Short answer: No, you will not be able to do a direct copy of a commercial DVD
using the DVR-AO3.
The DVD-Rs that the Pioneer drive uses are slightly different
from commercial DVDs, they use General media instead of Authoring Media, which
means they don't include the extra track for CSS keys and the like.
Longer Answer: Yes, if you can transfer the data from the DVD to your hard drive,
you should be able to re-author that data to a General DVD which will work
just like the original did. You will need to make some changes to the
menu structure and the .vob files, so it will not come out as an exact copy, but
should come out as a workable one.
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And before the Mods jump on me, this type of copy would be perfectly legal as
an in-house backup of a frequently used DVD (such as a copy that might risk getting
damaged by kids or irresponsible roommates). As long as you don't give the
copy to anyone else you should be okay.