bit rate


(n.) The speed at which data is moved, expressed in bits per second (bps). If a file size is known and the data transfer rate at which it streams is known, it is possible to determine the duration of time that an audio or video file will play, based on its size. To calculate the duration of playback for an existing MPEG file of known size and bit rate, divide the file size by the data transfer rate. A 5-MB (megabyte) file equals 5000 KB (kilobytes). If the data transfer rate is 150 KBps, the 5000-KB file contains 33 seconds of running video (5000 divided by 150). A bit rate expressed in megabits per second (Mbps) is a factor of 8.192 times the same rate expressed in kilobytes per second (KBps), because a kilobyte is equal to 1024 bits times 8.