Open iTunes and then open iTunes preferences.
Select the "General" tab from within the preferences menu.
Click the "Import Settings" button.
Choose the "MP3 Encoder" from the "Import Using" menu.
Click "OK."
Drag the MP4 you would like to turn into an MP3 into iTunes.
Highlight the MP4 and click "Advanced."
Choose "Create MP3 Version" and the MP4 will be turned into an MP3.
Open Switch and click "Add Files."
Choose the MP4 you would like to turn into an MP3.
Click "Select" to import this MP4.
Choose "MP3" from the "Output Format" menu.
Click "Browse" and select the folder in which you'd like the converted file to be saved.
Click "Convert" and the MP4 will be turned into an MP3.
Open dBpoweramp and click "Browse."
Choose the MP4 you would like to turn into an MP3.
Click "Open" to import this MP4.
Choose "MP3" from the "Converting To" menu.
Click "Folder" next to Output Location and select the folder in which you'd like the converted file to be saved.
Click "Convert" and the MP4 will be turned into an MP3.