If you're interested in music licensing, there are three main types of rights: Mechanical, Synchronization, and Broadcast. There's also a fourth type of right, print rights, but those aren't as common unless you have a big hit.
Now music licensing is super complicated, but I'm hoping to explain it in simple terms. These types of rights are all a little different, and all require different organizations to collect the money for you. Also note, this is not legal advice, just one musician talking to another about the types of rights we're entitled to with our music.
Now, each type of right leads to a corresponding royalty. Basically, as musicians we trade away part of our right, let's say to synchronize our song with a video, in exchange for money and publicity.
So let's dig into the types of rights for music from the perspective of royalties, cause getting paid is always more fun.
The first type of right is to mechanical royalties. This is basically your right to get paid every time a "copy" of your song is "sold." So this can mean if you sell a physical CD at through Amazon. Or if someone buys an MP3 from iTunes. Or even if someone streams your song on Spotify. Mechanical royalties can add up quickly, but they require a distributor like CD Baby or Distro Kid to actually collect your earnings.
The second type of right is a synchronization right, or synch right. Basically, no one is allowed to use your music in the background of their video without your permission. And you (or your agent) can negotiate whatever rate you want to give up that right.
This is basically how I make hundreds of dollars a month licensing royalty free music. With royalty free music, the "royalty" that is being licensed is the synch royalty, allowing the purchaser the right to synchronize your song wit their videos or audio.
The third type of right is the broadcast or public performance right. Whenever a song is performed publicly, the songwriter is entitled to a payment.
So if your song is broadcast on TV, the TV Network has to pay you. If it's played in a large store, it's still a public performance, and you are entitled to a royalty from the shop. Hell, if a cover band plays your song, theoretically you get paid for that too.
If you're interested in learning how to get started selling royalty free music, check out this video.