BLACK BOX WHITEPAPER Piecing Together the 4K Puzzle INTRODUCTION TO THE 4K PUZZLE

4K video, also known as Ultra High Definition (UHD), delivers Display technology is evolving too, and 4K screens are readily outstanding picture quality for digital signage and video available from most display manufacturers. The giant leap in extension applications. But, unlike its beautiful picture resolution quality that you get with 4K displays coupled with quality, deploying a 4K distribution system can be ugly if you declining prices make this technology very attractive to the don’t know what you’re doing and don’t address these four consumer market. pieces of the 4K puzzle: • Heavy bandwidth requirements of up to 10 Gbps WHAT IS 4K? • Supporting 4K with multiple AV interfaces Unlike previous generations of video resolutions that were • Modern cable lengths described by the vertical resolution (1080p refers to a signal • Incompatible resolutions with 1080 vertical lines), “4K” refers to video signals with a horizontal resolution on the order of 4,000 pixels (generally, 3840 or 4096 pixels). In short, 4K is going to push your infrastructure to its limits. To achieve total 4K success in everyday applications, your 4K’s astounding resolution boost is shown in Figure 1: distribution systems must be tailored to perfectly fit these puzzle pieces. FIGURE 1: VIDEO RESOLUTIONS.

Full and thorough testing of 4K sources and displays by UHD 3840 x 2160 (4K) manufacturers is the key to overcoming the obstacles an ULTRA HIGH DEFINITION integrated 4K system presents. Without it, the timely tasks of 4K deployment and maintenance will fall on the shoulders of system designers and integrators.

1920 x 1080 HD 1080i/1080p WHY 4K? ProAV professionals should be aware of developments 1280 x 720 HD 720p in 4K because it is quickly becoming the standard for new installations.

2 1.877.877.2269 BLACKBOX.COM/4K A growing number of displays show resolutions between Another important detail regarding HDMI 2.0 is that the 1080p and 4K. These resolutions are known as between quality improvements have been made at the device level. resolutions. Even if a system is not made for 4K content, This means that the same High-Speed HDMI cables used for hardware made for 2K signals will not support these higher lower resolutions will still work with no quality loss. It will, resolutions. Meaning, following the concepts in this paper however, require that all devices used support the higher speed. is critical for any system that might come up against resolutions like those in the next figure. PIECE #2: 4K IS SUPPORTED BY FIGURE 2: TWEENER RESOLUTIONS. MULTIPLE AV INTERFACES

HDMI is not the only way to extend 4K. Here are the typical UHD 3840 x 2160 (4K) video interfaces and frame rates they support. ULTRA HIGH DEFINITION

DVI is used in professional AV and PC environments.

The DVI standard is based on transition-minimized 1920 x 1080 HD 1080i/1080p differential sampling (TMDS). DVI comes in single-link and dual-link. 1280 x 720 HD 720p

The DVI specification enables 1920 x 1200 pixels to be transmitted in single-link format or 2560 x 1600 (2048 x 2048) MAXIMUM RESOLUTION pixels in dual link. Typically, single link is supported by 23/24” FOR 2K SWITCHES displays, commonly called Full HD panels. Dual-link resolutions require larger screen sizes of typically 27” (2560 x 1440), 30” In some professional spheres, the terms 4K and Ultra High (2560 x 1600), or square ATC displays of 2048 x 2048. Definition (UHD) have become conflated; however, they are not interchangeable. As far as a consumer is concerned, Full 4K resolutions of 3840 x 2160 or higher over dual- link there is little practical difference, but they do mean DVI are possible, but only at less than 30 Hz due to different things. bandwidth limitations.

Simply put, 4K is a professional production and cinema Required bandwidth is up to 4.95 Gbps (165 Mhz) for single standard. UHD is the standard for consumer displays and link or 9.9 Gbps (2 x 165 Mhz) for dual link. broadcast. To get a better understanding of 4K technology, let’s look at the pieces of the 4K puzzle. FIGURE 3: REQUIRED DATA RATES, INCLUDING HDMI OVERHEAD.

480i PIECE #1: 4K RESOLUTION 60 fps 1.62 Gbps 4:4:4

REQUIRES 10 GBPS BANDWIDTH 720p 60 fps 2.23 Gbps 4.46 Gbps is the data rate needed to deliver 1920 x 1080 4:4:4 video at 60 fps. Meaning, a four-times increase in pixels 1080p 60 fps 4.46 Gbps would increase the necessary data rate by a factor of four. 4:4:4 But, HDMI 1.4 supports a maximum data rate of 10.2 Gbps, 4K which includes overhead. HDMI 2.0 increases that bandwidth 24 or 30 fps 10.2 Gbps to 18 Gbps. Before, devices were limited to 30 fps (frames per 4:4:4 second or less). For film, this is not a change, as the original 4K source material is 24 fps. 50 or 60 fps 10.2 Gbps 4:2:0

Since the release of the HDMI 2.0 spec, 4K resolution can HDMI 2.0 support a full 60 fps, which has further increased demand for 4K 60 fps 18 Gbps 4K technology. 4:4:4

The difference between 30 fps and 60 fps can be significant when viewing video. When operating a computer at 30 HDMI is most commonly used on almost all consumer and fps, you’re likely to get some jitter or jumping which isn’t professional AV equipment. noticeable when viewing 30 fps video on TV shows or movies. 60 fps video eliminates the jitter and provides Basically the same signal format as DVI, HDMI allows higher smoother, seamless video, which is especially important pixel-clock frequencies and by that, higher bandwidth of in a live production or control room environment. resolutions and deeper color. Details depend on the different evolution versions of HDMI.

1.877.877.2269 BLACKBOX.COM/4K 3 Up to HDMI 1.2, it more or less reflects the DVI video specs 1.3. Furthermore, HDMI 1.4 exceeds the dual-link DVI specs, although it is using only a single link. HDMI 1.3/1.4 bandwidth is 10.2 GBps (single link 340 Mhz).

The HDMI 2.0 standard increases the bandwidth to 18 Gbps (600 Mhz), effectively matching the bandwidth of DisplayPort for supporting 4K at up to 60 frames per second (fps). The number of sources and displays supporting this standard are rapidly increasing.

The newer HDMI 2.1 standard allows for support of 4K HDR (High Dynamic Range) as well as higher resolutions, such as 5K, 8K and beyond.

DisplayPort is a slightly different, micro-packet-based video standard using a maximum data rate of about 17 Gbps as of version 1.2.

DisplayPort is mainly used on graphic adapter cards of PCs. It is also being used more on computer monitors and other professional grade equipment.

The DisplayPort 1.2 spec was the first to accommodate 4K at 60 fps. The newer DisplayPort 1.3 and DisplayPort 1.4 specs introduce additional support

FIGURE 4: HDMI CONNECTOR. FIGURE 5: DISPLAYPORT CONNECTOR.

PIECE #3: 4K REQUIRES FIGURE 6: DVI-D, FIGURE 7: DVI-D, SINGLE-LINK CONNECTOR. DUAL-LINK CONNECTOR. NEW CABLE LENGTHS

Reduced frame rate and the potential positive impact from chroma subsampling do not minimize the overwhelming bandwidth requirements of 4K video. When extending 4K over CATx cable, maximum twisted copper cable lengths (CATx STP) are much shorter than the industry is used to with HD video, producing a new headache for system designers.

Lengthy cable run can mean a degraded image in analog systems. In current digital systems, lengthy cable run can result in no picture whatsoever (this is known as the cliff effect). On top of all that, incompatibilities between sources and displays are made worse by lengthy cable runs. So a device testing ok with a lengthy cable run does not indicate that every device introduced into the system at a later time will test ok as well. Realistically, HDMI cable lengths could be more limited at the higher bandwidths that 4K requires as well.

In order to combat these negative effects, high-speed HDMI cables are recommended for use in transmitting 4k. To reach farther, extenders can be used. HDBaseT is the most common standard for 4K.

4 1.877.877.2269 BLACKBOX.COM/4K PIECE #4: TWO STANDARD 4K RESOLUTIONS

1.78.71 (16:9) is the shared aspect ratio between 720p, 1080i and 1080p. Due to almost all sources and displays using this aspect ratio, we’ve been treated to a period of simplicity. For a while now, no adjustments have been needed for different aspect ratios. Unfortunately, 4K bucks that trend entirely with two different standard resolutions to manage and adapt to.

The resolution called UHD, 3840 x 2160, is exactly four times the resolution of 1080p, and results from doubling the horizontal and vertical pixel count of 1920 x 1080. Therefore, it has the same aspect ratio as high-definition (HD) video, that is, 16:9. The majority of 4K devices have a native resolution of 3840 x 2160. The second type of 4K resolution is 4093 x 2160, which has an aspect ratio of 19:10; this resolution is called 4K DCI. This resolution is used in movie production and in commercial cineplexes. Some display devices have a native resolution of 4093 x 2160, but it’s not as common as 3840 x 2160.

4K also means the horizontal pixel count (4096) is roughly four thousand. 4K is four times the previous standard for digital editing and projection, 2K or 2048.

Most 4K source devices and cameras can be set to either of the two 4K resolutions. Storied AV pros can remember the SXGA computer resolution of 1280 x 1024, which had a non-standard aspect ratio of 5:4 when almost every other signal was 4:3. This led to similar issues that will likely arise with 4K. To display video without cropping or stretching, sources and displays will have to be perfectly matched and accurately configured. Preventing difficulties in adopting 4K comes down to understanding how conventional display resolutions and 4K resolutions differ.

CONCLUSION

The businesses producing 4K sources and displays are asking themselves one pressing question: How do you check for interoperability with other 4K devices when there are so few of them available? No one will buy 4K televisions until there is a wealth of 4K content, and there won’t be a wealth of 4K content until there is a higher amount of 4K displays. Compatibility issues can even exist between products from the same company in these early days of adoption. 4K is an adjustment, and the video distribution industry faces some growing pains. However, companies will do their best to alleviate these difficulties. As a reference standard is developed, prices will continue to drop, and adoption will © COPYRIGHT 2018 BLACK BOX CORPORATION. ALL RIGHTS RESERVED. WP00068_6.20.18 increase significantly.

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