Avisynth not working in Phonon?

Question

Qt

In the process of writing a simple Qt player for Windows based on Phonon, I ran into trouble: *.avs files cannot be opened. No errors, just 100% percent and silence. On small files, it’s realistic to wait for the end of this process, but it doesn’t start playing - just nothing. Other files open fine, even those included in the avs script. Through Melia Player Classic, which uses the same codecs from ffdshow, everything opens normally. What could it be?
Even the simplest scripts don't work, even just Version().
I don’t attach the code, since the qmediaplayer from the Qt examples behaves in the same way.
Backend phonon'a DirectShow, with vlc and mplayer did not check, but in them, as far as I understand, avs should not work.
I would like to understand: I have a mistake, or everyone behaves like this phonon.