Does Channel-LastN saves bandwidth in server?

I read about “channelLastN” configuration on jitsi meet’s config.js file. I want to understand how it works in order to improve our bandwidth estimation on the server side.

Assuming I have a conference with 50 participants with camera turned on and a “channelLastN” value equal to 10. Does videobridge receive video from all 50 participants and only forward the video from 10 participants? Or from the client side it is determined whether or not it should send its video stream to videobridge and jvb only receives the video streaming from 10 participants at a time?

I hope someone can solve this question for me.


This is correct.

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Also worth noting that the JVB and jitsi meet clients support the suspension of some streams: if no receiver it receiving a stream–which is more likely to happen with last-n set–then JVB will tell the sender to stop sending it, meaning fewer streams go to the JVB as well.


Thank you very much for the clarification, with this I will be able to do better estimations :slight_smile:

So that means that at a first moment, in the above example, jvb will be receiving all 50 participants streams but after a while if a participant is not in the last 10 last active speakers or is not pinned by other participant, will stop sending its video stream to jvb? That’s great! (as far as I know, this will not work that way on firefox clients, is that right?).

Thank you for your response!


So how does the Jitsi Meet web application respond to the notifications about the last 10 active speakers?
So for in the example of 50 participants, does the client see 50 video “windows” in a grid and 40 are blacked out or does it only show the 10 last active ones in a grid?
Does Jitsi have a configuration setting that sets the maximum number of video “windows” that can be shown at a time and you have to scroll to see the next set?