Average bit rate refers to the average amount of data transferred per second. This is commonly refered to for digital music or video. An mp3 file, for example, that has an average bit rate of 128 kbit/s transfers, on average, 128,000 bits every second. It can have higher bit rate and lower bit rate parts, and the average bit rate is obtained by dividing the sum of the bit rate of each sample by the number of samples. Bit rate is not the only measure of audio/video quality, as some formats such as wma and Vorbis produce higher sound quality than the standard mp3 format at the same bit rate. MPEG Audio Layer 3, more commonly referred to as MP3, is a popular digital audio encoding and lossy compression format invented and standardized in 1991 by a team of engineers directed by the Fraunhofer Institute in Germany. ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... Digital sampling, PCM sampling, or just sampling is the process of representing a signal waveform as a series of numbers which represent the measurement of the signals amplitude, taken at regular intervals. ... Windows Media Audio (WMA) is a proprietary compressed audio file format developed by Microsoft. ... Vorbis is an open and free audio compression (codec) project from the Xiph. ...
The averagebitrate r.sub.a =B.sub.z.multidot.d.sub.2 /T.sub.2 is monitored with the second leaky bucket unit, and the maximum duration t.sub.max.apprxeq.S.sub.2.multidot.B.sub.z /(r.sub.p -r.sub.a) of a burst with the peak bitrate r.sub.p (peak rate burst) is defined (Niestegge, op.
When the bitrate before a bitrate peak remains at the declared value r.sub.a for the averagebitrate for a longer time, then the counter of the second leaky bucket unit is held roughly at the counter reading 0 due to the decrementation.
However, it is also possible that the clock rate is higher than the cell rate corresponding to the averagebitrate r.sub.a and is lower than the cell rate corresponding to the peak bitrate r.sub.p, particularly lower than the cell rate corresponding to half (r.sub.p /2) of the peak bitrate.
In digital multimedia, bitrate is the number of bits used per unit of time to represent a continuous medium such as audio or video.
While often referred to as "speed", bitrate does not measure distance/time but quantity/time, and thus should be distinguished from the "propagation speed" (which depends on the transmission medium and has the usual physical meaning).
When describing bitrates, binary prefixes are almost never used and SI prefixes are almost always used with the standard, decimal meanings, not the computer-oriented binary meanings.
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