Keeping up with 4K post

Broadcast

Extra storage and an efficient workflow are just two of the essential elements of an effective UHD post-production pipeline.

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While far from the norm, 4K UHD workflows often with a High Dynamic Range sheen are being commissioned with increasing regularity.

“We are ramping up our UHD content supply,” confirms Julia Barry, entertainment marketing director at Sky. “Our research shows that 4K is among the most popular features for Sky customers.”
She points to Sky drama like Tin Star, Riviera and Guerrilla as UHD shows with a HDR grade. “We are also talking to U.S studios and content partners about their plans for commissioning UHD and what the best ways are to acquire and post produce the format.”

It’s not just drama though. Documentaries and entertainment content are also being given a 4K upgrade. But what all UHD productions highlight are the preparations needed in both storage space and time built into the workflow to accommodate the four times more data.

Riviera
Archery Pictures and Primo Productions wanted to make the most of the light on location in Côte d’Azur-set thriller for Sky Atlantic making UHD and High Dynamic Range (HDR) a natural choice.
“We’ve worked with 4K since Wallander (2008), a show which did not demand a 4K master or deliverable,” says CEO David Klafkowski. “Most dramas we receive now are shot at higher than HD resolution and processed for mastering and delivery.”

The Farm’s involvement with on / near set dailies work on Riviera was mainly confined to pre-production technical discussions, with the data management and processing during the shoot taken care of by Digital Orchard.

Shot predominantly on Alexa at 3.2K, both the original camera and production audio were contained on RAID storage on set, along with LTO backup copies. At the end of each shoot block, each RAID was shipped to The Farm. Media required for conform and tracklay was then transferred to the facility’s internal nearline Isilon storage and online SAN. To maintain the security of the final deliverables on physical media, they were supplied on Apricorn's hardware encrypted drives.

Proxies were transcoded from the ARRI RAW files in DNxHD 36 for offline in Avid with conform to the original media in Resolve. The grade was made directly from the RAW files reduced to 10-bit space in Nucoda Film Master. The online, VFX and mastering was handled on an Autodesk Flame Premium by Clyde Kellet.

“The upscale was very slight from the 3.2K material and the combination of software used for both conform and visual effects work gave us very good results indeed,” explains The Farm’s workflow manager, Peter Collins.

Colourist Aidan Farrell, was keen for the grade to look as natural and cinematic as possible to take full advantage of the existing picture shot (for the first two of ten episodes) by DOP Laurie Rose.
“We decided the only way to achieve this vision both technically and creatively was to adopt a 16-bit ACES pipeline,” says Collins.  “This granted us a great deal of flexibility in the grade and online for both SDR and HDR, and ensured we retained as much latitude as possible from the recorded camera files through to the final masters.”

The HDR was approached as a separate grade from SDR. “ACES enable us to use the SDR grade as ‘milestone’ going into the HDR grade, without the existing grade being constrained to the smaller colour gamut,” he says.

“HDR, along with and other aspects of the UHD ecosystem such as HFR, are creative tools,” he adds. “Like all tools they can be misused. HDR should be considered from the beginning as an integral part of the character of the show, and how, and if, it can be used to better tell the story. It should never overshadow the content it is designed to accentuate.”

Captive

Netflix 8x 60 minute docu-drama Captive investigated hostage situations and negotiations around the world and made significant use of archive material to inform each ‘pulled from the headlines’ story.

Acquisition was predominantly on Sony F55 captured in XAVC at 23.98p and full 4K (4096 x 2160) and delivered to Molinare on drives. Over 600 hours of material (including archive) were ingest into the facility’s EMC Isilon storage cluster with a transcode made to DNxHD36 for offline. The total storage requirements were in excess of 16TB.

“We had eight suites running at time with each episode treated as a distinct standalone film with a different DOP, director and editor,” explains post production manager, Reiko Shimazaki.

The archive material was supplied in various formats and from all over world with different - frame rates, formats and as file or on tape. Interviews, drama reconstruction and footage taken from a drone were the only 4K sources.

 “We decided to standardise all the archive to HD 23.98p so that once all the archive pieces were selected we had a standarised set of compilation reels for cutting back into the edit,” explains Shimazaki. “These were upconverted to 4K during the conform in Flame.”

Shows with a very heavy archive content always present challenges in media management. “You have so many different media sources coming in and out of the facility. Media management needs to be well controlled.”

Netflix prefer to online from an ungraded master and is one of the deliverables it requires for futureproofing. “We had a sign off session with all pre-grade effects to make sure the client was happy with how the show looked before the grade started,” says Flame artist Gareth Parry.

Senior colourist Chris Rogers handled the grade in Baselight: “We looked to make it as cinematic as possible, avoiding TV documentary clichés. For example, with episode 1 (Prison Riot U.S.A.), we looked to emulate a kind of 'dirty 16mm film print’ and added lots of grain and diffusion with muted colours. Other episodes had a much cleaner feel with more natural colours, and with ep 5 (British Aid Workers, Chechnya), we used the grade to blur the lines between the drama and actuality.” 

Without Molinare’s investment in 4K storage infrastructure and key creative equipment servicing this project “could have been a very painful process,” says Shimazaki. “When you are working across a series of shows all at 4K and at the same time you need to make sure you’re well prepared for storage requirements.

“We planned very precisely the way we moved the shows through the post process and ensured the content was signed off at various points to keep the media moving to QC.”

Secrets of the Brain
Lambent Productions first UHD project entailed a “massive jump in storage” plus “added time in all the processing and backing up that goes along with it,” according to managing director Ollie Tait.
Fronted by neuroscientist Dr Jack Lewis and magician Pete Heat, the 10x 60’ series for TERN-owned fact ent channel Insight, used experiments and illusions to reveal the inner workings of the mind.
Since TERN’s remit for Insight is UHD the commission mandated a 4K deliverable. After the success of the first run last autumn, Lambent is now producing a second series for the broadcaster.
“The post workflow not too dissimilar to HD in that we produced low res proxies to edit before relinking to high res media,” explains Tait.
Both series are recorded using Sony PXW-FS7 XDCAM with Canon CN cine 17-120 zoom by self-shooting director Nathaniel Walters. The big change between series is that the frame rate has been increased from 25p to 50p.
“The biggest challenge has been managing the huge file sizes,” says Tait.
Some 31 TB of rushes are copied from SD cards to nearline server with the high-res media backed-up to LTO 5 tape. The tapes are transported to United, a post facility near Amsterdam which is the preferred partner of TERN. “It took about four hours to transfer 1.4 TB of data to tape so we had to send in batches,” says Tait.
Lambent hired a render farm running Adobe Media Encoder to process the raw media to low-res files for offline on Premiere in-house. For series One the proxies were 25p but since this encountered issues when conforming at United, series two is being cut at the higher 50p frame rate.
“We manage metadata religiously by paying detailed attention to the overall file structure,” says Tait. “The proxies and raw rushes need to be identical to one another for relink.”
Effects are added in offline and replicated online at United. “When it comes to the grade we learned that it pays not to be tricksy,” says Tait. “Part of the process with series One was stripping out a lot of the filmic and colour effects which we found can look a little cheap when played back on a 4K monitor. 4K 50p is unforgiving; the footage is already saturated, so we find it best to let the material speak for itself.”
Tait adds, “For a small company starting from no experience in 4K we have made a good looking piece of work on a very competitive tariff. We would not be afraid of using 4K again.”

Landscape Artist of the Year
Sky Arts added UHD to the palette of Storyvault Films’ painting competition in its second season. Although the format and workflow were a known quantity, managing significantly larger volumes of data required additional headroom in terms of time and storage capacity.
The multi-camera show is covered in six heats, a semi-final, final and a winner’s special with each 60-minute episode generating 5TB of rushes. Seven Sony F55 cameras were used handheld or shoulder-mounted while 10 Canon 5D DLSR’s were recording time-lapse photography of each artist’s canvas and the changing weather.

“It’s a big operation with six laptops running all the time during filming ingesting and backing up the cards to G-Raid and Lacie drives,” explains Storyvault unit manager Ali Brodie. “One copy is sent to Procam for backup onto LTO and the other goes to Sky.”

Procam supplied all the camera kit and have a secure LTO storage facility which the production used.

“The data is massive,” says Brodie. “You can’t guarantee that you’ll have time to back up all the media in one day so you have to increase the number of memory cards and drives for safety.”

Post was managed in house at Sky. “With four times more data than normal the main challenge was building enough time into the schedule from ingest to delivery to meet deadlines for QC and TX packaging to meet all our delivery platforms,” says post producer Vickie Mansell. “As the broadcaster, we had the advantage of being part of a wider team with clear lines of communication between both the production and post teams so were able to give a clear direction on timescales to manage expectations.”

The show was offlined in Avid media composer. Since Sky Post Production were evaluating UHD workflows the main ingest codec was Avid’s DNxHRHQX UHD codec. This created over 40TB of media. During the offline editors were supplied DNxHD 120 as their offline resolution.

The online and grade were completed in Avid Symphony v8.6 Avid 8.6 with DNXIO hardware by colourist Ben Whitney. The grading suite included a HP Z840 workstation and Sony’s BVMX300 UHD monitor.

“The intention was to enrich the colour with a filmic quality yet not to make it so glossy as to appear unreal,” says Brodie. “An HD version was down-converted from the primary UHD grade.”

While this 2016 run was Storyvault’s first UHD production it is due to shoot the next series of Portrait Artist of the Year for the channel in 4K and is already prepping a third run of Landscape in the format with both series due to be graded on Baselight.