNxHD, HDCAM, and RGB color timing.
Still, integrating SR's linear tape into today's nonlinear post workflow requires careful consideration, explains writer/director Christopher Zalla. He decided to try out PostWorks' HDCAM SR approach to DI on Padre Nuestro, an indie film he was shooting on Super 35mm about stolen identity among undocumented Mexican immigrants.
In discussions with his DP, Igor Martinovic, Zalla found they had a common interest in this workflow. Pricing out HDCAM SR with Per Melita, one of his producers, Zalla found it was cheaper to scan all footage onto HDCAM SR tape than to go the more traditional route of creating DVCAM dailies to edit, followed by scanning in an EDL.
“I went around town and visited several post facilities with Igor Martinovic,” Zalla says. “At most places, you were faced with transferring to D5 to work in a 4:2:2 colorspace, or jump all the way up to 2K.”
At New York-based firm PostWorks, though, he says he found a room full of engineers thrilled with the prospect of making this still-nascent approach to DI work. A Spirit 2K transferred the project's 3-perf Super 35mm footage to HDCAM SR tape's 4:4:4 log-based color space. A cross-conversion to standard 4:2:2 HDCAM took place simultaneously, along with the creation of a LUT to address the log format's flat look. That enabled 24p offline editing on Avid Adrenaline systems.
As a busy facility with dozens of features, TV pilots, and indie projects inhouse, PostWorks used Avid's DN×HD codec to tame the project's HD storage requirements without adding new drive arrays. The setup delivered time savings at preview screenings. HD output ran directly from the Adrenaline systems to PostWorks' NEC iS8-2K DLP projector with no need to reload and re-conform the project.
“SR is a great alternative to 2K, since it allows post to get visual again,” says Joe Beirne, senior technical advisor at PostWorks. Rather than going the standard DVCAM route, Beirne compares editing with HD to editing 35mm dailies — allowing an editor to catch problems such as soft focus, dirt, and dust, which can hide when working in SD.
An engineer further tested the format during a screening and dragged a wipe bar across the screen between a frame of Padre Nuestro scanned with the Datacine at 2K res and one played out from the HDCAM SR tape. “The difference between HDCAM SR and 2K was imperceptible,” Zalla says. “[When both formats used the same LUT,] I couldn't even perceive the movement of the wipe.”
That made producer Ben Odell happy. “I have conducted a dozen test screenings for films, normally apologizing as we output a low-res version off of an Avid or [Final Cut Pro] system,” he says. “But with our workflow on Padre Nuestro, we can show a quality, high-res image. We can send festivals great-looking HD-DVDs too, and not have to go out to 35mm until the film has been sold.”
