語音對講

定義

• 用戶端向設(shè)備通過視音頻點播請求音頻數(shù)據(jù)；
• 用戶端接收音頻數(shù)據(jù)并通過特定的播放設(shè)備（如音響）播放；
• 用戶端向設(shè)備發(fā)送廣播請求；
• 設(shè)備解析廣播成功后通過INVITE方法向用戶請求音頻數(shù)據(jù)；
• 用戶通過音頻采集設(shè)備獲取音頻數(shù)據(jù)；
• 用戶將采集的音頻數(shù)據(jù)發(fā)送至設(shè)備；

可以總結(jié)為：音頻數(shù)據(jù)的雙向傳輸。

抓包

1. 發(fā)送INVITE請求（ mysipsdk—>設(shè)備）

INVITE sip:xxx@192.168.0.111:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: sip:xxx@192.168.0.107;tag=xxx
To: sip:xxx@192.168.0.111
Contact: <sip:xxx@192.168.0.107:5060>
Call-ID: xxx
CSeq: 18467 INVITE
Allow: SUBSCRIBE, NOTIFY, INVITE, ACK, BYE, CANCEL, UPDATE
Supported: 
Subject: xxx:xx,xxx:xx
Content-Type: application/sdp
Content-Length:   169v=0
o=xxx 0 0 IN IP4 192.168.0.107
<!--請求媒體流的操作類型:Talk-->
s=Talk
c=IN IP4 192.168.0.107
t=0 0
<!--媒體類型:音頻(audio) 傳輸端口:38000 傳輸方式:UDP 負載類型:8(PCMA)-->
m=audio 38000 RTP/AVP 8
a=sendrecv
<!--負載類型:8(PCMA) 時鐘頻率:8000-->
a=rtpmap:8 PCMA/8000
<!--"f=v/編碼格式/分辨率/幀率/碼率/碼率大小a/編碼格式/碼率大小/采樣率"-->
f=v/a/1/8/1
y=0100000001

2. 接收設(shè)備響應(yīng)（設(shè)備—>mysipsdk）

SIP/2.0 200 OK
Call-ID: xxx
Contact: <sip:xxx@192.168.0.111:5060>
Content-Length: 270
Content-Type: application/sdp
CSeq: 18467 INVITE
From: <sip:xxx@192.168.0.107>;tag=xxx
To: <sip:xxx@192.168.0.111>;tag=xxx
User-Agent: SIP UAS V.2016.xxxx
Via: SIP/2.0/UDP 192.168.0.107:5060;rport=5060;branch=xxxv=0
o=xxx 0 0 IN IP4 192.168.0.111
s=Talk
i=VCam Talk Session
c=IN IP4 192.168.0.111
t=0 0
m=audio 9712 RTP/AVP 8
a=recvonly
a=rtpmap:8 PCMA/8000/1
m=audio 9712 RTP/AVP 8
a=sendonly
a=rtpmap:8 PCMA/8000/1
y=0100000001
f=v/0/0/0/0/0a/0/0/0

3. 發(fā)送ACK到設(shè)備（mysipsdk—>設(shè)備）

ACK sip:xxx@192.168.0.111:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: sip:xxx@192.168.0.107;tag=xxx
To: sip:xxx@192.168.0.111;tag=xxx
Call-ID: xxx
CSeq: 18467 ACK
Content-Length:  0

4. 接收音頻數(shù)據(jù)（設(shè)備—>mysipsdk）

代碼

• 組裝sdp

static std::string CreateSDPForAudio(const GB28181MediaContext& mediaContext)
{char str[500] = { 0 };pj_ansi_snprintf(str, 500,"v=0\n""o=%s 0 0 IN IP4 %s\n""s=Talk\n""c=IN IP4 %s\n""t=0 0\n""m=audio %d RTP/AVP 8\n""a=sendrecv\n""a=rtpmap:8 PCMA/8000\n""f=v/a/1/8/1\n""y=0100000001\n",mediaContext.GetDeviceId().c_str(),mediaContext.GetRecvAddress().c_str(),mediaContext.GetRecvAddress().c_str(),mediaContext.GetRecvPort());return str;
}

• 音頻數(shù)據(jù)接收與視頻數(shù)據(jù)接收類似，根據(jù)sdp協(xié)商確定接收的音頻格式；

語音廣播

要求

流程

抓包

1. 發(fā)送廣播通知（mysipsdk—>設(shè)備）

MESSAGE sip:xxx@192.168.0.111:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.107:5060;rport;branch=xxx
Max-Forwards: 70
From: <sip:xxx@192.168.0.107>;tag=xxx
To: <sip:xxx@xx>
Contact: <sip:xxx@192.168.0.107:5060>
Call-ID: xxx
CSeq: 18467 MESSAGE
Content-Type: Application/MANSCDP+xml
Content-Length:   186<?xml version="1.0" encoding="UTF-8"?>
<Notify>
<CmdType>Broadcast</CmdType>
<SN>130</SN>
<!--語音輸入設(shè)備的設(shè)備編碼-->
<SourceID>xxx</SourceID>
<!--語音輸出設(shè)備的設(shè)備編碼-->
<TargetID>xxx</TargetID>
</Notify>

2. 廣播通知響應(yīng)（設(shè)備—>mysipsdk）

SIP/2.0 200 OK
Call-ID: xxx
Content-Length: 0
CSeq: 18467 MESSAGE
From: <sip:xxx@192.168.0.107>;tag=xxx
To: <sip:xxx@xxx>;tag=xxx
User-Agent: SIP UAS V.2016.xxxx
Via: SIP/2.0/UDP 192.168.0.107:5060;rport=5060;branch=xxx

3. 廣播通知結(jié)果（設(shè)備—>mysipsdk）

MESSAGE sip:xxx@192.168.0.107 SIP/2.0
Call-ID: xxx
Content-Length: 180
Content-Type: Application/MANSCDP+xml
CSeq: 2 MESSAGE
From: <sip:xxx@192.168.0.111:5060>;tag=xxx
Max-Forwards: 70
To: <sip:xxx@192.168.0.107>
User-Agent: SIP UAS V.2016.xxxx
Via: SIP/2.0/UDP 192.168.0.111:5060;rport;branch=xxx<?xml version="1.0" encoding="GB2312" standalone="yes" ?>
<Response>
<CmdType>Broadcast</CmdType>
<SN>130</SN>
<DeviceID>xxx</DeviceID>
<Result>OK</Result>
</Response>

4. 廣播通知結(jié)果響應(yīng)（mysipsdk—>設(shè)備）

SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.0.111:5060;rport=5060;received=192.168.0.111;branch=xxx
Call-ID: xxx
From: <sip:xxx@192.168.0.111>;tag=xxx
To: <sip:xxx@192.168.0.107>;tag=xxx
CSeq: 2 MESSAGE
Content-Length:  0

5. 廣播請求（設(shè)備—>mysipsdk）

INVITE sip:xxx@192.168.0.107:5060 SIP/2.0
Call-ID: xxx
Contact: <sip:xxx@192.168.0.111:5060>
Content-Length: 240
Content-Type: application/sdp
CSeq: 1 INVITE
Expires: 120
From: <sip:xxx@192.168.0.111:5060>;tag=xxx
Max-Forwards: 70
Subject: xxx:xxx,xxx:xxx
To: <sip:xxx@192.168.0.107:5060>
User-Agent: SIP UAS V.2016.xxxx
Via: SIP/2.0/UDP 192.168.0.111:5060;rport;branch=xxxv=0
o=xxx 0 0 IN IP4 192.168.0.111
s=Play
i=VCam BroadCast Session
c=IN IP4 192.168.0.111
t=0 0
m=audio 9712 RTP/AVP 8 96
a=recvonly
a=rtpmap:8 PCMA/8000/1
a=rtpmap:96 PS/90000
y=0022371912
f=v/0/0/0/0/0a/1/8/1

6. 廣播請求響應(yīng)（mysipsdk—>設(shè)備）

SIP/2.0 200 OK
From: <sip:xxx@192.168.0.107:5060>;tag=xxx
To: <sip:xxx@192.168.0.111:5060>;tag=xxx
Call-ID: xxx
CSeq: 1 INVITE
User-Agent: General SIP UAS V1.0
Via: SIP/2.0/UDP 192.168.0.111:5060;rport;branch=xxx
Contact: <sip:xxx@192.168.0.107:5060>
Content-Type: application/SDP
Content-Length: 182v=0
o=xxx 0 0 IN IP4 192.168.0.107
s=Play
c=IN IP4 192.168.0.107
t=0 0
m=audio 40000 RTP/AVP 8
a=rtpmap:8 PCMA/8000
a=sendonly
y=0022371912

7. 廣播請求響應(yīng)ACK（設(shè)備—>mysipsdk）

ACK sip:xxx@192.168.0.107:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.0.111:5060;rport;branch=xxx
From: <sip:xxx@192.168.0.111:5060>;tag=xxx
To: <sip:xxx@192.168.0.107:5060>;tag=xxx
Call-ID: xxx
CSeq: 1 ACK
Contact: <sip:xxx@192.168.0.111:5060>
Max-Forwards: 70
User-Agent: IP Camera
Content-Length: 0

8. 關(guān)閉廣播（設(shè)備—>mysipsdk）

BYE sip:xxx@xxx SIP/2.0
From: <sip:xxx@xxx>;tag=xxx
To: <sip:xxx@xxx>;tag=xxx
CSeq: 2 BYE
Call-ID: xxx
Via: SIP/2.0/UDP 192.168.0.111:5060;branch=xxx
Max-Forwards: 70
Content-Length: 0

9. 關(guān)閉廣播響應(yīng)（mysipsdk—>設(shè)備）