Audio CODEC stands for Coder/Decoder and is a piece of software or hardware used in the process of compressing and decompressing audio into a digital format. It is used to reduce the file size of an audio file while maintaining its fidelity. Audio CODECs are used in encoding and decoding audio signals in a wide range of applications, including audio and video streaming, digital storage media, television broadcasts, cellular telephony, and Internet applications. Audio CODECs can be optimized for signal quality, efficiency, and bit rate, among many other variables. Audio CODECs are often used to ensure that the encoded signal retains its quality when stored on hardware or in a file, and also to convert between different audio formats.