It is most likely a codec problem. Can you play the videos in Windows Media Player?
Check for updated video drivers (though this probably isn't directly related) and Windows updates in general (particularly anything related to Windows Media Player codecs).
You can also try installing the
AC3filter audio codec. Some people have fixed codec problems by either uninstalling or installing codec packs.
You can rename the intro.wmv and loading.wmv videos in the '..\SteamApps\common\divinity2_dev_cut\Data\Video' folder to get the game to skip them.
As mentioned above, try starting a video in Windows Media Player, pause it, and leave it running in the background when you start the game. That can help if there are problems with certain video filters or codecs.
