In past, I made a video to upload in my YouTube Channel, I got penalized because of audio I had used in the video. The audio was property of some music brand. I received a mail form YouTube to immediately remove that video. It was not longer than 2 days I uploaded that video and I got a mail. So I removed that video immediately, and flushed it.
Reason was simple, I used an audio which is already claimed by a music brand on YouTube that is anyone’s else property and cannot be shared or used without owners permission.
Read: Do you know recently YouTube has changed channel URL settings.
So as to make this problem resolved, YouTube itself has added a library of royalty free audio. This library of free music is updated and loaded with lot of free music.
Library is created and music files are distributed in various categories like, Genre, Mood, Instrumental, Duration. There is also most featured audio which is liked by most users, and also on marking as favorite, it will add up under your favorites tab.
There are also many online websites like Royalty Free Music, Royalty Free Music Production, etc but they will charge you for downloading those audios. So best place to download and add music is YouTube library.
Note and Conclusion:
YouTube may take down your video if it found copyrighted audio. So it is better to use Royalty free audios as background music.