Parse the #GstNavigation command query and retrieve the nth command from it into cmd. If the list contains less elements than nth, cmd will be set to #GST_NAVIGATION_COMMAND_INVALID.
a #GstQuery
the nth command to retrieve.
a pointer to store the nth command into.
true if the query could be successfully parsed. false if not.
Parse the #GstNavigation command query and retrieve the nth command from it into cmd. If the list contains less elements than nth, cmd will be set to #GST_NAVIGATION_COMMAND_INVALID.