By Lance Holte
Like virtually everything in post production, storage is an ever-changing technology. Camera resolutions and media bitrates are constantly growing, requiring higher storage bitrates and capacities. Productions are increasingly becoming more mobile, demanding storage solutions that can live in an equally mobile environment. Yesterday’s 4K cameras are being replaced by 8K cameras, and the trend does not look to be slowing down.
Yet, at the same time, productions still vary greatly in size, budget, workflow and schedule, which has necessitated more storage options for post production every year. As a post production supervisor, when deciding on a storage solution for a project or set of projects, I always try to have answers to a number of workflow questions.
Let’s start at the beginning with production questions.
What type of video compression is production planning on recording?
Obviously, more storage will be required if the project is recording to Arriraw rather than H.264.
What camera resolution and frame rate?
Once you know the bitrate from the video compression specs, you can calculate the data size on a per-hour basis. If you don’t feel like sitting down with a calculator or spreadsheet for a few minutes, there are numerous online data size calculators, but I particularly like AJA’s DataCalc application, which has tons of presets for cameras and video and audio formats.
How many cameras and how many hours per day is each camera likely to be recording?
Data size per hour, multiplied by hours per day, multiplied by shoot days, multiplied by number of cameras gives a total estimate of the storage required for the shoot. I usually add 10-20% to this estimate to be safe.
Let’s move on to post questions…
Is it an online/offline workflow?
The simplicity of editing online is awesome, and I’m holding out for the day when all projects can be edited with online media. In the meantime, most larger projects require online/offline editorial, so keep in mind the extra storage space for offline editorial proxies. The upside is that raw camera files can be stored on slower, more affordable (even archival) storage through editorial until the online process begins.
On numerous shows I’ve elected to keep the raw camera files on portable external RAID arrays (cloned and stored in different locations for safety) until picture lock. G-Tech, LaCie, OWC and Western Digital all make 48+ TB external arrays on which I’ve stored raw median urging editorial. When you start the online process, copy the necessary media over to your faster online or grading/finishing storage, and finish the project with only the raw files that are used in the locked cut.
How much editorial staff needs to be working on the project simultaneously?
On smaller projects that only require an editorial staff of two or three people who need to access the media at the same time, you may be able to get away with the editors and assistants network sharing a storage array, and working in different projects. I’ve done numerous smaller projects in which a couple editors connected to an external RAID (I’ve had great success with Proavio and QNAP arrays), which is plugged into one workstation and shares over the network. Of course, the network must have enough bandwidth for both machines to play back the media from the storage array, but that’s the case for any shared storage system.
For larger projects that employ five, 10 or more editors and staff, storage that is designed for team sharing is almost a certain requirement. Avid has opened up integrated shared storage to outside storage vendors the past few years, but Avid’s Nexis solution still remains an excellent option. Aside from providing a solid solution for Media Composer and Symphony, Nexis can also be used with basically any other NLE, ranging from Adobe Premiere Pro to Blackmagic DaVinci Resolve to Final Cut Pro and others. The project sharing abilities within the NLEs vary depending on the application, but the clear trend is moving toward multiple editors and post production personnel working simultaneously in the same project.
Does editorial need to be mobile?
Increasingly, editorial is tending to begin near the start of physical production and this can necessitate the need for editors to be on or near set. This is a pretty simple question to answer but it is worth keeping in mind so that a shoot doesn’t end up without enough storage in a place where additional storage isn’t easily available — or the power requirements can’t be met. It’s also a good moment to plan simple things like the number of shuttle or transfer drives that may be needed to ship media back to home base.
Does the project need to be compartmentalized?
For example, should proxy media be on a separate volume or workspace from the raw media/VFX/music/etc.? Compartmentalization is good. It’s safe. Accidents happen, and it’s a pain if someone accidentally deletes everything on the VFX volume or workspace on the editorial storage array. But it can be catastrophic if everything is stored in the same place and they delete all the VFX, graphics, audio, proxy media, raw media, projects and exports.
Split up the project onto separate volumes, and only give write access to the necessary parties. The bigger the project and team, the bigger the risk for accidents, so err on the side of safety when planning storage organization.
Finally, we move to finishing, delivery and archive questions…
Will the project color and mix in-house? What are the delivery requirements? Resolution? Delivery format? Media and other files?
Color grading and finishing often require the fastest storage speeds of the whole pipeline. By this point, the project should be conformed back to the camera media, and the colorist is often working with high bitrate, high-resolution raw media or DPX sequences, EXRs or other heavy file types. (Of course, there are as many workflows as there are projects, many of which can be very light, but let’s consider the trend toward 4K-plus and the fact that raw media generally isn’t getting lighter.) On the bright side, while grading and finishing arrays need to be fast, they don’t need to be huge, since they won’t house all the raw media or editorial media — only what is used in the final cut.
I’m a fan of using an attached SAS or Thunderbolt array, which is capable of providing high bandwidth to one or two workstations. Anything over 20TB shouldn’t be necessary, since the media will be removed and archived as soon as the project is complete, ready for the next project. Arrays like Areca ARC-5028T2 or Proavio EB800MS give read speeds of 2000+ MB/s,which can play back 4K DPXs in real time.
How should the project be archived?
There are a few follow-up questions to this one, like: Will the project need to be accessed with short notice in the future? LTO is a great long-term archival solution, but pulling large amounts of media off LTO tape isn’t exactly quick. For projects that I suspect will be reopened in the near future, I try to keep an external hard drive or RAID with the necessary media onsite. Sometimes it isn’t possible to keep all of the raw media onsite and quickly accessible, so keeping the editorial media and projects onsite is a good compromise. Offsite, in a controlled, safe, secure location, LTO-6 tapes house a copy of every file used on the project.
Post production technology changes with the blink of an eye, and storage is no exception. Once these questions have been answered, if you are spending any serious amount of money, get an opinion from someone who is intimately familiar with the cutting edge of post production storage. Emphasis on the “post production” part of that sentence, because video I/O is not the same as, say, a bank with the same storage size requirements. The more money devoted to your storage solutions, the more opinions you should seek. Not all storage is created equal, so be 100% positive that the storage you select is optimal for the project’s particular workflow and technical requirements.
There is more than one good storage solution for any workflow, but the first step is always answering as many storage- and workflow-related questions as possible to start taking steps down the right path. Storage decisions are perhaps one of the most complex technical parts of the post process, but like the rest of filmmaking, an exhaustive, thoughtful, and collaborative approach will almost always point in the right direction.
Main Image: G-Tech, QNAP, Avid and Western Digital all make a variety of storage solutions for large and small-scale post production workflows.
Lance Holte is an LA-based post production supervisor and producer. He has spoken and taught at such events as NAB, SMPTE, SIGGRAPH and Createasphere. You can email him at firstname.lastname@example.org.