How can I mass convert MIDIs to MP3s?

I happen to have multiple MIDIs, and I have to convert them to MP3s for a certain task.
I simply can't trust online convertors.

I have looked into using ffmpeg, but I believe it does not have MIDI support.

It doesn't matter what soundfont is used, since the only voice used is the piano.

How can I mass convert MIDIs to MP3s?

I am on Windows, but I can boot Lubuntu if needed.