Getmein " SLR original puts 2D images in a 3D space."
If I understand you correctly, you are talking about the multicam / picture in picture videos?
Those are not a separate stream, they are part of the frame, added in post-production.
Nonetheless, lower than 1080p should be very easy and fast to do yourself, even with older gen GPU's/CPU's. If that would be an option for you.