Nope. They vary greatly, even between models of the same brands. There are basically no standards for the manufacture of DVD recorders. The mfg’s can put any kind of circuitry or software/firmware in them they want. They have certain standards books, but they still can manufacture a machine the way they want to.
Opposite this, there are VERY exacting standards for DVD, DVD-R, DVD+R, DVD-RW and DVD+RW disc media manufacturing. They must adhere to those very tight standards to get the various DVD seal of approvals- and to make their product work with the majority of recorders/players. If their product/discs didn’t play in the vast majority of players, they’d go broke. Manufacturers not so much, at least not to the extreme that disc/media mfgs are held to.
DVD’s are molded discs that use actual pits and lands (physical holes and ridges in the metal substrate) to encode the data on them. DVD-+R’s use dye layer substrates, not metal, that are burned by a laser to create the equivalent of pits and lands, but they are not the same as physical P&L’s. DVD-+RW’s again use different dye layer technology to allow re-recording over the same disc once it has been written to. There actually are vast differences between the three types of media, technologically speaking, even though they may seem to be the same to a consumer. [And this doesn’t even take into consideration the actual data encoding, media headers and other data that is different, and encoded, on each type of disc media.]
You should do a search online, maybe for “DVD forum”, research some consumer forums for compatibility issues among makes/models, etc. I used to have a bunch of links to those things, but I don’t have them on this machine. Do some searches and you should find a lot of good info, as I’ve given you the basics to start with.
The bottom line I’ve found through the years is that the media is almost never to blame for things like this, the machines are. Also, you’ll get bad media occasionally. Manufacturing processes aren’t perfect, especially when you get down to measuring things in fractions of microns. When that happens, use a completely different brand of disc to test for that.
But, again, if you’ve got DRM problems, you’re pretty much screwed. That’s how RIAA/MPAA wants it to be and they’re the big money boys who can bully even high end machine mfgs into line. A bit of research will help you find ways around this. Maybe there are some non-DRM conforming machines out there. I don’t know. I haven’t worried about that for several years.
Good Luck!
Thanks. I figured it was the programing. I still have my trusty VCR and gobs of tapes. Quality at VHS SP is nowhere near HQ on DVDR but it’s watchable.