one of my next B4R Maker Projects is an Arduino with Camera, sending pictures and stream to an Android Device and additional to a Raspberry Pi (Android Things, B4A) and PC (B4J).
Befor starting, seeking advice which Arduino Camera module - preferably I2C - and B4R,B4A,B4J libraries to use.
I don't think that Arduino is a good choice for video streaming. It is not powerful enough.
You can use a RPi with a camera instead or an Android device.
Streaming the video frames is easy with the MJPEG server code.
You can also take video recordings by RPi + USB Webcam, using FFMpeg (need installation on the RPI, google for it), but this is not for realtime sending to other devices.
I use it to record the front view of my car while driving.