 Dolby TrueHD and DTS-HD Master Audio have become sound format of choice for many studios on their Blu-ray titles but ever since Blu-ray won the format war, it has not become clear if they are now Mandatory for all new Blu-ray disc players since the end of the format war.Blu-ray Disc has a higher maximum disc capacity than HD DVD (50 GB vs. 30 GB for a double layered disc).In September 2007 the DVD Forum approved a preliminary specification for the triple-layer 51GB HD DVD (ROM only) disc though Toshiba never stated whether it was compatible with existing HD DVD players.