Consider the following scenario:
You have a computer that is running Windows Vista or a later Windows operating system.
Your computer supports two or more monitors.
You have the Duplicate (Clone Mode) display configured.
Your display is not set to use Windows Aero.
You play a DVD movie in Windows Media Player or a third-party video application.
In this scenario, you notice a cut line in the video on one of the monitors.
This problem occurs because of a hardware limitation that is known as "tearing." Tearing is a video artifact in which the top portion of the screen shows a different frame of video than the bottom portion. This is more noticeable during scenes that contain fast motion. There may be a noticeable horizontal line at the point where the two frames meet.
When it is playing video content such as a DVD, the operating system has to synchronize playback with the display redraw rate. The video frame is updated during the vertical blanking interval so that the complete, correct frame will be displayed without any tearing every time that the video card refreshes the monitor.
When windows synchronizes DVD playback with the monitor refresh rate, it synchronizes with the timing of the primary monitor. This is determined by the video driver. Some video hardware supports multiple monitors but does not synchronize the display redraw timing of the two monitors. Even though the two monitors are configured for the same refresh rate (for example, 60 Hz), the second monitor may not be refreshed at the same time. In this case, there may be unavoidable tearing on the second monitor.
Windows Vista or Windows 7
If the computer system meets the hardware and software requirements to run Windows Aero, you may be able to reduce or eliminate the problem by enabling Aero. Otherwise, set the display to PC Only or Extended. For more information about Aero, go to the following Microsoft website:
What is the Aero desktop experience?
If your computer does not meet the requirements for Aero, set the display to PC Only or Extended. For information about how to change this setting, go to the following Microsoft website:
Windows 8 or Windows 8.1
Set the display to PC Only or Extended. For information about how to change this setting, go to the following Microsoft website:
If you experience noticeable cut lines or tearing, and not only when you play a DVD movie, the display may be configured to a refresh rate that one of your monitors does not support. If this is the case, you can resolve the issue by configuring the display to a refresh rate that is supported by all monitors.
To configure the refresh rate of the display:
Right-click the Windows desktop, and then select Screen resolution
Select Advanced settings
Select List All Modes
Select a resolution and refresh rate that is supported by all monitors. (Your monitors may support multiple refresh rates. See your manufacturer's documentation for information about the settings that your monitor supports.)
Select OK, and then Apply.