DD4T Training Room should have voice and mute all character

Today we have TestComplete course.
Trainer is from Moscow, 25 delegates form China and Philippines.
The requirement are:

Simplification, Jitsi-Audio/Training room-Video, takes a long time to testing audio in Jitsi, and still need to going in to Training room, un-continent for this kind of training. 

Also if we need to deploy a whole training environment in Training room with voice, the automatically voice device change/select, fast connection from the nearest DaDesktop server is crucial 

3.1. Voice is quite important inside training room, and trainer should have a button to mute all (which jitsi can’t for the training which delegates are 20 or more)

3.2. The whole process should be-delegates only needs to register, join Training room, have desktop and voice as well.

3.3 Frequently asking of trainer and participants is that, “can we recording a video with voice?” I know this will consume much more disk place etc. But they are not satisfied with the recording without Trainer’s voice.
In result of this, some trainers are going to use third party’s application for recording. Because this can really helps delegates a lot compare with session recording which without voice.

Voice inside is important for business site. 

With everything inside DD4T(DaDesktop, Slides,Voice,Video) , both trainer/delegates with not have to have voice chat via-third party(skype, microsoft-meet/wechat china/QQ), we can create a nobleprog environment that clients only need to use DD4T, no extra contact/info leak during training by using external application.

https://trac.nobleprog.com/ticket/2615

Done except 3.1. “trainer should have a button to mute all”.

Only moderator can mute all in Jitsi, and Jitsi will set the first connected person as a moderator, which maybe isn’t the trainer