[angry_octet]

The clients can dynamically adjust their sending rate and resolution. It is pretty easy to downgrade your video when not talking. Its also possible to number and label the encrypted frames (I frames or B frames), allowing decimation for low bandwidth clients without recoding, which is expensive and slow.

There are also ways to send additive resolution streams -- a base stream and additional detail layers (multiresolution like JPEG2000).

[tommoor]

Clients already do this yes, but to achieve the reliability that zoom is renowned for you also need to dynamically adjust what is sent _TO_ individual clients

[angry_octet]

Can the clients not advise the server what bandwidth and packet loss rate they are seeing, so the server can adjust their traffic rate? There is no reason not to allow a signalling channel separate to the E2E encrypted data channels.

[xeromal]

The server would then have to tell the streamer / talker to reduce their quality for that one client while degrading all other clients that have a fine connection right?

[angry_octet]

If you absolutely must have high frame rate for everybody then you might make that choice. But generally you could just drop B frames from the stream for the slow client, so they get a slower frame rate.

If you wanted to be fancy you could do distributed processing, whereby another node downscales and re-publishes the feed.