This project demonstrate how to read microphone input data and compress it to mp3 using Swift 3.0. Fat lame 3.99.5 lib with bictode enabled already included into the project.
To test just run the project on iOS device, tap Start button, which will initiate recording into buffer.
Tap Stop when you finish. Compressed mp3 buffer will be stored in a file in Documents folder.
iTunes File Sharing enabled, so you can access file via iTunes, copy it to Mac and play.