The actors, directors and producers are all saying it, and the viewers seem to agree. Many of the most creative projects are no longer traditional film projects, but long form television dramas. With shows like The Man in the High Castle, Orange is the New Black, and Game of Thrones, viewers are no longer tuning in but instead streaming in. The ability to binge high quality television production has certainly resonated with viewers, and streaming services around the world are capitalising on the frenzy.
While HBO is currently the exception, more and more streaming services are insisting on 4K UHD delivery. With sales of 4K capable devices (such as TVs, mobile phones, mobile PCs, desktop monitors and public displays) expected to reach almost 200 million units this year*, it would appear unlikely that this is a short term trend. If you haven’t been faced with shooting in 4K yet, it would appear certain that you soon will.
So what does 4K delivery mean for your production? Probably the most significant issue currently is that Netflix requires source material to be captured at 4K resolutions, and this requirement means native 4K resolutions and this will eliminate the possibility of using certain cameras. But first let’s take a look at how shooting for 4K delivery affects your storage requirements, and in future posts we’ll dive into some of the other practical effects of shooting natively in 4K. Hopefully, we can help you prepare for the inevitable, highlight some of the big challenges you should expect to encounter, and as well offer some new workflows that will ensure high quality delivery while streamlining your production.
Let’s start with a baseline example of a production that might occur today. A typical long form drama might have:
A production schedule of 12 weeks
60 shooting days
2 ½ hours of footage shot per day when shooting in HD/2K ProRes 4444.
We’ll use Arri ProRes 4444 for our example since, compared to 2K available from Sony and RED cameras, the Alexa ProRes 4444 has the higher data rate and therefore will generate the most material in terms of storage, in addition to being the most commonly used camera for television drama. Using the production schedule above your production will be generating somewhere around a maximum of 360GB of source material per day, which will translate to roughly 20 to 25 TB total for the production. This would be considered a simple, straightforward workflow for HD/2K productions, where the size of the source files even allows for delivery over secure private networks.
Now, what happens when your acquisition requirements change to 4K? The natural inclination is to think, 2K to 4K, that’s twice as big so the size should double, but that is incorrect! Let’s take a look at the actual pixel resolution in the image below:As we look at the sizes above, we can see that it’s actually significantly more than double the size, and in fact UHD is actually 4 times the number of pixels as HD. And this brings us to an important distinction: the difference between 4K and UHD. We can see above the slight resolution difference; true 4K is 4096x 2160 which equates to a 1.89 aspect ratio, while UHD is 3840x 2160, which is a 1.77 or 16×9 aspect ratio. Netflix stipulates a 4K cinema acquisition., that is, a camera sensor with 4096 photosites. Therefore, cameras that natively capture in UHD are not approved for use by Netflix. WIth other streaming services the water is a bit murkier regarding these requirements, so we’ll include UHD in our discussion as the overall impact to the amount of storage required, as we’ll see later, is similar. But in terms of shooting 4K natively, the diagram below shows various camera sensor sizes and their corresponding native resolution. It is important to note that the image below is to scale of the physical size of the sensor, and not the corresponding resolution it captures natively.
While we anticipate that this will likely change by IBC this year when manufacturers announce new cameras,as we can see in the diagram, for the moment, capturing natively in 4K will likely mean capturing RAW.
In dealing with RAW, it is important to note that each camera generates RAW in their own way. Each camera manufacturer employs their own type of compression, and this, along with various native resolutions of the camera sensor itself, results in varying file sizes, as we can see in the image below.
We can see that simply going from 2K to 4K ProRes 4444 (which is actually UHD) our storage requirements per minute of footage shot have nearly quadrupled. However some 4K RAW codecs are more efficient than others, and often more efficient than ProRes. What this means in practice is that our original 2.5 hours of footage in UHD will now be approximately 1.3TB in ProRes or potentially up to 2.25 TB with no compression at all. This would result in your 60 day scheduled shoot acquiring approximately between 78 and 150TB, all of which requires both a master and a clone copy.
But perhaps most importantly, with RAW comes the added benefit of greater flexibility through your post pipeline. Exposing the perfect digital negative and telling the story you want tend to be two different things. Not only will shooting in RAW meet the requirements for capture from companies like Netflix, you will also produce a better image for post, which gives you greater control over how you set your look, along with greater flexibility further down the line.
We’ll delve more into the specifics of camera sensors and the importance of grading and metadata when dealing with RAW data in our next post, so to conclude: providing native 4K material is not as straightforward as simply doubling the amount of storage available for a production, other technical issues must be taken into consideration, and Mission Digital are to help you decide how to best tackle the new decisions that shooting for 4K delivery will require.
*As estimated by IHS http://blog.ihs.com/q22-with-double-the-resolution%2C-4kuhd-aims-to-be-the-next-lure-in-displays