Tuning Zoom Videoconferencing

Today was my third video conference for the week, Reading the Corona: extraordinary responses during an extraordinary time, hosted by the ANU Indonesia Project. Chatib Basri and Rizki Siregar discussed policy options for dealing with the the COVID-19 Coronavirus in Indonesia.
With 300 participant, this Zoom video conference had many more than those yesterday, but worked much better. This is a good way to keep in touch, but I am worried about the amount of bandwidth which might be used. So I tried shaping (limiting) my network connection.

Shape Your Video Conference

I am using 4g wireless broadband, with two out of five bars of signal strength, running at 2.63 Mbps download, 1.54 Mbps upload and a ping speed of 34 ms from Canberra to Sydney (at other times it has been 9.1 Mbps download, 12.8 Mbps upload and pink speed of 29 ms). That is modest by current standards, but adequate for attending, and presenting at a Zoom video conference.

I stared shaping with 150 kbps, which is Zoom's recommended minimum, for screen sharing plus a thumbnail video. But Zoom reported an unstable link and it was unusable. Increasing to 512 kbps worked well. The video was then at 256 x 144 pixels and 5 frames per second (sometimes 320 x 180 at 12 frames per second). Shared screens were very clear at 1440 pixels wide, with a small, but clear, video window next to them.

Yesterday I was using video conferencing via the Australian National University's very high speed network. I discovered I could reduce the data requirements for Zoom by keeping the video window small. Today I am using a much slower cellular modem wireless connection. But with the bandwidth shaped, and resulting lower resolution video, the experience is much better than on the higher bandwidth connection.

I used the Linux tool Wondershaper to slow down my network connection, but there are similar tools for other operating systems (and using routers). Wondershaper is not ideal, as it slows down everything, not just Zoom (other tools can select just one application to shape). Of course it would be better to tell Zoom to use less bandwidth, but I have not been able to find a way to do that.

Flip your Video Event

Keep in mind that glitches happen with video conferences. Yesterday I had four scheduled Zoom meetings. The first two worked flawlessly. The third had some glitches, and the last did not work at all.

I suggest 'flipping' the format for online events. That is, provide the presentation slides and, if possible, a short recorded video by each speaker beforehand. That way, if there are intermittent problems, the presenters can skip the full presentation and go straight to questions. Also I suggest reducing the length of events, and break them up into segments of no more than ten minutes. For example, instead of an hour long seminar, make it 15 minutes, including 5 minutes for questions.

Organizers need to be ready to switch off the video, leaving just slides and audio, if there are bandwidth problems. Also the organizers should have copies of slides and be ready to manually change them, if the presenter has difficulty doing that at their location. They should be ready to just talk, with no slides, as I have told ANU TechLauncher students.