No. 295 (July 2003)
HDTV revisited ...
One of the key uncertainties about the future of TV broadcasting is when High Definition TV (HDTV) will become important for European broadcasters.
Given that broadcasters in Europe decided in the early to mid-1990s that they would not pursue HDTV, it seems sensible to review this decision in the light of subsequent developments, such as:
Following the fiasco of Europe's HD-MAC initiative in the early 1990s, even the most ardent technocrats have been reluctant to suggest launching HDTV services in Europe. With the benefit of hindsight, we can see that there were two problems with the HD-MAC approach: first, HD-MAC's analogue technology was about to be superseded by digital technology and, second, it was a case of "technology push" rather than being driven by consumer demand or "market pull".
Broadcasters in Japan, the USA and Australia have launched HDTV services. After several years of poor sales of HDTV equipment, there are now encouraging signs, especially in the USA, that consumer interest in HDTV is beginning to pick up – prompted mainly by the falling prices of HDTV displays.
In the Summer 1998 issue of EBU Technical Review in an editorial entitled "HDTV or not?", I wrote "The market pull for HDTV will be the arrival in the consumer market of large flat panel displays at affordable prices".
In 2003, large flat panel displays are now available on the consumer market. The first generation of 16:9 flat panels (Wide-VGA) typically has 852 pixels horizontally and 480 pixels vertically, whilst the second generation (Wide-XGA) has 1366 x 768 or 1280 x 768 pixels. Without getting diverted by the endless arguments about the meaning of "HDTV", it is obvious that Wide-VGA displays cannot offer true HDTV but most broadcast engineers would consider that Wide-XGA displays offer HDTV quality.
So large flat panels are here, but are they affordable? In the USA, retail prices for 42-inch (107 cm.) flat panel displays are about $3,000 for Wide-VGA and $6,000 for Wide-XGA. Although some manufacturers have announced displays with 1920 x 1080 pixels, such displays will obviously be much more expensive. Fortunately, prices will reduce in the next few years – thus stimulating more demand and, hopefully, even lower prices.
The arrival of large flat-panel displays in European shops has renewed interest in HDTV – mainly because Standard Definition TV (SDTV) pictures can look poor on such displays. Tests conducted by EBU Members suggest that, when viewed at a distance of 4 times picture height, Wide-VGA flat panels require bitrates of 8 - 10 Mbit/s compared with the typical data rate of 4.5 Mbit/s used for most of today's digital SDTV broadcasts. Unfortunately, few broadcasters can dedicate more bits to each digital TV service because there is insufficient spectrum.
Even worse, DVDs typically deliver much better picture quality on such displays than analogue or digital SDTV broadcasts. Many consumers assume that DVDs already offer HDTV! There are several reasons for this difference in quality:
It will be difficult to satisfy viewers who have spent a lot of money on a high-quality TV display if they find that digital TV pictures are inferior to DVDs. This situation is likely to get worse, rather than better. Digital SDTV broadcasts can look poor on Wide-VGA displays, but they look even worse on Wide-XGA displays. This is not particularly surprising because HDTV displays require HDTV signals. As an additional complication, HD-DVDs will probably be launched within 3 - 5 years, thus adding a significant driver for the adoption of HDTV displays.
How should broadcasters in Europe respond to these trends? If 1% of homes had HDTV displays, it could be argued that EBU Members can safely ignore HDTV. But could they ignore complaints from, say, 20% of viewers?
During a panel session at IBC in 1999 entitled "HDTV: has Europe missed the boat?", I joked that there were some boats that I would not mind missing - for example, the "Titanic"! More seriously, I suggested that the main obstacle to the consumer adoption of HDTV would be the price of display devices and I therefore proposed that Europe should take a relaxed attitude towards the introduction of HDTV services. The resulting delay would allow European consumers to avoid the initial high prices of HDTV equipment – because the prices of HDTV displays would be driven downwards by the success of HDTV elsewhere. My advice was essentially that European broadcasters should not launch HDTV services until the price of displays had dropped to a sensible level.
Broadcasters planning to launch new HDTV services in 2007 or later will probably choose one of the emerging video compression schemes, such as MPEG-4 Part 10, rather than relying on the much less efficient MPEG-2 scheme currently used for all digital TV (SDTV and HDTV) broadcasts. In other words, this is one occasion when delay offers a significant benefit.
When NHK demonstrated HDTV in 1981, I recall being extremely impressed by the picture quality – but, as I left the room, I said to a colleague "It's wonderful, but it won't happen for 10 years". There have been many optimistic declarations such as, for example, "The year of HDTV" being adopted as the theme of IBC in 1988. It seems to me that HDTV has long been "10 years in the future". Now, perhaps, we are getting closer than 10 years – thanks to the pioneering efforts of our colleagues in Japan, the USA and Australia.
European broadcasters should consider using HDTV for the production of expensive programmes with a long shelf life – but there is no imminent requirement or, indeed, commercial justification for delivering HDTV services to consumers. Taking a longer term perspective, HDTV will eventually become a mass-market consumer product. Even so, my personal view is that European broadcasters should remain cautious about HDTV.
Philip Laven
Director
EBU Technical Department
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