You can hide a portion of the video screen by using the Picture in Picture Transition in Video Edit Magic.
Add the video to the Timeline in Video 2 track. Make sure Video1 track is empty. Now add the Picture in Picture transition and stretch it for whatever duration you want. Set the Bounding Rectangle to the position you want to hide. Check the Swap video tracks for this transition option.
When you play the video, the desired portion will appear black. This happens because what you see in that portion is actually the first video. Since there is no video on Track 1, it is treated as a black screen.
Read our article on applying the Picture in Picture transition. The URL is:
https://deskshare.com/re...nPicture_Transition.aspx