The hardware or software that performs compression is called a codec ( coder / decoder ).

* An audio codec converts between analog and digital representations or performs data compression.

* Electronic encoding transforms a signal into a code optimized for transmission or storage, generally done with a codec.

A codec is a device or computer program capable of encoding or decoding a digital data stream or signal.

Using more than one codec or encoding scheme successively can also degrade quality significantly.

* FFmpeg MPEG-4: Included in the open-source libavcodec codec library, which is used by default for decoding or encoding in many open-source video players, frameworks, editors and encoding tools such as MPlayer, VLC, ffdshow or GStreamer.

MPEG-1 Audio Layer 2 encoding was derived from the MUSICAM ( Masking pattern adapted Universal Subband Integrated Coding And Multiplexing ) audio codec, developed by Centre commun d ' études de télévision et télécommunications ( CCETT ), Philips, and Institut für Rundfunktechnik ( IRT ) in 1989 as part of the EUREKA 147 pan-European inter-governmental research and development initiative for the development of a system for the broadcasting of audio and data to fixed, portable or mobile receivers ( established in 1987 ).

The default MPEG-4 codec used by FFmpeg for encoding has the FourCC of FMP4.

Depending on the complexity of the source material, the codec may switch between lossy and lossless encoding to enhance compression efficiency.

The first version of the codec was WMV 7 Screen, The second and current version, WMV 9 Screen, supports VBR encoding in addition to CBR.

* PSP codec, a program capable of encoding and / or decoding a digital data stream for the H. 264 standard for video compression

Although the ASF container format can technically include any codec, Microsoft's encoding tools ( including Windows Media Encoder and Windows Movie Maker ) produce ASF / WMA / WMV files using the DirectX Media Objects ( DMO ) framework.

Final Cut Pro 7 claims better integration with Apple's other professional applications and improved codec support for editing HD, DV and SD video formats, including encoding presets for devices such as iPod, Apple TV, and Blu-ray discs.

The method of encoding and decoding the audio stream is called a codec, such as the AMBE family of codecs.

* MACE ( codec ), ( Macintosh Audio Compression and Expansion ) an audio encoding system

Such information may be used by the source for adaptive media encoding ( codec ) and detection of transmission faults.

The Animation codec uses run-length encoding for compression, and as such works well for traditional 2-D animation where there are large areas of constant color, or have little change of pixels frame to frame ( like screencast ).

Variable-Rate Multimode Wideband ( VMR-WB ) is a source-controlled variable-rate multimode codec designed for robust encoding / decoding of wideband / narrowband speech.

The exact encoding of the granule position is up to a specific codec.

The DivX 3. 11 Alpha codec allowed a user to control three aspects of the encoding process: the average bitrate, keyframe interval, and whether the codec preserved smoother motion or more detailed images.

The proprietary TwinVQ codec supports constant bit rate encoding at 80, 96, 112, 128, 160 and 192 kbit / s.

It is a hybrid block-transform and wavelet codec capable of using 16 different encoding techniques allowing it to compress any type of video.

It uses a regular 33, 600 bit / s modem for transmission, the H. 263 codec for video encoding and G. 723. 1 for audio.

When estimating quality of a video codec, all the mentioned objective methods may require repeating post-encoding tests in order to determine the encoding parameters that satisfy a required level of visual quality, making them time consuming, complex and impractical for implementation in real commercial applications.

This source coding and decoding is carried out by codec equipment.

For this reason, the quality of the video produced by decoding the results of different encoders that use the same video codec standard can vary dramatically from one encoder implementation to another.

The viewpoint held by Christopher Montgomery, creator of the Ogg format, is that the units of muxed codec data should be a separate abstraction layer from the units of data used by the codec in order to limit the amount of buffering necessary when decoding the contained data.

This update is not expected to result in widespread availability of 1080p60 programming, since most of the existing digital receivers in use would only be capable of decoding the older, less-efficient MPEG-2 codec, and because there is a limited amount of bandwidth for subchannels.

The codec places emphasis on lower decoding requirements over other video codecs with specific optimizations for the different computer game consoles it supports.

The DXVA is used by software video decoders to define a codec-specific pipeline for hardware-accelerated decoding and rendering of the codec.

Upon creation of the file, the codec translates between raw data and the ( compressed ) data format used inside the chunk.

It is important to distinguish between a file format and an audio codec.

* mpc-Musepack or MPC ( formerly known as MPEGplus, MPEG + or MP +) is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160 – 180 kbit / s.

* TTA-The True Audio, real-time lossless audio codec.

Reduction of jitter ( and also end-to-end round-trip delays ) is particularly important when carrying voice traffic, because the conversion of digitized voice into an analogue audio signal is an inherently real-time process, and to do a good job, the decoder ( codec ) that does this needs an evenly spaced ( in time ) stream of data items.

An audio codec converts analog audio signals into digital signals for transmission or storage.

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.

Not all audio codecs can be used for streaming applications, and for such applications a codec designed to stream data effectively will usually be chosen.

In conjunction with an appropriate codec using MPEG or various manufacturers proprietary algorithms, an ISDN BRI can be used to send stereo bi-directional audio coded at 128 kbit / s with 20 Hz – 20 kHz audio bandwidth, although commonly the G. 722 algorithm is used with a single 64 kbit / s B channel to send much lower latency mono audio at the expense of audio quality.

LAME is a free software codec used to encode / compress audio into the lossy MP3 file format.

; Part 3: Audio – compression codec for perceptual coding of audio signals.

The audio layer is most commonly provided by the music-oriented Vorbis format but other options include the human speech compression codec Speex, the lossless audio compression codec FLAC, and OggPCM.

** POTS codec, a digital audio device