The slide transition slides the first video out while bringing the second video in. This differs from a Wipe transition because the images or video clips move. In a Wipe, the video clips remain still and the Mask moves.
This transition supports three types of slide styles:
The Open style slides the first clip to the left to uncover the second clip. That is, the second clip is stationary, and the first one gets out of the way to show it.
In this style, the second clip pushes the first clip and slides it off to the left. Both clips move simultaneously.
The Swap style moves the first clip halfway-out to the left, and the second to the right, and then back in front of the first clip. It's designed to look as if the second image is moving around and then in front of the first.
The slide transition splits the clip horizontally into the number of specified bands and then applies the selected slide style. The bands move in alternate directions (if the top band is moving right, the next one down will move left).
Swap video clips for this transition
By default this transition starts from the first video clip and ends with the second video clip. Check this option to transition from the second clip to the first clip.