Copy restricting software

Good luck with that one seeing how the major studios cant do it.
Newer DVDs are made more difficult to copy using "tricks" ( file system is modified with fake info or fake read errors) to make it harder to rip them but newer programs have come out that can circumvent these "tricks".
You cant really introduce a new copy protection scheme without making existing DVD players obsolete.

If you're producing runs of 500 DVDs or more then you'll be getting them stamped (i.e. silver disc) and as a result you can author your discs to have Macrovision protection (can't run a DVD player through a recorder and record the video stream), region-locking and copy protection (copy the disc via a computer to DVD-R). You will pay extra for the Macrovision license. The authoring process too will require you to create a master image to an old-school tape drive as I'm not sure the replication plant can take a disc-based master and add the security features.

If your runs are 500 or less they'll be burned (purple DVD-R) which will have none of these features.

BUT, as stated above, there's plenty of software available now that will circumvent all this protection - at the end of the day it all depends on how badly people want to copy your DVDs. If they want it they will find a way.