Audio files are files that store digital audio data on a computer system. The bit layout of the audio data (excluding metadata) is called the audio coding format and can be uncompressed (e.g AIFF & WAV), or compressed to reduce the file size (e.g FLAC), often using lossy compression (e.g MP3). The data can be a raw bitstream in an audio coding format, but it is usually embedded in a container format or an audio data format with defined storage layer.