Gonk is right on the money. I have "older" DVDs that do this, they are set to play back in 2.0, the user has to go to the menu to select 5.0 or 5.1. However the intros are in surround but once the movie is loaded they revert back to 2.0. You don't see much of this practice anymore. And I understand that there are some higher-end players that can find the surround track and automatically select it for you.