In the "Epic Pinball" TAS,
the blue android in the background seems to be not tall enough - the artist probably took the monitor's 4:3 screen area into account. The video is 640x400, but should be 640x480 with the correct aspect ratio. Unfortunately just adding 80 lines
looks very unnatural.
The correct way would be to
add one blank scanline after 5 image lines, and scale the result back down
to a resolution that the user's monitor can display.
DirectShowSource("dwangoAC-WIP-Epic-Pinball-05.mkv") # YV12 640 x 400
ConvertToYUY2 # Crop can't do odd numbers in YV12
PointResize(Width, Height * 5).Scanlines # add scanline after every 5 lines
#BilinearResize(1280, 960) # resize to final video size (optional)
function Scanlines(clip) {
clip
top = Crop(0, 0, 0, 5).AddBorders(0, 0, 0, 1)
bottom = Crop(0, 5, 0, 0)
bottom = (bottom.Height > 5) ? bottom.Scanlines : bottom.AddBorders(0, 0, 0, 1)
StackVertical(top, bottom)
}
This is the AviSynth version; a custom plugin could be much more optimized.
EDIT: Converting a 320x200 RGB source to 320x1200 and encoding that with ZMBV could be the best solution. The user's gfx card could stretch that without speed penalty.