Introduction
The number of bits that are conveyed or processed per unit of time. Bit rate is measured in bits per second (symbol: bit/s). For example, a transmission or processing task that handles one byte per second (1 B/s) has a bit rate of 8 bit/s. The non-standard abbreviation "bps" is often used to replace the standard symbol.
Source: Wikipedia contributors, "Bit rate," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Bit_rate&oldid=817574715 (accessed January 21, 2018).
Calculating bit rate
Bit rate can be calculated with the following formula: bit rate = sample rate x bit depth x number of channels
For example, CD-DA audio streams are two channels of 16-bit audio with a sample rate of 44.1 kHz. The bit rate of CD-DA audio can be calculated as: 2 x 16 x 44,100 = 1,411,200 bit/s
Bit rate measurements are usually represented with SI prefixes (base 10), such as kilo, mega, giga, and tera. 1,411,200 bit/s can be represented as 1.4 Mbit/s or 1,411.2 kbit/s. With non-standard abbreviations, this would be 1.4 Mbps or 1411.2 kbps.
Bit rate indicates the amount of digital storage required to store one second of music. The total size in bits of a CD-DA stream can be calculated as: 2 x 16 x 44,100 x length of time in seconds
The total number of bytes can be calculated by dividing the size in bits by 8 (the number of bits in one byte): size in bytes = size in bits/8
Example: calculate storage requirements for 30 minutes of CD-DA data
CD-DA with the following characteristics:
- 2 channels
- 16 bit
- 44.1 kHz sample rate
- 30 minutes (1,800 seconds)
2 x 16 x 44,100 x 1,800 = 2,540,160,000 bits of storage
2,540,160,000 bits divided by 8 = 317,520,000 bytes (317.52 MB)