Comparing analog and digital video

on Monday, February 4, 2008

Digital recordings are theoretically inferior to analog recordings because analog recordings can contain more information. But the truth is that major advances in digital technology mean that this really doesn’t matter. Yes, a digital recording must be made up of specific individual values, but modern recordings have so many discrete values packed so closely together that human eyes and ears can barely tell the difference. In fact, casual observation often reveals that digital recordings actually seem to be of a higher quality than analog recordings. Why?

A major problem with analog recordings is that they are highly susceptible to deterioration. Every time analog data is copied, some of the original, infinitely variable data is lost. This phenomenon, called generational loss, can be observed in that dark, grainy copy of a copy of a copy of a wedding video that was first shot more than 10 years ago. However, digital data doesn’t have this problem. A one is always a one, no matter how many times it is copied, and a zero is always a zero. Likewise, analog recordings are more susceptible to deterioration after every playback, which explains why your 1964-vintage Meet the Beatles LP pops, hisses, and has lost many of its highs and lows over the years. Digital recordings are based on instructions that tell the computer how to create the data; as long as it can read the instructions, it creates the data the same way every time.

Whether you are editing analog or digital material, always work from a copy of the master and keep the master safe. When adding analog material to your project, the fewer generations your recording is from the original, the better. When you consider the implications of generational loss on video editing, you begin to see what a blessing digital video really is. You’re constantly copying, editing, and recopying content as you edit your movie projects —and with digital video, you can edit to your heart’s content, confident that the quality won’t diminish with each new copy you make.