Bit rate measures the speed that information can be transferred between two locations. The standard unit of this rate is “bits per second,” but this is often prefixed with kilo- or mega- to recognize the high rates found in modern digital technology. Communications technology measures speed by bit rate, especially on the Internet, where the rate of transfer provides an insight into how quickly data can be downloaded. This measurement is also commonly used to describe audio and video; higher rates signify greater quality.
At its most basic level, bit rate describes how many bits are transferred between two different locations per second. The higher the rate, the faster information can be communicated between them. For this reason, bit rate can be especially important for communications technology such as broadband because it defines how quickly a user can download or upload information.
The standard unit of bit rate is “bits per second” (bps). This measurement is usually far too small to be practical in modern communications technology, however, because millions of bits can be communicated every second. To get around this problem, the unit is often prefixed with another letter denoting its size. Kbps, for example, stands for kilobits per second or thousand bits per second. Megabits per second is written as Mbps and stands for million bits per second.
Bit rate is an important measurement in a variety of different computing fields. Broadband, for example, is often quoted as having a certain number of Mbps, with speeds of about 2 Mpbs being common. Fiber optic broadband, which is much faster, can offer speeds of up to 5 Mbps. This measurement also describes the speed of mobile connectivity such as 3G and Bluetooth.
Audio and video quality is commonly written in terms of bit rate, with higher rates signifying greater picture or sound quality. In multimedia, this measurement is a quick way of showing how much information is stored within each second of recording, which is why higher rates result in increased quality. The bit rate can depend on a variety of factors including whether the information has been compressed.
The standard bit rate for audio is between 100 and 160 kbps, while the highest quality recordings may go up to 320 kbps. Video rates can be considerably higher than this, with Blu-ray discs capable of up to 40 Mbps. Standard DVDs only have a rate of about 9 Mbps, which is why there is such a noticeable difference in quality.