Digital technology has significantly altered the way video is shot, processed, and edited. Standard analog video signals consist of smoothly varying voltage levels that closely mirror the original image. Digital technology, on the other hand, divides a signal into tiny segments of time and measures the quality of the signal within each segment. The segments and their measurements are expressed in binary digits, a complex series of positive (one) and null (zero) values. Binary digits are more easily processed than analog signals and can be copied without the generational loss of quality that occurs with analog signals.

Nowadays, is almost common knowledge to all digital video enthusiasts that digital technology in video often depends on converting analog signals to digital signals. Analog-to-digital converters and digital-to-analog converters accomplish these functions. Graphics may thus be created in the digital domain and integrated into an analog system.

There are four primary digital formats in use. Like analog video recording, digital video can be either component or composite. The D1 recording format, developed by Sony, and Ampex digital format, called DCT, both have separate Y, R-Y, and B-Y portions (component recordings). The D2 and D3 formats, developed respectively by Ampex and Panasonic, feature composite recording. Since the composite signal requires less processing, D2 and D3 are less expensive than D1, but D1 offers superior quality and is ideal for effects and graphics work. If all the editing equipment is kept in the D1 digital domain, hundreds of generations of copying can be performed with little signal degradation.

By: Willis J. Watson

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