1. When installing the camera in the banquet hall, two kinds of wires should be laid: power cable and video cable. The camera should have more than 700 lines, and the video line should go to the projector in the second hall.

2. The video cable of the surveillance camera should be connected to the converter (BNC to VGA converter), and the converter can be connected to the projector through VGA cable. It's best to buy a converter with two VGA outputs, so that the other VGA port can connect to the TV, OK. If the converter has only one VGA socket, then buy a VGA distributor with one input and two outputs.

I don't think it is necessary to go to such trouble. Prepare a hand-held camera near the stage, connect the composite video line directly to the projector in Hall 2, and connect a composite video distributor. One in, two out, or one in, four out is ok. One projects a TV. Not counting cameras, it's around 200 yuan.