"Meanwhile the video concept for ‘Dull Flame' is as unique. Out of hundreds entrants for the “Innocence” music video competition (which ran on www.bjork.comoffering new directors the chance to work with Björk), she chose 3 new directors to collaborate on the “Dull Flame” video.
Björk and Antony performed against green screen in New York then each director was sent the raw footage to edit and create their piece. Christoph Jantos (Berlin) Masahiro Mogari (Tokyo) and Marçal Cuberta Junca (Girona) are the chosen directors. Each director was given their own section of the film, to develop how they wished - on completion the 3 films were edited together in London to make the final music video."
This explains the 3 different styles of the video.
http://www.youtube.com/watch?v=BWV4N-ZcDJg