DVDSP 4 on Sierra and DVD DL Authoring Question...

DVDs are standard definition and DVD players can only play back standard definition unless said DVD player happens to also be a Blu-ray player or HD-DVD player. So no. You'll have to make a standard definition DVD and it will be standard definition forever unless you make a Blu-ray which DVD Studio Pro forbids you to do. Apple does not want you making physical discs because it is time to store everything in the cloud (which is stupid I know, but we don't argue with Apple because Apple is God). You can make an AVC-HD DVD but again only Blu-ray players can play it. DVD-DL is about (nearly) doubling the amount of data that can be stored on a single disc. You'd need dual layer DVD-Rs to create them as well.