A null terminated array of strings that contains the UUID values of each protection system that is to be checked.
Return: One of the strings from @system_identifiers that indicates the highest ranked element that implements the protection system indicated by that system ID, or %NULL if no element has been found.
1.6
Iterates the supplied list of UUIDs and checks the GstRegistry for an element that supports one of the supplied UUIDs. If more than one element matches, the system ID of the highest ranked element is selected.