School use case: moderator-only video stream

Hi, I’m new here and, first and foremost, I want to thanks you all for this great software! :wink:

I’ve setup a couple of Jitsi Meet servers for Italian schools facing the pandemic lock-down. It works great, but some teachers have issues with channelLastN (as they want to see their pupils) while some students have issues with its lack due to their own client (either old pcs or low bandwidth) so they prefer a low channelLastN (say 3 or 4).

Now, I’d like to know if it would be possible to configure so that only teachers (moderators/organizers) can see the students (non-moderator). I think that would lower the load on student’s client while helping teachers with their needs. Is it something that can be obtained with a proper configuration? Is it something one developer could code in a reasonable amount of time?


Not sure if this would work but you could try to hand out different links to teachers and pupils where you set channelLastN in the URL fragment like (for students) and for teachers.

If this works it may also be possible to configure nginx (or whatever webserver you use) to serve different config.js files based on subdomains or URL parameters so that only the teacher would need to change the URL, although I am currently not sure how exactly this could to be done.

a One-to-Many setup with a possible solution that may be of interest for you has also been discussed in another thread:

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Another idea could be to inject some javascript that sets channelLastN=-1 if isModerator() returns true

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what is channel?
I have run the same example that you have given but i have not seen any changes.
Please help me

channelLastN is a setting from config.js:

My understanding is that channelLastN tells the videobridge to only send the mediastreams of the last N speakers.
Note however, as mentioned above, that I did not test if it is possible to apply different channelLastN settings per participant. It is well possible that it is a conference wide setting that is determined by the first participant who joins a conference.

Thanks a lot.

Thanks a lot @plokta, that’s exactly what I was looking for.

As far as I can see, it works like a charme with browser clients, but it doesn’t work with mobile ones.
Maybe the document.hash is lost during browser redirection?

Is there an hook available already for such kind of customizations?