This allows you to choose between the EVR, VMR9 and VMR7 renderers that are used to display video in the player. It is recommended that you leave EVR or VMR9 selected, but some older graphics cards (or buggy drivers) may play "blank" video using EVR or VMR9 - in such cases choosing VMR7 may solve this problem. Note that VMR7 may use video overlay if your graphics card supports it.
You can also choose between the windowless or windowed mode of the VMR9 or VMR7. Windowless mode is preferred, but the older windowed mode (also referred to as compatibility mode) is sometimes useful for supporting older graphics cards.
Note that windowed mode may be the only mode which works in virtual machines such as VirtualBox and VMWare Fusion due to the limited capabilities of the virtual graphics drivers. For this reason the use of DVMP Pro on virtual machines is not recommended.
The Force Display Aspect Ratio option can be used to force the video to be displayed in the player as 16:9 or 4:3. You should find that nearly all of the supported video file formats play with the correct display aspect ratio, so we recommend that you leave this option un-checked.