Unable to set remote answer on Android (Flutter)

mediasoup libraries
1

Hi,

I am building a flutter app that will connect to a mediasoup server.

I am getting the following error when trying to produce an audio stream:
Failed to set remote answer sdp: Failed to set remote audio description send parameters.

See below the offer and answer sdp.

Any help would be much appreciated.
Cheers,
Yonatan

Offer:

v=0
o=- 5877506085759590400 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE audio
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:PV0d
a=ice-pwd:q98Z4y4llyjg4smZvNPzz90i
a=ice-options:trickle renomination
a=fingerprint:sha-256 BA:26:2B:12:75:4D:5E:EF:66:35:0F:0A:A6:1B:88:94:D3:83:31:5D:24:E4:50:1D:09:6F:EA:6C:36:14:71:0C
a=setup:actpass
a=mid:audio
a=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level
a=extmap:2 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01
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

Answer:

v=0
o=mediasoup-client 10000 1 IN IP4 0.0.0.0
s=-
t=0 0
a=ice-lite
a=fingerprint:sha-512 9A:52:B3:8B:9B:CC:32:2A:45:9E:73:4A:BE:1E:43:39:AD:A1:B3:43:53:F0:3D:DB:2F:1E:C1:91:14:D9:EA:3D:40:A0:4E:C4:6F:B1:46:28:A7:B2:41:78:BD:5C:EE:0E:25:34:B3:C3:09:BC:06:C2:A8:D8:C7:9C:E3:6A:A8:22
a=msid-semantic: WMS *
a=group:BUNDLE audio
m=audio 7 UDP/TLS/RTP/SAVPF
c=IN IP4 127.0.0.1
a=extmap:2 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01
a=mid:audio
a=recvonly
a=ice-ufrag:2ed3ax7wqk29a70n
a=ice-pwd:n7y0b6w5jx3erwlk8wvxorxqoycnoha9
a=candidate:udpcandidate 1 udp 1076302079 0.0.0.0 42643 typ host
a=end-of-candidates
a=ice-options:renomination
a=rtcp-mux
a=rtcp-rsize

2

No idea what Flutter is. Does it use react-native? If so ensure you are using the latest version of react-native-webrtc dep.

3

Hi,
Flutter is the next generation mobile development platform from google.
It is rapidly growing and provides a clean cross platform development experience.

The code is written in Dart so the react native libraries will not work.

I have made more progress by now and I am starting to translate all the SDP transformations + Device and Transport concepts from javascript to Dart…

I believe that a mediasoup plugin for dart will be super useful and I will try to package my code once it is working.

I will keep you updated

4

Nice. So it would be like a mediasoup-cient version written in Dart, right?

5

Yes exactly