Well, you need to get your pre-keyed image/video into your video bar (not the timeline), and then select it (it should be outlined with yellow). Drag the pre-keyed thing into the timeline, onto the other video, where you want it to appear. Then, let go of it, and a little menue should appear. Select "Picture in a picture". Then you should be able to manipulate it (with size and area), and that's how it's done.
Pre-Keyed relates to footage or video effects that have been rendered out with the RGB+Alpha Channels. So it's essentially "Green Screened" Your footage will have no background and can be placed over top of other footage or images, or colours as a separate layer with the "keyed" footage showing as well as your footage underneath it. Most programs can do this - After Effects, iMovie, Camtasia Studio, PowerPoint, FinalCut Studio, And I'm sure there are others as well. It becoming more and more popular and software developers are recognizing this. The term "Pre-Keyed" is on a "Breakout" in Google's search Trends.
broken windows, keyed cars,spraypainted buildings/property, expensive repairs or replacements, ect.
A
Keyed Up was created in 1983.
Pre-valve trumpets they were either natural or keyed trumpets. They didn't have valves. They weren't invented until 1822.
boner
Yes, Trapcode for Adobe After effects is free.
You speed the word as 'miskeyed'. When you put the prefix with the word keyed, you do not use the two 's' as when you say the word 'miss'.
pre mature balding
low-keyed
Low-keyed