RTSP協議分析（二）

以下是某省IPTV的RTSP協商過程：

DESCRIBE rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp?playtype=1&boid=001&backupagent=118.122.89.27:554&clienttype=1&time=20100929182111+08&life=172800&ifpricereqsnd=1&vcdnid=001&userid=123&mediaid=ch10083121594790060557&ctype=2&TSTVTimeLife=1800&contname=&authid=0&UserLiveType=1&nodelevel=3 RTSP/1.0
/媒體URL
Accept: application/sdp
//協商用於描述媒體資訊協議
CSeq: 1

User-Agent:ZTE Ltd.co RTSP protocal verion 1.0 guid-2.1.1.100/B519D290-C0EC-EE35-7368-893BE4C0B347
//User Agnet資訊，顯示是中興的伺服器，1.0的版本。如果是Helix伺服器的話會有Helix 伺服器的標識。
x-NAT:2.1.1.100:20081
//主要用於NAT穿透
x-zmssRtxSdp: yes

RTSP/1.0 200 OK
//應答編號
Server: ZXUSS100 1.0

Cache-Control: no-cache

Content-Base: rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp/

Content-Length: 320
//內容長度資訊
Content-Type: application/sdp
//描述內容資訊所用的協議
CSeq: 1

Date: Wed, 29 Sep 2010 10:20:38 GMT

Expires: Wed, 29 Sep 2010 10:20:38 GMT
// SDP 描述資訊

v=0

o=- 296874273 1 IN IP4 118.122.89.27

s=envivio

c=IN IP4 0.0.0.0

b=AS:1500

t=0 0

a=range:clock=20100929T095038.00Z-20100929T102038.00Z

m=video 5140 RTP/AVPF 33 96

a=control:trackID=2

a=rtpmap:33 MP2T/90000

a=3GPP-Adaptation-Support:5

a=rtcp-fb:33 nack

a=rtpmap:96 rtx/90000

a=fmtp:96 apt=33;rtx-time=0

SETUP rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp/trackID=2 RTSP/1.0
//用於建立RTSP串連，協商傳輸用的協議。
CSeq: 2

3GPP-Adaptation: url=rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp/trackID=2;size=1061400;target-time=2200

Transport: MP2T/RTP/UDP;unicast;destination=2.1.1.100;client_port=8360-8361,MP2T/RTP/TCP;unicast;destination=2.1.1.100;interleaved=0-1,MP2T/UDP;unicast;destination=2.1.1.100;client_port=8360-8361,MP2T/TCP;unicast;destination=2.1.1.100;interleaved=0-1
// MP2T/RTP/UDP表示是TS流用於RTP打包，基於UDP傳輸。MP2T/RTP/TCP表示是TS流用於RTP打包，基於TCP。
User-Agent:ZTE Ltd.co RTSP protocal verion 1.0 guid-2.1.1.100/B519D290-C0EC-EE35-7368-893BE4C0B347

RTSP/1.0 200 OK

Server: ZXUSS100 1.0

CSeq: 2

Date: Wed, 29 Sep 2010 10:20:38 GMT

Expires: Wed, 29 Sep 2010 10:20:38 GMT

Session: 65565885

Transport: MP2T/RTP/UDP;unicast;destination=2.1.1.100;client_port=8360-8361;server_port=13306-13307;source=118.122.89.29
// 通過協商MP2T/RTP/UDP表示是TS流用於RTP打包，基於UDP傳輸。server端連接埠：13306-13307。client端連接埠：8360-8361
3GPP-Adaptation:url=rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp/trackID=2;size=1061400;target-time=2200

PLAY rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp?playtype=1&boid=001&backupagent=118.122.89.27:554&clienttype=1&time=20100929182111+08&life=172800&ifpricereqsnd=1&vcdnid=001&userid=123&mediaid=ch10083121594790060557&ctype=2&TSTVTimeLife=1800&contname=&authid=0&UserLiveType=1&nodelevel=3 RTSP/1.0
//播放視頻。對於有些視頻可能會分別要對音頻視頻進行play。
CSeq: 3

Session: 65565885

User-Agent:ZTE Ltd.co RTSP protocal verion 1.0 guid-2.1.1.100/B519D290-C0EC-EE35-7368-893BE4C0B347

Scale: 1.0

Range: npt=end-

//npt=end-在IPTV2.0裡面有其自身的定義（可參看上海電信IPTV2.0標準）

RTSP/1.0 200 OK

Server: ZXUSS100 1.0

CSeq: 3

Range: npt=end-

Scale: 1.0

Session: 65565885

RTP-Info: url=rtsp://118.122.89.29:13306/live/ch10083121594790060557.sdp/trackID=2

......

PLAY rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp?playtype=1&boid=001&backupagent=118.122.89.27:554&clienttype=1&time=20100929182111+08&life=172800&ifpricereqsnd=1&vcdnid=001&userid=123&mediaid=ch10083121594790060557&ctype=2&TSTVTimeLife=1800&contname=&authid=0&UserLiveType=1&nodelevel=3 RTSP/1.0
//play的另外一種用法。用於快進和快退。
CSeq: 43

Session: 65565885

User-Agent:ZTE Ltd.co RTSP protocal verion 1.0 guid-2.1.1.100/B519D290-C0EC-EE35-7368-893BE4C0B347

Scale: -32.0
//Scale: -32.0，表示以32倍速快退。Scale: 32.0，表示以32倍速快進。
Range: npt=now-

RTSP/1.0 200 OK

Server: ZXUSS100 1.0

CSeq: 43

Range: clock=20100929T102609.02Z-20100929T095637.75Z

Scale: -32.0

Session: 65565885

RTP-Info: url=rtsp://118.122.89.36:10084/live/ch10083121594790060557.sdp/trackID=2;seq=22277;rtptime=1792329138

GET_PARAMETER rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp?playtype=1&boid=001&backupagent=118.122.89.27:554&clienttype=1&time=20100929182111+08&life=172800&ifpricereqsnd=1&vcdnid=001&userid=123&mediaid=ch10083121594790060557&ctype=2&TSTVTimeLife=1800&contname=&authid=0&UserLiveType=1&nodelevel=3 RTSP/1.0
//擷取當前的一些播放參數。
CSeq: 44

Session: 65565885

User-Agent:ZTE Ltd.co RTSP protocal verion 1.0 guid-2.1.1.100/B519D290-C0EC-EE35-7368-893BE4C0B347

x-Timeshift_Range
//請求時移的範圍
x-Timeshift_Current
//擷取當前的時間點

RTSP/1.0 200 OK
//返回當前的媒體資訊。
Server: ZXUSS100 1.0

CSeq: 44

Session: 65565885

x-Timeshift_Range: clock=20100929T095638.83Z-20100929T102638.83Z

x-Timeshift_Current: clock=20100929T102530.20Z;rtptime=1788844914

中間省去了45，46，47三個包。通過CSeq: 48欄位可以看出來

PLAY rtsp://118.122.89.27:554/live/ch10083121594790060557.sdp?playtype=1&boid=001&backupagent=118.122.89.27:554&clienttype=1&time=20100929182111+08&life=172800&ifpricereqsnd=1&vcdnid=001&userid=123&mediaid=ch10083121594790060557&ctype=2&TSTVTimeLife=1800&contname=&authid=0&UserLiveType=1&nodelevel=3 RTSP/1.0
用於恢複正常的播放速度。
CSeq: 48

Session: 65565885

User-Agent:ZTE Ltd.co RTSP protocal verion 1.0 guid-2.1.1.100/B519D290-C0EC-EE35-7368-893BE4C0B347

Scale: 1.0

Range: npt=beginning-

RTSP/1.0 200 OK

Server: ZXUSS100 1.0

CSeq: 48

Range: clock=20100929T095730.00Z-20100929T102730.61Z
//可以時移的範圍。
Scale: 1.0

Session: 65565885

RTP-Info: url=rtsp://118.122.89.36:10084/live/ch10083121594790060557.sdp/trackID=2;seq=39900;rtptime=1637595010

＜中間在Descript應答中所用的ＳＤＰ協議將會在以後中描述＞