I’ve attached a video file from my Cam Pan. It’s taken from inside my house looking down my driveway at around 3:07 am. The flashing light in the video is actually my wife’s car.
Recently, I’ve noticed that the camera is recording sound events that capture a “knocking noise”, or, a “tick-tock” sound. I don’t know if this is a camera artifact, or, a bug somewhere. I can clearly hear the noise on my Andoid app version 2.22.21. However, when I download the video and play it on Windows 10 using several video apps, there’s no sound.
There’s no consistency to when this happens. I’d like to find the cause. Any troubleshooting tips would be helpful.
No Audio in this clip, speaker shows muted
If I play the video from this site on my phone, I can hear the sound. So, I’m wondering if it’s a codec issue.
Either way, I need to find out what is causing the sound.
sounds like the I.R. cut filter switching in or out.
While it is light put your hand over camera and filter should click out.
Monitor in your app and see if that is the sound.
(Yes codec, sound on my phone worked)
This did not work. I held my hand in front of the camera and did not cause the sound. I also took a mail piece and held it in front with the same results. No sound was emitted.
This is what the IR cut filter sounds like, did it manually with the auto-on-off button for night vision
The video you posted will not play for me while logged on to the website from my Windows 10 laptop. I’ve also tried to toggle the Night Vision Mode like you did and it did not generate a sound event. It’s probably because I have Night Vision IR Lights set to off. My camera is on the inside of the house looking through a window.
Additionally, the sound was recorded this morning again at around 2:03am. This time, it was a single knock whereas the sample I posted is a knock-knock.
Try video from your smartphone maybe?
Listening to your video and my videos audio this in my opinion is the I.R. cut filter.
Or maybe you have a ghost 
I would be inclined to agree with your assumption, however, I don’t understand why the filter would trigger at different times, all when it is dark out. I guess I don’t fully understand how it works.