Great addon but just a small request. Could you please add the option to the addon to start the new youtube tab before the old reach the very end of the video? Lets say 4 seconds before the end of the video. That would be really nice idea, as it will give a crossfade effect to the transition of videos.

Very good add-on. For it to work, you have to allow audio and video for the Autoplay settings by clicking the site information button inside the address bar to the left.

Works as advertised! Make sure that youtube is allowed to autoplay media, so the next video starts automatically.