If this parameter is defined to 0 the music you added will not Autoplay. Alternatively, if this parameter is set to 1 it will Autoplay. Note that if you don't set the parameter to anything, it will default to 0.
NOTE: playlist does loop - Set this parameter to part of URL for the playlist that's after <a href="http://www.youtube.com/,">http://www.youtube.com/,</a> usually p/RANDOMCODE, found by adding a video to a playlist, going to your videos, then to playlists, clicking share, then embed, then copying the code after <a href="http://www.youtube.com/">http://www.youtube.com/</a> and before ?version=3). Note that you do not need both the VideoURL parameter and the PlaylistURL, yet one or the other
NOTE: music does not loop - Set this parameter to part of the URL for the video that's after <a href="http://www.youtube.com/,">http://www.youtube.com/,</a> usually embed/RANDOMCODE, found by going to a video, clicking share, then embed, then copying the code after src="http://www.youtube.com/ and before the " after the URL. Note that you do not need both the VideoURL parameter and the PlaylistURL, yet one or the other.