Free open source alternatives to Zoom for Videoconferences

I spent much of the week in Zoom based video conferences, only one of which did not work. This is remarkable, given how heavily Zoom is being used due to the COVID-19 Coronavirus. In contrast, I had considerable difficulty with Blackboard Collaborate. Collaborate seems to be less able to cope with my 1 mbps broadband connection than when I used it at 28.8 kbps dial-up speed in 2011. 

There are also some open source video conference products. Hamza Mu has detailed 15 of them in "Top 15 Open source Video conference and Team Communication Solutions for Windows, Linux, Mac OSX and Phones (Medevel.com, 30 Mar 2019). The only one of these open source products I have used is BigBlueButton, which is commonly teamed with the Moodle learning management system. However, Apache OpenMeetings looks interesting.

However, these video conference tools have not changed much, from the user's point of video, for decades. The quality of the video has improved, but that is about all, and that is about the least important aspect of a video conference. These events should really be called audio conferences with a shared screen and optional video.