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This page leaves the impression that a codec by definition involves compression. A CODEC mediates transitions between the analog and digital realms. The process of digital sampling imposes truncation in the frequency domain above the Nyquist frequency. However, this is a separate issue from compression.

I believe the acronym CODEC was coined to combine the terms COde DECode. A CODEC includes circuitry or software that

A. encodes analog signals as streams of digital information in one direction, and B. decodes streams of digital information to analog signals in the other direction.

The encoding can be a one-to-one mapping of analog to digital representations. There are variations in which a disproportionate number of bits are devoted to low amplitude signals (companding). Companding does involve a certain kind of compression. Other codecs explicitly compress the analog signal when they convert to digital.

This page is very PC-centric. In fact, it appears to ignore the central role of codecs in telephony. This is ironic, since I believe codecs were initially developed for telephone systems, and remain at the core of such systems.

Humev (talk) 20:08, 17 April 2008 (UTC)Reply


You are very close to the proper definitions. Here's some clarification:
  • A codec is a digital process. It's a process in which any information (analog or digital) is encoded into a new digital scheme, and later decoded to replicate the original information to various qualities. There are lossy and lossless codecs.
  • The analog equivalent to a codec is a modem (modulate-demodulate). Again, anything that modulates an analog signal (either a digital or analog source) and is later demodulated to replicated the original source is a modem. For all practical purposes, all modems are lossy to one degree or another.
  • The term companding that you use is actually a mashup of the terms "compress" and "expand" and is a term used in analog noise reduction systems. You really mean to use the term "digital compression" where you use compand.
If this article is going to stay, it needs to be expanded to include at least a list of popular and important audio codecs. Most importantly it needs to describe how the study of Psychoacoustics is what separates audio codecs from any other generic codec. —Preceding unsigned comment added by Babar77 (talkcontribs) 05:15, 31 October 2009 (UTC)Reply

Wiki Education Foundation-supported course assignment

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  This article was the subject of a Wiki Education Foundation-supported course assignment, between 16 May 2019 and 24 August 2019. Further details are available on the course page. Student editor(s): MaxLT16384.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 14:59, 16 January 2022 (UTC)Reply

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