Choosing a 4K Camera for Live Events

The question of whether to stream an event in 4K or Ultra HD (UHD) resolution usually has producers scrambling to ascertain facts about the best available codecs, 4K-capable encoders, supported streaming providers, and bandwidth requirements. Although each of these components is necessary and critical to a successful live stream—especially when dealing with these high resolutions—sometimes the camera can be overlooked, given the vast array of 4K-capable cameras currently offered.

But as is often the case with new technology, all 4K cameras are not created equal. In this article, I analyze to what degree they differ, and why those differences matter to live producers.

Encoding

When discussing the current state of UHD/4K, we must remember that “current” is a fast-moving target in mid-2016. While 4K television sets have been available for some time, they continue to evolve rapidly along with the accepted standards for acquisition, encoding, and broadcast. Since codecs form the foundation for these three modes of UHD transportation, let’s survey the current options.

H.265 (HEVC)

High Efficiency Video Coding (HEVC) is arguably the front-runner in the race to be the primary UHD delivery compression standard. It provides the same quality as the current HD favorite, H.264, but uses a lower bitrate (see Robert Reinhardt’s Streaming Media East 2016 presentation on H.265). Of course, this also provides more efficiency in delivery (hence the “efficiency” part of the name). In 2015, Adobe started supporting the H.265 export natively in its Media Encoder product. This is by far the most common codec currently in use for UHD content.

VP9

Google/WebM-developed VP9 is the second most well-known codec currently in use with UHD. The advantage of VP9 is its open source nature, which provides royalty-free access to compressionists. The downside is that it’s not easily available for practical use. Google has developed and used the codec on its own YouTube web property, but it has yet to gain a simple-to-use outlet such as HEVC. Current methods of encoding to VP9 involve using utilities such as FFmpeg and command line terminals.

AV1

The AV1 codec, recently announced by the Alliance for Open Media, is a partnership among Adobe, Amazon, AMD, ARM, ATEME, Cisco, Google, Intel, Ittiam, Microsoft, Mozilla, Netflix, NVIDIA, and Vidyo. Based on Google’s VP10, this codec is expected to ship sometime between the end of 2016 and 1Q 2017. Until more is known about this codec, it’s not practically relevant to broadcasters in mid-2016, but it is worth monitoring.

Bitrates

The bitrate of a file encoded for UHD or higher resolution typically ranges from 50Mbps to 250Mbps on the low side to a Super Hi-Vision (7680x4320) image’s uncompressed bitrate of 48Gbps. However, there are examples of some users streaming a UHD video at 8Mbps and 14Mbps.

This brings us to the next logical question: “Is it practical to stream UHD?” The short answer for viewers in the U.S. is, “Yes,” because American broadband speeds continue to improve greatly each year.

The top five broadband providers (by speed) ranked by Speedtest all boast average download speeds well over 50Mbps (www.speedtest.net/awards/us). However, Speedtest also reports upload speeds for those same providers of anywhere from 4Mbps to 87Mbps. Unless you can guarantee higher-than-average upload speeds at your broadcast location, your UHD live stream will likely struggle.

Hardware

As with almost any new technological development, working with UHD and higher formats requires all-new hardware. Cameras, encoders, switchers, editing gear, and software are all part and parcel of keeping up with the latest tech. Of course, as previously mentioned, UHD is still a moving target. Granted, its rate of change has slowed during the past 2 years, but it hasn’t completely settled. The inherent risk is purchasing all-new UHD-capable gear and having it underperform or become obsolete in short order.

Case in point: Remember your first digital camera? Mine was a Sony Mavica that stored directly to a 3.5" floppy disk. The thought of a camera relying on a floppy is laughable these days. Conversely, if there’s client demand for providing the content in UHD formats, then it isn’t a bad time to consider upgrading.

In theory, any UHD-capable camera can be used for live-stream broadcasting. Any of these cameras can probably produce a signal via HDMI or SDI that can be routed through a streaming box out to the web.

Of course, there are different categories of cameras to consider, as well as cameras that offer to livestream their signals directly from the camera. I spoke to representatives from some of the big-name camera companies to find out what they offer in four different categories.

Interchangeable-Lens Video Cameras

Sony offers several 4K cameras that are intended for big-time sports and event productions. First up is the HDC-4300 (Figure 1, below, approximately $64,000 without lens). This 4K camera is a 2/3" sensor, 3 CMOS-on-prism imaging system capable of 59.94 fps at 4K and higher frame rates when reduced to HD resolution.

Figure 1. The Sony HDC-4300. Click the image to see it at full size.

The newest Sony camera in this category is the HDC-4800. Among other improvements, it offers super-high 4K frame rates with 8x speed recording on-board.

Blackmagic’s Studio Camera 4K (Figure 2, below, $2,495 without lens)--name notwithstanding--is designed for all sorts of live productions, in-studio or on-location. Its "studio" designation refers to its tight integration with Blackmagic ATEM 4K switchers, specifically the ability to control the camera remotely from the switcher software. This Micro 4:3 mount camera is capable of standard 4K frame rates up to 60p. It offers the standard array of broadcast camera features such as talkback, tally lighting, and SDI out. One “big” additional feature is the enormous 10.1" TFT-LCD 1920x1200 screen. Lens adapters can also be used to support any standard broadcast lens available.

Figure 2. The Blackmagic Studio Camera 4K. Click the image to see it at full size.