Bitrate is the rate at which bits are transmitted, encoded or processed per unit of time, typically expressed in kilobits or megabits per second. It determines the bandwidth a signal consumes and, for audio and video, the trade-off between file size or transmission cost and perceptual quality. Bitrate is a fundamental parameter in broadcast systems and adaptive streaming, where it is dynamically adjusted, and in video compression, where techniques such as motion estimation influence how efficiently a target bitrate is achieved.