36 relations: A-law algorithm, Bit numbering, Clock recovery, Comfort noise, Companding, Comparison of audio coding formats, Decibel, Discontinuous transmission, Encoder, Exponentiation, Fax, Floating-point arithmetic, G.703, H.320, H.323, ITU-T, List of codecs, Logarithmic scale, Lossless compression, Mean opinion score, Modified discrete cosine transform, Narrowband, Packet loss concealment, PSQM, Pulse-code modulation, RTP audio video profile, Signed number representations, Significand, Speech coding, T.38, Telephony, Two's complement, Voice activity detection, Voice over IP, Waveform, Wideband.
An A-law algorithm is a standard companding algorithm, used in European 8-bit PCM digital communications systems to optimize, i.e. modify, the dynamic range of an analog signal for digitizing.
In computing, bit numbering (or sometimes bit endianness) is the convention used to identify the bit positions in a binary number or a container for such a value.
In serial communication of digital data, clock recovery is the process of extracting timing information from a serial data stream to allow the receiving circuit to decode the transmitted symbols.
Comfort noise (or comfort tone) is synthetic background noise used in radio and wireless communications to fill the artificial silence in a transmission resulting from voice activity detection or from the audio clarity of modern digital lines.
In telecommunication and signal processing companding (occasionally called compansion) is a method of mitigating the detrimental effects of a channel with limited dynamic range.
The following tables compare general and technical information for a variety of audio coding formats.
The decibel (symbol: dB) is a unit of measurement used to express the ratio of one value of a physical property to another on a logarithmic scale.
Discontinuous transmission (DTX) is a means by which a mobile telephone is temporarily shut off or muted while the phone lacks a voice input.
An encoder is a device, circuit, transducer, software program, algorithm or person that converts information from one format or code to another, for the purposes of standardization, speed or compression.
Exponentiation is a mathematical operation, written as, involving two numbers, the base and the exponent.
Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer or other output device.
In computing, floating-point arithmetic is arithmetic using formulaic representation of real numbers as an approximation so as to support a trade-off between range and precision.
G.703 is a 2016 ITU-T standard for transmitting voice or data over digital carriers such as T1 and E1.
H.320 is an umbrella recommendation by the ITU-T for running Multimedia (Audio/Video/Data) over ISDN based networks.
H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network.
The ITU Telecommunication Standardization Sector (ITU-T) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU); it coordinates standards for telecommunications.
The following is a list of compression formats and related codecs.
A logarithmic scale is a nonlinear scale used when there is a large range of quantities.
Lossless compression is a class of data compression algorithms that allows the original data to be perfectly reconstructed from the compressed data.
Mean opinion score (MOS) is a measure used in the domain of Quality of Experience and telecommunications engineering, representing overall quality of a stimulus or system.
The modified discrete cosine transform (MDCT) is a lapped transform based on the type-IV discrete cosine transform (DCT-IV), with the additional property of being lapped: it is designed to be performed on consecutive blocks of a larger dataset, where subsequent blocks are overlapped so that the last half of one block coincides with the first half of the next block.
In radio, narrowband describes a channel in which the bandwidth of the message does not significantly exceed the channel's coherence bandwidth.
Packet loss concealment (PLC) is a technique to mask the effects of packet loss in voice over IP (VoIP) communications.
PSQM (Perceptual Speech Quality Measure) is a computational and modeling algorithm defined in ITU Recommendation ITU-T P.861 that objectively evaluates and quantifies voice quality of voice-band (300 – 3400 Hz) speech codecs.
Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals.
The RTP audio/video profile (RTP/AVP) is a profile for Real-time Transport Protocol (RTP) that specifies the technical parameters of audio and video streams.
In computing, signed number representations are required to encode negative numbers in binary number systems.
The significand (also mantissa or coefficient) is part of a number in scientific notation or a floating-point number, consisting of its significant digits.
Speech coding is an application of data compression of digital audio signals containing speech.
T.38 is an ITU recommendation for allowing transmission of fax over IP networks in real time.
Telephony is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties.
Two's complement is a mathematical operation on binary numbers, best known for its role in computing as a method of signed number representation.
Voice activity detection (VAD), also known as speech activity detection or speech detection, is a technique used in speech processing in which the presence or absence of human speech is detected.
Voice over Internet Protocol (also voice over IP, VoIP or IP telephony) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet.
A waveform is the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.
In communications, a system is wideband when the message bandwidth significantly exceeds the coherence bandwidth of the channel.