With transport-cc enabled video is more laggy and has higher latency


#1

Hi guys,

We use jitsi-videobridge (1077) and we create the offer for our peers.
If we put transport-cc (https://tools.ietf.org/html/draft-holmer-rmcat-transport-wide-cc-extensions-01) in the sdp then the video is laggy and has a higher latency compared to if we do not put it in the sdp. The video is a screenshare between Chrome and Chrome. If the two peers communicate peer-to-peer (with transport-cc) then the video is the same like without transport-cc at jitsi-videobridge, fine.
The same happens for older jitsi’s (for example 879, where I guess there is no transport-cc support yet, are the unknown rtcp-packets/header-extensions dropped in this case or just forwarded, I don’t know) as well.

Do you have a guess why could this happen?

Thanks,
nojz


#2

Adding this header extension activates send-side bandwidth estimations (ssbwe). If anything, this should improve things, not make it worst; so we’ll have to dig in further to find any answers.

Although unlikely, could it be that for some reason your clients don’t support ssbwe (so it gets activated in the bridge but not in the client)? Is this the only difference between your experiments? Is the latency difference significant enough to say with confidence that something is broken?

Also, just to have some context here, could you please post your JVB sip-communicator.properties?

Thanks for reporting the issue here.

Best,
George