Why is there no audio?

Since the video is compressed into a hyperlapse, the audio is also compressed and therefore unintelligible. 

However, if you're rendering a hyperlapse at normal speed (1X) on Hyperlapse Mobile only, the audio remains intact. This is an excellent way to stabilize a normal speed video.  

I suggest using your favorite video editing software, such as Windows Movie Maker, to add audio and background music to your hyperlapse videos.