A video codec is an electronic circuit or software that compresses or decompresses digital video, thus converting raw (uncompressed) digital video to a compressed format or vice-versa. In the context of video compression, "codec" is a concatenation of "encoder" and "decoder"; a device that can only compress is typically called an encoder, and one that can only decompress is known as a decoder.The format of the compressed data usually conforms to a standard video compression specification.