The overall input-output accuracy of a signal storage or transmission system. Many attributes contribute to fidelity. In an audio recording-playback system, some of the individual attributes are distortion, bandwidth, signal-to-noise ratio, group delay, and loudspeaker dispersion. Most system designers would agree that noise and distortion are of chief importance. The fidelity of video systems depends on many attributes, including optical quality, bandwidth, dynamic range, and phosphor brilliance, whereas that of a motion picture system depends on optical quality, mechanical stability in camera and projector, and the exposure-density relationships of the film.