Youtube deleted the sound recording 7-hour conference because of the music that sounded a break
It's no secret that YouTube videos are downloaded checks for possible copyright infringement Audio dubbing recording. Normal video, which shows, for example, build a blowtorch with some music, can be removed from service, as the music is copyrighted.
It is clear that manually check all the videos, no one will, everything works automatically. But algorithms checks are sometimes interesting results. For example, a couple of years ago, a user YouTube could not put the video shooting wildlife to the service. Algorithms service recognized bird trills as copyrighted material, and in the video required to put a link to the website owner's rights to the sound. Even the appeal did not get anywhere.