Video, an Audiovisual Medium

6 Video and Computer

In the 1980s, the development of video stood at the threshold of analog and digital devices. Characteristic of this period is the use of keyers for the control and arrangement of multilayered image segments whose textures can be cut out, — that is, keyed in and out. As early as the beginning of the 1970s, there were keyers with digital components which allowed the variable mixing of different video sources (foreground-background relationships) in a single video output.[8] The first testing of digital computers for image processing began in the late 1970s. In 1978, the Digital Image Articulator constructed by Jeffrey Schier and Woody Vasulka allowed one to change the format, scale, resolution, and size of the image field in individual programming steps as well as the determination of the color values for individual image positions in real time. The device, which is designed for internal image generation on an algorithmic basis, processes external image sources that are transformed into data by means of an analog-digital converter. At the digital processing level, the electronic signal is sampled and construed in discrete units.

Overall, the methods and concepts of analog video processing were continued with increased complexity with the digital programmability and greater storage capacity of the digital computer. In the 1980s this was achieved above all by modularly combining analog and digital applications.

Video may have initially been an analog medium based on modular plug connections; however, due to its analog processuality it can be considered a precursor of the digital programming function in the computer. Video devices that work with electric variables on the basis of plug and switch connections and that arrange sequences can be regarded as analog computers.[9] The difference between analog devices and digital devices consists in the fact that the former is plugged and the latter is programmed.

One example is George Brown’s Variable Clock (1972), an impulse generator that represents a programmable instrument.