Always(!) get a licence

Disclaimer

This is NOT legal advice

If you depend on the advice below, and that lands you in legal trouble: sorry, I am not taking responsibility for that. Now you are warned.

TL;DR?

Read here, this answers your question a whole lot better and applies exactly to your situation.

Never assume you may use it...

Assumption, my dear Mitz, is the mother of all fuck-ups.

— Marion, The Adventures of Priscilla, Queen of the Desert

NO, it does not matter that someone else used it.

NO, it does not matter that this has been overused.

NO, you can never make the assumption that you do not need to check if you have a licence.

For example: Happy Birthday To You was not free to use in the European Union until January 1 2017, because that was the time Patty Hill's copyright ran out.

So no, you cannot make any assumption that results in you uttering the words "...so I do not need to check if I may use it", not unless you think that the risk of a Cease & Desist order, along with a forced take-down of your work, is a welcome little bit of excitement in your life.

...unless otherwise specified...

The big exception to the "never" above is if you come across anything like this...

• A Creative Commons License
• The work is in Public Domain
• ...or any other of the Free Licences attached to the work you are interested in.

If you find that the work you want to use is subject to any of these, then you may use it.

...but beware of the details.

A licence does not mean that you can do whatever you want with it, for every kind of purpose, without fulfilling some criteria. Licences are usually quite limited in what you may do with the original work, in what contexts you may do it, and what you may do with your — derived — work afterwards.

You need to check:

Is it a valid licence?

• Does the one that published the licence really have the right to do so?

Is the licence actually about that work which you want to use?

• Just because — for instance — Jules Verne's De la terre à la lune is now under public domain, and I have given you a licence to use my translation of it (had I had one), that does not mean you have the right to use Blackstone Audio's version of it.

  When it comes to music, arrangements, versions, remixes, the lyrics, the tune... everything may be subject to different licences. For example: Madonna in Hung Up got the right to use the a sample of the instrumentals of ABBA's Gimme Gimme Gimme. That does not mean she also automatically had the right to all the instrumentals, the vocals, the lyrics and the arrangement of the original.

Does it allow you to do that which you want to do?

• Are you allowed to publish it on the platforms you want to do so on? May you charge money for it? Are you allowed to transform in the ways you need, such as applying audio filters, edit, re-mix and sample it? Are you allowed to make money from adverts attached to your work that uses the original work? And many, many more questions like that.

  You must check that the licence actually does give you the specific rights you need to do that which you want to do with the work.

What does the licence say you need to do to in order to use the work?

• Must you credit the authors? Do you need to pay royalties? Do you need to extend the licence to your work?

  A licence may oblige you to do certain things in order to use the work. "Creative Commons, Share Alike" for instance says that if you use a specific work that is subject to CC-SA, then you must attach a CC-SA licence to your derivative.

In conclusion

You need to get a license and you need to check and double-check that it applies to what you want to do. The link above tells you what you need to do next to obtain a license for the music you want to use.