Codec is a technical name for "compression/decompression". It is computer programs that can both shrinks' large movie files, and makes them playable on your computer. Codec programs are required for your media player to play your downloaded music and movies. With codec, downloading of video and music are five times faster than before. Due to the fact that video and music files are large, they become difficult to transfer across the Internet quickly. Codecs were built to encode ("shrink") a signal for transmission and then decode it for viewing or editing, it help speed up downloads. In telephone companies, they use codecs to convert binary signals transmitted on their digital networks to analog signals converted on their analog networks. Other applications include; videoconferencing, streaming media and video editing applications.