There are as many ways to connect AV devices as there are imaginations involved in the AV industry! Quite often we think of DVI-D, HDMI or HDBaseT as mutually exclusive choices, but the truth is that all those connectivity solutions are transporting essentially the same content. Picking just one solution from the industry’s entire menu of possible connections is far less effective than defining the parameters surrounding the needed link and then finding the solution that satisfies those parameters. Instead of thinking about resolution and length, we should be analyzing the choice in terms of meeting current image-data payload demands, selecting connections that feature appropriate scalability, implementing connections that meet user expectations for convenience and ruggedness, and specifying those solutions with an eye on meeting budget demands and leveraging existing infrastructure where that is an issue. In this paper we will look at various digital video connectivity solutions and provide guidance on when and why you should select each.
Let’s start with a few technical items that can help narrow your search. Before beginning any project, you should understand the need for scalability and future compatibility with new devices. Let’s discuss a couple of the more pressing decisions.
HDMI and 4K
4K is A/V “shorthand” for video content that offers approximately an 8-million-pixel image and has the proper name UltraHD (UHDTV or UHD). Your current display is most likely a 1080p HDTV 16:9 display. This means that it delivers a picture by painting 1080 horizontal lines of picture elements (pixels) with each line under the previous, much like the text in this article. Each line consists of 1920 pixels presented side-by-side. Displays that use this format deliver 1080 lines of 1920 discrete pixels for a total of 2,073,600 pixels displayed.
4K displays and content feature twice as much information along each axis. That is to say that a typical 4K LCD display delivers a picture by painting 2160 (1080 x 2) horizontal lines of picture elements. Each line consists of 3840 (1920 x 2) discrete pixels for a total of 8,294,400 pixels for a total of nearly four times the picture “quality” of the more traditional 1080p displays.
Note: there is another 4K “system” that uses 2160 scanning lines of 4096 pixels each. Naturally it is also called “4K.” This format is primarily used in broadcast and content production. It is specialized.
There is one more thing you need to know about digital video images and 4K before you can make a connectivity decision. Not all High Definition video is the same. We have to incorporate “color space” into our thinking. While this is a challenging concept to understand the effect is pretty easy to quantify.
Most video content uses a form of compression known as “chroma decimation.” This system has been in use since the very first color TV’s in the 1950’s and is present in both analog and digital content. In brief, this system uses about half the information to deliver color content as compared to the black-and-white luminance content, which is perceived as the detail in the image. There is no real perceptual penalty in this technique because our eyes can only see about half as much “color” detail as “B&W” detail. But if we cut the color payload in half, we can minimize the overall bandwidth and make the signal easier to transport and reconstruct. You can identify Chroma-decimated content by noting its color space specification. This is written as a ratio. The most common you will see are 4:2:0 and 4:2:2.
Computers in particular have a problem delivering “Chroma-decimated” content, as the graphics cards in almost all computers treat the RGB elements of the picture equally. Therefore, most computer content has a much higher data payload than the streaming video you might watch on Netflix or the Blu-Ray disc you might rent from Red Box, even if they’re all identified as 1080p. In fact, computer image payload can be as much as twice or more the payload for the same image resolution and color bit-depth coming from a disc player, satellite receiver or cable set-top box. Computer color space is identified as 4:4:4 (RGB), or sometimes 4:4:4:4 if there is a transparency channel (RGB + alpha).
An easy way to understand the data payload comparison is this simple trick. 4+2+0=6. 4+2+2=8. 4+4+4=12. 4+4+4+4=16. A 4:2:0 color space (6) is half as big as a full RGB color space of 4:4:4 (12) and just under 40% the payload of content with an RGB signal using a transparency channel 4:4:4:4 (16).
All HDMI interconnects rated as “High Speed” will support UltraHD 4K images delivered in a 4:2:0 or 4:2:2 color space, which technically has about the same data payload as 1080p in a 4:4:4 configuration. To support 4:4:4 full bandwidth UltraHD 4K signals demands a more advanced cable topology, such as our RapidRun Optical solution.
When selecting the right connectivity solution for your project you might run into the need to extend network connectivity to connected AV devices. HDMI standards anticipate this and you can use a special HDMI cable that offers Ethernet extension and/or audio return channel . Both of these features are handled on a single conductor within the HDMI cable, so you can support one or the other but not both simultaneously. The cable to support both features is the same. There is no performance penalty for selecting a cable with HDMI(e) capability and there is seldom a significant difference in cost. Choose an HDMI(e) cable when possible.
Mini and Micro HDMI Connectors
In the past some computers and other devices with a small form factor offered mini-HDMI connectors. These are about half the size of a standard HDMI plug. Additionally, some cell phones used a micro-HDMI connector. Both of these formats have diminished in popularity, and we expect that they will be used less and less as the industry advances. There is nothing special about these smaller HDMI connectors other than the size. You can purchase mini-HDMI and micro-HDMI to standard HDMI connector cables or use an adapter on a standard cable.
C2G HDMI Cables
This is our basic line of HDMI cables. C2G HDMI cables C2G HDMI cables deliver High Speed connectivity in lengths from 1.5 feet up to 16 feet and are designed for source to display connectivity in typical non-critical home theater and desktop applications. HDMI 2.0 rated as High Speed means these cables will support UHDTV 2160p and 3D video content in a 4:2:0 color space. This line of cables supports Ethernet/ARC and are HDMI(e) rated. Also, C2G standard HDMI cables use a 30AWG signal conductor. This is a good cable to select when the budget is tight.
Select HDMI Cables
C2G Select HDMI cables differ from our standard C2G HDMI cables in that they’re UL CL2 rated for low-voltage in-wall deployment. Like the standard cable above, the Select interconnect is fully UltraHD compliant for 4:2:2 and 4:2:0 content at lengths up to 25 feet. Lengths from 35 feet to 50 feet in the Select line are rated at Standard Speed and aren’t intended to support UltraHD 4K content.
The C2G Select line of HDMI interconnects supports 3D and HDMI(e) features.
The Select line of interconnects use a 23AWG signal conductor to safeguard performance at longer lengths. The Select line of cables comes in lengths from 1.5 feet up to 50 feet. Select cables are also available in metric lengths from 0.5 meter to 15 meters. Choose the C2G Select HDMI cables for typical high-performance installations in home or office.
Ultra-Flexible HDMI Cables
C2G Ultra-flexible HDMI cables are the perfect solution for short distance connections and component-to-component patching in an equipment rack. Ultra-Flexible HDMI cables are high-speed rated and support UltraHD content in a 4:2:0 or 4:2:2 color space and also feature HDMI(e) capability for Ethernet or Audio Return Channel applications. The Ultra-Flexible HDMI cables use a 36AWG signal conductor, and so are designed for short distance connections where physical flexibility is paramount and are available in 1, 2, 3, and 6 foot lengths.
Plenum HDMI Cables
C2G plenum cables are CMP-rated by UL (FT6 in Canada) for installation in plenum air spaces behind walls, under floors and in ceilings. The C2G line of Plenum HDMI Cables is standard speed rated and is not intended to support UltraHD or 4K content. This line of interconnects is available in 15, 25, 35, and 50 foot lengths. The C2G Plenum line of HDMI cables is perfect for typical K12 classroom and most meeting room/collaboration space installations.
HDMI Cables with Gripping Connectors
Although the weight of an interconnect or patch cord should never be supported by the connector alone, there are times when the additional security of a “locking” connector comes in handy. Enter the C2G HDMI Cables with Gripping Connectors . This line of interconnects delivers about 3 times greater grip between cable and jack. Keep in mind that if you trip over a “locked” connector its really easy to pull the jack out of the device and do permanent (and expensive!) damage. A gripping connector is a better choice as it prevents slippage while still allowing connector release in the event of a catastrophic jerk!
C2G HDMI Cables with Gripping Connectors are high-speed UltraHD compliant in lengths from 1.5 feet to 25 feet. 35, 40 and 50 foot cables are standard speed for 1080p applications. HDMI Cables with Gripping Connectors are a good choice when you need the added security of a snugger fit.
HDMI over Coax
Sometimes there is already wire in a building that’s in good shape and can be repurposed during a retrofit renovation. Most boardrooms, educational facilities and houses of worship were wired a decade or more ago using quality RG6 quad-shield coaxial cable. Quite often there are five of them and they were used for RGBHV analog video connectivity. Wouldn’t it be great if you could just run an HDMI signal over those wires that are already in place? You can.
C2G HDMI-over-Coax solutions support 1080p video content for runs up to 160 feet (50 meters) and can even distribute the signal to as many sixteen displays over a single coaxial cable. This is ideal for a small scale digital signage system or an easy upgrade during a system renovation. This solution isn’t designed to support UltraHD 4K or 3D video content, but it’s fine with standard high definition content from just about any device you can imagine including workstations and laptop computers.
HDMI over Cat5
Often when an installation is taking place in commercial spaces, we need to work with the category cables that are typically associated with local area networks (LANs). In this scenario we use the same unshielded-twisted-pair (UTP) to carry digital video as would be used to connect a network switch to a device like a desktop workstation. This makes installing the system easier and sometimes more cost effective by leveraging the scale of economy associated with purchasing large quantities of cable. Since tens of thousands of feet of Cat cable may be installed in a school, facility or house of worship it is often less expensive and more efficient to pull more category cable for the A/V system, too. As with all things associated with digital video, there’s more than one way to get from here to there. In fact, there are at least three.
IPTV is a method of encrypting video content into a format that can then be streamed over the actual network including wireless access points. There are significant benefits to using an IPTV design, such as freedom to access content anywhere in the network and the number of end-points in the design can be very high. This is how you get YouTube videos – by streaming. But there is a corresponding downside – IPTV is resource intensive and can add a tremendous burden to the LAN. Most schools and universities, business and churches my find that their LAN simply can’t support the additional payload.
Short Range HDMI over Cat5 Extenders
Short Range HDMI over Cat5 Extenders don’t leverage the LAN, but work by amplifying and equalizing the signal so it can move through the UTP category cable directly from source to sink. This simple technology is similar to the HDMI-over-coax solution above in that it provides a cost-effective method of delivering standard HD 1080p content up to 160 feet (50 meters) over a cabling infrastructure that is probably already there, or is being run during the project to support other systems.
The challenge with an HDMI extender that relies on equalization and amplification is that its effective length can change with varying content. For example, the C2G HDMI-over-Cat solution can support 1080p content up to 65 feet over Cat5e, or 130 feet over Cat6. Lower resolution content in 720p can travel even farther, as the carriage distance of this type of solution is inversely proportional to the size of the digital video payload.
HDBaseT is the new IEEE 1911™ standard that enables the optimized delivery of uncompressed, UltraHD digital media. HDBaseT features its powerful 5Play™ feature set, including transport of ultra-high-definition digital video & audio, 100BaseT Ethernet, USB 2.0, up to 100W of Power (through POH, similar to POE) and various control signals, all through a single 100m/328ft Cat6 cable. Generally speaking, most HDBaseT solutions don’t support the uppermost level of 4:4:4:4 RGB 2160p 4K content. Like high speed rated HDMI cables, HDBaseT is best for 4:2:0 and 4:2:2 content.
HDBaseT doesn’t travel over the LAN. Although it uses an Ethernet jack (RJ-45) HDBaseT is based on a different protocol that standard Ethernet equipment can’t work with.
HDBaseT solutions are also available in an HDBaseT Lite for projects that aren’t limited by the Lite versions 50-meter length limitation or constrained feature set consisting of audio, HD video, control signals and limited power. Naturally the HDBaseT Lite solutions also come with a lighter price tag, all the better to fit into that stretched budget!
Active HDMI Cables
It’s been said by a number of industry experts that active cabling is the future of A/V electronics. In particular, if we want to limit the physical size, thickness, weight and stiffness of cables then we need to employ the power of a chipset. A silicon chip, powered by the source or sink devices themselves, can do a lot to limit attenuation, crosstalk and group velocity distortions that limit the effective length and physical size of passive copper links. In this way we can run a longer link over a lighter cable that might only support a run of a few meters in a passive application. The benefit of embedding chip technology in cables is the reduction of expensive copper used in production, reduced overall form factor, longer reach and lower power consumption than active solutions like HDBaseT.
Available in 35, 50, 75 and 100 foot lengths, C2G Active High Speed HDMI cables are CL3-rated for in-wall installation and support payloads up to 1080p, including 3D. Active HDMI cables are a good choice when you need to get a longer run, but there isn’t much room for big, thick cables in the cabinet or through the conduit and you want to avoid having a physical device at each end as would be the case with HDMI-over-Cat or HDMI-over-Coax solutions.
Active Optical HDMI Cables
Active Optical HDMI Cables are a variation on the theme above. In this case the actual digital video payload is converted from electrons to photons, and then sent over a set of fiber optic links thereby delivering the very best performance. C2G Active Optical HDMI Cables can be used in plenum applications (they are CMP/FT6 rated) where the standard Active HDMI cable can’t go. C2G Active Optical HDMI Cables support 4:2:0 and 4:2:2 UltraHD resolution, including 3D and deep color payloads.
RapidRun Optical Cables
This changes everything. Rapid Run Optical isn’t just using fiber optics to transport the signal. It’s using VCSEL lasers to provide the absolute highest performance connectivity in the industry. Unlike the Active Optical HDMI Cable, RapidRun Optical doesn’t use a hybrid interconnect assembly. There is no copper between the source and the sink. This means perfect isolation, perfect immunity from RFI and EMI and perfect performance to the very limits of 4:4:4:4 RGB UltraHD 2160 by 3840 video at lengths to an astounding 1,000 feet (330 meters)!
RapidRun Optical is a Plenum-rated solution that supports not only HDMI, but DisplayPort or DVI-D too. Its six channels of clear glass can deliver upwards of 20 Gbps of thru-put per channel, making this one of the most powerful point-to-point video connections on the market. Select RapidRun Optical when you need the best performance and the best scalability the industry has to offer!