The two options are:
Prevent access to a dialogs format tab via source dialog
Allow this access
Video for Windows applications access the Source and Format pages as separate commands and do not assume that the driver allows you to switch from one to the other.
Some applications, when they access the Source page, do not check to see if you also made changes to items in the Format page. The result is that the application and the driver may assume different settings and not work properly together.
This control in its default "prevent access" setting prevents you from entering the Source page or Closed Caption page, switching to the Format page, and inadvertently making changes that the application will not pick up. It also disables the Board Select control on the Source and Closed Caption pages since the driver maintains separate format information for different boards. The "prevent access" setting is recommended for maximum compatibility with all applications.
The "prevent access" settings is, however, inconvenient. The alternative setting to "allow this access" allows you to switch between pages without restriction. This will work with many applications; however, the responsibility lies with you to make sure no problems arise.