An audio codec is a device or computer program capable of encoding or decoding a digital data stream (a
codec
A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder.
In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or ...
) that encodes or decodes audio.
In software, an audio codec is a computer program implementing an algorithm that
compresses and decompresses digital audio data according to a given audio file or streaming media
audio coding format. The objective of the algorithm is to represent the high-fidelity audio signal with minimum number of bits while retaining quality. This can effectively reduce the storage space and the
bandwidth required for transmission of the stored audio file. Most software codecs are implemented as
libraries which interface to one or more
multimedia players. Most modern audio compression algorithms are based on
modified discrete cosine transform (MDCT) coding and
linear predictive coding (LPC).
In hardware, audio codec refers to a single device that encodes analog audio as digital signals and decodes digital back into analog. In other words, it contains both an
analog-to-digital converter (ADC) and
digital-to-analog converter
In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function.
There are several DAC archi ...
(DAC) running off the same
clock signal
In electronics and especially synchronous digital circuits, a clock signal (historically also known as ''logic beat'') oscillates between a high and a low state and is used like a metronome to coordinate actions of digital circuits.
A clock s ...
. This is used in
sound cards that support both audio in and out, for instance. Hardware audio codecs send and receive digital data using
buses such as
AC-Link,
I²S,
SPI
SPI may refer to:
Organizations
* Indian Protection Service (''Serviço de Proteção ao Índio''), Brazil
* Shotmed Paper Industries, an Egyptian paper manufacturers
* Simulations Publications, Inc., a former US board game publisher
* Sony P ...
,
I²C, etc. Most commonly the digital data is
linear PCM, and this is the only format that most codecs support, but some legacy codecs support other formats such as
G.711 for telephony.
See also
*
Comparison of audio coding formats
*
List of codecs
*
List of open-source codecs
*
Transcoding
Transcoding is the direct digital-to-digital conversion of one encoding to another, such as for video data files, audio files (e.g., MP3, WAV), or character encoding (e.g., UTF-8, ISO/IEC 8859). This is usually done in cases where a target ...
*
Video codec
References
{{DEFAULTSORT:Audio Codec
fr:Codec