ASIA'S SOUND DECISIONSby Mark Long Broadcast organizations with a major role to play in Asia have recently made some "sound decisions" concerning the future of digital TV broadcasting. Thanks to a recent meeting of Europe's DVB Group, for example, the Dolby Digital audio system developed by Dolby Laboratories of San Francisco has become an accepted multichannel audio format for digital video broadcasting (DVB) applications worldwide. What's more, several Asia/Pacific nations already have tapped Dolby Digital to be the audio standard of choice for a variety of new digital TV services slated for introduction within the next few years.
The recent move to embrace Dolby Digital is largely due to its unrivaled ability to transport TV viewers right to where the action is: on the battlefield, in the middle of a jungle, at the front and center of a sports telecast or anywhere else that the TV experience takes us. What's more, a Dolby Digital "surround sound" decoder is the one component in any home theater system that has the power to conjure up the armchair-gripping realism that one normally associates with seeing a first-run movie at the local theater multiplex. This is no coincidence because Dolby Digital technology is based on the same high-tech audio delivery system that more than 50 thousand theaters worldwide already use to dramatically enhance the collective viewing experience of their customers.
Stereo home entertainment systems typically offer just two audio channels, which are located to the front-left and front-right of the listener. The sound separation between the two speakers is what transforms the listening experience from a one-dimensional, "monaural" experience to a "two-dimensional" stereo medium.
Dolby Digital, however, creates a three dimensional listening experience through its use of six crystal-clear digital audio channels that are delivered to multiple speakers that literally surround the home viewing audience. In addition to the front-left and front-right speakers normally associated with home stereo systems there are three additional full-bandwidth (3-20,000 Hz) channels: a front-center channel to handle the audio dialog as well as two "surround-left" and "surround-right" stereo channels.
What's more, Dolby Digital includes a sixth partial-bandwidth (3-120 Hz) channel that carries low-frequency sound effects to a special subwoofer speaker that faithfully reproduces deep-base sounds, such as the rumbles, explosions and other spine-tingling effects that have long kept moviegoers on the edge of their seats. The partial-bandwidth response of this low-frequency sound channel is why Dolby Digital is technically described as a 5.1 channel system rather than a 6-channel system.
Each of the 5.1 Dolby Digital sound channels can carry a different audio signal simultaneously, for the maximum possible separation of audio sources within any TV program's sonic mix. Dolby Digital also features advanced audio "panning." For the uninitiated, audio panning is the movement of various sound elements between multiple speakers, which lends a heightened sense of motion and direction to the images appearing on the TV screen. The Dolby Digital system can shift sounds from any one of the two front and two rear speakers to any of the other three speakers, or pan the dialog from the center speaker to either of the rear speakers.
DOLBY DIGITAL PROGRAM RESOURCES
The one essential software ingredient that is required before Asian TV viewers can enjoy Dolby Digital soundtracks is access to video program source material that contains the coded audio information that makes Dolby Digital possible. The good news is that Dolby Digital technology has already been embraced by a wide spectrum of TV program producers and distributors worldwide.
Released in 1992, "Batman Returns" was the first major motion picture to feature a Dolby Digital surround-sound audiotrack. To date, more than 2,600 DVD movie titles featuring Dolby Digital surround sound technology have been released or announced. For this reason, Dolby Digital has become an accepted multichannel audio standard for all DVD discs and players manufactured worldwide.
Dolby Digital made its first appearance on laser disc back in 1995. Since then, more than 500 movies have appeared on laser disc featuring Dolby Digital soundtracks.
In the field of regional broadcasting, Singapore holds the distinction of being the first country in Southeast Asia to have tested all of the options available for digital television before making a final decision in favor of Dolby Digital. Moreover, Singapore is expecting to launch its new DTV broadcasting system quickly, with digital television services starting as early as later this year (Editor: year 2000).
"Besides the existing sound format in stereo or Dolby Surround sound, we recommended that a 5.1 multichannel audio format should be considered in our DTV transmissions to add realism in the reproduced sound effect," says Roland Tan, the primary expert on the Singapore DTV Technical Committee. "With the growing popularity of home theatre systems in Singapore, such a multichannel setup should not be a problem for the new digital TV sound."
Australia's Digital Terrestrial Television Broadcasting (DTTB) Selection Panel has recommended Dolby Digital as the preferred method of audio encoding for the digital broadcasting of high definition television (HDTV) signals. "We believe that using Dolby Digital audio encoding will help provide Australia with the best available HDTV service," commented Bruce Robertson, Chairman of the Federation of Commercial Television Stations (FACTS) Specialists Group-DTTB.
The newly adopted Australian HDTV format combines MPEG video and Dolby Digital audio coding. While other audio formats are not precluded, the DTTB specifically recommends Dolby Digital based upon technical performance, the large population of audio products that exist within the community, and the existing widespread licensing arrangements that are in place between Dolby and many manufacturers.
South Korea and Taiwan have also announced formal decisions to adopt the American ATSC digital television standard for terrestrial broadcasting in their respective countries--a system that uses Dolby Digital as the audio format of choice for all standard digital TV (SDTV) and high definition TV (HDTV) broadcasts. In the USA, more than 66 broadcast TV stations are already using the advanced capabilities of the ASTC system to deliver free, over-the-air video and audio signals to households equipped with high-resolution digital TV sets. Nearly 50 percent of all American TV households already have potential access to these advanced terrestrial TV signals. In South Korea, the decision came after eight months of deliberations on the ATSC standard as well as a competing European system. The ATSC system received broad support from the Committee for Promotion of Terrestrial Digital TV Broadcasting, consisting of experts from academia and the electronics and broadcast industries who urged its adoption by the Ministry of Information and Communication.
The ASTC standard includes a high definition television (HDTV) option that is capable of transmitting crystal-clear pictures featuring the same wide-screen cinemascopic format that most major motion pictures already use. Reception of HDTV programming will require the purchase of an HDTV-compatible TV set and the local availability of HDTV signals. TV viewers who wish to fully experience the Dolby Digital soundtrack that accompanies the high-resolution HDTV picture will also need to connect a Dolby Digital decoder to their home theater system, or purchase an HDTV set that already has a built-in Dolby Digital decoder.
DOLBY DIGITAL HARDWARE REQUIREMENTS
Asian digital TV viewers also will need to acquire the following hardware components before they can experience up-close and personal the brave new world of Dolby Digital.
1. A Dolby Digital surround-sound decoder will be required to convert the digital audio bitstream into the six equivalent sound channels that were previously described above. Some home theater system manufacturers build this decoder right into the latest models of their audio/video (A/V) receivers. These products are readily identified by the "Dolby Digital" logos that they sport on their front panels. They also contain an audio/video switcher, which will allow you to connect multiple video and audio sources to the system to implement push-button selection of the desired TV program resource.
2. Other A/V home entertainment systems are marketed as "Dolby Digital Ready." These products offer six-channel input and output jacks so that a Dolby Digital decoder can be added to the system at any time to complete a digital surround-sound system for your home. Some satellite IRDs and DVD players even come with built-in Dolby Digital decoders so that their Dolby Digital outputs can be directly connected to a "Dolby Digital Ready" A/V home entertainment system.
3. Five speakers capable of full audio bandwidth response and a powered subwoofer for reproducing low frequency effects also will be required to complete the audio side of a Digital Dolby surround sound system.
4. A high-quality TV set--preferably with a direct video input connection--is the final hardware ingredient required. In this case, the sound capabilities of the TV set are unimportant as all six Dolby Digital Surround Sound channels connect to the decoder of the "Dolby Digital Ready" A/V home entertainment system. Consumers in any of the above-mentioned countries introducing DTTB services may also elect to purchase a new digital TV set that is compatible with the new digital broadcasting standard for their nation. Not all of these new DTV sets, however, will have built-in 5.1 channel Dolby surround-sound decoders. The ever vigilant consumer will need to purchase a DTV set that has the output ports required for connection to a Dolby Digital surround sound system.
A DOLBY DIGITAL FUTURE
What about receiving Dolby Digital Surround soundtracks from existing digital DTH service operators right here in Asia? Now that Dolby Digital has become an accepted audio format within the DVB standard already used by most satellite broadcasters it will be a simple affair for any service provider to include coded Dolby Digital soundtrack information in their digital bitsreams. The addition of Dolby Digital soundtracks is a no-brainer for satellite broadcasters because many of their program source materials already arrive at their uplink facilities with a ready-to-go Dolby digital soundtrack in place.
The one difficulty that the region's digital DTH programmer must face, however, is that none of their existing subscribers have a receiver that provides the output connections that would allow a direct connection between the satellite receiving system and a Dolby Digital decoder. This is precisely what millions of digital DTH subscribers in the USA have learned to their dismay. Since 1994, digital DTH operators DirecTV and Echostar have sold millions of receivers that do not feature Dolby Digital output connections. To remedy this shortcoming, DirecTV and Echostar recently began offering Dolby Digital compatible receivers to new subscribers to permit reception of the Dolby Digital Surround soundtracks available from various satellite-delivered pay-per-view movie channels as well as from premium channels such as Encore. Existing subscribers, however, will need to purchase a new Dolby- Digital-compatible receiver before they can get in on the action. In this case, the old receiver can be used in a second room so that two satellite TV channels can be viewed independently at any given moment.
It is only a question of time before Asian digital DTH operators offer their subscribers the option of acquiring Dolby Digital compatible receivers. This will allow the satellite operators to keep pace with competing digital cable and broadcast TV services that will be able to offer multiple channel services of their own, as well as facilitate the retransmission via satellite of the new DTTB services that national broadcasters intend to begin offering in the not too distant future.