INTERACTIVE VIDEO WITH DISCS
The use of a separate code to identify each individual chapter, section and frame on a Laservision or DVD disc (Chapter 20) opens the way to a whole new system of controlling replay picture sequencing by an external computer, which can generate picture and chapter addresses for the disc player’s syscon. The computer program determines the order and rate of change of the images, and is itself under a degree of control by the viewer – hence the term interactive. In an interactive learning programme at any level from primary school to university, the student’s progress will depend on his own abilities, as reflected by his answer (or multiple-answer choice) to the questions presented to him. In a simulation exercise for car drivers, aircraft pilots or railway signalmen the results of their actions are graphically displayed in a situation representing, if necessary, the actual working environment involved. For computer shopping the disc’s picture code number can be passed over a telephone or other feedback route to identify and order goods from a catalogue on video disc.
The master computer links up with the disc player’s syscon via a multi-pin socket on the player, typically to standard RS232 interface specification. The presence of some ‘local intelligence’ in the disc player’s syscon microprocessor is fully used with feedback passing
to the control micro. Extensions of the technique include the possibility of superimposing computer- and disc-sourced pictures, alpha- numerics and graphics for advanced learning programmes, computer- aided design (CAD) and very advanced TV games with detailed and realistic settings.