What is 4K and What Does it Mean for Broadcasters?

Do I need to stream my broadcast content in 4K?

Well, to answer that question, we’re going to need to understand what 4K is, and how it performs compared to its alternatives. In this blog post, we will give a brief explanation of 4K video, including its common derivatives. We will also explore some alternatives to 4K, comparing the resources required and the difference in viewer experience.

With a better understanding of the options, you’ll be better equipped to find the right video streaming solution for your needs.

Let’s dive in, shall we?

What is 4K resolution?

4K refers to 4K resolution, which is a standard for a horizontal display of approximately 4,000 (4K) pixels or four times that of HD. In recent years, 4K has garnered a considerable buzz – and consumers have been responding. With prices continuing to drop, more consumers are buying 4K televisions, with roughly half of U.S. households expected to have a 4K television in their home by 2020 – a much faster rate of adoption than seen with 1080p (full HD).  

There are two common derivatives of 4K, both with little more or a little less than 4,000 pixels wide. They are:

• DCI 4K (4096 × 2160)
• 4K UHD (3840 × 2160)

DCI 4K is the standard used in the movie projection industry, whereas 4K UHD is much more popular among consumers. When monitors and televisions are being advertised as “4K,” it is usually in reference to 4K UHD. As more consumers choose to watch movies at home, more 4K cinema content will be ported to home cinemas as resolutions are very similar.

As noted above, 4K is defined as “approximately” 4,000 pixels wide, which is why UHD is referred to as 4K, even though it’s 160 pixels short. It is the most common form of 4K, and is what broadcasters are most interested in. (Of course, UHD is about more than simply 4K, including 10-bit color spaces and faster frame rates, but that is a discussion for another time.) For the purposes of this post – we will be referring to 4K UHD as 4K.

So, 4K is being adopted faster than 1080p – is it that much better?

That depends on where you’re sitting – literally. If you are watching a broadcast video in 1080p, and you are sitting at a distance where the picture is clear, then you won’t see a difference in 4K. (A gentleman named Bernard J. Lechner actually created a chart for the optimal viewing distance for HD, you can read more about it here.) The difference with 4K, is that you would have to get much closer to the screen than you would with 1080p before the image started to break down and you could start to see the individual pixels.

Consumers noticed a significant difference when they moved to full HD. That is because for many, the change to a flat-screen television also included a much larger display. For viewers to see a comparable jump in picture quality, they will likely need a comparable jump in screen size.

The return is not the only concern that many broadcasters have with 4K – the investment required is significant. Videos in 4K require roughly quadruple the data of HD videos. This has sparked a rise in popularity of the HEVC (H.265) codec – 4K in HEVC is little more than double HD in H.264. However, most live sports in 4K are 60 frames per second (fps), which doubles the amount of data again, more or less – 4Kp at 60fps uses about 3-4 times more data in HEVC than 1080p at 30fps in H.264.

All of a sudden, with 4K, bandwidth becomes a very serious concern. Contribution will require 4K-capable cameras, 12G cables, and the right video encoders to ensure your content arrives at your production studio. And we haven’t even started discussing the delivery issues.

Okay, so maybe switching to 4K is a little more complex than flipping a switch. However, broadcasters don’t simply have to choose between 1080p and 4K – you also have the option of Quad Full HD.

Two ways to capture and encode 4K content

Quad Full HD (QFHD) has the same resolution as 4K UHD – 3840×2160 pixels. The big difference between QFHD and 4K is how your picture arrives, and the hardware required. To encode in 4K, you need 12G cables. QFHD content, by contrast, allows you to continue to use your 3G cables – you’re just going to need four of them.

There are two main fashions, called quad links, to create QFHD content: Square Division Quad Split (SQD) and 2 Sample Interleave (2SI). Let’s go over them briefly.

SDQ: There are four links, each which contain on quarter of the original image – but each “quarter” is in 1080p HD. When these four quarters are arranged into one image, it creates a full 4K UHD image. SDQ was the first quad link method introduced to create a 4K UHD, as the hardware technology was not quite ready at the time. Most people were running SDQ with four separate video encoders.

2SI: There are four links, each of the full image, in 1080p HD resolution. However, each of the four images is focused on different pixels of the image. The information from these four images is then combined to create a 4K UHD image.

Although the newer method, 2SI is gaining popularity, as it requires fewer monitoring resources. With a modern video encoder, like the Makito X4, you can plug in four 3G cables to encode your video, simplifying the workflow. Furthermore, in terms of image quality, SDQ creates four separate, isolated, images – it is harder to create smooth motion and synchronized images. With 2SI, you don’t have to worry about something happening in the top left of the screen out of sync with the bottom right.

Does this mean I need to change all of my equipment?

The reality is, 4K UHD is the way of the future for broadcast. Television sets continue to grow, meaning that consumers will notice smaller details in picture quality as the display becomes larger. At the same time, this pull to 4K is also increasing the demand for 1080p HD, as displays move further from SD.

It is important that broadcasters are able to support both 4K UHD and HD. Fortunately, you can prepare for the future without flipping your entire production workflow upside down. Thanks to QFHD, you can create content in 4K UHD dimensions without needing to immediately switch to 12G cables. The Makito X4 video encoder is able to stream in both HD and 4K, using 3G or 12G cables. Download our free datasheet to learn how the Makito X4 can help you future-proof your workflows.