Analog and digital recording

• Not synonymous with linear and non-linear
• Analog recording produces a continuous electrical signal with a shape that is defined by the video wave it is representing
• A digital video camera records the video information as a series of discrete on and off pulses in the form of 0s and 1s
• Digital video generally is of superior quality and is not subject to degradation as a result of copying

In short you can record video (and audio for that matter) in one of two ways: either as a continuous streaming signal, or as a sequences of measurements in digital format. VHS and cassettes are analog formats, whereas CD and DVD are digital formats.