DVD+R format is physically different from DVD-R. After reading how a burner must burn in a different way each format. How can a DVD-R player understand a DVD+R disc only changing a value in a high level structure(book type)?
If physically they are burnt differently, a DVD-R player can’t understand such format. Also as both are optical DVD, made of same media, can a DVD-R be burnt as DVD+R?
But at low level, DVD-R, DVD+R, DVD-ROM are different. So i think that a player must support all 3 formats. So i don’t understand, if a player that can read DVD-ROM and DVD-R, in theory it can’t read DVD+R(even changing an high level structure like booktype, some simple bits). because bits in a DVD+R are written differently from a DVD-R(after reading the cdfreaks article about differences between + and - fromat). So my question is:
There are DVD players that can read DVD-ROM, DVD-R and DVD+R, but at low level, at high level(bit, byte level) only can read DVD-ROM, DVD-R(not DVD+R because they doesn’t understand the bit setting). So, is this right?
Yes, they are all different. I can see where the problem lies. I can see that there is a confusion between recording vs reading. The differences that people talk about are for the recording process. But the reading process is an entirely different matter (I don’t have the specs to confirm) and are all based on the DVD-ROM (pressed disc).
To put it plainly, the specs for all those formats are similar for when you are [U]reading them[/U], e.g. you have same specs for the pits/lands for all of them.
Compare it to CDs and you’ll understand what I mean. We have CD-ROM(pressed disc), CD-R and CD-RW. Clearly they all have differences, but they are all read using the same method, i.e. no differences in pit/land spec. For example, a CD player that wasn’t designed to read CD-Rs can still read them!
Manufacturers (or engineers) have to follow specs and standards fully, and if they release a player early, or say they only had specs for DVD-ROM and DVD-R, it only makes sense that they incorporate some sort of method to prevent you trying to read a DVD+R, simply because they would have no way of knowing whether the player would be ok to read such discs. One such method is that the player can use the booktype set on the disc as a way to acheive that.
I’m not an expert on DVDs - maybe someone like RichMan or spath can enlighten this a bit more.