I have never seen any ad on youtube; are they really integrated into the video itself ? from the fact that I never saw any either in the browser (with ublock or

I have never seen any ad on youtube; are they really integrated into the video itself ? from the fact that I never saw any either in the browser (with ublock origin) or through youtube-dl, I kinda just assumed they were distinct videos played by the JS player beforehand - and thus easy to bypass - and not an integral part of the main video file. Anyway, to answer your question: youtube-dl can perform the page fetching and the download in the context of an authenticated user (for example for age-limited videos), so I assume that any advantages associated with a youtube account would most likely work with it.