Explaining Digital Television

28Aug07

Update: The book will be out soon – details on the Television & American Culture website.

I just realized it’s been over a week of blog silence. The semester approaches, summer is waning, and I’ve been uninspired to write in a bloggy fashion. So I’ll share what I have been writing – continual work on my American television textbook. This section is in the chapter on television technology and follows a historical survey of TV’s origins and transformations in the 20th century. In trying to chart out the digital transformation of television, here’s the section on Digital Television, which is a specific term (as will hopefully be clear) – the section will be followed by sections on recordings (DVD, DVRs, iTunes) and convergence of screens (gaming, online video, mobile TV, etc.).

What do you think? Too techie? Too confusing? Too much detail? Not enough detail? If you were to read this as a student or just an interested reader, what more do you want to know? And if you’re in the know, what did I get wrong?

The Resolution Revolution

The NTSC standard persisted as the only way to receive over-the-air broadcasts into the 1990s not because it was the most technologically advanced system—it was surpassed within years of its debut by other national standards—but because changing broadcast standards is a costly and complicated task. The television industry made slight upgrades to NTSC over the years, incorporating color and stereo sound, but these changes were made without requiring an entire overhaul of stations’ transmission equipment or consumers’ television sets. Yet in the 1990s, the Federal government started the process to convert American television broadcasting into a digital television standard, a transition that is still being worked out at the time of this writing in late 2007.

The story of digital television is quite complicated, influenced by the competing interests of broadcasters, television technology manufacturers, the computer industry, Congressional budget priorities, and countless other players. Possibly the most confusing element for everyday consumers is the issue of terminology—the phrase “digital television” can refer to a wide range of different technologies, including DVDs, videogames, HDTV, digital cable, DBS, downloadable programming, and online video. For the purposes of clarity, this book will use digital television and its abbreviation DTV to refer to the system of digital broadcasting and its associated set of standards, also known as Advanced Television Systems Committee (ATSC), designed to replace analog signals and NTSC screen specifications.

The technical specifications for DTV broadcasting shift the signals transmitted by stations from analog to digital, encoding the visual and sonic information of television into binary data—the effect of this shift is to increase both the fidelity and amount of information that can be broadcast on a television signal, reducing interference and variable reception typifying many over-the-air broadcasts. To accomplish this transition to a more reliable and efficient broadcast signal, the Telecommunication Act of 1996 directed the FCC to allocate a new portion of the spectrum for DTV, issuing licenses for all analog TV stations to create parallel DTV channels. As discussed in Chapter 2, this decision to duplicate existing television broadcasting licenses at no cost was seen by many as a corporate giveaway and a missed opportunity to strengthen the competition and public service obligations among broadcasters—the television industry countered that this process of duplication was needed to allow stations to fund the high cost of transitioning to DTV equipment, requiring new broadcast towers, cameras, and transmission infrastructure.

The DTV transition was launched with a series of deadlines for analog conversion, starting in major markets in 1999 and with a final requirement that all analog stations mirror their broadcasts in DTV by 2003, with a planned elimination of the analog spectrum and full switch to digital in 2006. These deadlines were routinely missed, leading the FCC to rollback the proposed timetable for eliminating analog broadcasting to February 2009, at which point all stations will be exclusively available in DTV—the FCC will convert the analog television spectrum to serve wireless communications services, which will have to pay for their licenses at auction in stark contrast to the free licenses receive by commercial television broadcasters. When analog broadcasting ceases operation, all traditional television sets will need to be outfitted with a converter box to receive over-the-air DTV signals or be hooked into a cable or DBS system that provides analog conversion—these analog conversions will not be able to take advantage of the higher resolution pictures afforded by DTV. All television sets sold since 2007 are mandated to have built-in DTV tuners, although there is a good deal of confusion amongst consumers as to how to interpret phrases like “Digital Ready” or “HDTV Monitor” on television sets, as these terms do not necessarily indicate a DTV tuner.

DTV and the ATSC standards do more than just change the way transmissions are coded, as they significantly upgrade the resolution of images available through television. For most consumers, DTV is most recognizable as High-Definition Television (HDTV), the highest quality image resolution available via DTV transmissions. Unlike NTSC’s single image specification, DTV allows for over a dozen different variations on the image resolution, shape, scanning technique, and frame rate—DTV can either feature progressive scan images, where every line of resolution is rendered in each frame, or interlaced scan images, rendering every other line per frame in an alternating pattern. This difference was crucial to satisfy the competing interests of companies involved in creating ATSC standards, as televisions have traditionally used interlaced scanning, while computer monitors use progressive scan; the compromise allowing for dual systems appeased both industries. The two highest quality ATSC resolutions qualify as HDTV, with the 1080i and 720p systems referring to the lines of resolution and either interlaced or progressive scanning—there is no consensus as to which standard is better, with each offering its own technical advantages and weaknesses. HDTV features a 16:9 aspect ratio, allowing for a wider rectangular screen than NTSC that has become the standard shape for nearly all DTV sets.

While HDTV’s image resolution has become the main selling point for early adopters of digital television sets, the majority of DTV broadcasts are not in HDTV. Many local stations have found the upgrade of production technology to HD too costly, and it is questionable whether people wish to see local news in such high-definition. Likewise, much of television consists of airing older rerun material, which will be impossible to upgrade to HD resolution. DTV allows for broadcasting in other standards with lower resolution than HD, including Enhanced-Definition Television (EDTV) images in 480p or 576p. These images are still higher than Standard-Definition Television (SDTV) of NTSC in 480i resolution, although DTV can still display SDTV programming with improved image quality due to its better signal reception.

For broadcasters, the biggest advantage of EDTV and SDTV is not lower production costs, but the potential of multicasting—the efficient DTV signals allow for multiple simultaneous SD or ED broadcasts to be transmitted on one station license, creating up to five subchannels of SD programming. Potential uses for multicasting, which broadcasters see as an opportunity to compete with the niche programming typical of cable, include public television offering a broader array of educational programming at any given time, sportscasts providing access to multiple games simultaneously, or local stations offering continual weather and traffic broadcasts on a subchannel. While these practices are still emerging, networks have generally shifted their much of their primetime entertainment and sports programming into HD, but have been slower upgrading daytime and news programming. Additionally, each DTV channel has sufficient bandwidth to include a datacasting signal in addition to television programming or subchannels, allowing any device receiving a DTV signal to access a stream of data. Datacasting allows for high-speed broadcast of digital software data for a range of purposes, including advertiser information, educational content, video-on-demand, or computer upgrades, although these usages are still being explored and have yet to become widespread as of this writing in 2007.

DTV has most direct implications for broadcast stations, which must transfer all of their operations from analog to digital, but the transition has also impacted cable and satellite providers and channels. Many subscribers receive “digital cable,” and all DBS service is digitally encoded as well, but these systems do not necessarily feature DTV signals—typically DTV service including HDTV programming is an extra feature from cable or DBS systems requiring a special set-top box to receive HD reception. In 2007, a provision of the Telecommunications Act of 1996 finally went into effect after years of legal battles that mandated cable systems to offer consumers the ability to use a CableCARD inserted into a digital television set or DVR, eliminating the separate set-top cable box to access HD programming. The cable systems industry has been resistant to shifting to DTV, as it requires carrying numerous local subchannels and upgrading infrastructure to be able to transmit HD signals effectively via cable; however for some cable channels, like ESPN and the upstart HDNet, it has been an effective way to build an audience among early adopters of DTV technology.

The broader cultural impacts of DTV have yet to be fully felt, as the technology has not penetrated most American television households—less than one quarter of Americans had DTVs in 2007, although this number is certain to grow rapidly in the face of the 2009 analog cutoff. DTV is potentially fostering class distinctions, as the current cost of HDTV-equipped sets are prohibitive for most working-class families—television has long been one of the most economically diverse media, with consumers of all incomes owning sets, and DTV threatens to create unequal access to America’s central medium except through low-fidelity converter boxes. Currently around 15% of American households receive television only through over-the-air signals, presumably with many of those opting for the free broadcasting service for economic reasons—these households will be most impacted by the switch to DTV, forced to purchase converter boxes, subscribe to cable or satellite, or invest in an expensive DTV set. Another social impact of the switch to digital is the environmental impact of millions of analog sets that will probably be discarded after digital upgrades, with toxic materials like lead that will need to be recycled and processed to avoid a serious polluting impact.

For early adopters willing to invest thousands of dollars into their television set-ups, HDTV has been a chief appeal in building home entertainment systems to screen films and sports in a home theater experience to rival cinema. Some viewers complain that certain programs look worse in HDTV because the high-resolution images highlight visual imperfections, often undermining make-up and other techniques to make performers seem beautiful and attractive. It will be interesting to see if particular genres or modes of programming become more or less popular under the DTV paradigm and high-resolution of HDTV—for one potential sign of cultural shift, Discovery Channel’s 2007 HD presentation of the British nature documentary Planet Earth set records for cable ratings driven in part by the spectacular visuals featured on the program. Perhaps the higher fidelity of visual resolution afforded by DTV and HD will increase the fortunes of naturalistic styles, like documentary, sports, and gritty dramas, over more presentational modes, like multicamera sitcoms, newscasts, or game shows. However, it is far too soon to tell how the DTV change might impact American culture and the formal norms of television.

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