That location is the background for character creation, with the camera in the opposite direction.
You can use the Developer Mode 'goto Region' function to teleport there, then jump out and explore some empty areas you can not get to normally.
Try installing the AC3filter audio codec
. Some people have fixed codec problems by either uninstalling or installing codec packs, so that was worth trying, anyway.
When you checked for updated drivers, did you also check Windows updates, particularly anything related Windows Media Player or its codecs?
Can you play the game videos in Windows Media Player? If you leave WMP running with a video paused and start the game, does that help?
You can rename the intro.wmv and loading.wmv videos in the '..\SteamApps\common\divinity2_dev_cut\Data\Video' folder (or similarly for other releases/versions) to get the game to skip them.
In the '..\data\Video\Story\' folder, the video Start_Movie.wmv should be played when starting a new game, and ToBrokenValleyRide.wmv after character creation.
Something like Codec Tweak Tool
or the Direct Show Filter manager
could help identify and fix codec or filter problems.
You can try lowering the game resolution, and then set the game to run in windowed mode (unsupported). To do that, edit the file below in a text editor and change the one to a zero in Fullscreen="1".
You may need to set Windows Explorer to show hidden files and folders
(covers Vista through Win 10).