The Skew transformation lets you skew an entire image horizontally or vertically.
In the Properties Window you can change the effect properties. The properties of the Skew effect available for setting are angle and the Vertical option. The vertical direction is set by default, if you'd like to skew the image horizontally, you should untick the Vertical option.
On the figures below you can see the video picture before and after applying the Skew effect:
Before applying the Skew effect
After applying the Skew effect