Microsoft has released a hotfix to resolve an issue, where the video image flickers when you configure Windows Media Player 12 to display the subtitles of a DVD in Windows 7 or Windows Server 2008 R2.<
Windows Media Player Video Flickering
The issue occurs if you have a computer that is running Windows 7 or Windows Server 2008 R2. You configure Windows Media Player 12 to display subtitles when you play a DVD. However, the video image flickers every time that a new line of the subtitle is displayed.
This problem occurs because of an issue in the way that the Enhanced Video Renderer (EVR) handles subtitle notifications.
To resolve this issue download and apply Fix 291755 from Microsoft.
Visit KB975806 for details.