Not always
I was trying to use that plugin (dfttest(sigma=0.4)) that you have mensioned before and when I try to load libfftw3f-3.dll library it tells me that it isn't an avisynth 2.5 plugin. I'm using the latest stable version of avisynth and I've tried 2 diferent versions of the file and still doesn't work. Could you please advise? Thank you.