What is High-Definition Video?

HD video can be thought of as the third generation of video technology. Analog video was the first, offering instantaneous playback of recorded images. Next came digital video, which emulated the analog video process in the form of digital data, opening up the possibilities of non-linear editing. HD video represents another paradigm shift. Not only is HD "larger" than older forms of video (in resolution, screen size, digital and file size), but as we will see, it is uniquely "flexible," with more technical variables.

The term "HD" is often used as a meaningless marketing buzzword. Look around and you"ll find "HD" sunglasses, "HD" lightbulbs, moisturizer, acrylic paint. However, the term does have a concrete, objective definition. HD is digital video with a resolution of at least 1280 x 720 pixels.

HD is a broad category with a minimum quantitative requirement. Just as a person must have at least one million dollars to be called a millionaire, video must meet this minimum number of pixels to qualify for HD status. Therefore, the term can apply to the full spectrum of digital video contexts, from IMAX 3D to YouTube. This guide will focus on the forms of HD video likely to be encountered in museums, galleries and classrooms.

What do we mean, specifically, when we say HD video is the "third generation" of video? The concept best applies to non-broadcast video, which is what is most often found in museum collections and small archives. The first generation of non-broadcast or "personal" video began in the late 1960s, when the first portable video systems arrived on the American market. These "portapaks" (not a brand name) were self-contained, battery-powered, reel-to-reel videorecorders using analog tape; throughout the 1980s, they were replaced by smaller cameras that recorded to videocassettes, most popularly Betamax, VHS and Hi8. The era of analog video lasted through the mid-1990s, when digital standard-definition video became available to consumers in formats like DV, which allowed users to record on tape and edit on a computer. Today, the new HD formats are replacing DV, Digital Betacam and other standard-definition digital formats.

The leap from standard-definition (SD) video to HD is as significant as the analog-to-digital transition. In fact, we can group the first two generations together as "SD," since both are based on the same legal television standards (NTSC in the North America and Japan, and PAL throughout much of the rest of the world). SD digital video translated the standards for analog recording--NTSC--into digital form. By contrast, HD video has a purely digital foundation and does not rely on the NTSC or PAL.

Note: The rest of this guide will pertain specifically to video in North America, describing contemporary HD video as an outgrowth of the former NTSC television standard. It will not cover the PAL or SECAM standards. Also, from this point on, "SD" will refer to analog video as well as standard-definition digital video.