12. Can a DVD contain hidden video or audio contents ?
Each DVD disc contains many segments of video and audio contents organized as chapters in separate video titles. The author of the disc may add optional navigation commands to skip certain chapters or titles on the DVD. The author can prohibit access to certain program material on the disc so that one or more segments of the disc cannot be seen or played back without some means of human intervention. In this case, it is difficult or even not possible to access these hidden contents from a stand-alone DVD player.
However, most DVD backup software can display the entire contents of the DVD so the user can select which chapter or title to back up. The hidden portions of the disc by restricting access with DVD navigation commands can then be displayed on the computer and backed up accordingly. The navigation commands which skip the display of these hidden contents can be removed or modified so that a standard DVD player may gain access to these portions via the menu or the remote control buttons.

On Paramount Home Entertainment’s Special Collector’s Edition of "Mission: Impossible" the studio has also included a hidden feature. From the DVD’s Main Menu go to the "Special Features" section and highlight the menu entry "More." Then, press the "Left" arrow key on the remote control to highlight the IMF logo. Press "Enter" to select the logo as if it is a menu button to see the hidden trailer for "Mission: Impossible 3".