The first thing to clarify is that there is a difference between the sound recording, which is the mastered track, and the musical composition. The mastered track incorporates the musical composition. However the properties that make up the finished mastered track are treated separately for copyright purposes i.e. the songwriter and the singer each have their own rights. The singer owns the copyright in the sound recording, and the songwriter owns the copyright in the musical composition. Some artists are the authors of both the musical composition and the sound recording, and so are entitled to the rights that are attached to both properties. Every time a mastered track is copied both rights holders are entitled to royalties. The licence for copying of the mastered sound recording is called a mechanical licence.