In the early days of broadcast television, all programs were broadcast live. The only means of archiving a television program was by using a process called kinescope. Kinescoping was the process of focusing a 16mm motion picture camera at a television monitor and photographing the images. The shutter was adjusted to accommodate 30 fps of video, though the film ran at 24 fps.
Starting in the mid-1950s, when videotape recording was invented, programs were taped live and then played back for broadcast at a different time. These programs were played in real time without the benefit of instant replays or freeze frames. When videotape began to be used for editing purposes, it became critical to identify specific frames of video, ...