(Challenges, Opportunities and Implications on Bandwidth)

High definition TV is now no more just a topic of discussion at seminars and conferences. It is a reality that will hit our households some time soon. With Europe and then USA having tasted High Definition picture quality, viewers are getting increasingly hooked on, and there is intense pressure for all key players to go HD.

What is HDTV?

Let us take a moment to understand what HDTV really provides. High definition television is the highest form of digital television. It has a 6:9 of aspect ratio, which is the same as a movie theater screen. Again in terms of resolution, high definition is the best available picture on a television.

High definition programs can be encoded in three types of resolution: 720p, 1080i or 1080p. The number stands for the amount of lines embedded within the signal. The accompanying letter describes the type of scan the television uses to display the picture. The ‘i' means interlaced and ‘p' means progressive.

The number of lines on a television is important because it allows for a greater detail in the image. The greater the number of lines on a TV, the more detailed and defined is the picture/video quality. The standard definition televisions, which most viewers had before the onset of LCD TV, have 480 visible lines on the screen. Thus, by increasing the number of lines in combination with the type of scan, HD essentially more than doubles the picture quality.

The type of scan most suited is arguable considering the amount of lines for each HD format. Progressive scan is a better type of scan because it doubles the amount of times the TV displays the image per one second in comparison to interlaced. Still, the difference between 720p and 1080i is so minimal that it is hardly discernable to a viewer's eye. While 1080p is better than 720p and 1080i, few programs are made in this resolution as of today. However, with the constant push toward the best, 1080p would ultimately be the resolution standard, not to mention super-high definition and further advances that are likely to follow, as viewers push for ever better picture quality.

Trends in HDTV

Though the concept of HDTV was introduced long ago, with production equipment being manufactured in the mid 80s, a lot of time was spent by the industry to come to an agreement on standards, regulations and the like, resulting in the first regular HD broadcast starting only around the turn of 21^st century. Initially, Europe took the lead, quickly followed by USA, and now South Asia.

Today, DirecTV alone has 110 HD channels in its bouquet, with plans of adding another 20 channels in the next couple of months.

HD in news

Among the first channels to go HD were sports channels, followed by entertainment channels. News channels have been comparatively a bit more tentative, primarily because of the nature of content processing involved. However, today there are over 100 HD news channels being shown in USA alone, with all major news channels like ABC, NBC, Fox, CBS and PBS going HD. These however include all types of transmission: satellite, terrestrial wireless, cable, and IP. The most popular satellite TV services in USA, namely Dish and DirecTV have 3 to 4 HD news channels in their bouquet. This number is slated to reach over 50 within the next year or two.

Back home, HDTV is like a bomb waiting to explode. Most big players have plans to go HD, and there are many unofficial news releases about one or the other media house planning to launch their first HD channel. Most of them aim to launch HD versions of their non-news channels.

Creating content for news

News channels by their very nature have to create live or near live content. Hence the technical infrastructure requirement is very high. The complete production chain starting from studio cameras, production switchers, monitors and MCR switchers, logo generators, and DSK require to be HD compliant. The IT infrastructure including video servers, edit suites and centralized graphics also require the ability to deliver HD format. Thus news channels are faced with the big question of viability, given the relatively limited viewership of HD transmission.

This choice is easier for new channels, since they have to start from scratch. Existing news channels, however, having made the initial investment, have a tougher choice to switch to HD and make new investments. In India, already most new news channels are setting up HD-ready facilities.

HD contribution

Content in news channels is not produced in studios alone. A major portion of content is in fact, captured live from DSNG/OB vans, or recorded and sent in from news bureaus. This necessitates the procurement of HD compliant equipment for news contribution as well. With plans of HD news channels becoming more concrete, HD DSNG/OB vans and bureaus are also becoming a reality in India. In fact HD contribution infrastructure requirement is also being driven by the Commonwealth Games in 2010. Doordarshan has already floated tenders for HD OB Vans.

DSNG specifications

The implications of HD transmission on DSNG vans would be on two fronts, namely HD format compliance and high data rates of transmission. Hence, all production and compression chains have to be HD compliant. This includes HD field camera, HD camera cables up to DSNG van, HD switcher (if required for multi-cam operation), HD monitors as well as HD encoder/modulator. Regarding transmission, typically, SD video transmission in contribution links is being done at 2 to 4 Mbps for news channels, using MPEG 2 compression. However, in order to transmit HD signal, the transmission rates in MPEG 2 compression would reach 8 to 12 Mbps. This necessitates the use of MPEG 4 compression, which brings down the transmission rates to around 4 to 6 Mbps.

It is important to also talk here about MPEG 2 and MPEG 4 compression. MPEG 2 has till recently been the most popular coded for video compression for purposes of broadcast transmission. A typical TV channel in SD using MPEG 2 compression is broadcast at around 3 Mbps to 6 Mbps (9 Mbps for channels where high degree of movement is expected on screens). Due to economic as well as satellite space constraints, the industry has started moving to more efficient compression format - MPEG 4. This codec reduces the bandwidth requirement to nearly half while retaining the picture quality. In India, the first MPEG 4 TV channel broadcast was started 3 years ago by MM News (Malayala Manorama), operating from India's leading teleport of Essel Shyam Communication Limited, in Noida. Thereafter, many channels from the same teleport are being uplinked on the MPEG 4 format. These include 9X, 9XM, NewsX, and News24.

Two factors drive the selection of the antenna system; first being the higher emissions which can be potentially harmful to the satellite and neighboring users, thus requiring selection of high quality accurately profiled reflectors (usually carbon fiber reflectors) with accurately designed feed mounting systems.

Already, Essel Shyam Communication Limited, the leading broadcast services provider is fabricating over a dozen HD DSNG vans for a new news channel which plans to create HD news content so as to be able to launch HD news at the shortest notice.

Challenges

High investments. HD production and transmission equipment is obviously more expensive compared to the SD counterparts. Though with time, the price differential is narrowing, it is still between 40 percent and 100 percent more depending on the type of equipment. This difference is much lower in IT products. However higher investment at production and transmission level is hardly any challenge, as compared to distribution.

Distribution upgrade. To deliver HD to homes requires the entire distribution to be HD ready. For a cable distribution network the entire chain is needed to be upgraded including the decoders, modulators, multicore cable, and set-top boxes. All this, assuming that the home viewers already have HD ready TV sets. Obviously the odds are huge, but these hurdles have been overcome in other countries, and will definitely be over come in India, a country full of entrepreneurs.

DTH distribution will require only the transmission chain to be upgraded and only such subscribers, as require the "platinum HD service" need buy the HD set-top box. Hence it is safe to say that we would be viewing the first HD channels on DTH.

Implications on bandwidth

From contribution point of view, the challenge in HD contribution would be largely in the form of high cost of bandwidth. As already discussed, HD contribution bandwidth would be 4 to 6 times. This not only means higher cost of transmission, but also higher consumption of a resource which is presently in very short supply. With limited parking slots, this problem will not get resolved very quickly, unless the government permits the use of foreign satellites for use in news contribution.

One step toward managing this problem is to have a very efficient system of bandwidth management. Today, there are solutions for extra quick DSNG deployment using a hub and remote architecture, where the carrier can be allocated from one DSNG to another in a matter of a couple of minutes, thus enabling a channel to share the same carrier between many transmission sites. Today, most news channels have three to six contribution carriers. These could be reduced to one to three, using these systems. However, the requirement of carriers also depends on the number of live windows planned for a bulletin/program.

Conclusion

In the broadcasting business, the viewer is the ultimate king. With onset of LCD TVs, the viewers' appetite for better picture quality is increasing, and with viewers getting their taste of the first HD channel, there is bound to be a spurt in demand for more. Broadcasters will have no option but to deliver on this promise.