RTSP protocol analysis (2)

The RTSP negotiation process of IPTV in a province is as follows:

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
/Media URL
Accept: application/sdp
// Negotiation is used to describe the Media Information Protocol
CSeq: 1

User-Agent: ZTE Ltd. co RTSP protocal verion 1.0 guid-2.1.1.100/B519D290-C0EC-EE35-7368-893BE4C0B347
// User Agnet information, indicating that it is a ZTE server, Version 1.0. If it is a Helix Server, there will be a Helix Server ID.
X-NAT: 2.1.1.100: 20081
// Mainly used for NAT penetration
X-zmssRtxSdp: yes

RTSP/1.0 200 OK
// Response ID
Server: zxus-9 1.0

Cache-Control: no-cache

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

Content-Length: 320
// Content length information
Content-Type: application/sdp
// Protocol used to describe content information
CSeq: 1

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

Expires: Wed, 29 Sep 2010 10:20:38 GMT
// SDP description

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 = pp-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
// Used to establish an RTSP connection and negotiate the transmission protocol.
CSeq: 2

Export pp-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 indicates that TS streams are used for RTP packaging and UDP-based transmission. MP2T/RTP/TCP indicates that the TS stream is used for RTP packaging and is based on 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: zxus-9 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
// Through negotiation, MP2T/RTP/UDP indicates that the TS stream is used for RTP packaging and UDP-based transmission. Server port: 13306-13307. Client port: 8360-8361
Export pp-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
// Play the video. For some videos, play the audio and video separately.
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: Treaty = end-

// The NMT = end-has its own definition in IPTV2.0 (see the IPTV2.0 standard of Shanghai Telecom)

RTSP/1.0 200 OK

Server: zxus-9 1.0

CSeq: 3

Range: Treaty = 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
// Another usage of play. Used for fast forward and fast return.
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, indicating to return quickly at 32 times. Scale: 32.0, indicating fast forward at 32 times.
Range: Treaty = now-

RTSP/1.0 200 OK

Server: zxus-9 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
// Obtain some current playback parameters.
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
// Request time shifting range
X-Timeshift_Current
// Obtain the current time point

RTSP/1.0 200 OK
// Returns the current media information.
Server: zxus-9 1.0

CSeq: 44

Session: 65565885

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

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

Three packages, 45, 46, and 47, are saved in the middle. It can be seen from the CSeq: 48 Field

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
It is used to restore the normal playback speed.
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: Treaty = beginning-

RTSP/1.0 200 OK

Server: zxus-9 1.0

CSeq: 48

Range: clock = 20100929T095730. 00Z-20100929T102730.61Z
// The time shifting range.
Scale: 1.0

Session: 65565885

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

<The SDP protocol used in the Descript response in the middle will be described later>