A codec is a device or program that compresses data to enable faster transmission and ecompresses received data. In the context of video format files, a codec is a standard used for compressing and decompressing digital media, especially audio and video.
Since audio and video traditionally consume significant bandwidth due to their size, a codec (abbreviation for "coder-decoder" or "compression-decompression") is a device or computer program that encodes or decodes a digital data stream or signal.
Codecs can be viewed as compression technologies with two main components: an encoder to compress the files and a decoder to decompress the files.