Hey @metin! Thank you for posting that example. The video does appear to freeze for the first couple seconds, while the rest of the video looks to operate as intended. If this is happening frequently, and resulting in black video for the first portion of your videos, it would be best to start with uninstalling and reinstalling the Ring app.
If this concern persists, I recommend checking the device RSSI in the Device Health section in the app. Check out our Community post on RSSI to see how your signal strength is delivering video. Minimizing the distance, walls, and appliances/ solid objects between your router and the connecting device, it always a great way to improve signal and video delivery. Let us know if this helps!