Jitsi and Firefox, no video incoming ( but works on chrome and safari )

[Qualcuno]

Hi all. 

I hope to explain my problem clear as possible.

My environment consists of 3 main actors:

1. Jitsi as SFU server ( and also works as signaler )

2. a my webrtc application ( called WebPeer in this post )

3. a nodejs server that convert SDPs into "Jitsi" messages and viceversa when communication is a multiconference and works like a signaler if communication is p2p (and so no Jitsi is presents) 

So a multiconference communication sequence looks like that:

• WebPeer1 notify to Jitsi its presence and Jitsi create the room and join WebPeer1 to the room
• WebPeer2 notify the presence too and Jitsi join WebPeer2 to the room
• Now Jitsi create the offer with empty audio and video (into sdp they looks like msid:mixedmslabel mixedlabelaudio0 and msid:mixedmslabel mixedlabelvideo0) and sends this offer to WebPeer1 and WebPeer2
• Each WebPeer set this first remote offer and responds with their answer
• Jitsi, after answers set, send another offer with new ssrc informations
• Each WebPeer receive new offer and set as remoteDescription

Now, all works well in chrome and safari where all peers have audio and video streams in both directions ( managed by Jitsi becouse we are in a SFU ). 

But in firefox i have only remote audio, remote video ( incoming from Jitsi ) is not presents.

If i run into p2p mode ( so no Jitsi between WebPeers ) on Firefox it works well. 

I checked the content of transceiver ( after setRemoteDescription of first offer and after setRemoteDescription of second offer ) in a chrome session and in a firefox session and both looks similar.

Why multiconference works in chrome and safari and not in firefox??? 

Attached into SDPs.txt you can see the first offer from Jitsi, the answer of WebPeer and the second offer incoming from Jitsi. 

I spent several days with no solutions.