必须要素:
1. 必须包含subject头域
2. SDP中session name必须填写Play
3. SDP中不能懈怠audio
4. SDP中的video必须携带PS属性
以上4要素缺一不可。
示例:
1. 正确流程
P1->IPC
INVITEsip:[email protected] SIP/2.0
Via: SIP/2.0/UDP192.168.50.22:5060;branch=32dbcde3
From: "1001"<sip:[email protected]>;tag=591cf984
Contact:<sip:[email protected]:5060>
To:<sip:[email protected]>
Call-ID:[email protected]
CSeq: 172 INVITE
Max-Forwards: 70
Subject:34020000001320000001:0,1001:0
Content-Type: application/sdp
Content-Length: 381
v=0
o=root 853265891 853265891 IN IP4192.168.50.22
s=Play
c=IN IP4 192.168.50.22
t=0 0
m=video 19690 RTP/AVP 126 125 99 34 96
a=rtpmap:126 H264/90000
a=fmtp:126 profile-level-id=42e01e
a=rtpmap:125 H264S/90000
a=fmtp:125 profile-level-id=42e01e
a=rtpmap:99 MP4V-ES/90000
a=fmtp:99 profile-level-id=3
a=rtpmap:96 PS/90000
IPC->P1
SIP/2.0 200 OK
Via: SIP/2.0/UDP192.168.50.22:5060;branch=32dbcde3
From: "1001"<sip:[email protected]>;tag=591cf984
To:<sip:[email protected]>;tag=1292444290
Call-ID:[email protected]
CSeq: 172 INVITE
Contact:<sip:[email protected]:5060>
Content-Type: application/sdp
User-Agent: IP Camera
Content-Length: 267
v=0
o=1005 1935 1935 IN IP4 192.168.50.171
s=play
c=IN IP4 192.168.50.171
t=0 0
m=video 15060 RTP/AVP 96
a=sendonly
a=rtpmap:96 PS/90000
2. 不正确流程
P1->IPC
INVITEsip:[email protected] SIP/2.0
Via: SIP/2.0/UDP192.168.50.22:5060;branch=55b46723
From: "1001"<sip:[email protected]>;tag=1a72242e
Contact: <sip:[email protected]:5060>
To:<sip:[email protected]>
Call-ID:[email protected]
CSeq: 170 INVITE
Max-Forwards: 70
Subject:34020000001320000001:0,1001:0
Content-Type: application/sdp
Content-Length: 553
v=0
o=root 1437886243 1437886243 IN IP4192.168.50.22
s=Play
c=IN IP4 192.168.50.22
t=0 0
m=audio38406 RTP/AVP 0 8 3 114 18
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:3 GSM/8000
a=rtpmap:114 AMR/8000
a=fmtp:114 mode-set=7
a=rtpmap:18 G729/8000
m=video24674 RTP/AVP 126 125 99
a=recvonly
a=rtpmap:126 H264/90000
a=fmtp:126 profile-level-id=42e01e
a=rtpmap:125 H264S/90000
a=fmtp:125 profile-level-id=42e01e
a=rtpmap:99 MP4V-ES/90000
a=fmtp:99 profile-level-id=3
IPC->P1
SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.50.22:5060;branch=55b46723
From: "1001"<sip:[email protected]>;tag=1a72242e
To:<sip:[email protected]>;tag=2000948179
Call-ID:[email protected]
CSeq: 170 INVITE
Contact:<sip:[email protected]:5060>
Content-Type: application/sdp
User-Agent: IP Camera
Content-Length: 108
v=0
o=1005 3764 3764 IN IP4 192.168.50.171
s=play
c=IN IP4 192.168.50.171
t=0 0
m=video 15060RTP/AVP