Codec

: For other uses of codec, see Codec (disambiguation).

Codec is a portmanteau of either Compressor-Decompressor or Coder-Decoder, which describes a device or computer program capable of performing transformations on a Data stream or signal (information theory). Codecs can both put the stream or signal into an encoded form (often for transmission, storage or encryption) and retrieve, or decode that form for viewing or manipulation in a format more appropriate for these operations. Codecs are often used in Video teleconference and streaming media solutions.

The raw encoded form of audio and video data is often called essence, to distinguish it from the metadata information that together make up the information content of the stream and any wrapper data that is then added to aid access to or improve the Robust of the stream.

Most codecs are lossy, in order to get a reasonably small file size. There are lossless codecs as well, but for most purposes the almost imperceptible increase in quality is not worth the considerable increase in data size. The main exception is if the data will undergo more processing in the future, in which case the repeated lossy encoding would damage the eventual quality too much.

Many Multimedia data streams need to contain both audio and video data, and often some form of Metadata (computing) that permits synchronization of the audio and video. Each of these three streams may be handled by different programs, processes, or hardware; but for the multimedia data stream to be useful in stored or transmitted form, they must be Encapsulation together in a container format.

An endec is a similar (but not identical) concept for hardware.

=See also=

*Audio codec, Video codec *Audio signal processing *List of codecs *Digital signal processing *Lossless data compression *Lossy data compression *Multimedia compression *Comparison of container formats *Open source codecs and containers

=External links=

*[http://www.codecpackguide.com/ Codecpackguide.com] *[http://www.fourcc.org/codecs.php List of video codecs from FOURCC] *http://www.free-codecs.com A resource site providing codec news, DivX and XviD-related tools and forum *http://www.xpcodecpack.com XP Codec Pack *http://mirror.edskes.com K-Lite Codec Pack