Computers represent a video as a sequence of images (frames) projected at rate that is typically about 30 frames per second. Thus, the size of a 5-second movie = 5 x 30 x number of pixels/frame x number of bits/pixel. When the computer plays these frames at a rate of 30 frames/second, they appear to the human eye as a real continuous movie. Methods (MPEG for example) have been developed so as to compress movies so that they are represented using a fewer number of bits.
