but the term HD means different things to different people, and it's not at all clear what the practical advantages to using HD in the business world might be. Not yet, anyway.EVERYWHERE YOU TURN THESE DAYS PEOPLE ARE TALKING ABOUT HIGH-DEFINITION VIDEO, OTHERWISE KNOWN SIMPLY AS HD. BUT SCARCELY ANYONE STOPS TALKING LONG ENOUGH TO LEARN PRECISELY WHAT HD IS (AND ISN'T), OR TO CONTEMPLATE WHETHER THERE ARE ANY PRACTICAL REASONS FOR INVESTING IN THE EQUIPMENT AND KNOW-HOW NECESSARY TO CREATE AND DISPLAY HD CONTENT, ESPECIALLY IN THE WORKPLACE.
To address these issues intelligently, it's necessary to understand that the acronym HD currently is an umbrella term that refers to a number of video protocols with varying resolutions and specifications. There is no "standard" HD format, so each time you see the initials HD, it's likely to mean something different.
Unraveling the mystery of HD
The key to understanding high-definition video is first to grasp the current state of television. Before the HD moniker, we just called video … uh … video. Once the demons of alphabet soup and buzzwords came along — inventing such terms as HD, hi-def, 1080i and so forth — the video we grew up on was renamed standard definition, or SD.
The National Television Standards Committee (NTSC) standardized our analog color television system back in the 1950s. Imperative at the time was backward compatibility among all the black-and-white televisions that landed in American living rooms after World War II. The NTSC's decisions have affected U.S. TV quality ever since, leading some disgruntled customers to suggest that NTSC really stands for Never Twice the Same Color.
Traditional television screens are made up of tiny pixels arranged in lines from top to bottom. Inside the box, a cathode-ray tube (CRT) generates beams of light that strike a phosphor layer and make it glow. The CRT displays images line by line, and those collective lines make up an individual TV frame. TV displays an image at 30 individual frames per second of video (29.97, to be exact). The lines that create the image are not displayed sequentially, however; in a process called interlacing, the odd lines of each frame are displayed first, in sequence, then the even lines.
The number of lines, top to bottom, is called vertical resolution. For broadcast SD video there are 525 lines, but only 480 lines hold picture information. The VHS video format tops out at about 330 lines of total vertical resolution. This accounts for the general "fuzziness" to the look of even the highest-quality VHS tapes. Video on DVDs, on the other hand, contains 480 lines of vertical resolution, which is why video on DVD looks so much clearer than on VHS. And since video on DVD is a digital medium, much of the "noise" inherent in its analog VHS counterpart is vastly reduced.
Also note that the standard screen dimension, or aspect ratio, of analog TV is 4:3 (i.e., four units wide by three units tall). Therefore, the maximum screen resolution is 640 pixels x 480 vertical lines, for a total of about 300,000 pixels of information. For this reason, standard-definition video is often referred to as 480i for its 480 lines of interlaced vertical resolution. Technically, anything better than 480i could be considered high-definition video. And so, it is.
HD, soup to nuts
As I've said, HD is actually an umbrella term that covers many different formats of video. For example, HDTV scans 1,125 lines, with 1,080 of them reserved for the picture's vertical resolution. The signal is still interlaced, so it's designated 1080i. However, the aspect ratio for HDTV is a widescreen 16:9. This translates into a screen resolution of 1,920 pixels x 1,080 vertical lines, or an equivalent of 2,073,600 total pixels — nearly seven times that of SD.
Another HDTV format, called 720p, uses what's known as progressive scanning. This technique displays all vertical lines in order, top to bottom, the way a computer monitor displays an image. The 720p format has a lower vertical resolution but the same 16:9 aspect ratio. This yields a screen resolution of 1,280 pixels x 720 lines. However, this format makes up the resolution difference by doubling the frame rate to 60 progressive frames per second.
Most people are becoming acquainted with HD through advertisements for digital television (DTV). But DTV doesn't just support one HD format, it supports 18 formats, ranging from SD up to several iterations of HD. Developed by the Advanced Television Standards Committee (ATSC), the DTV specification includes SD 480i on the low end and HD 1080p on the high end. Other formats fall in between and vary by television network. For instance, ABC has elected to use 720p, while CBS uses 1080i.
Regardless of the designation, HDTV in all its various forms offers a distinctly improved viewing experience from VHS, DVD and SD video. Unfortunately, not everyone likes the clarity of HD video, particularly in movies, because they have become accustomed to the "feel" of film. Consequently, videographers and producers have been trying for years to develop a form of HD video that has HD's advantages in shooting and editing, but also has the warmer feel of film.
24 p's and q's
The primary reason video looks different from film is that video runs at 29.97 frames per second and is interlaced, whereas film operates at 24 frames per second and is fundamentally progressive. Many filmmakers, including George Lucas, maker of the "Star Wars" movies, loved HD but didn't like its video look. Lucas' suggestion was to shoot video at the same frame rate film shot, thus 24p was born (that is, 24 frames per second, progressive video). Sony's CineAlta HD line of professional video equipment emerged as the 24p HD standard. Director Robert Rodriguez, of "Spy Kids" fame, is another leading proponent of the 24p movement.
The 24p video format isn't limited to Hollywood, though. Last year, Panasonic released the AG-DVX100, an SD Mini-DV camcorder that will shoot 24p. Canon also released the XL2 camcorder, which offers a 24p recording option as well. These bring the film look to anyone willing to shell out about $3,000 for it. Most of the current crop of video-editing software and nonlinear editing systems (NLEs) can handle the 24p format, and many documentary and independent filmmakers are embracing this format because it costs so much less to shoot than film. It's not HD, per se, but 24p Mini-DV upscales, or converts, well to HD formats and often is output on film for theatrical distribution. For example, the current independent film "Looking for Kitty" was shot with the aforementioned Panasonic camera, bumped up to HD in production, and ultimately output to film.
How to see HD
No matter how high the HD output resolution is, though, no one can see it without a monitor or projector that can display it. Only professional videotape recorders (VTRs) and monitors or TVs with HD-compatible input/output can display the high-definition signal effectively.
To view HD content requires an HD display device in one of several flavors: CRT, plasma, LCD or DLP. CRT is the well-known basic TV with which we are all familiar, but enhanced for HD. Plasma uses gas sealed within the device to create its images. LCD, short for liquid crystal display, is the primary display technology for laptops and flat-panel LCD TVs. DLP (Digital Light Processing) is a projection-based format that is less expensive than LCD, and comes in both front- and rear-projection models. Be aware, though, that not all models of these displays can support full-resolution HD content.
Some HDTVs come with an HD tuner built in. Other displays are only "HD ready," which means they can usually play analog as well as digital TV signals, provided you purchase a separate HD tuner. With a tuner built in or separate, all one has to do is connect to an HD source (over-the-air, satellite service or cable) to enjoy amazing video quality. Satellite and cable providers offer HD content from channels such as Discovery and ESPN. Local HD broadcasts, such as ABC, CBS and NBC affiliates, require connecting an over-the-air antenna to the HD tuner. Additionally, many digital-cable providers deliver local HD broadcasts. What's important is making sure that the tuner you have is compatible both with the display you have and your HD provider.
HD at work?
That's all fine and dandy for the home, but how do you create and deliver original HD content in the work environment — in, say, corporate presentations or product demonstrations? Unfortunately, the barriers to using HD in a professional setting are in many ways more formidable than those presented at home. All that increased resolution has a price, and it's a hefty price indeed. In addition to the special equipment and software needed to shoot and edit HD video, it requires lots of bandwidth and storage space. While you can send Mini-DV and its 25 Mbps video over Firewire, HD has a bandwidth of 100 Mbps and higher.
So, if you want to use HD, you also have to be prepared to invest in special hardware to record, capture, edit and display it. High-quality displays and projectors coupled to HD VTRs will doubtless be commonplace in corporate America someday, but right now, the cost barriers are prohibitively high for most organizations.
The biggest problem with HD
Aside from equipment costs, the thorniest problem for companies that want to migrate to HD is the lack of a format standard for delivering HD video. DVDs, though they look and sound fantastic, are still standard-definition and don't have the ability to deliver HD with their current specifications. There is talk of using new high-capacity DVDs — known as Advanced Optical Disc (AOD) and Blu-Ray — to deliver HD to consumers, but that's still talk at the moment. The other approach is to use more efficient compression schemes to deliver HD content on standard DVD discs. MPEG-4 and what's known as the H.264 format specification is one such proposal.
Right now, only Windows Media High Definition Video supports HD, and even then only on computer screens and some HDTV monitors. Though not a done deal, Microsoft is pushing hard to make Windows Media HD the format for consumer use (in computers and set-top high-definition DVD players). In either case — high-capacity discs or more efficient video codecs — nothing has been decided yet.
At the moment, the best approach is to acquire and edit content in HD, then deliver it in SD. What's the sense in that? Well, shooting video and editing in HD maintains the highest possible quality until the final rendering step. The resulting SD video should be far superior than if SD video is used throughout the production work. As a plus, acquiring video on HD makes it easy to eventually deliver the HD content at a later date, when a standard delivery format is decided upon.
HD in production and post-production
Unfortunately, that may take a while. There are several competing HD formats on the production side. Two leaders are Panasonic's DVCPro HD and Sony's HDCam. DVCPro HD supports both 1080i and 720p, using compression to bring the data rate to 100 Mbps. HDCam supports 1080i and 1080p (including 24p), and uses compression to deliver a 140 Mbps data rate. Cameras that support these formats are extremely expensive (in the $25,000 to $50,000 range) as are their HD VTR counterparts.
Capturing the HD data stream into a computer requires specialized computer capture hardware, too. For example, the Blackmagic DeckLink HD Pro connects computers to HD VTRs for capture. As luck would have it, there are several video NLEs that already support HD-editing, including Adobe Premiere Pro, Apple Final Cut Pro HD, Pinnacle Liquid Edition, Sony Vegas and Ulead Media Studio Pro 7. Most of these programs output HD, and a few render to WMV-HD, too — but again, an HD-compatible monitor is required to view the content.
One promising development is Panasonic's new AJ-HD1200A HD videotape recorder, which can deliver DVCPro HD format over Firewire, specifically to Apple's Final Cut Pro HD. Panasonic developed special compression codecs to squeeze the information down the relatively skinny Firewire pipe. (Remember when it was fat?) Unfortunately, this VTR comes with a $25,000 price tag.
HD for the rest of us
Another emerging and increasingly popular format is called HDV. It's a fixed format that comes in two flavors: HDV1, which is essentially 720p, and HDV2, which is 1080i. HDV brings HD acquisition to the masses via JVC's HD10 camcorder. Sony and Canon have also announced support for the HDV format, but Panasonic doesn't support it as of this date.
HDV is actually compressed MPEG-2 video (the same you find on a DVD) that can be captured over standard Firewire and edited in various NLE applications. What's great about HDV is its affordability (the JVC HD10 is less than $3,500). Editing MPEG-2 video had been problematic in the past, but software programmers have now succeeded in making HDV nonlinear-editing viable. For example, Ulead's Media Studio Pro 7, with its HDV plug-in, edits HDV natively captured from the JVC HD10. Its workflow is smooth and the output looks gorgeous. Rendering the final output to Windows Media HD Video can bring eye-popping video to computer-based presentations, too.
The best part
It will likely be a while before HD plays a role in your presentations, but this is new technology, and as with all new technologies, prices will drop precipitously in the next few years. More affordable hardware for recording and editing in HD becomes available every day, and more TV and film content is produced in HD as well. Also, while we sit and wait for a viable HD delivery format, the SD video generated from HD acquisition is better than anyone could have imagined a few years ago. Until we finally make the transition to an entirely HD world, we'll just have to settle for what we have — and that's not so bad at all.
Jeffrey P. Fisher provides music, sound, and video production and post-production services. He can be reached at 630.378.4109; firstname.lastname@example.org.