.wav to MIDI? Mmmmmm, what exactly are you trying to achieve?
Ok look.
.wav is an audio format and MIDI is form of communication between electronic equipment. MIDI does not transmit audio data it transmits messages like pitch information, velocity, clock signals, etc.
This is a common misconception between MIDI and audio.
However you might be able to convert simple 'single' monophonic notes into MIDI information using something like Melodyne, I use it sometimes to correct vocal pitching, and Melodyne DNA can decipher more complex polyphonic material; but it takes a lot of work and understanding of the application to extract the MIDI information.
Unless you have a piece of audio, a piano for example, that you want to re-program using another virtual instrument then I see no need for you to convert any audio into MIDI.
As for 'people talking' or 'rain' forget it cause your going to get MIDI information you seriously won't comprehend.