The Service


In Commerce, in Industry, in Institutions — whatever the applications — interactive video is only as good as its software.

That is why THORN EMI VIDEODISC is making available a comprehensive service you can draw on, ranging from the development of the initial idea right through to the delivery of the system — and beyond.


Consideration of a videodisc system may involve major investment decisions by a company. Careful planning of both software and hardware requirements is needed.

THORN EMI Videodisc can provide it full consultancy and advisory’ service to translate these needs into decisions, and then actions.

Programme Design

THORN EMI has the videodisc design experience. This experience is available to your team to assist in the development and design of your interactive programmes. Help can be given with the new conceptual approach, flow-charting and with technical requirements.


Our Software Advice Centre is available to work with your own in-house video or film unit, or with your chosen production and facility companies, keeping a close liaison with both creative and technical teams.

Post Production

We will monitor progress during this important phase and ensure that the programme design, programme material and videodisc technical capabilities are correctly integrated.


We will supervise this final post-production stage where the video and audio information is committed to 1″C Format video tape.

Our associate company THORN EMI Video Facilities is able to quote favourable rates for this stage of the work. They are one of London’s leading video facilities companies and have gained unique experience in videodisc pre-mastering.

Making the Disc

Our own factory at Swindon is dedicated to the mastering and pressing of VHD videodiscs for the commercial, industrial and institutional markets.


The VHD videodisc players will be delivered and installed by trained THORN EMI personnel. Demonstrations will be given to familiarise staff with the system.

The Service Continues

Apart from maintenance and warranty arrangements, we offer to monitor — with the user — the effectiveness of this new form of communication and will advise on future applications.


Disc Manufacturing

JIM JOHNSTON – VHD Manager, Swindon


The THORN EMI Videodisc factory at Swindon was purpose built to master and press VHD Videodiscs.

This is where the new technology takes over. Videodisc manufacture involves a blend of old and new technologies — and from the old demands higher standards than ever before.

The factory itself is a building within a building. The mastering and manufacturing processes all take place in an environmentally controlled series of clean rooms. The standard demanded throughout is not less than Class 10,000 and in the most sensitive areas is better than Class 100 — fewer than 100 microscopic particles in every cubic foot of air.


Programme material from virtually any source can be considered for videodisc. The final stage of post-production is to edit all the material onto a broadcast standard 1″ C format videotape in the order in which it is required on the final disc.

All audio must also be recorded in the correct places on the correct tracks.

During this process the exact location of each of the special VHD control signals is determined. These signals identify chapters, time code, page addresses, autostops, and automatic audio switching.

The finished videotape is called the PREMASTER TAPE.

Videodisc Mastering

In the VHD videodisc plant the Glass Master is prepared. This is an optically perfect glass disc which has been cleaned, coated with a photo-resist solution and baked to harden the coating. After careful checking it is placed in the Laser Cutter.

The Premaster Tape is played back to the Laser Cutter which encodes the signals into a form which drives the powerful laser. A complex series of optics condense and shape the laser beam and focus it onto the Glass Master to create the latent image of the microscopic pits in the surface.

The Glass Master is then developed, checked for flaws and after thorough cleaning is ready for the next stage in the process.