I wonder is there midi writer plugin for foobar?

Converting a purely digital signal to MIDI is a very complicated process, prone to error, and this is only dealing with a monophonic performance. Throw in polyphony and multiple instruments, and you have something that note recognition software won't be able to sort through.

Most of the published MIDI files floating around the web are sequenced by hand, or scanned from sheet music, or performed live on MIDI instruments.