@takemehomegrandma
"Sour grapes"
Not at all, I'm just question if its worth it.
“Overlay is isn't a video playback function per se (although it is often used in that context) “
I have not seen it used any ware else, well I have seen it in Basilisk II, but it does really work, because colors are YUV and not RGB, so all you get is green screen with horrible colors.
“Like showing a 320 x 200 Amiga screen on a moden high-res monitor in full screen.“
Sour up-scaling will be many time faster, but at cost of having to do color conversion.