IM, video and voice chat
1 video cap
http://blog.chinaunix.net/uid-15063109-id-4530994.html
2 video encode and decode
http://blog.chinaunix.net/uid-15063109-id-4531903.html
3 udp send and recv
http://blog.chinaunix.net/uid-15063109-id-4532768.html
http://blog.chinaunix.net/uid-15063109-id-4536610.html
http://blog.chinaunix.net/uid-15063109-id-4544203.html
4 stun server
http://blog.chinaunix.net/uid-15063109-id-4548099.html