Apple has released DVD Player Update 3.1 for Mac OS X.
As well as a wider layout for the info window and a number of stability enhancements, the update adds features for DVD authors, including the ability to select and play the contents of VIDEO_TS folders from a local volume.
The update introduces AppleScript support for selecting and playing back DVD content. DVD Player Update 3.1 is available for download using the Software Updates Control Panel of OS X. It's not yet available for Web download.