hello friends,

As a professional doctor's platform we had quite a lot live web conference experiences during the pandemic.

After some (may be many :) ) failures let me share my experiences and the working solutions:

•    after doing some not good resulting setups we needed to seperate the lecturers and audience because if there are any problems with the server (attacks, nasty people) where many audience are this effected the all presentation.
•    for this we moved the lecturers out of the jitsi conference rooms to melonapp.com (web based streamyard like app up to 10 speakers at once, with graphical tools to put banners, titles, intro videos etc.)
•    for the audience we setup custom jitsi servers like 16 GB RAM + 8 vCPUS, each may host up to 150 clients even to 200, but my recommendation is do not go on the limits.
•    with jitsi server all settings are optimised for audience role, all notifications are closed (very important), everybody joins muted and cameras closed on default.
• On each server you need an admin to take care of the problems.
• We first tried to broadcast to youtube from melonapp and play it in jitsi conference rooms with youtube embed function of jitsi. But this caused problems for the people who joined after the broadcast started-actually they didnt see the youtube video on jitsi room.   

As a practical solution we setup a transfer server which will take the broadcast from melonapp to jitsi conference rooms. In our set up we came up with a minimal linux desktop + remote desktop + chromium/google chrome.

On this server we used the screen share feature of jitsi conference room within chrome and share the melonapp broadcast to jitsi conference rooms. This server needs a lot of CPU power add as much as you may have and monitor it during the event. (we used cloud servers that we can inflate and shrink instantly from upcloud.com  with this setup there is no limit on scaling we did conferences up to 1000+ online participants.

   there are some disadvantages of this setup:

• The audience needs to feel that they are in the same room with the lecturers -"joining the conference"- . This setup does not fully provides that feeling.
• if they need to ask questions to the lecturers, they write in jitsi chat and your admins in the rooms transfer these to the broadcast room (melonapp in our model). If they want to ask the questions with camera we invite them to the lecture room. Not too bad :)
• you need strong servers you need rules to manage people, like closing the cameras and mics when not used to reduce server loads, expecting the responds to the questions at the end of the programs etc.

If you need only up to ~80-100

participants in a jitsi conference room, you may even have the lecture from there too, but we tried this many problems are happening, like opened microphones of the others etc. People continuesly logging in and out to hack the system. (if jitsi notifications are open this will easly collapse the system as each notification needs to be distrubited to all) etc.

If you have any more questions I will try to answer.