Bluetooth audio as input for video recording
I requested developer Bluetooth Mono Router to explain this and if possible answer the question here but there is no response. What I could gather from comments and reviews is this :


App creates a virtual call environment thereby letting audio (music etc) be treated as voice and hence you can hear using mono ear sets meant for voice calls.
Recording of audio is not  by design. It's an incidental artifact of the virtual call feature. It's not a design feature.
This has nothing to do with Bluetooth versions