In order to playback a DVD using TriDef Media Player, a DVD decoder is required. DVD decoders are available from third party software providers. The following decoders are supported. Please note: it is possible that you may already have a supported DVD decoder pre-installed on your PC. InterVideo WinDVD (versions 6.0-9.0) or DVD XPack (Windows XP Only) Approximate Cost: US$50 / US$15 MPV decoder (Video) MPA decoder (Audio) Free AC3 Filter (Audio Only) Free If you are installing the MPV or MPA DVD decoder on Windows Vista or Windows 7, please read our FAQ regarding installation.