In 16.04, when a DVD movie is accessed in Nautilus there is a button in the top right corner to play the movie in Totem.
Can this be replaced by other player like VLC or MPV?
This is not asking how to change the overall preferred application (as said above, under Settings - Details - Default applications), nor how to change the player per-file-type (under file's properties, "Open With"), therefore it is not a duplicate of How do I set VLC media player as default video player?.