En réponse à Stéphane Crozat.

Apparemment ça devrait s'adapter à la bande passante depuis le 23 avril 2016 d'après https://jitsi.org/

> Simulcast now in production on meet.jit.si!
> Tired of having to choose between 1080p and reasonable bandwidth consumption? The new simulcast support on meet.jit.si should make you happy then! Also run it yourself by installing Jitsi Meet and Jitsi Videobridge

Des infos techniques sur Simulcast : https://github.com/jitsi/jitsi-videobridge/blob/master/doc/simulcast.md