
Just Say "Yes"
To A Digital Television Standard
After years of
progress in the private sector, the Federal Communications Commission
(FCC) has been presented with a complete and flexible standard for
digital television. Acceptance of this technology would open up vast
opportunities for further investment and put the United States
clearly ahead of the world in its implementation of digital broadcast
technology. The FCC, after a decade of work with its industry
advisory committee (ACATS*), is finally in the position of simply
having to say "yes." But an eleventh hour action on the part of some
in the computer industry may cause the FCC to back away from this
opportunity at the last minute. This would be a mistake of historic
proportions.
What is Digital TV?
The centerpiece application of Digital Television (DTV), known as
High Definition Television (HDTV), is a common picture format and
transmission standard for bringing broadcast television into the
digital age.
A Better Picture
The new picture format offered by DTV allows for both a
highresolution and a wide-screen presentation. (In existing TVs, the
ratio of picture width to height is only 4:3, or 12:9. DTV allows a
ratio of 16:9). The combination of wide screen and photographic
quality resolution ultimately will allow for the presentation of an
entire football game with a single camera, showing the viewer all of
the field as it can be seen from seats on the 50-yard line, with no
fuzziness or blurring of the images, no matter how close one sits to
the screen.
Access to n Wide Range of Digital
Services
The move to digital broadcasting, in addition to supporting the
superiority of the DTV signal, allows new services to be created. The
broadcaster can choose multiple channels of television in lower
resolution and screen width and provide data, information, and
interactive services, bringing all consumers into the digital age.
What Are the Goals for
DTV?
Unlike Europe and Japan, the United States is committed to free
and local terrestrial television broadcasting. This means that no
matter how many other media are available, Americans expect to be
able to move anywhere in the country and receive local TV signals
without buying a new receiver or adapter for each region or each
station! DTV is simply a standard for preserving this freedom and
assurance for consumers, at a level of much higher quality and
flexibility, in the digital age.
DTV broadcasting, to be phased in while the existing analog system
is phased out, will require new frequencies and new investments in
equipment. But the number of consumers in the marketplace and the
nature of television programming will remain relatively constant. For
DTV to attract the necessary investment, broadcast television must
remain a national market that is compatible with other media (such as
cable television) that carry signals into homes. It must also provide
a platform for the new digital services that will help support new i
nvestment.
Thus, the goals of DTV
are:
- Offer better picture and sound quality Transmit in a
wide-screen format through multiple channels
- Provide free over-the-air transmission in every locality, on
a national basis
- Give consumers a range of receivers to chose from - all with
compatibility to operate in every community across the country
Allow the introduction of new digital services provided by the
broadcaster
Why is Any Standard
Necessary?
It has been suggested that the goals and benefits of DTV can be
achieved without a government standard, or without the adoption of
the full standard recommended by the Advanced Television Systems
Committee (ATSC), a private-sector advisor to the FCC. This is a
recipe for disaster.
The massive investment in broadcast television in the United
States, and the phenomenal consumer value represented by TV media and
receivers, are a result of a standard-based service system. This is
true for radio broadcasts, as well. The certainty provided by a
governmentendorsed standard ensures consumer and service-provider
investment and maintains the systems viability. For example,
broadcast television, color television, and FM-radio stereo are all
based on standards devised by private sector advisory committees and
accepted or adopted by the FCC. By contrast, the FCC reviewed four
potential standards for AM stereo and, rather than endorse one, left
the selection "to the marketplace." The result was predictable:
neither broadcasters or consumers made the necessary investment in
any one standard and the market value of AM stations collapsed. When
the FCC finally reversed itself and chose a standard, it was too
late.
Other electronics products that do not require the national and
local investment and support structure of broadcasting have survived
without a standard. When it comes to television, however, consumers
must know that the TV they buy in Illinois will work in Iowa, and
broadcasters - if they are to invest sufficiently in DTV must know
that consumers all over the country will be able to receive their
programming.
Is DTV Sufficiently
Flexible?
In this era of computers, multi-media and new broadcast digital
services, is the ATSC standard for DTV technically flexible enough?
Yes, because a thorough and cooperative advisory process has assured
that it is.
Originally, the FCC's private sector advisory committee solicited
competing proposals for DTV transmission methods. Ultimately, it
recommended that the best aspects of competing digital systems be
combined. In the formulation of the resulting "Grand Alliance"
system, parallel advisory committees covering every aspect of the
system, and drawing on every potentially concerned industry, were
established and participated in every stage of the development
process.
One key decision was to adopt the worldwide MPEG-2 standard for
compression of digital signals. In this process, representatives of
the computer industry were active participants. They also contributed
to further determinations to adopt "square pixels" and multiple modes
of progressive scanning, so that both the transmission method and the
picture format of the standard are interoperable with computer
techniques. To the extent future technological advances and their
acceptance in the marketplace allow, progressive scan techniques
favored by the computer industry can be adopted universally within
the framework of the current standard.
What are the Main Objections to
the Standard?
The most vigorous concerns over the ATSC standard for DTV have
come from some in the computer industry and some movie directors and
cinematographers who argue with particular advisory committee
decisions.
Progressive v. Interlace
Scanning
"Interlaced" scanning is a display technique universally used in
the broadcast industry that halves the bandwidth relied upon,
allowing the effective lines of resolution to be doubled.
"Progressive" scanning is commonly used in computer displays; the
lines of resolution are sequentially displayed, requiring twice the
signal bandwidth.
As a result of the thorough consultations and attempts at maximum
flexibility inherent in the ATSC process, the DTV standard relies on
progressive scan wherever possible - five out of the six HDTV formats
in the DTV standard employ progressive scanning, while one uses
interlaced scanning.
While attacking the DTV standard as supposedly inflexible, some
elements of the computer industry are trying to REMOVE a key element
of choice, flexibility and interoperability - the option for use of
interlaced" scanning techniques.
The DTV Standard is a transmission standard, not a display
standard. Neither program producers, broadcasters, nor consumers will
be forced to use an interlaced display just because it exists in the
standard. Computers (or televisions) can use conversions to display
the signal in any format they wish. Even material that is transmitted
using the lone interlaced HDTV format may be displayed in a
progressive format.
Aspect Ratio
Some cinematographers and movie directors assert that the DTV
standard does not go far enough toward a broadband, highresolution
presentation of DTV that would allow their work to be seen in its
original format. They insist that the wide screen format, or aspect
ratio, should be 2:1 or 18:9, rather than 16:9. But:
The 16:9 format reflects a broad consensus as to the best balance
among resolution, bandwidth, receiver cost, and compatibility with
the existing format;
Accommodating an 18:9 broadcast in a 16:9 transmission would
require only very marginal "letter-boxing" to present the whole
picture; and, The Motion Picture Association of America (MPAA) was a
party to the consensus on the 16:9 presentation and continues to
support it;
If the much publicized computer industry "alternative" were
adopted, there would likely be no wide-screen DTV, ever.
What Is At Stake?
The FCC has the opportunity to embrace the superb achievement of
U.S. industry in creating the world's leading HDTV standard. If the
FCC hesitates, investment will languish in the United States, while
it continues in Europe and Japan. The clear leadership the United
States has established will be squandered if the FCC does not act
quickly to adopt the standard, and a mix of inferior foreigndeveloped
systems, put to provisional U.S. use, will be inconsistent with any
future standard.
October 1996
