The Flash application can send a license preview request,
meaning that the application can carry out a preview operation before
asking the user to buy the content in order to determine whether
the user’s machine actually meets all the criteria required for
playback. License preview refers to the client's ability to preview
the license (to see what rights the license allows) as opposed to previewing
the content (viewing a small portion of the content before deciding to
buy). Some of the parameters that are unique to each machine are:
outputs available and their protection status, the runtime/DRM version
available, and the DRM client security level. The license preview
mode allows the runtime/DRM client to test the license server business
logic and provide information back to the user so he can make an
informed decision. Thus the client can see what a valid license
looks like but would not actually receive the key to decrypt the content.
Support for license preview is optional, and only necessary if you implement
a custom application that uses this functionality.