Adding a blur filter to a video using Avidemux 2.6.9

[Jentleness]

I'm creating a screen cast tutorial on how to process employee attendance and I want to add a blur to certain frames to protect the names and ID numbers of our employees but I am having trouble figuring out how to do this. I tried using a delogo filter but I can't figure out how to set it so it is only on for just that frame during that time period. I've attached a screen shot of my set up. Any help would be appreciated, including letting me know if there is an easier/better program to use for doing this. Thank you.