During the Authoring process, the author creates the structure for navigation (menus and chapters), that a user will experience while navigating a disc. Authoring determines which menus will be presented to the viewer for navigation and the associated video that will be played when the user selects a button. Once the code is finished for the program, the compiled disc is emulated in the computer. It is checked for broken links and for proper playback. Once the program passes the emulation phase, a DVD check disk is created and tested in an assortment, of set top players. Only after the program passes all quality checks do we create a DLT duplication master.