I have XP and Vista installed on my laptop, and PowerDVD installed in both. This evening I will try to change region setting in PowerDVD in Vista and see whether this will affect the number of remaining changes in XP.
As I expected, changing Blu-ray region setting in PowerDVD in Vista had absolutely no effect on PowerDVD in XP. I even found where PowerDVD stores region settings and how to reset them, but I'm not sure whether forum rules allow me to tell my findings here.
So it is now 100% certain, that Blu-ray regions only exist on application level. "Blu-ray drive region" is completely out of the equation, because it does not exist.
Based on my experiments, I come up with a theory on how Blu-ray regions work. Here it is:
Blu-ray region settings on a disc are not flags indicating players configured for which regions are allowed to play the disc. They are rather rules telling the player what it should play if it relates to a given region. Rules are checked at the beginning of the playback. These rules are specified for players of each region, and the player does not know in advance what it will get if it follows rules for its region. If it is lucky, it will get a main movie. If not - a short clip saying that the player has a wrong region to play the movie.
What AnyDVD probably does when you opt to remove Blu-ray region coding and select a preferred region - it changes those rules for two other regions making them the same as the rules for the region you selected. Thus even players with 'wrong' region will get the same content as those with the 'right' one. All this is accomplished by altering a few bytes in MovieObject.bdmv file (so I assume these rules are not even encrypted or something).
An analogy is this: You are a good driver who always follow the rules. You intend to reach some City, and you are approaching (actually, starting at) a crossroad with a road sign saying "Red cars must turn left, Blue and Green cars must turn right." You are driving a green car, so you turn right hoping to reach the City. But instead you get to a dead end with a sign saying "Sorry, only red cars can reach the City.". You might turn back, and go to the service and get your car painted in red (then you will be able to turn left at that crossroad), but you can (in theory) only do this trick 5 times. So instead you call your friend (Peer) in RTA and ask him to change the sign (it is an illuminated indicator board, so it can be changed remotely) so that it now says "All cars must turn left.". This way you reach the City.
But I still do not completely understand what Peer meant when he said (
http://forum.slysoft.com/showthread.php?p=15654#post15654):
AnyDVD HD for now simply lets the title "think" that your player has the correct region code (quite a mind twister...). So the region code is not actually removed.
Though I'm already thinking about a way to really remove it.
If my theory is right, then what he does IS indeed removing a region code.
Please correct me if I'm wrong somewhere.
Maybe it's a stored value somewhere....maybe.