I haven't been able to copy a DVD9 "game" onto a DVD5 disc. The only one I've tried is GT4 as it's the only one so far I care about backing up. All the rest of my games are DVD5.
When you rip it, if it's over 4.7 gigs(actually 4.37), it's a DVD9. You must use a dual layer burner to burn dual layer discs.
Not sure, but I think that if the original game was in OTP format (Opposite Track Path) it would work as a 1:1 copy. But for games like GT4, which is PTP (Parallel Track Path), it won't work. To find out the track path, AnyDVD will tell you (where it says "Layers:2 Opposite" or "Layers:2 Parallel") and Decrypter will tell you (where it says "Track Path: Opposite Track Path (OTP)" or "Track Path: Parallel Track Path (PTP)).
Convert PAL to NTSC or NTSC to PAL------>http://forums.afterdawn.com/thread_view.cfm/167922
ScubaPete's guides------>http://www.dvdplusvideo.com/tutorial007.html
Bbmayo's guides------>http://home.comcast.net/~bbmayo/index.html
My ever-growing movie collection------>http://www.intervocative.com/dvdcollection.aspx/squizzle
I've copied plenty of DVD9 games to DVD5 discs. With the exception of GT4. Champions, The Guy Game, Xenosaga, etc... All you have to do is research here on how to rebuild the ISO image.
I guess I need to make myself clearer. I am only referring to GT4. (I edited my previous post) I have backed up hundreds of DVD9's, using various apps. I have also authored many Dvd's using DvdLab Pro, NVE 3, and Sony Architect.
All of my games will fit on DVD5. GT4 is the only DVD9 I have tried that I can't back up. I am trying something new this weekend and I will post my results if it works.