Find this Linphone when looking for Open Source SIP Phone reference, download: http://www.linphone.org/eng/download/packages/linphone.html
After reading about the structure, we used Osip, exosip, and ortp protocol stack for development. 264 of the support was x264 (a sub-project of VLC ).
Haha, I had a lot to do with what I used to do. Basically, I used to develop the SIP protocol stack based on Osip, exosip, and RTP protocol stack based on ortp, the exosip is encapsulated to form a SIP Communication structure, and the streaming media is added with audio and video processing.
But later I thought that if I continue to do this, it would be almost equivalent to developing a SIP protocol stack based on exosip. The API provided by exosip itself is too low-level, there is also a lack of communication framework design to support the media layer, such as SDP processing and media negotiation. It takes a lot of work to build a complete terminal. Therefore, I would like to refer to the pjsip framework design to see how he can build a sip telephone framework, how to combine sip processing with RTP protocol processing, including processing streaming media.
Finding a Linphone saves a lot of trouble. I will study Linphone and see how it is organized and whether it can be improved or modified based on it. But the Linphone interface... should be changed.