I use Midinotate most days to make a lead sheet with chords from a Midifile.
You can print out in different keys signature, and save the loaded midifile out as a different key signature. If you are trying to convert a 4/4 into a 3/4 then I am not sure why you would want to do this.
I am not to sure about your question. Are you saying it's garbled when you play the midifile back into the keyboard ?.

[This message has been edited by Graham UK (edited 10-14-2004).]