I had thought that such ads only appeared when the video included content that belonged to another company that chose to puts ads on it, like if you made a musi

I had thought that such ads only appeared when the video included content that belonged to another company that chose to puts ads on it, like if you made a music video but used a song owned by a record label. Do they put ads on stuff that's entirely yours? It's mentioned in their FAQ: https://support.google.com/youtube/answer/2475463 https://support.google.com/youtube/answer/2475463