# NDI

The VServer 4 can send one video feed to an output device such as a video projector via the NDI protocol.

![](/files/tvwUsXJ4yoLkzbEA0X7u)

If you are displaying a video on a waterscreen, Depence offers useful tools to adjust the video image.

* Keystoning\
  The keystone effect is the apparent distortion of an image caused by projecting it onto an angled surface. It is the distortion of the image dimensions, such as making a square look like a trapezoid.
* Softedge\
  The softedge values slowly fade out the video signal on the corresponding sides depending on the set value. This can be used to avoid transitions for a composite video image from several sources and the associated excess brightness at the edges.
* Waterscreen Mask\
  The Waterscreen Mask value places a semi-circular template on the top of the video image. This allows the video output to be adapted to the curves of a waterscreen, thus avoiding projection above the screen.
* Mask Edge\
  Mask Edge also forms a soft gradient of the Waterscreen Mask.


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