The authoring app only works with .wav files

[sarahakhavan]

Is your feature request related to a problem? Please describe.
The authoring app only works with .wav files, at least the last version of the jar file we have. This reduces the usability of the app.

Describe the solution you'd like
The app should work with at least the most common file types like mp3.

Describe alternatives you've considered
Address which file types the application is compatible with.