In your first post, you talked about a "good quality source". Now you're always talking about artefacts that have to be reduced. Could you please decide what's the real deal?
The following script loads and uses Spresso correctly. Get the plugins, adapt the pathnames, and it'll work:
Code:
LoadPlugin("X:\path\to\MaskTools.dll")
LoadPlugin("X:\path\to\RemoveGrain.dll")
Import("Y:\path\to\SPresso.avs")
XYZSource("Z:\path\to\YourSource")
SPresso()
The filtering chain you currently have gives a rather blurry output for sure. One should look into what the problem is with the actual source, and do specific filtering. Better then to produce this kind of universal mush.
BTW, you'll have no fun with a framesize of 800*450. You should resize to 800*448.
(And in case you like mush, write "BicubicResize(800,448,1,0)" -- no more artefacts...)
edit:
BTW2, I once put the "Dust" filter package online
here. Those who are afraid of Dust's potential blocking artefacts might want to use
PixieDustPP instead.