Sorry, I am new to Kaltura and have been trying to play with it and get insight. Please bare with me, hoping to get answers to all my questions 
I have been trying to use service = playlist and action = list without setting Filter and Pager parameters.
I saw too Kaltura test consoles:-
1. https://developer.kaltura.com/console/#/session.start
2. http://www.kaltura.com/api_v3/testme/
Q - Former gives me correct result and later wrong. Is it obsolete?
Q - What is the correct endpoint to access playlist-list action? Currently I am using:
https://www.kaltura.com/api_v3/?service=playlist&action=list&format=1&ks=**********
which gives me:-
Success : {
objectType = KalturaPlaylistListResponse;
objects = (
);
totalCount = 0;
}
Rather than giving me list of playlists 
Q- What am I doing wrong?
Q- I am working on iOS app and was wondering what is the difference between "User Secret" and "Admin Secret" and which one to use in my app?