A mechanical license grants the licensee permission from the owner(s) of a copyrighted work to reproduce and distribute a musical work in a physical or digital object such as CD, vinyl, digital download and interactive stream.
A mechanical license is required if you are releasing a cover of a work. If a work is protected by copyright law, reproducing and distributing the work without a mechanical license is copyright infringement.
Digital audio mechanical royalties are owed when works are copied in accordance with the mechanical license. Typically, the user or licensee must account to and pay the copyright owner or an authorized agent.