An update is available for Windows 8.1 Preview. This update includes fixes for adaptive streaming and Digital Rights Management (DRM) playback features in Windows 8.1 Preview.
This update (2875636) is available from Windows Update
Another update 2875111
is available that improves video playback.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
Description of the standard terminology that is used to describe Microsoft software updates