how to stream video in direct connection between 2 clients

If you stream video directly from one client to another, then you have to understand between two networking models: client-to-server and peer-to-peer. Server usually is static machine, with networking infrastructure, static ip and many things that allows accessibility by public. With peer-to-peer you will face many problems, first of them is going through NAT when you creating socket for receiving. One of client might need to create socket to accept connection, and second to accept. They might do both simultaneously and stick to first connected. Streaming video using web is not possible right now. There is only some beta development happening for Chrome and FireFox that will be publicly available not really soon. As well you can't establish peer-to-peer connection using WebSockets. So there is no way doing it using Web technologies. You might want to have a look into native Mobile development, but there you will face problems with peer-to-peer connections as well.