Unstable video/audio, depending of the environments


#1

Hello !

I resolved all majors problems relatives to conferences in my environments, now I’m trying to improve the quality of the conferences (really poor in some environments).

First, I tried to have a conference with 5-6 person in Jitsi Meet exemple servers, it was perfect, no connection drop, no problem.

Then, I tried the same experience in some of my environments. In all of them, there was more or less some connectivity issues, black screens, connection losses etc…

Please find here the main errors I found in jvb.log during these sessions :

WARNING: SCTP connection with 14583068 not ready yet.
WARNING: No available transport channel, can't send a message
WARNING: A jump was detected in the picture IDs.
WARNING: Probe packet received: send time=22875 ms, recv time=1536765975064 ms, send delta=-1 ms, recv delta=-1 ms.
WARNING: Probe failed, sent at 1.04368E8 bps, received at 5.2184E7 bps. Mean send delta: 0.09090909090909091 ms, mean recv delta: 0.18181818181818182 ms, num probes: 11
WARNING: Cannot find SSRC for RTX, retransmitting plain. SSRC=924033984
WARNING: Unknown DTLS handshake message type: -93
WARNING: Cannot find SSRC for RTX, retransmitting plain. SSRC=3034771701
WARNING: invalid_rtt,stream=1563961509 ssrc=924033984,rtt=4739,now=1536766090033,lsr=2936358961,dlsr=721
WARNING: Packets dropped (hashCode=1450581955): 14000
WARNING: RTT not calculated, or has a suspiciously high value (2228). Using the default of 100ms.

These errors happens randomly without explicit reasons. When they starts, the conference quality also starts to drop.

Please let me know if you have any information on these errors.

Also, it there any server requirements to know if my set up is good or any test (iPerf) you could recommend to me ?

Thanks for your help !

Regards,

Jérôme


#2

What is the available bandwidth for your deployment? For 5 participants with simulcast 720p (chrome) you need very very roughly up to 30 Mbit/s upload and download.
One more thing, are you installing everything from debian packages? Jitsi-videobridge adjusts some network buffers on install, make sure those are set in your environment: https://github.com/jitsi/jitsi-videobridge/blob/master/config/20-jvb-udp-buffers.conf


#3

Hello !

Wow… 30Mb/s upload & download ? Even if we are only 3 or 4 people in a conference ? Actually, after some badwidth tests in my customer’s infrastructure, the server has 8Mb/s upload/download available.

Yep the buffers are properly configured !

Thanks for your answer

EDIT : For the record, when we started using Jitsi Meet, we did some consumption analyses and we found a usage of 12Mb/s output and 3Mb/s input. Do you think these numbers are obsolete ? Thanks !


#4

Yep, it was a real rough estimate. More on the bandwidth Bandwidth cost modeling
So meet.jit.si is using c5.xlarge for the bridges https://aws.amazon.com/ec2/instance-types/c5/, the bandwidth doesn’t go over 200Mb/s, this was just an example to say that 8Mb/s for jvb is very low.

So about the numbers in the link above the calculations are rough and the values are in best conditions, so real life values will be lower. So 4 people conference and 12Mb/s out and 3Mb/s in on the bridge means one person sending 3 and other muted, or 2 muted and 2 x 1.5 Mb/s and sending one large resolution and some thumbnails with lower quality.