Changes between Initial Version and Version 1 of 3rd_Party_Media

Timestamp:

Mar 15, 2008 9:38:41 AM (16 years ago)

Author:

bennylp

Comment:

--

3rd_Party_Media

@@ +1 @@
+= Integrating Third Party Media Stack with PJSIP =
+
+== Introduction ==
+
+PJSIP consists of several libraries which mostly are independent from one another. The library architecture diagram below shows how libraries are interacting with each other.
+
+
+
+== SIP and Media Interaction ==
+
+Pseudo-code when creating a call (same flow for caller and callee):
+
+'''create_call()'''[[BR]]
+{[[BR]]
+    ''// Create the dialog''[[BR]]
+    '''dlg = pjsip_dlg_create_uac/uas();'''
+
+    ''// Create media transport (pair of RTP/RTCP socket) for''[[BR]]
+    ''// transmitting/receiving the media from remote endpoint''[[BR]]
+    '''media_transport = pjmedia_transport_udp_create();'''
+
+    ''// Get the socket address info of the media transport''[[BR]]
+    ''// These are needed to create a complete SDP descriptor''[[BR]]
+    '''media_sock_info = pjmedia_transport_get_info(media_transport);'''
+   
+    ''// Create local SDP to be given to invite session''[[BR]]
+    '''sdp = pjmedia_endpt_create_sdp(media_sock_info);'''
+
+    ''// Create the invite session, giving it both the dialog''[[BR]]
+    ''// and local SDP to be negotiated''[[BR]]
+    '''inv = pjsip_inv_create_uac/uas();'''[[BR]]
+}
+
+'''pjsip_endpt_create_sdp(media_sock_info)'''[[BR]]
+{[[BR]]
+  ''// Query list of codecs that we support''[[BR]]
+  '''codec_list[] = pjmedia_codec_mgr_enum_codecs();'''
+
+  ''// Put each codec information in the SDP''[[BR]]
+  ...
+
+  ''// Put media socket address info in SDP c= and m= line''[[BR]]
+  ...
+
+  '''return sdp;'''
+}