NEP Visions provided a 4K OB workflow to facilitate the acclaimed National Theatre Live production Behind the Beautiful Forevers, projected to 83 Vue cinemas in Sony Digital Cinema 4K for the highest possible picture quality.
Two NEP Visions trucks worked together to establish the full 4K workflow whilst at the same time producing a 1080/50i broadcast of the event; NEP 1 was used for the production while CVT 1 housed the 4K layer.
Led by Technical Projects Manager Tom Giles, the 34-strong NEP Visions technical team worked hard to ensure that the 4K workflow was streamlined to make it as easy as producing HD.
The production was shot using six Sony F55 cameras, all with a CA4000, BPU4000 and HDC2500 CCU. This essentially turned each F55 camera into a broadcast camera, enabling a variety of timed 4K and HD signals. The set-up also gave all the controls required over lens dynamics and colourimetry to ensure the outputs from the six cameras were identical.
The cameras were fitted with 35mm Cabrio lenses, again the closest to a film camera in a broadcast environment that could be achieved.
The cameras fed back to two Sony PWS4400 4K recording devices, taking 4 x 1080/50p signals and stitching them together as four quadrants to make one overall 4K image. The 4K footage was then given to the client on external hard drives and taken away to make the DCP (digital cinema package). There were also several 4K monitors located throughout the trucks for both production and technical staff to view the footage.
A Sony MVS8000X switcher was set up to allow four separate outputs to switch on a single button push; the team was careful to ensure that each quadrant of the 4K image was inserted on to the right part of the switcher.
Tom Giles explains the workflow in more detail: “We recorded the footage in the rec709 colourspace, as it was the only standardised colour space available. Most 4K monitors can only display this colourspace - once you go wider you can’t be sure what you are looking at on these monitors is a true representation of the colour. Our long term plan is to go even wider with the colourspace to capture as much information as possible for the DCP and to give viewers the best possible image.
“The switcher was set up in 1080/50p and populated with the 1080/50p 4K camera signals from the BPU. The 4 x 4K TX outputs were then passed through 1080/50p embedders to add the correct audio configuration for the DCP, and recorded in the PWS4400 Sony server.
“We also recorded a backup of TX and two ISO cameras which meant we had an additional 12 outputs from the switcher, on top of the other five. The PWS4400 has the capability of recording four lots of 4K images but you have to be careful of disc space. We spread our recordings over two separate servers for redundancy.
The BPU also outputs a 4K combined image in 1080/50p which is sent to the switcher for an HD TX cut - this cut was passed through an X-50 to convert it to 1080/50i for HD records and monitoring.”
Brian Clark, Commercial Director, NEP Visions said, “We pride ourselves on pushing the boundaries of live broadcast coverage and the use of 4K technology. 4K is a major focus for the NEP Group, and combining this with working on such a prestigious project for the National Theatre culminates in the perfect balance of premium content and cutting edge technology.”