Although the majority of live television broadcasts remain in HD or even in SD, 4K screens are beginning to outsell HD displays. There is now a growing demand to differentiate and deliver premium service-quality content for 4K UHD screens. Consumer demand for better-than-HD content is unlike anything seen before the accelerating pace of consumer technology adoption and consumer expectations, for round-the-clock content delivered on any device, at any time, is the most disruptive change to our industry. The HD to 4K transition is proving to be dramatically different than the SD to HD transition, and is accelerated by new all-digital mediums and viewing platforms. 4K content has a resolution of 3840×2160 pixels, which is four times the resolution of HD video. In addition, content for live sports is typically captured at twice the frame rate of standard HD, i.e., 60 fps in North America and Japan, and 50 fps in most of the world. By doubling the frame rate, the size of raw video streams also doubles so that 4K p50 or p60 requires up to eight times the bandwidth as standard HD at 25 or 30 fps. The wide color gamut, supported by UHD (SMPTE ST 2036-1) and needed for HDR, requires that video is captured in 10-bit pixel depths which can increase content size by about 25 percent compared to 8-bit video.
How to build true 4K workflow
There are various recommended approaches to adopting a 4K production workflow that range from standing up an entirely brand new 4K environment to building a pilot or smaller environment to work with an existing environment.
Option A – Build a new 4K environment
Some broadcasters will be able to build a new environment with end-to-end 4K capability, from ingest through delivery. This is a superb time to assess the entire workflow, from asset managers to the complete content production and monetization lifecycle. Sizing for a fresh, end-to-end, 4K-capable production environment is similar to specifying an HD-production environment, with the caveat that the system will require fast and highly capable SAN Metadata Controllers, and enough fiber-channel storage and bandwidth scaled to serve all clients for the number and size of streams that are required for most efficient editing.
Option B – Stand up a parallel 4K environment
Another option is to simply stand up a new, smaller 4K-capable environment alongside an existing HD production environment. This smaller environment can realize all of the benefits of a true, collaborative workflow, while sharing key assets and finished files with the existing environment. While it may be necessary to run additional fiber channel or Ethernet networking to accommodate both the HD and 4K environment at the same time, the impact is much less than having to create an entirely new environment from scratch. Key production workstations can mount both the HD and 4K SANs at the same time to ease productivity between the two environments as needed – and as the 4K environment grows, it can begin to displace the existing environment over time.
4K contribution streaming over the internet and challenges
Advances in video encoding, like HEVC codec, now make it possible to stream 4K content over a standard internet connection. 4K video stream can typically be compressed from almost 12 Gbps down to as low as 25 Mbps, and even lower depending on the type of content, color coding, and frame rate used. High bandwidth internet, at over 100 Mbps, is now widely available and, therefore, 4K UHD content can be streamed at higher bitrates for better-quality video. However, worst case scenarios need to be considered in case bandwidth availability suddenly drops.
Customers today are much more discerning about the quality of their viewed content. They clearly appreciate the dramatic visual difference of 4K over HD content and have been constantly reminded that the latest phones and TVs have 4K capability, as do many viewing platforms such as Netflix and YouTube. Adopting 4K production capability can be done in stages to minimize the impact to already-existing HD production workflows, to develop familiarity and best practices, and ultimately scale to meet the largest needs and future challenges of 4K production and beyond.