I am curious as to the best placement for a video chat window UI when it comes to children's apps and interactive design. I keep asking to have the window UI placed at the upper middle right and the designer keeps placing it back on the bottom stating this is a common pattern and that the actual reading on the ebook should be the focus and not the video chat UI. My concern though would that kids tend to lean their upper arms on the bottom corners. I would love to hear what others are doing.
Have you noticed how the children hold the handheld device while using it? Most of the time they position it landscape using both their hands and press the buttons with their thumbs. Occasionally they would use the index finger to activate the area that's out of reach for the thumbs.
Therefore, the most optimal position for the video chat would be the middle of the screen leaving both sides for controls.
What kind of keyboard (if any) are you planning to use for entering text?
Well without screenshots to give an idea of how it is blocked out, and if you are targeting phone, tablets, laptops, or desktops it is hard to really answer this. But....
Yes it is common practice for the video chat to be in a secondary focus area when the primary point of focus should be somewhere else. In this case you want them focused on the reading and the video is secondary. This is a good design choice for just that reason.
Now if you are wanting to give equal weight to the video and the reading then yes you raise the video up from the bottom of the page.
But one thing to keep in mind is that anywhere that video box is place it is going to be an attention grabber away from the readable content on the page simply because it is video and there are things moving and the human eye naturally tracks towards movement. So to combat this putting the video in a place that may naturally be covered or otherwise not in an easy line of site it will allow the user to keep their focus on the readable text.
This is all about where you want your users to keep their focus.