Even really bad midis can be used to learn a tune when stripped back to bass and drums.
Using Live Intro (cheaper version of Ableton live, but there's heaps of other software will do the same job) I import the drums bass and melody, attach instrument samples. You can output from live to audio or midi or export as wave or Aiff. To convert wave to mp3 something like audacity will do it easy.
By doing it like this I can cut various tempos, transpose and set it up how I want and whatever structure (intro/verse/chorus etc.) I want.
Hope this helps,
roBb
