You cant convert MP3 into MIDI. Its not possible. MIDI consists of instrument sounds made with the computer hardware or something like that. Its all instruments only. MP3 is ...well... MP3.
Ya. He nailed it.
If that was posable, everyone would use midi because the files are so much smaller, with still near perfect tone and pitch.
MP3. to MIDI is a different matter...
These are my principles. If you don't like them, well... I have others.
Since brevity is the soul of wit, I will be brief. Auto Correctly.