1. Right click on a YouTube video and select "Copy Video URL"
  2. Open VLC Media Player, and then click on Media and select "Open Network Stream" 
  3. When the video has started playing, pause it and go to Tools, Codec Information
  4. In Codec information, copy everything in the "Location" box at the bottom, if you can't see this find a "Source" box instead.
  5. Copy this and paste it into a new webpage tab.
  6. Press enter, and then on the video click on the three dots icon, and Download the video. You will need to rename it afterwards as it downloads with a standard name every time.