Preview uncompressed RGB source doesn't work

[serg]

Attempt to use "Vapoursynth" Interframe/SVP to convert 23.976 fps to 59.94 fps or to 60 fps output nothing,
showing just "finished" in the "Jobs" .
(Original Avisynth Interfarame 2.8.2 standalone AVS script + Virtualdub works fine)
Hybrid's Avisynth "Interframe" looks like works (at least it outputs currently something).