Get a video-to-MP3 converter. You can download the trial version of the Absolute Video to Audio converter from the Resources section below, or you can try a free program like Free Audio Editor or the online site Media Converter.
Open your converter program. Choose the file or folder where you want your converted audio to be saved. This is done by selecting the "Output Path" icon.
Find the video file that you want to extract the audio from by clicking the "Add File" button, "Import from Video" button or simply clicking "Browse."
Double-click the video file you want to add after browsing. Set your output path to MP3 and click "Convert" to extract your video's audio and convert it. If you're using Free Video Editor, upload your video first, then click "Convert Files." On the next screen, choose MP3 as the file's output conversion format. Save the converted files to your computer's Desktop for easy access later.
Get an MP3 to MIDI converter from a site such as Mp3towav.org. Some of these converters are completely free, some of them you have to pay for, but all of them have free trials available.
Run your MP3 to MIDI converter after downloading and installing it. Choose "Add New File" or "Browse" to find the audio file you want to convert. Look on your computer's Desktop if you are ready to convert your extracted video's MP3 file into a MIDI file.
Choose "MIDI" as your output format and click "Convert" when you're ready to change your MP3 into a MIDI file. Take note of the folder where your MIDI files are being stored so you can easily find them later.