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2012-08-12T02:45:58Z

Pranala Menarik

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2012-04-14T13:19:26Z

Pranala Menarik

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2012-04-14T13:18:23Z

Pranala Menarik

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2012-04-14T13:17:25Z

Comparisons

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2009-12-21T03:02:50Z

Onnowpurbo: New page: A '''codec''' is a device or computer program capable of encoding and/or decoding a digital data stream or [[signal (information theory)|signal...

2009-12-21T03:02:25Z

New page: A '''codec''' is a device or computer program capable of encoding and/or decoding a digital data stream or [[signal (information theory)|signal...

New page

A '''codec''' is a device or [[computer program]] capable of [[encoder|encoding]] and/or [[Decoding methods|decoding]] a [[digital]] [[data]] stream or [[signal (information theory)|signal]]. The word ''codec'' is a [[portmanteau]] (a blending of two or more words) of ''''co'''mpressor-'''dec'''ompressor' or, more accurately, ''''co'''der-'''dec'''oder'.

Historically a modem was a contraction of modulator/demodulator (modem was called dataset by telcos) and converted digital data from computers to analog for phone line transmission. On the receiving end the analog was converted back to digital. CODECs did the opposite (convert audio analog to digital and then computer digital sound back to audio). There was no compression involved in CODECs, only coding and decoding.

== Related concepts ==
An [[endec]] (encoder/decoder) is a similar yet different concept mainly used for [[hardware]]. In the mid 20th century, a "'''codec'''" was hardware that coded analog signals into [[Pulse-code modulation]] (PCM) and decoded them back. Late in the century the name came to be applied to a class of software for converting among digital signal formats, and including [[compander]] functions.

A codec encodes a data stream or signal for transmission, storage or [[encryption]], or decodes it for playback or editing. Codecs are used in [[Video teleconference|videoconferencing]] and [[streaming media]] applications. A video camera's [[analog-to-digital converter]] (ADC) converts its analog signals into digital signals, which are then passed through a [[video codec|video compressor]] for digital transmission or storage. A receiving device then runs the signal through a video decompressor, then a [[digital-to-analog converter]] (DAC) for analog display. The term ''codec'' is also used as a generic name for a video conferencing unit.

An [[audio codec|audio compressor]] converts analog audio signals into digital signals for transmission or storage. A receiving device then converts the digital signals back to analog using an audio decompressor, for playback. An example of this are the codecs used in the sound cards of personal computers.

In the popular game series, Metal Gear Solid, the name of your communicator linked to you through your nanomachines is known also known as a codec.

== Compression quality ==
* Lossy codecs: Many of the more popular codecs in the software world are [[lossy]], meaning that they reduce quality by some amount in order to achieve compression, but use some algorithm to create the impression of the data being there. Smaller data sets ease the strain on relatively expensive storage sub-systems such as [[non-volatile memory]] and [[hard disk]], as well as write-once-read-many formats such as [[CD-ROM]], [[DVD]] and [[Blu-ray Disc]].

* Lossless codecs: There are also many [[lossless]] codecs which are typically used for archiving data in a compressed form while retaining all of the information present in the original stream. If preserving the original quality of the stream is more important than eliminating the correspondingly larger data sizes, lossless codecs are preferred. This is especially true if the data is to undergo further processing (for example [[editing]]) in which case the repeated application of processing (encoding and decoding) on lossy codecs will degrade the quality of the resulting data such that it is no longer identifiable (visually, audibly or both). Using more than one codec or encoding scheme successively can also degrade quality significantly. The decreasing cost of storage capacity and network bandwidth has a tendency to reduce the need for lossy codecs for some media.

Codecs are often designed to emphasize certain aspects of the media, or their use, to be encoded. For example, a digital video (using a DV codec) of a sports event, such as [[baseball]] or [[soccer]], needs to encode motion well but not necessarily exact colors, while a video of an art exhibit needs to perform well encoding color and surface texture.

Audio codecs for cell phones need to have very low latency between source encoding and playback; while audio codecs for recording or broadcast can use high-latency [[audio compression (data)|audio compression]] techniques to achieve higher fidelity at a lower bit-rate.

There are thousands of audio and video codecs ranging in cost from free to hundreds of dollars or more. This variety of codecs can create compatibility and obsolescence issues. By contrast, raw uncompressed [[PCM audio]] (44.1 kHz, 16 bit stereo, as represented on an audio CD or in a .wav or .aiff file) is a standard across multiple platforms.

Many [[multimedia]] data streams contain both [[Sound|audio]] and [[video]], and often some metadata that permit synchronization of audio and video. Each of these three streams may be handled by different programs, processes, or hardware; but for the multimedia data streams to be useful in stored or transmitted form, they must be encapsulated together in a [[container format (digital)|container format]].

Lower bit rate codecs allow more users, but they also have more distortion. Beyond the initial increase in distortion, lower bit rate codecs also achieve their lower bit rates by using more complex algorithms that make certain assumptions, such as those about the media and the packet loss rate. Other codecs may not make those same assumptions. When a user with a low bit-rate codec talks to a user with another codec, additional distortion is introduced by each transcoding.

The notion of [[Audio Video Interleave|AVI]] being a codec is incorrect as AVI is a [[container format (digital)|container format]], which many codecs might use (although not to [[ISO standard]]). There are also other well-known containers such as [[Ogg]], [[Advanced Systems Format|ASF]], [[QuickTime]], [[RealMedia]], [[Matroska]], [[DivX]] and containers defined as ISO standards, such as [[MPEG transport stream]], [[MPEG program stream]], [[MP4]] and [[ISO base media file format]].

== See also ==
{{col-begin}}
{{col-2}}
* [[Analog-to-digital converter]]
* [[Audio codec]], [[Video codec]]
* [[Amiga support and maintenance software#Datatypes|Datatypes (Amiga)]]
* [[Audio signal processing]]
* [[Digital signal processing]]
* [[Digital-to-analog converter]]
* [[List of codecs]]
{{col-2}}
* [[Lossless data compression]]
* [[Lossy compression]]
* [[Video coding]]
* [[Open source codecs and containers]]
* [[K-Lite Codec Pack]]
* [[Comparison of container formats]]
{{col-end}}

=== Comparisons ===
* [[Comparison of audio codecs]]
* [[Comparison of video codecs]]

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 * [[Driver dan CODEC untuk Multimedia di Linux]]
 * [[CODEC gstreamer untuk Totem Player]]
 [[Category: Multimedia]]
 [[Category: Linux]]

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 * [[MP3: Instalasi CODEC di Ubuntu]]
 * [[Driver dan CODEC untuk Multimedia di Linux]]
 [[Category: Multimedia]]
 [[Category: Linux]]

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 * [[Multimedia di Linux]]
 * [[MP3: Instalasi CODEC di Ubuntu]]
 [[Category: Multimedia]]
 [[Category: Linux]]

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	* [[Comparison of audio codecs]]		* [[Comparison of audio codecs]]
	* [[Comparison of video codecs]]		* [[Comparison of video codecs]]
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		+	==Pranala Menarik==
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		+	* [[Multimedia di Linux]]
		+	* [[MP3: Instalasi CODEC di Ubuntu]]
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		+	[[Category: Multimedia]]
		+	[[Category: Linux]]

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 == See also ==
 * [[Analog-to-digital converter]]
 * [[Audio codec]], [[Video codec]]
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 * [[Digital-to-analog converter]]
 * [[List of codecs]]
 * [[Lossless data compression]]
 * [[Lossy compression]]
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 * [[K-Lite Codec Pack]]
 * [[Comparison of container formats]]
 === Comparisons ===
 * [[Comparison of audio codecs]]
 * [[Comparison of video codecs]]

CODEC - Revision history

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Onnowpurbo: New page: A '''codec''' is a device or computer program capable of encoding and/or decoding a digital data stream or [[signal (information theory)|signal...