Looking for some VST Midi effect

Hi there,
Totally new here, and English is not my mother tongue, please apologize.

I searched, but may be with wrong terms, for a VST like midi effect that could take midi input (with channel/note range filter) as chord and output midi notes (along several channels) following a STY like file.

Does something like this already exist ?
Do you think it’s a good idea building such a VST ?
Do you think it’s impossible due to some SDK limitations or else ?

Thank you very much for your input.

Best regards,


Can you please explain what an “STY” file is?


Hi Creatine,

a STY file is built like an Standard Midi File but has markers cueing to Intro, Main A, Main B, Fill In and Ending sections within.
They are used on a wide range of Arranger keyboards. STY is the extension for Yamaha ones, PAT is for Ketron, and so on.

If you take a STY file and rename it to MID, you may play it on most midi file players.
But you’ll hear strange notes because usually, a CMaj7 chord is used to modelize rhythm patterns played by various instruments int he track.

So my idea was to write a midi filter in order to detect pressed keys as midi input, compute which chord is played and, according to clock, output midi patterns to other VSTi

Is it clearer ?

Thanks for stopping by.