If I use an app (Airstream) to stream videos from PC to android phone using Wi-Fi connected to a network will it consume internet The streaming works if I remove the lab cable from the router.?

If you're streaming videos from your PC to your Android phone over a Wi-Fi network without an internet connection (i.e., with the lab cable removed from the router), the streaming will not consume any internet data. Instead, the data transfer occurs locally within your network. However, if your Wi-Fi network is connected to the internet, and you access any online content, it will use internet data.