Question about DVD region checks

Hi all, i hope to not be in the wrong section and to not go against some forum rule.

it’s the first time i come accross dvd drive/player region stuff.
I’m working on SD-S802A hd-dvd drive.
Patching the drive to be RPC1 or automatically adapt the drive region to the disc inserted is not a problem (also without fw patching you can temporanely change the drive region because it’s cached in drive’s ram), but i would like to try the inverse: patch the disc region to match a fixed region (hum…)

I’ve read some info out here, and all places says that disc region is stored inside the leadin and into the VIDEO_TS.IFO, both must match.

I’ve taked a look at the leadin, the region code is found in the CPR_MAI flield of first sector of the ContentProviderInformation area inside the control data zone (PSN 0x02F202), patched here.

Now, ok, it’s quite hard work to intercept the reading of the VIDEO_TS.IFO file (but i’m optimistic it can be done) but actually there is another point that i’ve not clear, here is the situation:

-drive region 2
-disc region1 but the patched drive thinks to have readed region2 inside the leadin.

dvddecrypter see the disc as region2, can get keys from the drive without bruteforcing or asking to change region to 1.
Powerdvd asks to change region.
I’ve sniffed powerdvd, it sends various ReadDiscStructure and ReportKey-drive region, the answeres are correctly containing region2 info about the disc, then it reads sectors 16-31, then some other sectos near LBA 285, but seems no file is mapped there, video_ts.ifo is at LBA 440 and pdvd does not read it, it asks to change region wthout reading the video_ts.ifo

So finally the question: what else could a player cheks for a region match? Is there something region related inside the UDF description stuff?

BTW: the disc is not RCE protected
Geremia is online now Report Post Edit/Delete Message

As far as I know most drive’s just check the region code mask at byte 35 in VIDEO_TS.IFO. Maybe your Xbox 360 (SD-S802A) “self-checks” if the drive has been changed to RPC1 ? Maybe it tries to verify RCE protection and if it can’t then it will not let you play the disc ? I’ve heard the MS Vista OS does this maybe Server 2003 does too.

Isn’t it easier to keep the drive RPC2 so you can change the drive’s region code to match the disc instead of “the inverse” ?