Chapter 4: Understanding HD

Digital Display Technology. Learning the Basics of Digital Signage Chapter 4: Understanding HD

 INSIDE: Digital signage is emerging rapidly as a viable and effective communications tool. With that in mind, companies taking the first step in signage deployment will be much more successful on the playing field if they understand the basics of what digital media is and how it operates. For a crash course in digital signage, read on.

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Published by NetWorld Alliance

 © 2009
All photos courtesy of LG Electronics Inc. unless otherwise specified.
Written and edited by Travis K. Kircher, editor,

Dick Good, CEO
Tom Harper, President and Publisher
Bob Fincher, Executive Vice President and General Manager, Technology Division
Joseph Grove, Vice President and Associate Publisher


Chapter 4: Understanding HD


HD content and highresolution screens allow even everyday deployments to stand out.


If there’s one thing everyone wants, it’s better screen resolution. Screen resolution and screen size probably are the two biggest factors in the front of consumers’ minds when they start trolling the aisles for a new digital display. And who can blame them? That slam dunk at the end of the fourth quarter looks much clearer when displayed in a superior resolution. When No. 99 hits the wall and spins out during the NASCAR

NEXTEL Cup Series, a high-resolution television will enable the viewer to see each tiny spark in crystal clarity. Even the  political junkie will notice the difference when he can watch parliamentary discussions in sharp distinction. But more  importantly, superior resolution will increase the likelihood that the casual consumer will be drawn irresistibly to your digital signage display.

High-definition - or “HD” as it is commonly called - is the term used today to describe the highest screen resolution  available. It’s quickly becoming the standard for digital entertainment, and entertainment in general. Eager for a better picture, consumers increasingly are demanding HD.

“High-definition television, or HDTV, is the highest form of digital television,” stated a fact sheet on the LG Electronics Inc. Web site. “We’re in the midst of a national transition to this new form of televised entertainment - and for good reason. In the 1980s, at the urging of broadcasters, the Federal  Communications Commission began to explore ways in which to transition from fuzzy, old, analog TV to crystal-clear HDTV. In the ’90s, led by pioneering developments at U.S. companies (including LG’s Zenith Subsidiary), and due to the many efficiencies of digital, the FCC decided to take the 50-year-old television system from analog to digital.”


A looming deadline

The deadline is Feb. 17, 2009. By that time, all television broadcasters are urged by the FCC to convert their signals from analog to digital. Although some stations already broadcast in digital, others have yet to make the conversion. The deadline, mandated by the U.S. Congress, will force them to digitize. The FCC says this will create a dual advantage: It will free up the analog broadcast spectrum for public safety communications, while enabling broadcasters to offer high-definition programming to their viewers.

To educate consumers about the digital conversion, the FCC created a Web site called to disseminate information about digital television. A counter on the home page slowly ticks down the time remaining until the deadline.

Consumers are advised to take notice: After that point, conventional analog television sets no longer will be able to receive the digital programming without certain modifications.

“Because Congress mandated that the last day for full-power television stations to broadcast in analog would be Feb. 17, 2009, over-the-air TV broadcasts will be in digital only after that date,” according to the fact sheet. “If you have one or more televisions that receive free, over-the-air television programming (with a roof-top antenna or ‘rabbit ears’ on the TV), the type of TV you own is very important. A digital television (a TV with an internal digital tuner) will allow you to continue to watch free, over-theair programming after Feb. 17, 2009. However, if you have an analog television, you will need a digital-to-analog converter box to continue to watch broadcast television on that set. This converter box will also enable you to see any additional multicast programming that your local stations are offering.”

The choice will be simple: Purchase a digital television or a converter box. While special coupons will be offered by the National Telecommunications and Information Administration to make the purchase of a converter box cheaper for U.S. residents, it’s highly probable that many households will decide to purchase a new digital television.

Those developments are significant, not just for the casual TV watcher but also for digital signage deployers. The conversion will mean that consumers will feel much more at home with digital technology. Even more importantly, it likely will open the gates to unleash a flood of high-definition programming, some of which could by utilized by signage deployers. Although it’s a common misconception that digital television and HD are one and the same, digital television does enable the broadcaster to broadcast HD channels.

In any event, high-definition is here to stay — and that’s good news for everyone. For the committed couch potato, it’s a great way to watch his favorite TV show. For the digital signage deployer, it’s an effective tool to grab the attention of the consumer and hold it until the message is conveyed. With that in mind, it’s advantageous to have a basic understanding of some important terms related to HD, as well as the most prevalent screen resolutions on the market. For the rest of this chapter, we’ll delve into these facts.


Progressive scan vs interlaced scan
If you’ve been around the world of HD long enough, you’ve probably heard of the terms “progressive scan” and “interlaced scan.” But what do they mean? Are they significant?

According to experts in the digital signage industry, they are. They both refer to the process by which the CRT or digital display creates the image on the screen.


“A progressive scan DVD player in a residential environment can convey much better picture quality because it’s essentially writing twice the information versus an interlaced one.” - Sean Moran, president of Out-of-Home Media Networks Thomson


To understand the processes by which progressive scans and interlaced scans work, it helps to think of a television picture as a series of horizontal lines.

To put it simply, televisions using the interlaced scan method require two complete passes of the screen to produce the image. In this process, the television renders every other line. First, it might render all of the evennumbered lines. Then it goes back and renders the odd-numbered lines.

“There were technical reasons for (interlaced scans) to happen … when TVs weren’t fast enough to fill them all in at once,” said Bill Gerba, CEO of Fort Lauderdale, Fla.-based Wire- Spring Technologies Inc. “So it kind of became the standard format.”

In contrast, progressive scan renders each line in order, taking one pass.

“Progressive scan gets back to the idea of drawing every single line in every single frame,” Gerba said. “It gives you a much sharper image and smoother-looking motion.”

While interlaced scan often is associated with older-model CRTs, progressive scan often is associated with digital displays and high-definition televisions. But in reality, you can find HD digital displays that use either scan mode. Not surprisingly, industry experts prefer progressive scan hands-down.

“Progressive has really come online with digital coming online and really being able to do a much higherquality video image,” said Sean Moran, president of the Out-of-Home Media Networks business unit in the Technicolor services division of Parisbased Thomson. “A progressive scan DVD player in a residential environment can convey much better picture quality because it’s essentially writing twice the information versus an interlaced one.”


Understanding video modes
Now that you have a basic understanding of digital television, HD and progressive scan, you’re ready to launch into the intriguing realm of screen resolutions and video modes. Although the terminology may seem slightly off-putting at first, the concept behind it is relatively simple.

Content can be played or broadcasted by eight types of video modes: 480p, 480i, 576p, 576i, 720p, 720i, 1080p and 1080i.

As you can see, the video mode - as written - consists of two parts: a numerical figure and a suffix (expressed as “p” or “i”). The numerical figure refers to the lines of vertical resolution available on the display. For example, a display with a screen resolution of 1920 by 1080 pixels can display any content played or broadcast in a video mode of 1080 or below. The suffix denotes whether the image is broadcast or played using progressive scan or interlaced scan.

For example, a 480p video mode indicates that the display featuring 480 lines of vertical resolution is playing content in a progressive scan mode.

As you can imagine, a higher number of vertical lines usually results in a better picture, so 1080 is the optimum number, with 480 being the least appealing. Televisions and monitors that fall under the 480 and 576 families generally are standardresolution CRTs, similar to what would be found in households in the 1980s. Displays in the 720 and 1080 families typically operate in high definition. HD television broadcasts typically appear in 1080i, while content played from a Blu-ray disk appears in 1080p.

In a report titled “A Lesson in High- Definition,” authors David Berman and Richard Glikes explain the relation between  video modes and high definition. Berman is head of sales training for the Home Theater Specialists of America, a Chester Springs, Pa.-based association of home theater experts. Glikes is executive director of HTSA.

“To qualify as high definition, the minimum resolution currently available is 1366 by 768 (minimum pixel count required to display a 720p signal), and the maximum is 1920 by 1080 (the pixel count required to display 1080i or 1080p signals),”  according to the report. “The source, or signal, such as HD or DVD, is the device sending the media to your TV.

The control, or processing engine, such as the receiver or amplifier, and the display, or screen, be it a flatpanel or traditional cathode screen, must all be capable of either producing or processing this high resolution to maintain picture detail and achieve high definition.” The upshot of video modes is simple: To get the best possible picture, purchase a 1080 display.



Conclusion: Where you go from here


We hope you now have a firm grasp of what digital signage is and where it’s going. As anyone in the industry will tell you, it’s an exciting field to be involved in, as it’s poised to revolutionize the way advertising is conducted. By intercepting the consumer in a way that is both visually entertaining and informative, digital signage can cut through the annoying clutter of outdated posters and unwanted direct mailings to engage the prospective customer.

“I don’t want to put down traditional media like posters, print ads and banners, because I think that there will always be a place for such mediums,” said Ron Snaidauf, vice president, commercial products, LG Electronics USA. “But the problem  with print media is it quickly becomes outdated. That poster advertising the orchestral concert becomes worthless the moment the curtain is drawn. Then you have to spend additional dollars to create the next poster, and you have to send someone to take down the old one - and quickly, before people start to ignore that ad space.

“Compare that with digital signage, where content can be changed and updated at the click of mouse,” he added. “It’s all in real-time. That’s the greatest advantage.” Is digital signage right for you? If our only goal was simply to sell digital signage displays, we would give you a preprogrammed response: “Of course it is! Digital signage is the wave of the future!”

“The problem with print media is it quickly becomes outdated. That poster advertising the orchestral concert becomes worthless the moment the curtain is drawn. … Compare that with digital signage, where content can be changed and updated at the click of mouse.” - Ron Snaidauf, vice president, commercial products, LG Electronics USA

But that’s not always the case. It depends on your unique position in today’s market. What are your needs? What  messages do you need to communicate to your prospective customers? How often do you need to convey them? How can you best reach consumers where they are?

If you’re looking for a dynamic medium that grabs attention and holds it, that can be updated at the drop of a hat and installed quickly and easily, then digital signage might be right for you. The digital revolution is here. Will your company get on board?

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