Dynamic range (abbreviated DR, DNR, or DYR) is the ratio between the largest and smallest measurable values of a specific quantity. It is often used in the context of signals, like sound and light. It is measured either as a ratio or as a base-10 (decibel) or base-2 (doublings, bits or stops) logarithmic value of the ratio between the largest and smallest signal values.
Electronically reproduced audio and video is often processed to fit the original material with a wide dynamic range into a narrower recorded dynamic range for easier storage and reproduction. This process is called dynamic range compression.