Sorry. Wasn’t trying to be difficult. Just honest. The 3rd party screenshot taking apps that I’ve seen require the device to be *rooted* in order to get access to Google’s private/internal APIs. Otherwise, I’m not sure how else you can do it.
Now, there are native APIs to capture a frame from a VideoView. This is useful for apps that create their own videos via the camera. You can submit a feature request for this if you want.