To feature a song in a documentary must you buy the rights?

Yes, to feature a song in a documentary, you generally need to obtain the appropriate rights, which typically include both synchronization rights (to use the song in audiovisual projects) and master rights (to use the original recording). This involves negotiating with the copyright owner, which is often either the songwriter or the record label. Failing to secure these rights can lead to legal issues and potential copyright infringement claims.