Published July 2008

‘Signs’ Of Progress
By Sanjay Castelino

Deploying digital signage solutions in retail.

Digital Signage has moved beyond the niche it once occupied in the corporate world to become a business-critical communications vehicle, driving investments in infrastructure across multiple industries and business sizes. Although the past has seen some uncertainty about signage ROI—high cost of deployment, unproven effectiveness, lack of proven technology—virtually none of these issues is a concern today.

In fact, the growth in signage can be viewed indirectly through increased advertising dollars spent across multiple channels. According to a recent Deloitte & Touche report, in-store advertising has grown at a rate of 21% vs. 15% for online advertising, making in-store advertising one of the fastest-growing sectors for dollars spent. As more and more companies devote additional resources to audio/video solutions within traditional IT and data management budgets, we now see businesses embracing digital signage as a way to reach not only new and existing customers, but as an effective communications tool, as well.

There are a number of steps in developing the best digital signage solution for your customer’s needs. However, before we discuss the technical nuances, it’s important to consider how the technology is to be used. How often will the signage content have to change? Is the signage part of an employee communications effort or is it for a large retail store? Is it intended to be interactive? Understanding the business use will drive the technical implementation of the solution, as the costs and effort for implementations of those solutions can vary dramatically.

Content Needs

How often content changes is important to know when determining which solution—video-based signage or high-end signage—best fits your needs. A video-based signage solution is characterized by video content that is produced ahead of time and then scheduled and distributed as needed. Applications for this type of job tend to be more permanent looped display sequences that don’t have to be changed frequently (see Figure 1).

Because the complexities in video-based signage are in the video production process rather than the content distribution arena, it tends not to fulfill the original requirement for which digital signage was really envisioned: dynamically changing content. Instead, it provides a static looped video that is only marginally better than a static sign.

In contrast, high-end signage solutions are based on content that is rich in graphics, text and multiple video sources. This type of signage solution involves content that can be changed on the fly, where templates and content are rendered in real-time by each signage player, usually a high-end PC. Within this signage approach, you can have large- or small-scale implementations. An example of a small-scale application would be a business, such as a boutique clothing shop, that is creating a single signage channel that is to be distributed within a single location, with content updated regularly by internal staff.

At the other end, we have large-scale implementation, such as those found at chain stores with multiple locations. Here, each location has multiple signage channels and multiple displays, and content is created at a central location, and then distributed throughout the chain. Certain content might be overridden by individual stores; what channel is played on what display might be completely controlled locally, as well (Figure 2 shows the baseline topology of a small-scale digital signage solution.)

Now that we’ve covered video and high-end signage, let’s focus on the high-end, large-scale signage solutions because those have the most complex requirements, and smaller-scale solutions will involve a subset of the large systems’ needs.

Within the high-end signage solution, there are three major elements: video content (often shown within a window on the screen), graphics and text, and signage control. Although each element requires careful consideration, our focus here is on the video content and control aspect, because the graphics and text are primarily a creative function, and not typically addressed by the integrator.

Source Selection

In any system, each player has one to four video inputs, so any video elements that are to be part of the signage solution can be input into the player. Because the player does the rendering, each player must be able to accept signals from video sources, such as set-top boxes, DVD players or PCs with stored content.

Of course, as the scale of this type of deployment grows, it is evident that, in addition to the players, you also need to implement a video switching and distribution system. This allows you to locate the video sources somewhere within the facility, but avoids having to duplicate the video source at each player. Of course, once the video sources have been placed, they will have to be controlled. Each will have to be accessible so the content can be switched based on the signage channel that is being played.

However, the content likely will be formatted in different resolutions and connected to the video distribution system in different ways. For example, the DVD players might be connected via component cabling, whereas the PCs are connected via a VGA cable. This adds the additional complexity of transcoding or scaling the content so it is input into the signage players appropriately. We call this The Video Source Selection Challenge. One solution to The Video Source Selection Challenge, as shown in Figure 3, is to use an IP-based multimedia encoder and decoder to handle switching of sources, controlling the sources and displays, and outputting content appropriately between VGA and component.

Video Distribution

Once you’ve addressed The Video Source Selection Challenge, we next look at how to distribute the final rendered video content. There are two typical models here, with the scope and scale of the job dictating which model is best. The first model is where each player is placed next to, or mounted behind, the displays. This model is used when each display has its own unique content, for example, interactive signage displays.

The second model is where a limited number of signage channels is distributed to multiple displays. For instance, you might have five digital signage channels distributed to 50 displays. Putting signage players, which tend to be high-end PCs, behind each display might not be practical. Additionally, if the players are the primary video source for the display, you lose the ability to use the displays for other purposes without additional video distribution infrastructure.

To illustrate, we can take a look at a recent corporate customer that not only needed a signage solution for employee communication, but also used the same displays for satellite TV distribution throughout its facility. If the corporate customer had only used players as sources, it would have a completely separate video distribution and satellite TV control solution for each display. Either that, or it would have required multiple boxes behind each display...a messy and trouble-prone solution.

Instead, the corporate customer opted for a single solution that could distribute and control the satellite TV while, at the same time, distributing any signage when needed. This is the IP-based multimedia distribution solution shown in Figure 3. This solution also ensures that both the audio and video at each display, as well as across all displays, are synchronized to below 1ms. This means that, in a large-scale implementation, you don’t have to worry about content playing out of sync from one zone to the next.

IP-Based Video

The next step is to address the quality of video that you want in your solution. Although there are many ways to distribute video around a facility, the newest and most efficient are TCP/IP-based solutions. The benefits of IP are many: You can scale the solution as large as you want, you can control the solution from any point on the network, you get to leverage the client’s existing network infrastructure investment and you can combine control with the video signal distribution.

However, it must be noted that not all IP-based solutions are created equal: Some significantly compress the video to fit within the network. For example, a high-definition video signal (1080i) uncompressed is about 1 gigabit per second of network traffic. Some lesser-based IP solutions will compress the video to approximately 8 megabits per second using MPEG2, 4 or H.264 video codecs. That is a 125:1 compression ratio, resulting in a lot of lost detail.

Is 1 gigabit per second practical? The short answer is, yes. Network switching technology allows us to take full advantage of the Cat5 or Cat5e cable that runs to the display and delivers the highest quality video to that display. This can be done over a managed switch so no other network traffic is impacted. In some cases, quality might not matter but, in almost all scenarios that we have seen, given price/performance tradeoff between various IP-based solutions, end users will almost always select the high performance/quality solution with a price point similar to that of the compressed video solutions.

For many, there is the question of whether a compromise is possible on bandwidth. This is of particular concern where there might be a shared fiber link between buildings. In this case, look for a solution that can handle a 50Mbps stream. This stream can run over shared fiber links and also run within a premise on lower-cost 10/100 switches.

IP-Based Control

The last step in creating a high-end digital signage solution is control. Ideally, you want a solution where the client can control not only what content is rendered on what players and when, but also to which displays that content is finally sent. Again, this is where an IP-based solution really shines.

A traditional matrix switch at each facility would require a separate control system to direct it to distribute content to each display. This would involve programming for each location’s switch. In cases where there are facilities of varying size, you might have different size matrix switches, each of which would require its own separate programming efforts.

With the IP-based solution, it’s possible to have the players send network-based commands to the video distribution network when it starts to play a piece of scheduled content. For example, when a store opens in the morning, the players may be scheduled to play the welcome message; as they start to process this content, they can send a single message that selects all displays, powers on each display and tells the displays to play content from signage player one (the player with the welcome message). An hour after opening, the other players in the store can start their content and take over a pre-selected set of displays.

In the IP-based model, this is simple; in a matrix switch model, this is a significant programming effort. Figure 4 shows the solution once the pieces of video source selection, distribution, quality and control are addressed. This creates a solution that is easily maintainable, flexible for use with multiple source types and cost effective.


The professional digital signage solution has moved far beyond the days of a single LED or CRT display. Now that businesses understand the benefits of implementing digital signage solutions, the demands on the system have gone up commensurately.

IP-based video solutions are unique in their abilities to meet the demands of high-end signage requirements, such as being fully networkable, fully scalable as large as the network capacity allows, provide source and display control, enable source selection and rendered content distribution, transcode content from source to display or player, and full control by any player or application on the network.

Although there are many other solutions on the market, if you’re building a high-end signage system to fulfill the requirements of the most demanding environments, this integrated solution is unique in its ability to deliver what the market needs.

Sanjay Castelino is vice president of marketing and business development for Austin TX-based NetStreams LLC.

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