An audio file consists of several parts: a header, the audio data, and, optionally, metadata and a wrapper. The header provides information about the data in the file--the sampling rate, number of channels, bit depth, and similar technical specifications. The audio data--the bits representing the samples taken of the audio--make up the bulk of the file. Audio files may also include metadata--text describing the content of the audio file (performer, copyright information, track name, source album, etc.)--and a wrapper, which controls use of the file. Digital rights management and streaming capability, for example, are usually provided by a wrapper.