High-pitched ringing/buzzing when playing videos

I just noticed this happening earlier today. It is kind of hard to describe, but I will do my best to try.

When playing videos on Netflix, Youtube, VLC Player, etc. I get a distinct high pitched buzzing sound as an undertone to the video. The regular audio is still playing, but I clearly hear this ringing. I'm very confused about what could be causing it, so I'm asking the community.

Thanks in advance.