Codec

codecsdecoderdecodersdecodingencoding and decodingessencemultimedia codecAudio CodecsCODEC Device and SoftwareCoder-Decoder / Compressor-Decompressor / Compression-Decompression
A codec is a device or computer program for encoding or decoding a digital data stream or signal.wikipedia
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Videotelephony

videoconferencingvideo conferencingvideo chat
Codecs are used in videoconferencing, streaming media, and video editing applications.
The development of advanced video codecs, more powerful CPUs, and high-bandwidth Internet telecommunication services in the late 1990s allowed videophones to provide high quality low-cost colour service between users almost anyplace in the world that the Internet is available.

Encoder

encodingencodersencoded
A codec is a device or computer program for encoding or decoding a digital data stream or signal.
A compressor encodes data (e.g., audio/video/images) into a smaller form (see codec)

Audio codec

audio codecsaudio codingcodec
An audio codec converts analog audio signals into digital signals for transmission or encodes them for storage.
An audio codec is a codec (a device or computer program capable of encoding or decoding a digital data stream) that encodes or decodes audio.

Video codec

codecvideo decodingcodecs
A video codec accomplishes the same task for video signals.
In the context of video compression, "codec" is a concatenation of "encoder" and "decoder"—a device that only compresses is typically called an encoder, and one that only decompresses is a decoder.

DV

miniDVDVCPRO HDDigital Video
For example, a digital video (using a DV codec) of a sports event needs to encode motion well but not necessarily exact colors, while a video of an art exhibit needs to encode color and surface texture well.
In 2003, DV was joined by a successor format HDV, which used the same tape format with a different video codec.

Video editing

editingeditededitor
Codecs are used in videoconferencing, streaming media, and video editing applications.
Content is ingested and recorded natively with the appropriate codec that the video editing software uses to process captured footage.

MP3

.mp3MP3 downloadmp3s
For example, raw uncompressed PCM audio (44.1 kHz, 16 bit stereo, as represented on an audio CD or in a .wav or .aiff file) has long been a standard across multiple platforms, but its transmission over networks is slow and expensive compared with more modern compressed formats, such as Opus and MP3.
The psychoacoustic masking codec was first proposed in 1979, apparently independently, by Manfred R. Schroeder, et al. from Bell Telephone Laboratories, Inc. in Murray Hill, New Jersey, and M. A. Krasner both in the United States.

Latency (audio)

latencydelaylow-latency
Audio codecs for cell phones need to have very low latency between source encoding and playback.
In all systems, latency can be said to consist of three elements: codec delay, playout delay and network delay.

Digital container format

container formatcontainercontainer formats
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. Audio Video Interleave (AVI) is sometimes erroneously described as a codec, but AVI is actually a container format, while a codec is a software or hardware tool that encodes or decodes audio or video into or from some audio or video format.
This may be caused by the program lacking the required decoding algorithm.

Ogg

.oggOGMogg123
There are also other well-known container formats, such as Ogg, ASF, QuickTime, RealMedia, Matroska, and DivX Media Format.
Because the format is free, and its reference implementation is not subject to restrictions associated with copyright, Ogg's various codecs have been incorporated into a number of different free and proprietary media players, both commercial and non-commercial, as well as portable media players and GPS receivers from different manufacturers.

Audio Video Interleave

AVI.aviDV-AVI
Audio Video Interleave (AVI) is sometimes erroneously described as a codec, but AVI is actually a container format, while a codec is a software or hardware tool that encodes or decodes audio or video into or from some audio or video format.
By way of the RIFF format, the audio-visual data contained in the "movi" chunk can be encoded or decoded by software called a codec, which is an abbreviation for (en)coder/decoder.

Advanced Systems Format

ASF.asf.wma
There are also other well-known container formats, such as Ogg, ASF, QuickTime, RealMedia, Matroska, and DivX Media Format.
The format does not specify how (i.e. with which codec) the video or audio should be encoded; it just specifies the structure of the video/audio stream.

List of codecs

video codecsList of multimedia (audio/video) codecsaudio codec
List of codecs
The following is a list of compression formats and related codecs.

List of open-source codecs

freely-licensed data compression technologiesList of open-source audio codecs
List of open source codecs
This is a listing of open-source implementations of media formats—usually called codecs.

Delta modulation

delta PCMDM
Two principal techniques are used in codecs, pulse-code modulation and delta modulation.
Codec

QuickTime

MOV.movMOV (QuickTime)
There are also other well-known container formats, such as Ogg, ASF, QuickTime, RealMedia, Matroska, and DivX Media Format.
The original video codecs included:

Lossy compression

lossylossy data compressioncompressed
Many popular codecs are lossy.
In lossy transform codecs, samples of picture or sound are taken, chopped into small segments, transformed into a new basis space, and quantized. The resulting quantized values are then entropy coded.

Pulse-code modulation

PCMlinear PCMLPCM
For example, raw uncompressed PCM audio (44.1 kHz, 16 bit stereo, as represented on an audio CD or in a .wav or .aiff file) has long been a standard across multiple platforms, but its transmission over networks is slow and expensive compared with more modern compressed formats, such as Opus and MP3. Two principal techniques are used in codecs, pulse-code modulation and delta modulation. In the mid-20th century, a codec was a device that coded analog signals into digital form using pulse-code modulation (PCM).
The device that performs the coding and decoding function in a telephone, or other, circuit is called a codec.

MPEG-4 Part 14

MP4.mp4M4A
Some container formats which are ISO standards are MPEG transport stream, MPEG program stream, MP4 and ISO base media file format.
The widely supported codecs and additional data streams are:

Data compression

compressionvideo compressioncompressed
In contrast, audio codecs for recording or broadcast can use high-latency audio compression techniques to achieve higher fidelity at a lower bit-rate.
Audio compression algorithms are implemented in software as audio codecs.

Computer program

programprogramscomputer programs
A codec is a device or computer program for encoding or decoding a digital data stream or signal.

Decoding methods

decodingsyndromesyndrome decoding
A codec is a device or computer program for encoding or decoding a digital data stream or signal.

Data stream

datadata sourcedata-stream format
A codec is a device or computer program for encoding or decoding a digital data stream or signal.

Signal

signalselectrical signalelectrical signals
A codec is a device or computer program for encoding or decoding a digital data stream or signal.

Portmanteau

portmanteau wordportmanteauscombination
Codec is a portmanteau of coder-decoder.