Here are the experiments Tom was referencing:
https://fanrestore.com/thread-2807-post-...l#pid56276
I haven't tested this upscaling yet, having trouble getting it working but I will eventually. Just need time to work it out. Regardless, I used the THX Halloween DVD as an upscale test since I had it handy. I used this particular pic because fine hair is a great test for upscaling. Please don't take this as truth from on high, its just my little rough test. A lot of experience users here will find these results trivial. So here for baseline reference:
Original DVD (IVTC'd in AVIsynth, Converted to 709)
From here out everything is IVTC'd and converted from 601 to 709 in AVIsynth and then upscaled. No additional filters unless noted.
Bicubic/x200
Spline36/x200
Nnedi3_rpow2/x200
SuperRes x2 with Nnnedi3 upscale (AVIshader Version)/x200
SuperResXBR (AVIshader Version)/x200
SuperRes x2 with Nnnedi3 upscale (AVIshader Version)/x200 (this is with filters for deblocking, noise, halo removal, shaprening, blurring and re-graining)
Gigapixel Photo/x200 (50% sharpen, 0% noise reduction, upscale to 4K and down to 1080p)
Gigapixel Photo/x200 (50% sharpen, 0% noise reduction, upscale to 4K and down to 1080p plus a little blur and grain)
So the summary, if it is difficult to see, is that Superres is better than most AVIsynth filters. SRXBR is about the same level. Giga still wins hands down. With Giga you get a lot more detail in the hair.
The MPEG-2 of the DVD naturally has macroblocking. Running a deblock filter in AVI takes care of the problem whereas Giga naturally removes it. Adding grain covers a lot of the problems.
Macroblocking (Superes, SR processed with deblock/grain, Gigapixel, Gigal processed with grain)
So the next steps is that I need to add examples of AIupscale, SR from info and Gigapixel video.