一。webrtc视频播放的时序流程图![image]()
二。浏览器发送的offer信息
v=0
o=- 3802064708842271905 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE 0 1 2
a=extmap-allow-mixed
a=msid-semantic: WMS
m=audio 9 UDP/TLS/RTP/SAVPF 111 63 9 0 8 13 110 126 // 浏览器音频流通道
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:ofY1
a=ice-pwd:ePn5fvGsV4xYHuzDpZbPbaBr
a=ice-options:trickle
a=fingerprint:sha-256 3C:E1:95:E7:CA:07:3A:9E:76:51:A2:AD:56:D6:64:53:CE:6E:F0:B0:30:6C:AE:B4:BD:E9:26:0B:8F:9F:9B:FB
a=setup:actpass
a=mid:0
a=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level
a=extmap:2 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
a=extmap:3 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01
a=extmap:4 urn:ietf:params:rtp-hdrext:sdes:mid
a=recvonly // 浏览器只接收
a=rtcp-mux
a=rtcp-rsize
a=rtpmap:111 opus/48000/2 // 浏览器支持的音频编码
a=rtcp-fb:111 transport-cc
a=fmtp:111 minptime=10;useinbandfec=1
a=rtpmap:63 red/48000/2
a=fmtp:63 111/111
a=rtpmap:9 G722/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:13 CN/8000
a=rtpmap:110 telephone-event/48000
a=rtpmap:126 telephone-event/8000
m=video 9 UDP/TLS/RTP/SAVPF 96 97 98 99 100 101 35 36 37 38 103 104 107 108 109 114 115 116 117 118 39 40 41 42 43 44 45 46 47 48 119 120 121 122 49 50 51 52 123 124 125 53 // 浏览器视频流通道
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:ofY1
a=ice-pwd:ePn5fvGsV4xYHuzDpZbPbaBr
a=ice-options:trickle
a=fingerprint:sha-256 3C:E1:95:E7:CA:07:3A:9E:76:51:A2:AD:56:D6:64:53:CE:6E:F0:B0:30:6C:AE:B4:BD:E9:26:0B:8F:9F:9B:FB
a=setup:actpass
a=mid:1
a=extmap:14 urn:ietf:params:rtp-hdrext:toffset
a=extmap:2 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
a=extmap:13 urn:3gpp:video-orientation
a=extmap:3 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01
a=extmap:5 http://www.webrtc.org/experiments/rtp-hdrext/playout-delay
a=extmap:6 http://www.webrtc.org/experiments/rtp-hdrext/video-content-type
a=extmap:7 http://www.webrtc.org/experiments/rtp-hdrext/video-timing
a=extmap:8 http://www.webrtc.org/experiments/rtp-hdrext/color-space
a=extmap:4 urn:ietf:params:rtp-hdrext:sdes:mid
a=extmap:10 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:11 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=recvonly // 浏览器只接收
a=rtcp-mux
a=rtcp-rsize
a=rtpmap:96 VP8/90000 // 浏览器支持的视频编码
a=rtcp-fb:96 goog-remb
a=rtcp-fb:96 transport-cc
a=rtcp-fb:96 ccm fir
a=rtcp-fb:96 nack
a=rtcp-fb:96 nack pli
a=rtpmap:97 rtx/90000
a=fmtp:97 apt=96
a=rtpmap:98 VP9/90000
a=rtcp-fb:98 goog-remb
a=rtcp-fb:98 transport-cc
a=rtcp-fb:98 ccm fir
a=rtcp-fb:98 nack
a=rtcp-fb:98 nack pli
a=fmtp:98 profile-id=0
a=rtpmap:99 rtx/90000
a=fmtp:99 apt=98
a=rtpmap:100 VP9/90000
a=rtcp-fb:100 goog-remb
a=rtcp-fb:100 transport-cc
a=rtcp-fb:100 ccm fir
a=rtcp-fb:100 nack
a=rtcp-fb:100 nack pli
a=fmtp:100 profile-id=2
a=rtpmap:101 rtx/90000
a=fmtp:101 apt=100
a=rtpmap:35 VP9/90000
a=rtcp-fb:35 goog-remb
a=rtcp-fb:35 transport-cc
a=rtcp-fb:35 ccm fir
a=rtcp-fb:35 nack
a=rtcp-fb:35 nack pli
a=fmtp:35 profile-id=1
a=rtpmap:36 rtx/90000
a=fmtp:36 apt=35
a=rtpmap:37 VP9/90000
a=rtcp-fb:37 goog-remb
a=rtcp-fb:37 transport-cc
a=rtcp-fb:37 ccm fir
a=rtcp-fb:37 nack
a=rtcp-fb:37 nack pli
a=fmtp:37 profile-id=3
a=rtpmap:38 rtx/90000
a=fmtp:38 apt=37
a=rtpmap:103 H264/90000
a=rtcp-fb:103 goog-remb
a=rtcp-fb:103 transport-cc
a=rtcp-fb:103 ccm fir
a=rtcp-fb:103 nack
a=rtcp-fb:103 nack pli
a=fmtp:103 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f
a=rtpmap:104 rtx/90000
a=fmtp:104 apt=103
a=rtpmap:107 H264/90000
a=rtcp-fb:107 goog-remb
a=rtcp-fb:107 transport-cc
a=rtcp-fb:107 ccm fir
a=rtcp-fb:107 nack
a=rtcp-fb:107 nack pli
a=fmtp:107 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42001f
a=rtpmap:108 rtx/90000
a=fmtp:108 apt=107
a=rtpmap:109 H264/90000
a=rtcp-fb:109 goog-remb
a=rtcp-fb:109 transport-cc
a=rtcp-fb:109 ccm fir
a=rtcp-fb:109 nack
a=rtcp-fb:109 nack pli
a=fmtp:109 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f
a=rtpmap:114 rtx/90000
a=fmtp:114 apt=109
a=rtpmap:115 H264/90000
a=rtcp-fb:115 goog-remb
a=rtcp-fb:115 transport-cc
a=rtcp-fb:115 ccm fir
a=rtcp-fb:115 nack
a=rtcp-fb:115 nack pli
a=fmtp:115 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=42e01f
a=rtpmap:116 rtx/90000
a=fmtp:116 apt=115
a=rtpmap:117 H264/90000
a=rtcp-fb:117 goog-remb
a=rtcp-fb:117 transport-cc
a=rtcp-fb:117 ccm fir
a=rtcp-fb:117 nack
a=rtcp-fb:117 nack pli
a=fmtp:117 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=4d001f
a=rtpmap:118 rtx/90000
a=fmtp:118 apt=117
a=rtpmap:39 H264/90000
a=rtcp-fb:39 goog-remb
a=rtcp-fb:39 transport-cc
a=rtcp-fb:39 ccm fir
a=rtcp-fb:39 nack
a=rtcp-fb:39 nack pli
a=fmtp:39 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=4d001f
a=rtpmap:40 rtx/90000
a=fmtp:40 apt=39
a=rtpmap:41 H264/90000
a=rtcp-fb:41 goog-remb
a=rtcp-fb:41 transport-cc
a=rtcp-fb:41 ccm fir
a=rtcp-fb:41 nack
a=rtcp-fb:41 nack pli
a=fmtp:41 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=f4001f
a=rtpmap:42 rtx/90000
a=fmtp:42 apt=41
a=rtpmap:43 H264/90000
a=rtcp-fb:43 goog-remb
a=rtcp-fb:43 transport-cc
a=rtcp-fb:43 ccm fir
a=rtcp-fb:43 nack
a=rtcp-fb:43 nack pli
a=fmtp:43 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=f4001f
a=rtpmap:44 rtx/90000
a=fmtp:44 apt=43
a=rtpmap:45 AV1/90000
a=rtcp-fb:45 goog-remb
a=rtcp-fb:45 transport-cc
a=rtcp-fb:45 ccm fir
a=rtcp-fb:45 nack
a=rtcp-fb:45 nack pli
a=fmtp:45 level-idx=5;profile=0;tier=0
a=rtpmap:46 rtx/90000
a=fmtp:46 apt=45
a=rtpmap:47 AV1/90000
a=rtcp-fb:47 goog-remb
a=rtcp-fb:47 transport-cc
a=rtcp-fb:47 ccm fir
a=rtcp-fb:47 nack
a=rtcp-fb:47 nack pli
a=fmtp:47 level-idx=5;profile=1;tier=0
a=rtpmap:48 rtx/90000
a=fmtp:48 apt=47
a=rtpmap:119 H264/90000
a=rtcp-fb:119 goog-remb
a=rtcp-fb:119 transport-cc
a=rtcp-fb:119 ccm fir
a=rtcp-fb:119 nack
a=rtcp-fb:119 nack pli
a=fmtp:119 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=64001f
a=rtpmap:120 rtx/90000
a=fmtp:120 apt=119
a=rtpmap:121 H264/90000
a=rtcp-fb:121 goog-remb
a=rtcp-fb:121 transport-cc
a=rtcp-fb:121 ccm fir
a=rtcp-fb:121 nack
a=rtcp-fb:121 nack pli
a=fmtp:121 level-asymmetry-allowed=1;packetization-mode=0;profile-level-id=64001f
a=rtpmap:122 rtx/90000
a=fmtp:122 apt=121
a=rtpmap:49 H265/90000
a=rtcp-fb:49 goog-remb
a=rtcp-fb:49 transport-cc
a=rtcp-fb:49 ccm fir
a=rtcp-fb:49 nack
a=rtcp-fb:49 nack pli
a=fmtp:49 level-id=180;profile-id=1;tier-flag=0;tx-mode=SRST
a=rtpmap:50 rtx/90000
a=fmtp:50 apt=49
a=rtpmap:51 H265/90000
a=rtcp-fb:51 goog-remb
a=rtcp-fb:51 transport-cc
a=rtcp-fb:51 ccm fir
a=rtcp-fb:51 nack
a=rtcp-fb:51 nack pli
a=fmtp:51 level-id=180;profile-id=2;tier-flag=0;tx-mode=SRST
a=rtpmap:52 rtx/90000
a=fmtp:52 apt=51
a=rtpmap:123 red/90000
a=rtpmap:124 rtx/90000
a=fmtp:124 apt=123
a=rtpmap:125 ulpfec/90000
a=rtpmap:53 flexfec-03/90000
a=rtcp-fb:53 goog-remb
a=rtcp-fb:53 transport-cc
a=fmtp:53 repair-window=10000000
m=application 9 UDP/DTLS/SCTP webrtc-datachannel // 浏览器数据通道流
c=IN IP4 0.0.0.0
a=ice-ufrag:ofY1
a=ice-pwd:ePn5fvGsV4xYHuzDpZbPbaBr
a=ice-options:trickle
a=fingerprint:sha-256 3C:E1:95:E7:CA:07:3A:9E:76:51:A2:AD:56:D6:64:53:CE:6E:F0:B0:30:6C:AE:B4:BD:E9:26:0B:8F:9F:9B:FB
a=setup:actpass
a=mid:2
a=sctp-port:5000
a=max-message-size:262144
三。ZLM回复的answer信息
v=0
o=- 3802064708842271905 2 IN IP4 172.23.57.90
s=-
t=0 0
a=group:BUNDLE 0 1 2
a=msid-semantic: WMS
a=ice-lite // ZLM服务端采用ICE LITE模式
m=audio 8000 UDP/TLS/RTP/SAVPF 8 // ZLM的音频流
c=IN IP4 172.23.57.90
a=rtcp:8000 IN IP4 172.23.57.90
a=ice-ufrag:rBIABB9AH0A=_1427
a=ice-pwd:j9BnFnaGJTZuQ5xLlz8sP5Jb
a=ice-options:trickle
a=fingerprint:sha-256 5D:43:0F:2C:BD:82:BB:C5:B4:77:42:D3:8C:2B:D5:1A:32:59:39:1D:78:7A:BB:88:E2:EF:2A:60:37:AD:6E:A3
a=setup:passive
a=mid:0
a=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level
a=extmap:2 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
a=extmap:3 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01
a=inactive // ZLM中未包含音频流
a=rtcp-mux
a=rtpmap:8 PCMA/8000/1
a=msid:zlmediakit-mslabel zlmediakit-label-0
a=ssrc:2 cname:zlmediakit-rtp
a=ssrc:2 msid:zlmediakit-mslabel zlmediakit-label-0
a=ssrc:2 mslabel:zlmediakit-mslabel
a=ssrc:2 label:zlmediakit-label-0
a=candidate:udpcandidate 1 udp 120 172.23.57.90 8000 typ host // ZLM的候选地址UDP
a=candidate:tcpcandidate 1 tcp 115 172.23.57.90 8000 typ host tcptype passive // ZLM的候选地址TCP
m=video 8000 UDP/TLS/RTP/SAVPF 103 104 // ZLM的视频流
a=mid:1
a=extmap:14 urn:ietf:params:rtp-hdrext:toffset
a=extmap:5 http://www.webrtc.org/experiments/rtp-hdrext/playout-delay
a=extmap:6 http://www.webrtc.org/experiments/rtp-hdrext/video-content-type
a=extmap:7 http://www.webrtc.org/experiments/rtp-hdrext/video-timing
a=extmap:8 http://www.webrtc.org/experiments/rtp-hdrext/color-space
a=extmap:10 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:11 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=sendonly // ZLM只发送视频流
a=rtpmap:103 H264/90000 // ZLM协商出来支持的视频编码格式
a=rtcp-fb:103 ccm fir
a=rtcp-fb:103 goog-remb
a=rtcp-fb:103 nack
a=rtcp-fb:103 nack pli
a=rtcp-fb:103 transport-cc
a=fmtp:103 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42001f
a=rtpmap:104 rtx/90000
a=fmtp:104 apt=103
a=msid:zlmediakit-mslabel zlmediakit-label-1
a=ssrc:1 cname:zlmediakit-rtp
a=ssrc:1 msid:zlmediakit-mslabel zlmediakit-label-1
a=ssrc:1 mslabel:zlmediakit-mslabel
a=ssrc:1 label:zlmediakit-label-1
a=ssrc:3 cname:zlmediakit-rtp
a=ssrc:3 msid:zlmediakit-mslabel zlmediakit-label-1
a=ssrc:3 mslabel:zlmediakit-mslabel
a=ssrc:3 label:zlmediakit-label-1
a=ssrc-group:FID 1 3
m=application 8000 UDP/DTLS/SCTP webrtc-datachannel // ZLM的数据通道
a=mid:2
a=sctp-port:5000
