Doctor Who was chosen as one of six DVDs released to represent the BBC as a 'test' of the DVD market by BBC Worldwide. The other titles were The Black Adder, Noddy in Toyland, The Planets, Persuasion and Volume I of The Best of Monty Python's Flying Circus. The title chosen for this test was The Five Doctors. This was picked because of it already existing in a "Special Edition" format from the BBC Video release of 1995. This permitted better use of the DVD format with 5.1 surround sound. The Region 1 release of this title featured a commentary not available on the Region 2 and 4 versions, which would later be included on the 2008 re-release.