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1993 - The Development of 1250 HDTV

von Brian Scott - Vision 1250 (aus 1993 !!)

Abstract

Vision 1250 is a grouping set up with the participation of the European Commission to promote the 1250/50 High Definition Television standard throughout the world. It achieves this primarily by facilitating programme production by its participants: It has been instrumental in the HDTV coverage of the 1992 winter and summer Olympic games and has developed its services by the introduction of new equipment. Included are the award winning 1250/50 to 1050/59.94 digital standards converter and 35mm mm transfer systems, for which the 50 HZ frame rate is particularly suited.

Background

The organisation "Vision 1250" was set up in 1990 to promote the 1250/50 High Definition Television production standard not only in Europe but throughout the world. It has achieved much in its short life but, before describing the work, it is necessary to review a little of the history which led to the creation of the Grouping.

At the CCIR conference held in Dubrovnik in 1986 the Japanese proposal for a single world production standard based on 1125/59.94 was rejected. Although the concept of a unique worldwide production standard was a fine aim, there were obvious impediments, both technical and financial, in the way of 50 Hz. countries accepting a standard completely incompatible with their existing ones.

Following this decision the European Council of Ministers decided to encourage the formation of a special task force to develop a system suitable for Europe and the 75% of the world which uses a 50 Hz. field rate. As a consequence the Eureka 95 project group was formed which included manufacturers, broadcasters and universities among its members. It commenced work in 1986 and created the 1250/50 production standard which is compatible with existing PAL and SEC AM standards and, most importantly, with the 24/25 frame rate of film.

The 1250/50 standard has exactly twice the number of lines of existing 625 line systems, retains the 50 Hz. field rate, but uses the same 16:9 aspect ratio as the Japanese system. This standard ensures compatibility with existing transmissions and hence makes downconversion economical and free of artifacts.

The results of the Eureka 95 work were demonstrated on a number of occasions during the development programme. The success was such that by 1989 it was clear that a new organisation was needed to promote 1250 HDTV and take it from the engineering phase to a programme production stage with the ultimate aim of precipitating a broadcast service.
So the grouping Vision 1250 was created in July 1990 with the brief to promote the 1250/50 standard worldwide, primarily by facilitating program production. This method has a number of advantages for the introduction of a new service and helps all those in the industry who become involved:

1. Programme makers, broadcasters and other sectors of the HDTV industry get training and experience in HDTV production.
2. A programme library is built up forming a basis for the start of a regular service.
3. Demonstrations can be mounted using real programmes.
4. Industry receives feedback on the equipment which it manufactures.

The Grouping now includes some 30 participants from all branches of the television industry including Manufacturers, EBU Member Broadcasters, Independent Film and Television Companies and Transmission Authorities. They co-operate, together with the European Commission, to achieve the aims set out.

The principle of operation is that equipment is provided to the grouping by those members who are manufacturers (notably BTS and Thomson), with support from their national government where appropriate. The units are then made available, along with technical assistance and training, to all the participants for them to make their programmes. The European Commission supports this initiative and funds the technical assistance, maintenance and training as well as giving financial help for demonstrations and promotions.


The Fleet, the Equipment and Its Use

To carry out its brief a substantial amount of equipment had to be made available to Vision 1250 and its members. But in addition the events of 1992 were seen as important opportunities for the development and establishment of the system and were taken into consideration during the setting up phase. Both the Winter and Summer Olympic games were to be held in Europe as well as the Expo'92 in Seville. It was, therefore, decided that a fleet of outside broadcast units and supporting equipment large enough to cover these events had to be provided.

So although the initial amount of equipment acquired by Vision 1250 at the time of its inauguration in July 1990 was limited, the delivery of the main fleet of outside broadcast units made at the beginning of 1992 created the largest HDTV OB fleet in the world.

It comprises some 25 vehicles of all types: 6-camera units equipped for major sport or drama productions, 3-camera, 2-camera and single camera units with VTR's even a single camera "flight case" unit. Full support to these production units is given by editing units, slo-mo units, a Master Control Unit, HD-MAC encoders and decoders and by specialised centrally held fibre-optic link equipment, graphics and film transfer equipment.
The manufacturers retain ownership of the equipment, house and maintain it, and provide training on it for participants' staff thus ensuring the widespread expertise which was invaluable for the Olympic coverage.

With this equipment Vision 1250 can provide for its members the facilities for a complete service from the camera to the receiver. When transmissions are undertaken the services of the Transmission Authorities and EBU Broadcasters who are members are essential. Assistance from Eureka 95 is an additional help when major technical demonstrations are to be mounted.

This equipment which is available to Vision 1250 participants enables them to undertake all types of production and build up expertise. Over 200 hours of programming have been produced to date plus a further 500 hours of Olympic transmissions.

The Olympic Winter Games

The first major event to be covered in 1992 was the Olympic Winter Games, held in the Savoie region of France centred on Albertville. The French Government set up a special organisation for the HDTV coverage, called Savoie 1250. It accepted the responsibility of mounting the largest demonstration to date of the 1250 HDTV system using the brand new Vision 1250 fleet.

It decided to provide a comprehensive programme channel called "Euro HD" which would be on the air for 13 hours per day for the entire 15 days of the games. The channel would provide live and recorded coverage of the games linked in a 2-camera continuity studio in which Olympic news and interviews with notable visitors to the venue could be added. Interspersed with the sporting programmes would be other general entertainment programmes either previously recorded by Vision 1250 members or transferred from film to video. Thus a complete programme channel was provided just like any normal television service.

The output was seen by viewers on 60 HD-MAC receivers specially set up at "Eurosites" across Europe. In addition some 80,000 viewers of D2-MAC transmissions were also able to watch the channel via their regular programme source. Some of these were using 16:9 widescreen receivers, so with the inherent compatibility of the MAC family they were able to view in this format, although without the other enhancements of HDTV.

In all some 350,000 people across Europe were able to view this demonstration of European HDTV which was the most ambitious and successful demonstration of any HDTV system at that time.

The Olympic Summer Games

The games from Barcelona were an even bigger challenge. The Albertville demonstration had established beyond doubt the feasibilty of the system. From Barcelona it was important that the remaining technical problems were overcome and the demonstration made more widespread so that a springboard for commercial transmissions was created.

The coverage was for 14 hours per day, this time entirely of the sporting events which took place throughout the day. 18 events were covered from 16 venues, utilising the entire Vision 1250 fleet with 41 cameras and 35 VTR's operated by crews drawn from broadcasters across Europe.

This time there were some 700 viewing sites with HD-MAC receivers at points throughout Europe at which people could judge for themselves the quality of the transmissions. The results were excellent and proved that the 1250/50 standard was ready for the marketplace.

Other Programms

The Olympics were the major testing grounds for 1250 HDTV but the more usual work of the Vision 1250 participants is in making their own programmes and these have been produced in all genres.

  • Music and Arts
  • Advertisements
  • Drama
  • Documentaries and Features
  • Light Entertainment
  • Sport
  • Events
  • News and Current Affairs


The members of Vision 1250 choose for themselves the programmes they make and for a variety of reasons. Originally productions were frequently made with experimentation as the aim so that the new techniques of HDTV could be explored. This phase has passed and programmes are now made for good commercial reasons; for some there are co-productions and for others the fact that HDTV gives the quality necessary for large screen projection on video or film; always the archive value is a consideration. In building up a library of programmes it is natural to choose those which have a lasting quality and a commercial future.

The music and arts category is a favourite and documentaries about the culture of Europe are also popular. The big state occasions are frequently recorded on HDTV as are the big sporting events. For all these the future-proofing of the programme is seen as important. The 16:9 aspect ratio makes the programme equally suitable for cinema or widescreen television release since this is the ratio common to all existing and proposed HDTV standards. At the same time the quality of the finished product ensures that it will be suitable for the HDTV channels of tomorrow whatever the transmission standard.

To emphasise this universal appeal of the 1250 system two new developments were introduced last year. They have been part of Vision 1250 demonstrations at various exhibitions under the theme of "Bridging Three Worlds" - the worlds being those of prime interest to all programme makers - 1250/50 for 50 Hz. countries, 1050/59.94 for the USA and film for everywhere.

The first development is the new 1250/50 to 1050/59.94 digital standards converter designed by Thomson Laboratories and which has won several prestigious awards. 1050/59.94 is the production standard likely to be adopted in the USA and this converter enables programmes made in 1250 to be transferred to this HDTV standard with no noticeable loss of quality.

The second development is equipment to transfer from 1250 tape to 35mm film, a task made easier by the 25Hz. frame rate of the 1250 system. This process utilises computer techniques and digital VTR's to ensure that the final product is indistinguishable from a production shot on film. Thus the advantages of the electronic medium can be exploited to produce a film entirely suitable for cinema release.

HDTV Production

HDTV is revolutionising programme making. New techniques and operating practices taken from previous film and TV methods bring entirely new creative possibilities. They allow the amalgamation of operating techniques from the two worlds bringing together the advantages of both.

Looking at the equipment it is clear that any limitations caused by it are now being removed as new developments come on to the market. With the advent of the high definition 2.3 million pixel CCD the portable cameras look, weigh and handle just like a 625 line camera. Current generation tubed cameras are large and lack some sensitivity but the next generation of cameras will all contain CCD's thus removing these problems.

Video tape recorders have similarly been developed to overcome current disadvantages of size, weight and performance. The latest BTS recorder, based on their Dl machine and shown in prototype form last summer, is the first HDTV digital cassette recorder. It records the full 30 MHz. baseband signal at 1.3 Gbits to give 30 minutes play time on a Dl cassette. In this mode the original quality is maintained throughout all post production processing. However, with bit reduction the cassette capacity playtime can be increased to 2 hours for the final recorded programme.

The digital VTR is supported by a compatible digital mixer and effects giving the basic tools of a full production system of outstanding quality. Equally video post production can be undertaken for a production shot on 35mm film.
One remaining problem is the size and weight of the VTR where there is no unit currently able to be mounted as a camcorder. For the time being a separate unit connected to the camera with an umbilical is needed. No doubt smaller machines will be forthcoming but will be a few years yet.

There is a comparison to be made now with 35mm film production, not just because the final resolution is comparable but also because of the wider screen shape, said to be more akin to the field of view of the human eye. This camera resolution is not as great as on 35mm film but with digital production techniques the output quality is the same as the original recording. With film the show print does not retain the original resolution, the level of the degradation depending on the processing and printing. The practical result is that HDTV is equal or even superior to film.

There will always be reasons for choosing to shoot in either video or film and the ability to transfer in either direction between the two media with negligible degradation gives a programme producer a freedom which has not previously been enjoyed.

Shooting with 1250 HDTV can be more like film production than conventional video if the circumstances require it. Like film and by comparison with existing video production the lighting has to be better, the sets have to be better and make-up and costumes have to more carefully prepared. The camera sees every detail and the transparent production chain retains it.

This similarity with film can bring with it a change in traditional video crewing, with a team similar to that used with 35mm film cameras supplemented by technicians to optimise the electronics and operate the VTR. The great advantage of multi-camera working is there when required, as well as the all important ability to see what is recorded at the time of the shoot. Overall the cost of production in 1250 HDTV is less than with 35mm film.

Experience shows that the tight shot and rapid cutting are seldom applicable to HDTV; the film technique of keeping the camera still while the action goes by is generally the best. The huge benefit of being able to see the details of the action in a wide shot are immediately apparent and this is a major noticeable difference between conventional and HD television.

The Future

Developments going on in many parts of the world are focussed on HDTV; everywhere there is great interest in its development and potential. In some places it is seen as the most important electronic development currently taking place bringing the possibility of combining entertainment, education and home business. It is almost inconceivable that the transmission of HDTV will not be a regular part of our broadcasting systems within the next few years.

The 1250 system is ready now to meet this requirement. Programmes made on it today can be shown on the big screen with either film or electronic projection. Equally they can be standards converted or downconverted for transmission today in any standard or distributed as film to the world's broadcasters. In addition they can be placed in the archive ready to be shown on the HDTV channels of tomorrow in any transmission standard, analogue or digital, in any part of the world. They are future-proofed in a way that existing video productions are not.

1250 HDTV production has truly arrived as the universal standard for the programme maker.

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