For creating a DVD with motion menus, chapters, and Dolby audio, Roxio Toast 20 Pro is the closest modern equivalent to DVD Studio Pro’s core features. For a free, script-like approach (similar to old DVD Studio Pro’s “track” workflow), use DVDStyler – though the interface is less polished.

To run DVD Studio Pro 4.2.2 natively, you historically needed:

Apple discontinued DVD Studio Pro in June 2011 and no longer sells it or provides a direct download link on the App Store. To obtain it today, you typically need: Final Cut Studio 2: DVD Studio Pro 4.2 - Apple Support

Final Cut Studio 2: DVD Studio Pro 4.2 - Technical Specifications