The Video Server's power out can provide up to 1.6A of power, if USB ports are not used to power any external device such as 2.5" HDD.
For VS04A, each camera can acquire power up to 400mA each.
If USB ports are to be used, then it is recommended that external power is provided to either the USB in order for the video server to have enough power to power on the camera or decrease the number of camera connected to the video server.