Intel INDE - Video Capturing for Unity 3D (How to Capture only the App Video and Audio instead of using mic)

Question

Good Day!

I've followed the instruction from this link: Intel® INDE Media for Mobile Tutorials - Video Capturing for Unity3d* Applications on Android* and I've made it working with my app. The problem only is that the audio uses the microphone for the recording and it created lots of noise thus producing a lower quality output file. My question is that how can I can just have only the plain video and audio (output of the app) capture? If this is not possible, how can I integrate an audio file to the recorded video? I hope you could give some guides and examples.

Thank you in advance!