Downloading video from YouTube
1. Copy the URL of the YouTube video.
2. Open VLC, then:
PC: Go to Media menu -> Open Network Stream...
Mac: Go to File menu -> Open Network...
3. Paste the URL. It'll start playing, pause it, then:
PC: Go to Tools menu -> Codec Information
Mac: Go to Window menu -> Media Information
4. Select alllllll the text in the "Location" bar at the bottom and copy it. You may need to double-click in there and you might not see your cursor. Use ctrl-A on a PC or cmd-A on a Mac to select all, then copy.
Mac:
PC:
5. Open a browser tab and paste the location.
6. Select "Save as" and give it a name.
It can then be played offline in VLC or any other mp4 player.
Source:
https://www.wikihow.com/Download-YouTube-Videos#Using-VLC-Player-on-a-Computer_sub