Most of the time poor audio performance is due to a slow connection to the camera, preventing the app from maintaining a solid, reliable connection. It may also be because you have set the camera quality much higher than your devices processor is capable of decoding while also providing lip synchronous audio. Try reducing the image quality, size, and frame rate to improve performance.
If the audio is still not performing well you can enable diagnostics which will give some indication of what is going on. This information can also help us troubleshoot with you. To enable it, go to Settings for the camera you are having issues with and enable the diagnostics view at the bottom on the list.