PURRFECT TIMING
One of the biggest productions to shoot in the UK in 2018/2019 was Cats, based of course on the hugely successful Andrew Lloyd Webber musical of the same name, directed by Tom Hooper (The King’s Speech, Les Miserables, The Danish Girl) and shot by Christopher Ross BSC (Yesterday, Trust). Given the material, it was clear from the beginning there would be a lot of visual effects – in fact, every shot is a VFX shot. Creating an efficient pipeline from on-set through to post-production and VFX would be of paramount importance, especially given that production wrapped in March 2019 and the release date would be December 20th 2019. Mission, a leading UK-based DIT and digital services company stepped up to the plate and handled on-set DIT services, digital dailies, LTO archiving and VFX pulls, with an ACES color pipeline.
Chris Ross BSC and Tom Hooper chose the ARRI ALEXA 65 with a mix of ARRI Prime DNA lenses, all rented from ARRI Rental in the UK. Chris Ross again to turned to Mission and DIT Thomas Patrick with whom he had worked on Yesterday and Trust, both with director Danny Boyle, Thomas performed rigorous testing of both the cameras and the lenses during pre-production, explaining “Chris Ross agreed to shoot the whole project at 4000 Kelvin, picked a lens that he liked the color when looking through, and I matched every lens to that ‘hero’ lens. We tested eight ARRI ALEXA 65s at ARRI Rental to find three bodies that matched almost perfectly, so the color shifts would be minimal between A, B and C cameras. Then we modified the Kelvin in the metadata of each camera body so that everything matched almost perfectly”.
This exactitude meant that one CDL was used per scene for all the cameras. Sometimes adjustments were made with individual CDLs when exposure changed, for example there might be more exposure on close-ups so the final grading would be easier and faces would have more detail than in a wide shot exposed for the whole scene. Thomas Patrick elaborates, “Using multiple CDL adjustments to match up shots gives too much margin for error when data is passed down the pipe to VFX. Having things matched up at a metadata level means that workflow is much faster and easier down the line”.
Mission’s Technical Director Tom Mitchell worked with his team to set up a near-set Digital Lab at Leavesden Studios and worked hard at making the ALEXA 65 workflow much more cost-efficient and easier for VFX. Having serviced the dailies on Series One of His Dark Materials, Tom recognized that, given Tom Hooper’s style of shooting large volumes of footage, Mission would have to deal with volume plus very fast turnarounds. The three ALEXA 65’s shot Open Gate ARRIRAW at 6560 x 3100 resolution with an aspect ratio of 2:1:1. The camera original negative was recorded onto CODEX Capture Drives which have a bandwidth of up to 20 Gb/sec.
Before the introduction of CODEX’s High Density Encoding (HDE) technology, a lossless encoding method, that would have amounted to 13TB per day if we assume 4.5 hours of footage. HDE reduced the file size from 31.25 MB to 18.75 MB per frame. Tom explains, “Traditionally this is particularly challenging with the ALEXA 65 as the files it shoots are large and require quite a lot of computing power to process. This is something that only a few companies have been able to deal with and usually by having to do the work in-house with heavy infrastructure. We didn’t have that luxury as we knew we had to be at Leavesden. CODEX’s HDE reduces the file size by up to 40% with no loss in image quality and therefore provided efficiencies on shared storage as well as getting the data down to tape faster and cutting down on the total amount of storage required”.
Mission’s next challenge was to work with their partner software vendors to come up with a workflow that could support HDE from end to end. The files stayed as .arx files and Mission processed, archived and designed an automated pull system to recognize the files for VFX later on, when they would be converted to 16 bit Open EXR. And thanks to a great collaboration with ARRI Rental UK and CODEX, Mission was able to reduce what was going to be up to four CODEX Vault XL’S down to just one. With some further development, the files could be ingested straight to high-speed shared storage in a single step instead of ingesting, pre-processing, converting to HDE then offloading to lab storage speeding up the process by about 4 times.
This was possible due to Mission’s scalable render farm solution that allowed the digital lab to be scaled up and down as needed. Capture Drives were delivered from set to the lab three or four times a day and footage was in the hands of editorial within an hour of being shot. The process was so fast that by lunchtime director Tom Hooper was able to visit editorial and review footage in the timeline that was shot in the morning. This allowed him to review cuts so he knew he had a scene cut before releasing the actors. When you’re shooting up to 8 hours a day of footage that’s no small feat. Not only did this add to the creative process but it also led to real efficiencies because very little additional photography and fewer second units were needed. Another cost saving was in the number of CODEX Capture Drives required - Mission was able to typically clear the drives the morning after they were shot and free them up for the next shoot day.
Knowing up-front that this was going to be a very VFX intensive show, Mission did a lot of work to make the VFX pipeline as smooth as possible, and that meant incorporating a pipeline for metadata. Metadata is quickly becoming the third recording medium (after picture and sound) and Mission has been working on capturing and using as much metadata as possible. In the case of Cats, one of the challenges was that the lenses weren’t smart lenses (lenses that natively support the recording of metadata). Mission wanted to store the per frame/dynamic metadata and so they profiled all the lenses and recorded the dynamic metadata on-set. This metadata was passed along to the VFX vendors in the EXR files. This takes away a lot of the guesswork and enables the VFX artists to get to the creative stuff sooner.
Mission’s Head of Color, Pablo Garcia Soriano, worked closely with Thomas Patrick and Chris Ross BSC to create an ACES color pipeline from the camera through to post-production and VFX, providing a consistent look throughout. Chris Ross tried several LMTs (Look Modification Transforms) until he found the one that fitted best fitted his vision. The CDL information was embedded in the EDL and the EXR files and the LMT chosen by Chris was provided to all the VFX vendors.
Cats is a great example of people and companies working closely together to design an efficient pipeline that enabled a relatively small company in London to support a major Hollywood blockbuster that needed to be delivered in a relatively short period of time. Thomas Patrick and Chris Ross worked together on a much lower budget project, Everybody’s Talking About Jamie, later in 2019.
Director: Tom Hooper
DP: Chris Ross
DIT: Thomas Patrick
Camera Rental: ARRI Rental
DIT/Digital lab/VFX pulls: Mission
Digital Intermediate: Goldcrest
Camera: ARRI ALEXA 65 x 3
Format: ARRIRAW HDE
Resolution: 6560x3100 Open Gate
Codex related product and workflows
