Information about Audio Codec
An audio codec is a computer program that compresses/decompresses digital audio data according to a given audio file format or streaming audio format. Most codecs are implemented as libraries which interface to one or more multimedia players, such as XMMS, Winamp or Windows Media Player.
In some contexts, the term "audio codec" can refer to a hardware implementation or sound card. When used in this manner, the phrase audio codec refers to the device encoding an analog audio signal to a digital audio signal, or decoding an analog audio signal from a digital audio signal. Thus, in such a context, the term is actually referring to a combined audio AD/DA converter. One example is Intel Corporation's AC'97 standard, which comprises a digital controller paired with an analog unit.
The use of digital samples to represent audio data is subject to some fundamental limitations regardless of the codec. The bandwidth is limited by the Nyquist–Shannon sampling theorem so that the highest audio frequency that can be reconstructed from the digital data is half the sample frequency. The dynamic range is limited by quantization noise which is half the weight of the least significant bit of each sample. A perfect linear codec (which is considered lossless) will suffer these types of signal degradation but nothing else. Codecs which are considered lossy will suffer the same fundamental types of signal degradation plus some additional lost signal which varies from codec to codec.
(See for formats and for codecs)
A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. The word codec may be a combination of any of the following: 'Compressor-Dec
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In some contexts, the term "audio codec" can refer to a hardware implementation or sound card. When used in this manner, the phrase audio codec refers to the device encoding an analog audio signal to a digital audio signal, or decoding an analog audio signal from a digital audio signal. Thus, in such a context, the term is actually referring to a combined audio AD/DA converter. One example is Intel Corporation's AC'97 standard, which comprises a digital controller paired with an analog unit.
The use of digital samples to represent audio data is subject to some fundamental limitations regardless of the codec. The bandwidth is limited by the Nyquist–Shannon sampling theorem so that the highest audio frequency that can be reconstructed from the digital data is half the sample frequency. The dynamic range is limited by quantization noise which is half the weight of the least significant bit of each sample. A perfect linear codec (which is considered lossless) will suffer these types of signal degradation but nothing else. Codecs which are considered lossy will suffer the same fundamental types of signal degradation plus some additional lost signal which varies from codec to codec.
See also
- audio data compression
- codec
- digital signal processing
- list of codecs
- Open source codecs and containers
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A computer program is one or more instructions that are intended for execution by a computer. Specifically, it is a symbol or combination of symbols forming an algorithm that may or may not terminate, and that algorithm is written in a programming language.
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data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an un-encoded representation would use through use of specific encoding schemes.
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Digital audio uses digital signals for sound reproduction. This includes analog-to-digital conversion, digital-to-analog conversion, storage, and transmission.
Digital audio has emerged because of its usefulness in the recording, manipulation, mass-production, and
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Digital audio has emerged because of its usefulness in the recording, manipulation, mass-production, and
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An audio file format is a container format for storing audio data on a computer system.
The general approach towards storing digital audio is to sample the audio voltage (which on playback, would correspond to a certain position of the membrane in a speaker) of the
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The general approach towards storing digital audio is to sample the audio voltage (which on playback, would correspond to a certain position of the membrane in a speaker) of the
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This article has been tagged since October 2007.
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Please help [ improve this article] by introducing appropriate of additional sources. ()
This article has been tagged since October 2007.
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Media Player was a media player originally included in Windows 3.0 with Multimedia Extensions and a slightly updated version was included with Windows 3.1x. Media Player received a facelift with Video for Windows, with an OLE2 version provided with the runtime software.
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Maintainer: XMMS Team
OS: Unix-like
Use: Audio player
License: GPL
Website: www.xmms.org The X Multimedia System (XMMS
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OS: Unix-like
Use: Audio player
License: GPL
Website: www.xmms.org The X Multimedia System (XMMS
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Maintainer: Nullsoft
OS: Microsoft Windows
Linux (3.0 alpha 1 only)[1]
Use: Media player
License: Proprietary freeware, shareware
Website: [1]
Winamp
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OS: Microsoft Windows
Linux (3.0 alpha 1 only)[1]
Use: Media player
License: Proprietary freeware, shareware
Website: [1]
Winamp
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Windows Media Player (WMP) is a digital media player and media library application developed by Microsoft that is used for playing audio, video and viewing images on personal computers running the Microsoft Windows operating system, as well as on Pocket PC and Windows
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Sound Card
A Sound Blaster Live! Value card, a typical present-day PCI sound card
Connects to:
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A Sound Blaster Live! Value card, a typical present-day PCI sound card
Connects to:
- Motherboard via one of
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Intel Corporation
Public (NASDAQ: INTC , SEHK: 4335 )
Founded 1968 1
Headquarters Santa Clara, California
United States
Key people Paul S.
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Public (NASDAQ: INTC , SEHK: 4335 )
Founded 1968 1
Headquarters Santa Clara, California
United States
Key people Paul S.
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AC'97 (short for Audio Codec '97) is Intel Corporation's Audio "Codec" standard developed by the Intel Architecture Labs in 1997, and used mainly in motherboards, modems, and sound cards.
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Bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a filter, a communication channel, or a signal spectrum, and is typically measured in hertz.
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FreQuency is a music video game developed by Harmonix and published by SCEI. It was released in November 2001. A sequel, titled Amplitude was released in 2003.
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Dynamic range is a term used frequently in numerous fields to describe the ratio between the smallest and largest possible values of a changeable quantity, such as in sound and light.
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quantization error.
Many physical quantities are actually quantized by physical entities. Examples of fields where this limitation applies include electronics (due to electrons), optics (due to photons), biology (due to DNA), and chemistry (due to molecules).
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Many physical quantities are actually quantized by physical entities. Examples of fields where this limitation applies include electronics (due to electrons), optics (due to photons), biology (due to DNA), and chemistry (due to molecules).
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Audio compression is a form of data compression designed to reduce the size of audio files. Audio compression algorithms are implemented in computer software as audio codecs.
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- codec, see Codec (disambiguation).
A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. The word codec may be a combination of any of the following: 'Compressor-Dec
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Digital signal processing ('DSP') is the study of signals in a digital representation and the processing methods of these signals. DSP and analog signal processing are subfields of signal processing.
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Audio Video Interleave (AVI) is not a codec, rather it is a container format, like Matroska, that many video codecs can use.
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See also
- Open source codecs and containers
- Comparison of video codecs
- Comparison of audio codecs
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Ogg - Created by the Xiph Foundation. See also OGM, which is a fork of Ogg. Matroska - .mkv & .mka files. NUT - Developed by the MPlayer team.
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data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an un-encoded representation would use through use of specific encoding schemes.
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Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. This can be contrasted to lossy data compression, which does not allow the exact original data to be reconstructed from the
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Information theory is a branch of applied mathematics and engineering involving the quantification of information to find fundamental limits on compressing and reliably communicating data.
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Shannon entropy or information entropy is a measure of the uncertainty associated with a random variable.
Shannon entropy quantifies the information contained in a piece of data: it is the minimum average message length, in bits (if using base-2 logarithms), that must
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Shannon entropy quantifies the information contained in a piece of data: it is the minimum average message length, in bits (if using base-2 logarithms), that must
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In computer science, the Kolmogorov complexity (also known as descriptive complexity, Kolmogorov-Chaitin complexity, stochastic complexity, algorithmic entropy, or program-size complexity
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Redundancy in information theory is the number of bits used to transmit a message minus the number of bits of actual information in the message. Informally, it is the amount of wasted "space" used to transmit certain data.
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In information theory an entropy encoding is a lossless data compression scheme that is independent of the media’s specific characteristics.
One of the main types of entropy coding assigns codes to symbols so as to match code lengths with the probabilities of the
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One of the main types of entropy coding assigns codes to symbols so as to match code lengths with the probabilities of the
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Huffman coding is an entropy encoding algorithm used for lossless data compression. The term refers to the use of a variable-length code table for encoding a source symbol (such as a character in a file) where the variable-length code table has been derived in a particular way
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Adaptive Huffman coding (also called Dynamic Huffman coding) is an adaptive coding technique based on Huffman coding, building the code as the symbols are being transmitted, having no initial knowledge of source distribution, that allows one-pass encoding and adaptation to
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