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In
telecommunications Telecommunication is the transmission of information by various types of technologies over , radio, , or other systems. It has its origin in the desire of humans for communication over a distance greater than that feasible with the , but with ...
and
computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and software. It has sci ...

computing
, bit rate (bitrate or as a variable ''R'') is the number of
bit The bit is a basic unit of information in computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithm of an algorithm (Euclid's algo ...
s that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second unit (symbol: ''bit/s''), often in conjunction with an
SI prefix The International System of Units, known by the international abbreviation SI in all languages and sometimes Pleonasm#Acronyms_and_initialisms, pleonastically as the SI system, is the modern form of the metric system and the world's most wi ...
such as
kilo KILO (94.3 FM, 94.3 KILO) is a radio station broadcasting in Colorado Springs The City of Colorado Springs is the List of cities and towns in Colorado#Home rule municipality, Home Rule Municipality that is the county seat and the List of ci ...
(1 kbit/s = 1,000 bit/s),
mega Mega or MEGA may refer to: Science * mega-, the SI prefix for one million (106, symbol M) * Mega (number), a certain very large integer in Steinhaus–Moser notation * "mega-" a prefix meaning "large" that is List of commonly used taxonomic affi ...
(1 Mbit/s = 1,000 kbit/s),
giga Giga ( or ) is a unit prefixA unit prefix is a specifier or mnemonic that is prepended to units of measurement to indicate multiples or fractions of the units. Units of various order of magnitude, sizes are commonly formed by the use of such prefi ...
(1 Gbit/s = 1,000 Mbit/s) or
tera Tera or TERA may refer to: People * Tera Patrick Tera Patrick (born Linda Ann Hopkins July 25, 1976) is an American former pornographic film actor, pornographic actress and model who was the ''Penthouse (magazine), Penthouse'' Pet of the M ...
(1 Tbit/s = 1,000 Gbit/s). The non-standard abbreviation ''bps'' is often used to replace the standard symbol ''bit/s'', so that, for example, 1 Mbit/s is used to mean one million bits per second. In most computing and digital communication environments, one byte per second (1 B/s) corresponds to 8 bit/s.


Prefixes

When quantifying large or small bit rates,
SI prefix The International System of Units, known by the international abbreviation SI in all languages and sometimes Pleonasm#Acronyms_and_initialisms, pleonastically as the SI system, is the modern form of the metric system and the world's most wi ...
es (also known as
metric prefix A metric prefix is a unit prefixA unit prefix is a specifier or mnemonic that is prepended to units of measurement to indicate multiples or fractions of the units. Units of various order of magnitude, sizes are commonly formed by the use of such ...
es or decimal prefixes) are used, thus:
Binary prefix A binary prefix is a unit prefix for multiples of Units of measurement, units in data processing, data transmission, and digital information, notably the bit and the byte, to indicate multiplication by a Exponentiation, power of 2. The comput ...
es are sometimes used for bit rates. The International Standard (
IEC 80000-13 ISO 80000 or IEC 80000 is an international standard An international standard is a technical standard A technical standard is an established norm (social), norm or requirement for a repeatable technical task which is applied to a common and repeate ...
) specifies different abbreviations for binary and decimal (SI) prefixes (e.g. 1
KiB The byte is a unit of digital information that most commonly consists of eight bit The bit is a basic unit of information in computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It ...
/s = 1024 B/s = 8192 bit/s, and 1
MiB The byte is a unit of digital information that most commonly consists of eight bit The bit is a basic unit of information in computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It ...
/s = 1024 KiB/s).


In data communications


Gross bit rate

In digital communication systems, the
physical layer In the seven-layer OSI model The Open Systems Interconnection model (OSI model) is a that characterises and standardises the communication functions of a or computing system without regard to its underlying internal structure and technolo ...
''gross bitrate'', ''raw bitrate'', ''
data signaling rate In telecommunication Telecommunication is the transmission of information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" and thus defines both its essence and the nature of ...
'', ''gross data transfer rate'' or ''uncoded transmission rate'' (sometimes written as a variable ''R''b or ''f''b) is the total number of physically transferred bits per second over a communication link, including useful data as well as protocol overhead. In case of
serial communication In telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anything of, from, or r ...

serial communication
s, the gross bit rate is related to the bit transmission time T_b as: :R_b = , The gross bit rate is related to the
symbol rate In a digitally modulated In electronics Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. It uses active devices to control elect ...
or modulation rate, which is expressed in
baud In telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anything of, from, or r ...

baud
s or symbols per second. However, the gross bit rate and the baud value are equal ''only'' when there are only two levels per symbol, representing 0 and 1, meaning that each symbol of a
data transmission Data transmission and data reception or, more broadly, data communication or digital communications is the transfer and reception of data Data (; ) are individual facts, statistics, or items of information, often numeric. In a more techn ...

data transmission
system carries exactly one bit of data; for example, this is not the case for modern modulation systems used in
modem A modulator-demodulator, or simply a modem, is a hardware device that converts data from a digital format, intended for communication directly between devices with specialized wiring, into one suitable for a transmission medium such as telep ...

modem
s and LAN equipment. For most
line code In telecommunication, a line code is a pattern of voltage, current, or photons used to represent digital data transmission (telecommunications), transmitted down a transmission line. This repertoire of signals is usually called a constrained cod ...
s and
modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...

modulation
methods: :\text \leq \text More specifically, a line code (or
baseband Baseband is a signal In signal processing Signal processing is an electrical engineering subfield that focuses on analysing, modifying, and synthesizing signals such as audio signal processing, sound, image processing, images, and scien ...

baseband
transmission scheme) representing the data using
pulse-amplitude modulation Pulse-amplitude modulation (PAM), is a form of signal modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signa ...
with 2^N different voltage levels, can transfer N \text. A
digital modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...
method (or passband transmission scheme) using 2^N different symbols, for example 2^N amplitudes, phases or frequencies, can transfer N \text. This results in: :\text = \text \times N An exception from the above is some self-synchronizing line codes, for example
Manchester coding In telecommunication Telecommunication is the transmission of information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" and thus defines both its essence and the nature of ...
and
return-to-zero framed, The binary signal is encoded using rectangular pulse-amplitude modulation with polar return-to-zero code Return-to-zero (RZ or RTZ) describes a line code In telecommunication, a line code is a pattern of voltage, current, or photons use ...
(RTZ) coding, where each bit is represented by two pulses (signal states), resulting in: :\text A theoretical upper bound for the symbol rate in baud, symbols/s or pulses/s for a certain
spectral bandwidth Bandwidth is the difference between the upper and lower Frequency, frequencies in a continuous Frequency band, band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to ''passband bandwidth'' or ...
in hertz is given by the Nyquist law: :\text \leq \text = 2 \times \text In practice this upper bound can only be approached for
line coding In telecommunication, a line code is a pattern of voltage, current, or photons used to represent digital data transmission (telecommunications), transmitted down a transmission line. This repertoire of signals is usually called a constrained code ...
schemes and for so-called
vestigal sideband In radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an elec ...
digital modulation. Most other digital carrier-modulated schemes, for example
ASK Ask is the active verb for a direct question. Ask may also refer to: Places * Ask, Akershus, a village in Gjerdrum municipality, Viken county, Norway * Ask, Buskerud, a village in Ringerike municipality, Viken county, Norway * Ask, Vestland, a v ...
, PSK,
QAM Quadrature amplitude modulation (QAM) is the name of a family of digital modulation In electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electron ...
and
OFDM In telecommunications Telecommunication is the transmission of information by various types of technologies over , radio, , or other systems. It has its origin in the desire of humans for communication over a distance greater than that feas ...
, can be characterized as
double sideband, fm is the maximum modulation frequency In radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz ...
modulation, resulting in the following relation: :\text \leq \text In case of
parallel communication Image:Parallel and Serial Transmission.gif, 300px, Parallel versus serial communication In data transmission, parallel communication is a method of conveying multiple binary digits (bits) simultaneously. It contrasts with serial communication, which ...
, the gross bit rate is given by :\sum_^ \frac where ''n'' is the number of parallel channels, ''Mi'' is the number of symbols or levels of the
modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the ''carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informatio ...

modulation
in the ''i''-th
channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austr ...
, and ''Ti'' is the symbol duration time, expressed in seconds, for the ''i''-th channel.


Information rate

The
physical layer In the seven-layer OSI model The Open Systems Interconnection model (OSI model) is a that characterises and standardises the communication functions of a or computing system without regard to its underlying internal structure and technolo ...
net bitrate,Theodory S. Rappaport
Wireless communications: principles and practice
Prentice Hall PTR, 2002
information rate, useful bit rate, payload rate,V.S. Bagad, I.A. Dhotre
''Data Communication Systems''
Technical Publications, 2009.
net data transfer rate, coded transmission rate, effective data rate or
wire speedIn computer networking, wire speed or wirespeed refers to the hypothetical peak physical layer net bitrate (useful information rate) of a Electrical cable, cable (consisting of fiber-optical wires or copper wires) combined with a certain digital comm ...
(informal language) of a digital
communication channel A communication channel refers either to a physical transmission medium A transmission medium is a system or substance that can mediate the propagation of signal In signal processing Signal processing is an electrical engineering ...
is the capacity excluding the
physical layer In the seven-layer OSI model The Open Systems Interconnection model (OSI model) is a that characterises and standardises the communication functions of a or computing system without regard to its underlying internal structure and technolo ...
protocol overhead, for example time division multiplex (TDM)
framing bits In telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads or el ...
, redundant
forward error correction In computing, telecommunication, information theory, and coding theory, an error correction code, sometimes error correcting code, (ECC) is used for error control, controlling errors in data over unreliable or noisy communication channels. The cen ...
(FEC) codes, equalizer training symbols and other
channel coding In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softw ...
. Error-correcting codes are common especially in wireless communication systems, broadband modem standards and modern copper-based high-speed LANs. The physical layer net bitrate is the datarate measured at a reference point in the interface between the datalink layer and physical layer, and may consequently include data link and higher layer overhead. In modems and wireless systems,
link adaptationLink adaptation, comprising adaptive coding and modulation (ACM) and others (such as Power Control), is a term used in wireless communications to denote the matching of the modulation, Channel coding, coding and other Signalling (telecommunication), ...
(automatic adaption of the data rate and the modulation and/or error coding scheme to the signal quality) is often applied. In that context, the term peak bitrate denotes the net bitrate of the fastest and least robust transmission mode, used for example when the distance is very short between sender and transmitter. Some operating systems and network equipment may detect the "connection speed" (informal language) of a network access technology or communication device, implying the current net bit rate. Note that the term line rate in some textbooks is defined as gross bit rate, in others as net bit rate. The relationship between the gross bit rate and net bit rate is affected by the FEC
code rate In telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anything of, from, or r ...
according to the following. :Net bit rate ≤ Gross bit rate ·
code rate In telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anything of, from, or r ...
The connection speed of a technology that involves forward error correction typically refers to the physical layer ''net bit rate'' in accordance with the above definition. For example, the net bitrate (and thus the "connection speed") of an IEEE 802.11a wireless network is the net bit rate of between 6 and 54 Mbit/s, while the gross bit rate is between 12 and 72 Mbit/s inclusive of error-correcting codes. The net bit rate of ISDN2
Basic Rate Interface Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an Integrated Services Digital Network (ISDN) configuration intended primarily for use in subscriber lines similar to those that have long been used for Plain old telephone service, vo ...
(2 B-channels + 1 D-channel) of 64+64+16 = 144 kbit/s also refers to the payload data rates, while the D channel signalling rate is 16 kbit/s. The net bit rate of the Ethernet 100Base-TX physical layer standard is 100 Mbit/s, while the gross bitrate is 125 Mbit/second, due to the
4B5B In telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anything of, from, or rel ...
(four bit over five bit) encoding. In this case, the gross bit rate is equal to the symbol rate or pulse rate of 125 megabaud, due to the
NRZI In telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anything of, from, or r ...
line code In telecommunication, a line code is a pattern of voltage, current, or photons used to represent digital data transmission (telecommunications), transmitted down a transmission line. This repertoire of signals is usually called a constrained cod ...
. In communications technologies without forward error correction and other physical layer protocol overhead, there is no distinction between gross bit rate and physical layer net bit rate. For example, the net as well as gross bit rate of Ethernet 10Base-T is 10 Mbit/s. Due to the
Manchester Manchester () is the most-populous city and metropolitan borough A metropolitan borough is a type of local government district The districts of England (also known as local authority districts or local government districts to distinguis ...

Manchester
line code, each bit is represented by two pulses, resulting in a pulse rate of 20 megabaud. The "connection speed" of a
V.92 V.92 is an recommendation, titled ''Enhancements to Recommendation V.90'', that establishes a standard allowing near 56 download and 48 upload rates. With V.92 is used for both the upstream and downstream connections; previously 56K modems onl ...
voiceband A voice frequency (VF) or voice band is the range of audio frequencies used for the transmission Transmission may refer to: Science and technology * Power transmissionPower transmission is the movement of energy from its place of generation to ...
modem A modulator-demodulator, or simply a modem, is a hardware device that converts data from a digital format, intended for communication directly between devices with specialized wiring, into one suitable for a transmission medium such as telep ...

modem
typically refers to the gross bit rate, since there is no additional error-correction code. It can be up to 56,000 bit/s downstreams and 48,000 bit/s upstreams. A lower bit rate may be chosen during the connection establishment phase due to adaptive modulationslower but more robust modulation schemes are chosen in case of poor
signal-to-noise ratio Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and ...
. Due to data compression, the actual data transmission rate or throughput (see below) may be higher. The
channel capacity Channel capacity, in electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It em ...
, also known as the Shannon capacity, is a theoretical upper bound for the maximum net bitrate, exclusive of forward error correction coding, that is possible without bit errors for a certain physical analog node-to-node communication link. :net bit rate ≤ channel capacity The channel capacity is proportional to the analog bandwidth in hertz. This proportionality is called
Hartley's law Hartley's is a brand of marmalade Marmalade is a fruit preserve made from the juice and peel of citrus fruits boiled with sugar and water. The well-known version is made from bitter orange, but it is also made from lemons, limes, grapef ...
. Consequently, the net bit rate is sometimes called digital bandwidth capacity in bit/s.


Network throughput

The term ''
throughput In general terms, throughput is the rate of production or the rate at which something is processed. When used in the context of communication networks, such as Ethernet Ethernet () is a family of wired ing technologies commonly used in s ...
'', essentially the same thing as digital bandwidth consumption, denotes the achieved average useful bit rate in a computer network over a logical or physical communication link or through a network node, typically measured at a reference point above the datalink layer. This implies that the throughput often excludes data link layer protocol overhead. The throughput is affected by the traffic load from the data source in question, as well as from other sources sharing the same network resources. See also
measuring network throughput Throughput In general terms, throughput is the rate of production or the rate at which something is processed. When used in the context of communication networks, such as Ethernet or packet radio, throughput or network throughput is the rat ...
.


Goodput (data transfer rate)

''
Goodput In computer networks, goodput (a of and ) is the throughput of a communication; i.e. the number of useful information s delivered by the network to a certain destination per unit of time. The amount of data considered excludes bits as well as ...
'' or data transfer rate refers to the achieved average net bit rate that is delivered to the
application layer An application layer is an abstraction layerIn computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of ...
, exclusive of all protocol overhead, data packets retransmissions, etc. For example, in the case of file transfer, the goodput corresponds to the achieved file transfer rate. The file transfer rate in bit/s can be calculated as the file size (in bytes) divided by the file transfer time (in seconds) and multiplied by eight. As an example, the goodput or data transfer rate of a V.92 voiceband modem is affected by the modem physical layer and data link layer protocols. It is sometimes higher than the physical layer data rate due to
V.44 #REDIRECT List of ITU-T V-series recommendations The ITU-T V-Series Recommendations on Data communication over the telephone network specify the protocols that govern approved modem communication standards and interfaces. ''Note:'' the ''wikt:bis ...
data compression In signal processing Signal processing is an electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electro ...
, and sometimes lower due to bit-errors and automatic repeat request retransmissions. If no data compression is provided by the network equipment or protocols, we have the following relation: :goodput ≤ throughput ≤ maximum throughput ≤ net bit rate for a certain communication path.


Progress trends

These are examples of physical layer net bit rates in proposed communication standard interfaces and devices: For more examples, see list of device bit rates, spectral efficiency comparison table and OFDM system comparison table.


Multimedia

In digital multimedia, bitrate represents the amount of information, or detail, that is stored per unit of time of a recording. The bitrate depends on several factors: * The original material may be sampled at different frequencies. * The samples may use different numbers of bits. * The data may be encoded by different schemes. * The information may be digitally
compressed Compression may refer to: Physical science *Compression (physics), size reduction due to forces *Compression member, a structural element such as a column *Compressibility, susceptibility to compression *Gas compression *Compression ratio, of a co ...
by different algorithms or to different degrees. Generally, choices are made about the above factors in order to achieve the desired trade-off between minimizing the bitrate and maximizing the quality of the material when it is played. If
lossy data compression In information technology, lossy compression or irreversible compression is the class of data encoding methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size fo ...
is used on audio or visual data, differences from the original signal will be introduced; if the compression is substantial, or lossy data is decompressed and recompressed, this may become noticeable in the form of
compression artifact A compression artifact (or artefact) is a noticeable distortion of media (including Image, images, Sound recording, audio, and video) caused by the application of lossy compression. Lossy data compression involves discarding some of the medi ...
s. Whether these affect the perceived quality, and if so how much, depends on the compression scheme, encoder power, the characteristics of the input data, the listener's perceptions, the listener's familiarity with artifacts, and the listening or viewing environment. The bitrates in this section are approximately the ''minimum'' that the ''average'' listener in a typical listening or viewing environment, when using the best available compression, would perceive as not significantly worse than the reference standard:


Encoding bit rate

In digital
multimedia Multimedia is a form of communication that combines different such as , , , , or into a single interactive presentation, in contrast to traditional mass media which featured little to no interaction fr ...

multimedia
, ''bit rate'' refers to the number of bits used per second to represent a continuous medium such as
audio Audio most commonly refers to sound In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion ( ...

audio
or
video Video is an electronic Electronic may refer to: *Electronics Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. It uses active d ...

video
after
source coding In signal processing Signal processing is an electrical engineering subfield that focuses on analysing, modifying, and synthesizing signals such as audio signal processing, sound, image processing, images, and scientific measurements. Signal ...
(data compression). The encoding bit rate of a multimedia file is its size in
bytes The byte is a unit of digital information that most commonly consists of eight bit The bit is a basic unit of information in computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It ...
divided by the playback time of the recording (in seconds), multiplied by eight. For realtime
streaming multimedia Streaming media is multimedia Multimedia is a form of communication that combines different content forms such as text, audio, images, animations, or video into a single presentation, in contrast to traditional mass media, such as printed ...
, the encoding bit rate is the
goodput In computer networks, goodput (a of and ) is the throughput of a communication; i.e. the number of useful information s delivered by the network to a certain destination per unit of time. The amount of data considered excludes bits as well as ...
that is required to avoid interrupt: :encoding bit rate = required goodput The term
average bitrateAverage bitrate (ABR) refers to the average amount of data transferred per unit of time, usually measured per second, commonly for digital music or video. An MP3 file, for example, that has an average bit rate of 128 kbit/s transfers, on average, 12 ...
is used in case of
variable bitrate Variable bitrate (VBR) is a term used in telecommunications Telecommunication is the transmission of information by various types of technologies over , radio, , or other systems. It has its origin in the desire of humans for communication ...
multimedia source coding schemes. In this context, the peak bit rate is the maximum number of bits required for any short-term block of compressed data. A theoretical lower bound for the encoding bit rate for
lossless data compression Lossless compression is a class of data compression In signal processing Signal processing is an electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipme ...
is the source information rate, also known as the ''entropy rate''. :entropy rate ≤ multimedia bit rate


Audio


CD-DA

CD-DA Compact Disc Digital Audio (CDDA or CD-DA), also known as Digital Audio Compact Disc or simply as Audio CD, is the standardization, standard format for audio compact discs. The standard is defined in the ''Red Book'', one of a series of Rainbow ...
, the standard audio CD, is said to have a data rate of 44.1 kHz/16, meaning that the audio data was sampled 44,100 times per second and with a bit depth of 16. CD-DA is also
stereo File:Carsoundstereoshift.png, Time difference in a stereophonic recording of a car going past, 250px Stereophonic sound or, more commonly, stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible per ...
, using a left and right
channel Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austr ...
, so the amount of audio data per second is double that of mono, where only a single channel is used. The bit rate of PCM audio data can be calculated with the following formula: :\text = \text \times \text \times \text For example, the bit rate of a CD-DA recording (44.1 kHz sampling rate, 16 bits per sample and two channels) can be calculated as follows: :44,100 \times 16 \times 2 = 1,411,200\ \text = 1,411.2\ \text The cumulative size of a length of PCM audio data (excluding a file
header Header may refer to: Computers and engineering * Header (computing)In information technology, header refers to supplemental data placed at the beginning of a block of data being stored or transmitted. In data transmission, the data following the h ...
or other
metadata Metadata is "data Data (; ) are individual facts, statistics, or items of information, often numeric. In a more technical sense, data are a set of values of qualitative property, qualitative or quantity, quantitative variable (research), v ...

metadata
) can be calculated using the following formula: :\text = \text \times \text \times \text \times \text. The cumulative size in bytes can be found by dividing the file size in bits by the number of bits in a byte, which is eight: :\text = \frac Therefore, 80 minutes (4,800 seconds) of CD-DA data requires 846,720,000 bytes of storage: :\frac = 846,720,000\ \text \approx 847\ \text


MP3

The
MP3 MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III) is a coding format for digital audio Digital audio is a representation of sound recorded in, or converted into, Digital signal (signal processing), digital form. In digital a ...

MP3
audio format provides
lossy data compression In information technology, lossy compression or irreversible compression is the class of data encoding methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size fo ...
. Audio quality improves with increasing bitrate: * 32 kbit/s generally acceptable only for speech * 96 kbit/s generally used for speech or low-quality streaming * 128 or 160 kbit/s mid-range bitrate quality * 192 kbit/s medium quality bitrate * 256 kbit/s a commonly used high-quality bitrate * 320 kbit/s highest level supported by the
MP3 MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III) is a coding format for digital audio Digital audio is a representation of sound recorded in, or converted into, Digital signal (signal processing), digital form. In digital a ...

MP3
standard


Other audio

* 700 bit/s lowest bitrate open-source speech codec
Codec2 Codec 2 is a low-bitrate speech audio () that is free and . Codec 2 compresses speech using coding, a method specialized for human . Bit rates of 3200 to 450 bit/s have been successfully created. Codec 2 was designed to be used for and othe ...
, but barely recognizable yet, sounds much better at 1.2 kbit/s * 800 bit/s minimum necessary for recognizable speech, using the special-purpose
FS-1015 FIPS 137, originally issued as FED-STD-1015, is a secure telephony speech encoding Speech coding is an application of data compression In signal processing, data compression, source coding, or bit-rate reduction is the process of encoding infor ...
speech codecs Speech is human vocal communication Communication (from Latin Latin (, or , ) is a classical language A classical language is a language A language is a structured system of communication Communication (from Latin ''c ...
* 2.15 kbit/s minimum bitrate available through the open-source
Speex Speex is an audio compression codec specifically tuned for the reproduction of human speech and also a free software Free software (or libre software) is computer software Software is a collection of Instruction (computer science), ins ...
codec * 6 kbit/s minimum bitrate available through the open-source Opus codec * 8 kbit/s
telephone A telephone is a telecommunication Telecommunication is the transmission of information by various types of technologies over wire A wire is a single usually cylindrical A cylinder (from Greek Greek may refer to: Greece Anyt ...

telephone
quality using speech codecs * 32–500 kbit/s lossy audio as used in
Ogg Vorbis Vorbis is a free and open-source software Free and open-source software (FOSS) is software Software is a collection of instructions that tell a computer A computer is a machine that can be programmed to carry out sequences of ari ...
* 256 kbit/s Digital Audio Broadcasting (
DAB DAB, dab, dabs, or dabbing may refer to: Dictionaries * ''Dictionary of American Biography'', published under the auspices of the American Council of Learned Societies * ''Dictionary of Australian Biography'', published since 1949 Places * Dab, ...

DAB
) MP2 bit rate required to achieve a high quality signal *292 kbit/s - Sony
Adaptive Transform Acoustic Coding Adaptive Transform Acoustic Coding (ATRAC) is a family of proprietary audio compression algorithms developed by Sony , commonly known as Sony and stylized as SONY, is a Japanese multinational Multinational may refer to: * Multinational ...
(ATRAC) for use on the * 400 kbit/s–1,411 kbit/s
lossless audio In signal processing Signal processing is an electrical engineering subfield that focuses on analysing, modifying, and synthesizing signals such as audio signal processing, sound, image processing, images, and scientific measurements. Signal ...
as used in formats such as
Free Lossless Audio Codec FLAC (; Free Lossless Audio Codec) is an audio coding format An audio coding format (or sometimes audio compression format) is a content representation format for storage or transmission of digital audio Digital audio is a representatio ...
,
WavPack WavPack is a free and open-source Audio compression (data)#Lossless, lossless audio compression file format, format and application implementing the format. It is unique in the way that it supports hybrid audio compression alongside normal compres ...
, or
Monkey's Audio Monkey's Audio is an algorithm and file format ogg-file: 154 kilobytes. A file format is a standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage ...
to compress CD audio * 1,411.2 kbit/s
Linear PCM Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signal An analog signal is any continuous signal for which the time-varying feature of the signal is a representation of some other time-varying quantity ...
sound format of
CD-DA Compact Disc Digital Audio (CDDA or CD-DA), also known as Digital Audio Compact Disc or simply as Audio CD, is the standardization, standard format for audio compact discs. The standard is defined in the ''Red Book'', one of a series of Rainbow ...
* 5,644.8 kbit/s DSD, which is a trademarked implementation of PDM sound format used on
Super Audio CD Super Audio CD (SACD) is a read-only optical disc In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithm of an algo ...
. * 6.144 Mbit/s E-AC-3 (Dolby Digital Plus), an enhanced coding system based on the AC-3 codec * 9.6 Mbit/s
DVD-Audio DVD-Audio (commonly abbreviated as DVD-A) is a digital format for delivering high-fidelity High fidelity (often shortened to Hi-Fi or HiFi) is the high-quality reproduction of sound. It is important to audiophile An audiophile is a perso ...
, a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio is not intended to be a video delivery format and is not the same as video DVDs containing concert films or music videos. These discs cannot be played on a standard DVD-player without DVD-Audio logo. * 18 Mbit/s advanced lossless audio codec based on
Meridian Lossless Packing 200px, The Advanced Resolution logo Meridian Lossless Packing, also known as Packed PCM (PPCM), is a lossless compression technique for compressing PCM audio data developed by Meridian Audio, Ltd. MLP is the standard lossless compression method f ...
(MLP)


Video

* 16 kbit/s
videophone Videotelephony, sometimes also referred to as video teleconference or videoconferencing, comprises the technologies for the reception and transmission of audio Audio most commonly refers to sound In physics Physics (from grc, φυ ...
quality (minimum necessary for a consumer-acceptable "talking head" picture using various video compression schemes) * 128–384 kbit/s business-oriented
videoconferencing Videotelephony, sometimes also referred to as video teleconference or videoconferencing, comprises the technologies for the reception and transmission of audio signal, audio-video signals by users in different locations, for communication betwee ...
quality using video compression * 400 kbit/s
YouTube YouTube is an American online video sharing and social media platform Social media are interactive technologies that allow the Content creation, creation or information sharing, sharing/exchange of information, ideas, career interests, an ...

YouTube
240p videos (using
H.264 Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 MPEG-4 is a method of defining compression of audio and visual (AV) digital data. It was introduced in late 1998 and designated a standard for a group of audio and video codin ...
) * 750 kbit/s
YouTube YouTube is an American online video sharing and social media platform Social media are interactive technologies that allow the Content creation, creation or information sharing, sharing/exchange of information, ideas, career interests, an ...

YouTube
360p videos (using
H.264 Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 MPEG-4 is a method of defining compression of audio and visual (AV) digital data. It was introduced in late 1998 and designated a standard for a group of audio and video codin ...
) * 1 Mbit/s
YouTube YouTube is an American online video sharing and social media platform Social media are interactive technologies that allow the Content creation, creation or information sharing, sharing/exchange of information, ideas, career interests, an ...

YouTube
480p videos (using
H.264 Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 MPEG-4 is a method of defining compression of audio and visual (AV) digital data. It was introduced in late 1998 and designated a standard for a group of audio and video codin ...
) * 1.15 Mbit/s max
VCD Video CD (abbreviated as VCD, and also known as Compact Disc Digital Video) is a home video Home video is prerecorded media sold or rented for home viewing. The term originates from the VHS VHS (Video Home System) is a standard Sta ...

VCD
quality (using MPEG-1, MPEG1 compression) * 2.5 Mbit/s
YouTube YouTube is an American online video sharing and social media platform Social media are interactive technologies that allow the Content creation, creation or information sharing, sharing/exchange of information, ideas, career interests, an ...

YouTube
720p videos (using
H.264 Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 MPEG-4 is a method of defining compression of audio and visual (AV) digital data. It was introduced in late 1998 and designated a standard for a group of audio and video codin ...
) * 3.5 Mbit/s typ Standard-definition television quality (with bit-rate reduction from MPEG-2 compression) * 3.8 Mbit/s
YouTube YouTube is an American online video sharing and social media platform Social media are interactive technologies that allow the Content creation, creation or information sharing, sharing/exchange of information, ideas, career interests, an ...

YouTube
720p60 (60 Frame rate, FPS) videos (using H.264) * 4.5 Mbit/s
YouTube YouTube is an American online video sharing and social media platform Social media are interactive technologies that allow the Content creation, creation or information sharing, sharing/exchange of information, ideas, career interests, an ...

YouTube
1080p videos (using
H.264 Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 MPEG-4 is a method of defining compression of audio and visual (AV) digital data. It was introduced in late 1998 and designated a standard for a group of audio and video codin ...
) * 6.8 Mbit/s
YouTube YouTube is an American online video sharing and social media platform Social media are interactive technologies that allow the Content creation, creation or information sharing, sharing/exchange of information, ideas, career interests, an ...

YouTube
1080p60 (60 Frame rate, FPS) videos (using H.264) * 9.8 Mbit/s max DVD (using MPEG2 compression) * 8 to 15 Mbit/s typ High-definition television, HDTV quality (with bit-rate reduction from MPEG-4 AVC compression) * 19 Mbit/s approximate HDV 720p (using MPEG2 compression). * 24 Mbit/s max AVCHD (using H.264/MPEG-4 AVC, MPEG4 AVC compression) * 25 Mbit/s approximate HDV 1080i (using MPEG2 compression) * 29.4 Mbit/s max HD DVD * 40 Mbit/s max 1080p Blu-ray Disc (using MPEG2, MPEG4 AVC or VC-1 compression). * 250 Mbit/s max Digital Cinema Package, DCP (using JPEG 2000 compression) * 1.4 Gbit/s 10-bit Chroma subsampling, 4:4:4 Uncompressed 1080p at 24fps


Notes

For technical reasons (hardware/software protocols, overheads, encoding schemes, etc.) the ''actual'' bit rates used by some of the compared-to devices may be significantly higher than what is listed above. For example, telephone circuits using Mu-law algorithm, µlaw or A-law algorithm, A-law companding (pulse code modulation) yield 64 kbit/s.


See also

* Audio bit depth * Average bitrate * Bandwidth (computing) * Baud (symbol rate) * Bit-synchronous operation * Clock rate * Code rate * Constant bitrate * Data-rate units * Data signaling rate * List of interface bit rates * Measuring network throughput * Orders of magnitude (bit rate) * Spectral efficiency * Variable bitrate


References

*


External links


DVD-HQ bit rate calculator
Calculate bit rate for various types of digital video media.
Maximum PC - Do Higher MP3 Bit Rates Pay Off?

Valid8 Data Rate Calculator
{{DEFAULTSORT:Bit Rate Data transmission Temporal rates