未打开dtx时：
推流：
v=0
o=- 8155467687897462485 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE 0
a=msid-semantic: WMS stream_id
m=audio 9 UDP/TLS/RTP/SAVPF 111 103 104 9 102 0 8 106 105 13 110 112 113 126
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:ujEi
a=ice-pwd:tgWqJZt1eWauIk+z7I62NjiE
a=ice-options:trickle
a=fingerprint:sha-256 26:9B:97:4E:53:FB:DD:C5:97:8D:62:50:1D:88:FD:CC:AE:1C:75:CC:64:47:51:A8:56:4F:55:6B:31:F2:20:15
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=extmap:5 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:6 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=sendonly
a=msid:stream_id audio_label
a=rtcp-mux
a=rtpmap:111 opus/48000/2
a=rtcp-fb:111 transport-cc
a=fmtp:111 minptime=10;useinbandfec=1
a=rtpmap:103 ISAC/16000
a=rtpmap:104 ISAC/32000
a=rtpmap:9 G722/8000
a=rtpmap:102 ILBC/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:106 CN/32000
a=rtpmap:105 CN/16000
a=rtpmap:13 CN/8000
a=rtpmap:110 telephone-event/48000
a=rtpmap:112 telephone-event/32000
a=rtpmap:113 telephone-event/16000
a=rtpmap:126 telephone-event/8000
a=ssrc:91619396 cname:tJjk3m2s24XfEbkT
a=ssrc:91619396 msid:stream_id audio_label
a=ssrc:91619396 mslabel:stream_id
a=ssrc:91619396 label:audio_label
********************************************
v=0
o=- 8155467687897462485 2 IN IP4 120.24.60.187
s=VideoRoom 0
t=0 0
a=group:BUNDLE 0
a=msid-semantic: WMS janus
m=audio 9 UDP/TLS/RTP/SAVPF 111
c=IN IP4 120.24.60.187
a=recvonly
a=mid:0
a=rtcp-mux
a=ice-ufrag:32FU
a=ice-pwd:KetmlEXMpWb3UUHho4ZTX1
a=ice-options:trickle
a=fingerprint:sha-256 D2:B9:31:8F:DF:24:D8:0E:ED:D2:EF:25:9E:AF:6F:B8:34:AE:53:9C:E6:F3:8F:F2:64:15:FA:E8:7F:53:2D:38
a=setup:active
a=rtpmap:111 opus/48000/2
a=fmtp:111 useinbandfec=1
a=candidate:1 1 udp 2013266431 172.25.0.37 15928 typ host
a=candidate:2 1 udp 1677722111 120.24.60.187 15928 typ srflx raddr 172.25.0.37 rport 15928
a=end-of-candidates
订阅：
v=0
o=- 785276820297665115 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE 0
a=msid-semantic: WMS
m=audio 9 UDP/TLS/RTP/SAVPF 111 103 104 9 102 0 8 106 105 13 110 112 113 126
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:BvMy
a=ice-pwd:BDk32p1111WCKf4u5rE8ltjz
a=ice-options:trickle
a=fingerprint:sha-256 3C:05:89:FE:71:F1:FC:28:5E:24:BE:1E:80:A5:EF:16:36:1A:CC:65:40:C1:63:83:23:4B:7E:E5:BC:56:6F:A6
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=extmap:5 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:6 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=recvonly
a=rtcp-mux
a=rtpmap:111 opus/48000/2
a=rtcp-fb:111 transport-cc
a=fmtp:111 minptime=10;useinbandfec=1
a=rtpmap:103 ISAC/16000
a=rtpmap:104 ISAC/32000
a=rtpmap:9 G722/8000
a=rtpmap:102 ILBC/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:106 CN/32000
a=rtpmap:105 CN/16000
a=rtpmap:13 CN/8000
a=rtpmap:110 telephone-event/48000
a=rtpmap:112 telephone-event/32000
a=rtpmap:113 telephone-event/16000
a=rtpmap:126 telephone-event/8000
***************************************
v=0
o=- 1581003029264595 1 IN IP4 120.24.60.187
s=VideoRoom 0
t=0 0
a=group:BUNDLE 0
a=msid-semantic: WMS janus
m=audio 9 UDP/TLS/RTP/SAVPF 111
c=IN IP4 120.24.60.187
a=sendonly
a=mid:0
a=rtcp-mux
a=ice-ufrag:k00f
a=ice-pwd:rFeD8zMahXP5maEs6U7/jX
a=ice-options:trickle
a=fingerprint:sha-256 D2:B9:31:8F:DF:24:D8:0E:ED:D2:EF:25:9E:AF:6F:B8:34:AE:53:9C:E6:F3:8F:F2:64:15:FA:E8:7F:53:2D:38
a=setup:active
a=rtpmap:111 opus/48000/2
a=fmtp:111 useinbandfec=1
a=ssrc:3914013539 cname:janusaudio
a=ssrc:3914013539 msid:janus janusa0
a=ssrc:3914013539 mslabel:janus
a=ssrc:3914013539 label:janusa0
a=candidate:1 1 udp 2013266431 172.25.0.37 15541 typ host
a=candidate:2 1 udp 1677722111 120.24.60.187 15541 typ srflx raddr 172.25.0.37 rport 15541
a=end-of-candidates
推流audio_video
v=0
o=- 78571235875423419 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE 0 1
a=msid-semantic: WMS stream_id
m=audio 9 UDP/TLS/RTP/SAVPF 111 103 104 9 102 0 8 106 105 13 110 112 113 126
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:RFx3
a=ice-pwd:w4vWPBZuaTtJ9VU8Nl+LoRFC
a=ice-options:trickle
a=fingerprint:sha-256 7C:05:6D:D3:47:C4:1F:AB:87:8D:8C:B5:3E:6F:A8:6B:D4:75:28:A7:39:1B:77:7B:F6:74:78:D7:83:82:A9:15
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=extmap:5 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:6 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=sendonly
a=msid:stream_id audio_label
a=rtcp-mux
a=rtpmap:111 opus/48000/2
a=rtcp-fb:111 transport-cc
a=fmtp:111 minptime=10;useinbandfec=1
a=rtpmap:103 ISAC/16000
a=rtpmap:104 ISAC/32000
a=rtpmap:9 G722/8000
a=rtpmap:102 ILBC/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:106 CN/32000
a=rtpmap:105 CN/16000
a=rtpmap:13 CN/8000
a=rtpmap:110 telephone-event/48000
a=rtpmap:112 telephone-event/32000
a=rtpmap:113 telephone-event/16000
a=rtpmap:126 telephone-event/8000
a=ssrc:2384348938 cname:jl2sTthZYbId2i0t
a=ssrc:2384348938 msid:stream_id audio_label
a=ssrc:2384348938 mslabel:stream_id
a=ssrc:2384348938 label:audio_label
m=video 9 UDP/TLS/RTP/SAVPF 96 97 98 99 100
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:RFx3
a=ice-pwd:w4vWPBZuaTtJ9VU8Nl+LoRFC
a=ice-options:trickle
a=fingerprint:sha-256 7C:05:6D:D3:47:C4:1F:AB:87:8D:8C:B5:3E:6F:A8:6B:D4:75:28:A7:39:1B:77:7B:F6:74:78:D7:83:82:A9:15
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:12 http://www.webrtc.org/experiments/rtp-hdrext/playout-delay
a=extmap:11 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://tools.ietf.org/html/draft-ietf-avtext-framemarking-07
a=extmap:9 http://www.webrtc.org/experiments/rtp-hdrext/color-space
a=extmap:4 urn:ietf:params:rtp-hdrext:sdes:mid
a=extmap:5 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:6 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=sendonly
a=msid:stream_id video_label
a=rtcp-mux
a=rtcp-rsize
a=rtpmap:96 VP8/90000
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 red/90000
a=rtpmap:99 rtx/90000
a=fmtp:99 apt=98
a=rtpmap:100 ulpfec/90000
a=ssrc-group:FID 65423195 2078241068
a=ssrc:65423195 cname:jl2sTthZYbId2i0t
a=ssrc:65423195 msid:stream_id video_label
a=ssrc:65423195 mslabel:stream_id
a=ssrc:65423195 label:video_label
a=ssrc:2078241068 cname:jl2sTthZYbId2i0t
a=ssrc:2078241068 msid:stream_id video_label
a=ssrc:2078241068 mslabel:stream_id
a=ssrc:2078241068 label:video_label
打开dtx时：
rtp包会在E:webrtc-checkoutwebrtcsrcaudiochannel_receive.cc-OnRtpPacket因找不到编码器而丢弃
const auto& it = payload_type_frequencies_.find(packet.PayloadType());
if (it == payload_type_frequencies_.end())
return;
推流：
v=0
o=- 1579512236441539021 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE 0
a=msid-semantic: WMS stream_id
m=audio 9 UDP/TLS/RTP/SAVPF 96 103 104 9 102 0 8 106 105 13 110 112 113 126
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:jkUu
a=ice-pwd:fUwxMu4JoAK88edFKISUfasU
a=ice-options:trickle
a=fingerprint:sha-256 D7:CF:0D:9D:7F:B6:EC:80:F1:F1:6F:5F:72:6A:4A:1C:3D:97:5A:3C:0A:A5:0D:AA:F9:FB:1F:06:0C:AF:43:8F
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=extmap:5 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:6 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=sendonly
a=msid:stream_id audio_label
a=rtcp-mux
a=rtpmap:96 opus/48000/2
a=rtcp-fb:96 transport-cc
a=fmtp:96 minptime=10;usedtx=1;useinbandfec=1
a=rtpmap:103 ISAC/16000
a=rtpmap:104 ISAC/32000
a=rtpmap:9 G722/8000
a=rtpmap:102 ILBC/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:106 CN/32000
a=rtpmap:105 CN/16000
a=rtpmap:13 CN/8000
a=rtpmap:110 telephone-event/48000
a=rtpmap:112 telephone-event/32000
a=rtpmap:113 telephone-event/16000
a=rtpmap:126 telephone-event/8000
a=ssrc:3969198492 cname:RbwJRYnnvDufut7R
a=ssrc:3969198492 msid:stream_id audio_label
a=ssrc:3969198492 mslabel:stream_id
a=ssrc:3969198492 label:audio_label
**********************************
v=0
o=- 1579512236441539021 2 IN IP4 120.24.60.187
s=VideoRoom 0
t=0 0
a=group:BUNDLE 0
a=msid-semantic: WMS janus
m=audio 9 UDP/TLS/RTP/SAVPF 96
c=IN IP4 120.24.60.187
a=recvonly
a=mid:0
a=rtcp-mux
a=ice-ufrag:/wfc
a=ice-pwd:PzLfHlS22YjLqp8+KrMOlZ
a=ice-options:trickle
a=fingerprint:sha-256 D2:B9:31:8F:DF:24:D8:0E:ED:D2:EF:25:9E:AF:6F:B8:34:AE:53:9C:E6:F3:8F:F2:64:15:FA:E8:7F:53:2D:38
a=setup:active
a=rtpmap:96 opus/48000/2
a=fmtp:96 useinbandfec=1;usedtx=1
a=candidate:1 1 udp 2013266431 172.25.0.37 19601 typ host
a=candidate:2 1 udp 1677722111 120.24.60.187 19601 typ srflx raddr 172.25.0.37 rport 19601
a=end-of-candidates
订阅：
v=0
o=- 3720588689885472729 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE 0
a=msid-semantic: WMS
m=audio 9 UDP/TLS/RTP/SAVPF 96 103 104 9 102 0 8 106 105 13 110 112 113 126
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:JUJP
a=ice-pwd:k8QKVQLROATIdVBZUL0TCxVj
a=ice-options:trickle
a=fingerprint:sha-256 3A:9A:15:DA:E7:DF:97:D4:C4:CD:EB:A1:10:36:24:CE:7A:FE:D4:69:FC:14:D2:6C:6B:9D:B5:38:20:8F:D6:3A
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=extmap:5 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:6 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=recvonly
a=rtcp-mux
a=rtpmap:96 opus/48000/2
a=rtcp-fb:96 transport-cc
a=fmtp:96 minptime=10;usedtx=1;useinbandfec=1
a=rtpmap:103 ISAC/16000
a=rtpmap:104 ISAC/32000
a=rtpmap:9 G722/8000
a=rtpmap:102 ILBC/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:106 CN/32000
a=rtpmap:105 CN/16000
a=rtpmap:13 CN/8000
a=rtpmap:110 telephone-event/48000
a=rtpmap:112 telephone-event/32000
a=rtpmap:113 telephone-event/16000
a=rtpmap:126 telephone-event/8000
**************************************
v=0
o=- 1581002379465633 1 IN IP4 120.24.60.187
s=VideoRoom 0
t=0 0
a=group:BUNDLE 0
a=msid-semantic: WMS janus
m=audio 9 UDP/TLS/RTP/SAVPF 111
c=IN IP4 120.24.60.187
a=sendonly
a=mid:0
a=rtcp-mux
a=ice-ufrag:aH6Z
a=ice-pwd:IZC2IBO8rALtwCmdWuope+
a=ice-options:trickle
a=fingerprint:sha-256 D2:B9:31:8F:DF:24:D8:0E:ED:D2:EF:25:9E:AF:6F:B8:34:AE:53:9C:E6:F3:8F:F2:64:15:FA:E8:7F:53:2D:38
a=setup:active
a=rtpmap:111 opus/48000/2
a=fmtp:111 useinbandfec=1;usedtx=1
a=ssrc:3023736237 cname:janusaudio
a=ssrc:3023736237 msid:janus janusa0
a=ssrc:3023736237 mslabel:janus
a=ssrc:3023736237 label:janusa0
a=candidate:1 1 udp 2013266431 172.25.0.37 17313 typ host
a=candidate:2 1 udp 1677722111 120.24.60.187 17313 typ srflx raddr 172.25.0.37 rport 17313
a=end-of-candidates
推流audio_video
v=0
o=- 8883530653145943504 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE 0 1
a=msid-semantic: WMS stream_id
m=audio 9 UDP/TLS/RTP/SAVPF 96 103 104 9 102 0 8 106 105 13 110 112 113 126
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:CZQi
a=ice-pwd:jN80sL4owFKILohls5hwZsOX
a=ice-options:trickle
a=fingerprint:sha-256 75:1D:66:D6:D8:EF:CB:AB:65:72:C3:9A:0D:AE:3D:7C:33:E4:B1:74:BA:11:21:C3:1E:22:C0:57:A2:2A:BB:2E
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=extmap:5 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:6 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=sendonly
a=msid:stream_id audio_label
a=rtcp-mux
a=rtpmap:96 opus/48000/2
a=rtcp-fb:96 transport-cc
a=fmtp:96 minptime=10;usedtx=1;useinbandfec=1
a=rtpmap:103 ISAC/16000
a=rtpmap:104 ISAC/32000
a=rtpmap:9 G722/8000
a=rtpmap:102 ILBC/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:106 CN/32000
a=rtpmap:105 CN/16000
a=rtpmap:13 CN/8000
a=rtpmap:110 telephone-event/48000
a=rtpmap:112 telephone-event/32000
a=rtpmap:113 telephone-event/16000
a=rtpmap:126 telephone-event/8000
a=ssrc:2570390951 cname:NlH8KXjPM3OcPO5R
a=ssrc:2570390951 msid:stream_id audio_label
a=ssrc:2570390951 mslabel:stream_id
a=ssrc:2570390951 label:audio_label
m=video 9 UDP/TLS/RTP/SAVPF 127 97 98 99 100
c=IN IP4 0.0.0.0
a=rtcp:9 IN IP4 0.0.0.0
a=ice-ufrag:CZQi
a=ice-pwd:jN80sL4owFKILohls5hwZsOX
a=ice-options:trickle
a=fingerprint:sha-256 75:1D:66:D6:D8:EF:CB:AB:65:72:C3:9A:0D:AE:3D:7C:33:E4:B1:74:BA:11:21:C3:1E:22:C0:57:A2:2A:BB:2E
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:12 http://www.webrtc.org/experiments/rtp-hdrext/playout-delay
a=extmap:11 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://tools.ietf.org/html/draft-ietf-avtext-framemarking-07
a=extmap:9 http://www.webrtc.org/experiments/rtp-hdrext/color-space
a=extmap:4 urn:ietf:params:rtp-hdrext:sdes:mid
a=extmap:5 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
a=extmap:6 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
a=sendonly
a=msid:stream_id video_label
a=rtcp-mux
a=rtcp-rsize
a=rtpmap:127 VP8/90000
a=rtcp-fb:127 goog-remb
a=rtcp-fb:127 transport-cc
a=rtcp-fb:127 ccm fir
a=rtcp-fb:127 nack
a=rtcp-fb:127 nack pli
a=rtpmap:97 rtx/90000
a=fmtp:97 apt=127
a=rtpmap:98 red/90000
a=rtpmap:99 rtx/90000
a=fmtp:99 apt=98
a=rtpmap:100 ulpfec/90000
a=ssrc-group:FID 3626635693 2048413491
a=ssrc:3626635693 cname:NlH8KXjPM3OcPO5R
a=ssrc:3626635693 msid:stream_id video_label
a=ssrc:3626635693 mslabel:stream_id
a=ssrc:3626635693 label:video_label
a=ssrc:2048413491 cname:NlH8KXjPM3OcPO5R
a=ssrc:2048413491 msid:stream_id video_label
a=ssrc:2048413491 mslabel:stream_id
a=ssrc:2048413491 label:video_label
最后解决方法，直接通过修改sdp给opus字段加上usedtx=1;就可以打开dtx