High Definition Television

by Masudul Karim Biswas

Winter 2006

Overview

High Definition Television (HDTV) has been a much-awaited technology for the television industry. Scholars say that an updated format is overdue as the regular definition television picture has been in service since late 1930s (Ferguson, 2000). Though HDTV seemed to be an “impractical dream” a few years ago, video compression of digital HDTV signals in the nineties was a key development that made high definition video transmission, storage and retrieval feasible. With this technological breakthrough, the HDTV market witnessed an upward growth.

In the context of this and other technological developments on the horizon of broadcasting and prospective market growth in selling high definition television sets, the Federal Communications Commission (FCC) set a deadline for U.S. television stations converting to all-digital broadcasting by December 2006.

This briefing paper reviews how HDTV technology works, its background, the specific problems it is addressing, its interconnection with other media and also the technological, economic, regulatory and socio-cultural factors that can influence the technology’s viability in future.

What HDTV is and how it works

A higher definition television picture is made possible by increasing the number of scan lines in an electronically produced television image (Flournoy, 2004). By adding scan lines and enlarging the width to height ratio of the television picture, HDTV can have more than 2 million picture elements (pixels) per frame. Initially, TV stations conveyed only analog signals in an aspect ratio of 4:3. But now the signal is to be standardized in digital format and the aspect ratio is 16:9.

The basic concept behind high definition television is to not only increase the definition per unit area but to increase the percentage of the visual field contained by the image. The technology works on the basis of 100 per cent or greater increase in the number of horizontal and vertical pixels (Kuhn, 2004). HDTV standards put the screen width at 16:9 ratio replacing the 4:3. Compressed HDTV will typically require the whole bandwidth of a television channel, which is 6 Mhz, and can deliver up to 2,073,600 pixels (Ferguson, 2000). Prior to the application of digital compression, HDTV channels in analog format required up to 30 MHz of bandwidth for transmission, which was five times higher than the broadband capacity of a television channel (Flournoy, 2004).

Source: http://www.sbca.com/site_files/hdtv.asp (website of Satellite Broadcasting and Communication Association of America)

The electronic HDTV camera captures the physical image with a lens and pick-up devices for generating an analog HDTV signal consisting of both video and audio (Ferguson, 2000). For HDTV transmission, a band of frequencies in the electromagnetic spectrum is designated for each television channel assigned by the FCC. Digital television broadcasts only have a 6-MHz pipeline through which approximately 19.4 million bits per second (Mbps) of digital information can be transmitted. In practical terms, it would be next-to-impossible to accommodate the 200 Mbps of information generated by HDTV in such a limited pipeline. But MPEG-2 data compression allows redundant information to be eliminated from the bit stream (Ferguson, 2000).

The device used by local stations to compress the digital signal into 19.4 Mbps bit stream is known as an encoder. Once the signal is encoded and ready for broadcast, the local station requires an 8-VSB (eight-level digital Vestigial Sideband scheme)[1] transmitter to deliver the signal over the air . Digital HDTV recording devices are now used to record programs or events at 1200 Mbps (1.2 Gbps) or higher (Ferguson, 2000).

Background of HDTV technology

Today, there are more than 220 million television receivers in the United States. These TV sets have their historical roots in technology that was pioneered in the late 1920’s and 1930’s. In the history of television, HDTV is being considered to be the next major technological milestone after the invention of color television and cable TV boxes that occurred in the 1950s and 1960s (Barlow, 2005). Modern-day HDTV has its roots in research that was started in Japan by the NHK (Japan Broadcasting Corporation) in the late 1970s (Srivastova, 2002).

In 1977, the Society of Motion Picture and Television Engineers (SMPTE) Study Group on High Definition Television was formed (Barlow, 2005). The group published its initial recommendations in 1980, which included, among other things, the definition of a wide screen format and a 1100-line scanning structure. The first demonstration of HDTV in the United States took place in 1981. The FCC sought advice from the private sector and formed the Advisory Committee on Advanced Television Service in 1987 (Barlow, 2005). By mid-1991, the leading equipment providers for a new HDTV transmission changed their proposed designs based on a new all-digital approach. A joint proposal from several companies detailing an all-digital ATV system was given to the FCC in 1995 (Barlow, 2005). Following certain changes and compromises, this proposal was approved by the FCC in December 1996 and became the mandated Advanced Television Systems Committee (ATSC) standard for terrestrial DTV/HDTV broadcasting.

By 1997, the basic outline of the new Advanced Television (ATV) standard was in place. MPEG-2 was adopted as the standard for digital coding of interlaced TV images, compressing data of 270 Mbps down to 19.4 Mbps. This technological innovation was a “breakthrough” in HDTV’s advancement with regard to fitting high definition signals within the existing 6 MHz channel allocations for terrestrial TV stations (Flournoy, 2004).

After some 30 years of development, high definition television has finally entered the consumer market. To help consumers deal with the mounting tide of HDTV-related questions, the FCC created a consumer website http://www.dtv.gov in October 2004. The FCC also set a deadline of December 31, 2006 for the conversion from analog to digital television, although in 2005 that date was extended to 2009.

The latest development in HDTV technology is “HDTVs without a Set-Top Box.” JVC released three high-definition television models of this type: 9AV-56WP94, PD-50X795 and HD-61Z585 (IEEE, 2005). These receivers use ATI’s Xilleon 226 chip and demodulation technology for better signal reception. The chip integrates all the processing, graphics, video, audio and input/output capabilities needed in a set-top box or directly in the digital TV set. These TVs can catch a high definition digital signal without a set-top box.

Purposes served by HDTV

HDTV television gets its acceptance among the television users by addressing certain limitations of the conventional system, mostly related to image quality and broadcasting channel capacity. To make the image more “movie-like,” HDTV technology changes the aspect ratio of television screening to 16:9 from 4:3 to accommodate more scanning lines with increased numbers of horizontal and vertical pixels. The standard produces picture quality with the clarity of 35 mm film. According to the FCC website, rollout of HDTV would not have occurred without the enhanced viewing and listening experience that HD offers to consumers (“FCC Policy on Transition to Digital Television,” 2004).

HDTV delivers significantly higher resolution than the old National Television Standards Committee (NTSC ) signal[2]. An HDTV signal can offer about six times the resolution of a conventional analog signal. HDTV’s wider aspect ratio format is said to more closely resemble human peripheral vision than the aspect ratio used by the conventional TV sets. If installed properly, digital HDTV can provide pristine image quality. Image quality was being degraded in the conventional system as the signal was encoded and decoded. But digital TV is based on a system of three primary image signal components rather than a single composite signal that eliminates much of the need for signal encoding and decoding (Barlow, 2005). MPEG-2 data compression gives HDTV its biggest advantage over the old analog system (Barlow, 2005).

Despite the huge conversion costs, HDTV technology offers greater channel capacity, significantly better picture quality, larger screens, more programming, interactivity and new types of digital services (Ferguson, 2000 and Kosseff, 2003). The primary goal in switching to HDTV is to enhance video quality; but enhanced audio quality is also a direct benefit. And with digital processing there is little or no loss in quality from original to successive copies.

HDTV’s Interconnectivity with other media

In the transition period, television stations are broadcasting HDTV versions of some of their shows simultaneously with the conventional NTSC version using different frequencies assigned to them by the FCC. In broadcasting HDTV versions, TV stations usually use the Ultra High Frequency (UHF) channels and their non-cable and satellite customers will need an antenna for receiving that signal (Gillmann, 2004).

Cable and satellite service providers are regularly offering High Definition (HD) packages requiring use of special set-top boxes. About 45 per cent of the HDTV households worldwide get their service from a satellite TV service provider while terrestrial broadcasters and cable television operators provide high-definition service to the remaining HDTV households (Paxton, 2005). The digital television signal in satellite tends to be more compressed compared to over-the-air HDTV but satellite providers offer a greater number of HDTV channels.

Because HDTV signals were thought to take up too much bandwidth, the cable companies were initially not interested in carrying the HDTV signals. But to address growing demand within a segment of customers, local cable systems began offering a limited selection of HDTV content. For cable customers this is often at an additional fee and customers need to use a special set-top box.

Most Digital Video Disc or Digital Versatile Discs (DVDs) are widescreen and best work with a 16:9 monitor. For best results customers need a progressive scan DVD player (Gillmann, 2004). Some Digital Video Recorders (DVRs) for HDTV, such as the DishPlayer DVR 921 and DirectTV's HD-DVR250, are already available in the market in line with the rapid development of HDTV technology (Gillmann, 2004). Meanwhile, interconnectivity solution provider Gafen has released a new ‘ex-tend-it’ SDI [3] to DVI (Digital Visual Interface) [4] adapter. The new adapter enables high definition serial digital video transmitted through SDI to be converted to DVI for output to HDTV displays (Morgan, 2004).

Technological Factors

Television stations found that the 8-VSB modulation standard used for delivery of data services in HDTV broadcasting was not the best choice for delivery of data services to mobile antennas, to laptops and other wireless devices (Flournoy, 2004). U.S. manufacturers failed to come up with a solution for the 8-VSB problem. This indecision created an uncertainty about how to best deliver a high definition signal over-the-air, leading home users in the U.S. to go to carriers other than terrestrial broadcasters to get their DTV/HDTV programming (Flournoy, 2004). Standardization in transmission format continues to be a problem of HDTV technology. A recent Jupiter Media study found that almost half of HDTV set owners are not getting the real High Definition signal (Suciu, 2005).

Another problem is that fully HDTV compliant and high quality television sets are not affordable for all types of users. New Hampshire-based Leichtman Research Group survey found in 2003 that two percent of households with annual incomes of less than 75 thousand dollars had HDTV monitors while 12 per cent of households with income greater than 75 thousand dollars had HDTV monitors (Kosseff, 2003). Though less expensive sets are now available in the market, critics say their monitors have washed out colors and lack truly rich black tones.

Economic Factors

Despite the higher cost of HDTV compatible television sets and accessories, demand for HDTV viewing is growing. A 1993 survey result of the Consumer Electronics Association (CEA) showed positive sales of high-end monitors capable of displaying the crisp HDTV programs (Kosseff, 2003). By March 2005, some 10 million households around the world were watching HDTV programming on High Definition TV sets (Paxton, 2005). As terrestrial digital television broadcasts reach 98 per cent of the US households and satellite broadcasts reach all households, the expansion has laid the foundation for the switchover to HDTV (Kovar, 2004).

European broadcasters are coming around to the view that HDTV can provide sustainable business models (“The Challenge of HDTV in Europe”, 2005). HDTV content distribution for live events to theatres or digital cinemas is seen as a high growth opportunity in many regions (Brown, 2004). HDTV technology is also contributing to the growth of new business. Microsoft Corporation has named Samsung Electronics its HDTV worldwide marketing partner for its next generation Xbox high-definition gaming platform (“Samsung, Microsoft Ink HDTV Alliance for Next-Gen Xbox console.” May 2, 2005).

For station owners their biggest challenge and largest expense is their “High Definition migration budget” (Barlow, 2005). The old analog system of transmission has been made obsolete. For that reason, television station owners must spend millions of dollars to convert to full HDTV capability with little chance of increasing revenues to cover the cost (Sterling, 2003). Another constraint the HDTV conversion faces now is too little programming. As the equipment for HDTV technology is expensive, few programs have been developed. Due to these factors, the rising viewership is focused largely in five countries: Australia, Canada, Japan, the United States and South Korea (Paxton, 2005). But there are positive developments lading to the cost of high-definition-capable cameras and recording decks comeing down to US$80,000 from US$200,000, the price tag a decade ago (High-def meets low-cost, September 2005).

Regulatory Factors

In October 2006, the Federal Communications Commission (FCC) extended the deadline for TV broadcasters to broadcast only digital signals. To make the change-over easier for the viewer as well as broadcasters, every TV station in the United States was given a second 6 MHz channel, either VHF or UHF, to make possible the simulcast of analog and digital signals until the deadline. FCC expected that by 2006 a sufficient number of digital receivers would be in the marketplace and the government could then ask for the analog channel back It was a government move to push the broadcasting into the digital age (Flournoy, 2004).

Socio-cultural Factors

Client demand for HDTV programs has increased due to the clearer picture quality, larger screen and digital stereo aspects of the technology. In this context, big production houses are coming forward to invest in HDTV production. High Noon Entertainment, a leading production house has made a significant investment in HDTV production resulting in the creation of 375 hours of high-definition episodes for those networks (Haugsted, 2005). But the technology is yet to make any significant socio-cultural impact due to its internationally incompatible standards. To ensure the utility of broadcast contents, one of the major recommendations of the December 1998 Gore Commission Report included that broadcasters should keep diversity in mind when making decisions regarding the programming and political discourse (Flournoy, 2004). Except for news, such popular entertainment contents as movies, music, drama-series, documentaries, live events and comedies dominate HDTV programming. Already there are some channels dedicated exclusively to high definition content.

Conclusion

A conference held by French TV programmers and distributors in Summer 2005 came up with the observation that 2006 promises to be the year of High-Definition Television (HDTV), video on demand and television by mobile telephone (“HDTV, Video On Demand and Mobile TV to be flavours of the year in 2006”, 2005).
Despite this prediction, HDTV has still remained as a luxury item for many users. Israel based Scopus Network Technologies Inc. President Carlo Basile made a comment that the HDTV infrastructure is in place but it is still in maturing stage from the customer’s standpoint of accessing integrated capabilities and benefiting from greater bandwidth efficiencies (Brown, 2004). But there is a substantial room for future growth if more customers and business friendly policies are in place.

Notes

[1] 8-VSB is the 8-level Trellis coded Vestigial SideBand Modulation developed by Zenith and adopted for FCC and ATSC (Advanced Television Systems Committee) standard of DTV (Digital TeleVision) in the USA. HDTV uses this for terrestrial broadcast transmission. (http://www.8VGS.com)

[2] National Television Systems Committee of the FCC that established the U.S. technical standard for broadcast television using 525 scan lines to be transmitted at 30 images per second.

[3] Serial Digital Interface, used primarily in broadcasting, converts and transmits digital video through SDI connectors. It enables video sources to process high definition, high quality video.

[4] Short for Digital Visual Interface, a digital interface standard created by the Digital Display Working Group (DDWG) to convert analog signals into digital signals to accommodate both analog and digital monitors.

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