What the differences between cSIPSimple and Android's SIP stack? What are the differences between Android's SIP stack and CSIPSimple's? One thing that I know of is that Android lacks STUN support.

I've used both but the call quality is far, far better on cSIPSimple and I'm curious as to why?
I understand I am commenting on the last post. But for future references :-

What I believe is, that CSIPSimple uses, audio codes, which are better than one provided in normal SIP Stack.