Can I connect through wifi direct instead of using hotspot
No. The V2 and V3 require access to the Internet to boot, and the Outdoor Camera, while able to do without the Internet, still requires the 3rd party Base to make a connection. So no true peer-to-peer.
Your question is a little vague. Do you mean can you connect to your home wifi or do you need to connect with a hotspot? Or are you actually talking about the Outdoor camera and base?
WiFi direct is another way of saying peer networking. It’s point to point between, for example, a phone and camera, without any WiFi router/access point required. I think @Newshound answered the question. The RTSP firmware could conceivably work this way but it, too, needs to phone home across the Internet. (Not applicable to Dafang Hacks.)