What is a Codec?

There are many variants of codecs and they all perform this "encode" and "decode" function with some form of compression or reduction in size of source video and/or audio.

A codec encodes a data stream or signal for transmission, storage or encryption, or decodes it for playback or editing. Codecs are used in videoconferencing, streaming media and video editing applications. A video cameras analog-to-digital converter (ADC) converts its analog signals into digital signals, which are then passed through a 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 videoconferencing unit.

Video codecs commonly used in video conferencing applications are: H.264, H.263+, H.261. Common audio codecs are: G.711, G.728, Siren Audio. Common audio codecs are: G.711, G.728, Siren Audio.